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Bouhaben J, Delgado-Lima AH, Delgado-Losada ML. The role of olfactory dysfunction in mild cognitive impairment and Alzheimer's disease: A meta-analysis. Arch Gerontol Geriatr 2024; 123:105425. [PMID: 38615524 DOI: 10.1016/j.archger.2024.105425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 03/22/2024] [Accepted: 03/27/2024] [Indexed: 04/16/2024]
Abstract
PURPOSE This comprehensive meta-analysis investigates the association between olfactory deficits in mild cognitive impairment (MCI) and Alzheimer's disease (AD). METHODS A thorough search across databases identified articles analyzing olfactory status in MCI or AD patients. Methodological quality assessment followed PRISMA guidelines. Hedges' g effect size statistic computed standard mean differences and 95% confidence intervals. Moderator analysis was conducted. RESULTS Among the included studies (65 for MCI and 61 for AD), odor identification exhibited larger effect sizes compared to odor threshold and discrimination, in both MCI and AD samples. Moderate effect size is found in OI scores in MCI (k = 65, SE = 0.078, CI 95% = [-1.151, -0.844]). Furthermore, compared to MCI, AD had moderate to large heterogeneous effects in olfactory identification (k = 61, g = -2.062, SE = 0.125, CI 95% = [-2.308, -1.816]). Global cognitive status is positively related to olfactory identification impairment in both MCI (k = 57, Z = 2.74, p = 0.006) and AD (k = 53, Z = 5.03, p < 0.0001) samples. CONCLUSION Olfactory impairments exhibit a notable and substantial presence in MCI. Among these impairments, odor identification experiences the greatest decline in MCI, mirroring the primary sensory deficit observed in AD. Consequently, the incorporation of a straightforward odor identification test is advisable in the evaluation of individuals vulnerable to the onset of AD, offering a practical screening tool for early detection.
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Affiliation(s)
- Jaime Bouhaben
- Experimental Psychology, Cognitive Processes and Speech Therapy Department, Faculty of Psychology, Complutense University of Madrid, 28223 Pozuelo de Alarcon, Spain
| | - Alice Helena Delgado-Lima
- Experimental Psychology, Cognitive Processes and Speech Therapy Department, Faculty of Psychology, Complutense University of Madrid, 28223 Pozuelo de Alarcon, Spain
| | - María Luisa Delgado-Losada
- Experimental Psychology, Cognitive Processes and Speech Therapy Department, Faculty of Psychology, Complutense University of Madrid, 28223 Pozuelo de Alarcon, Spain.
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Frank C, Albertazzi A, Murphy C. The effect of the apolipoprotein E ε4 allele and olfactory function on odor identification networks. Brain Behav 2024; 14:e3524. [PMID: 38702902 PMCID: PMC11069025 DOI: 10.1002/brb3.3524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 04/11/2024] [Accepted: 04/17/2024] [Indexed: 05/06/2024] Open
Abstract
INTRODUCTION The combination of apolipoprotein E ε4 (ApoE ε4) status, odor identification, and odor familiarity predicts conversion to mild cognitive impairment (MCI) and Alzheimer's disease (AD). METHODS To further understand olfactory disturbances and AD risk, ApoE ε4 carrier (mean age 76.38 ± 5.21) and ε4 non-carrier (mean age 76.8 ± 3.35) adults were given odor familiarity and identification tests and performed an odor identification task during fMRI scanning. Five task-related functional networks were detected using independent components analysis. Main and interaction effects of mean odor familiarity ratings, odor identification scores, and ε4 status on network activation and task-modulation of network functional connectivity (FC) during correct and incorrect odor identification (hits and misses), controlling for age and sex, were explored using multiple linear regression. RESULTS Findings suggested that sensory-olfactory network activation was positively associated with odor identification scores in ε4 carriers with intact odor familiarity. The FC of sensory-olfactory, multisensory-semantic integration, and occipitoparietal networks was altered in ε4 carriers with poorer odor familiarity and identification. In ε4 carriers with poorer familiarity, connectivity between superior frontal areas and the sensory-olfactory network was negatively associated with odor identification scores. CONCLUSIONS The results contribute to the clarification of the neurocognitive structure of odor identification processing and suggest that poorer odor familiarity and identification in ε4 carriers may signal multi-network dysfunction. Odor familiarity and identification assessment in ε4 carriers may contribute to the predictive value of risk for MCI and AD due to the breakdown of sensory-cognitive network integration. Additional research on olfactory processing in those at risk for AD is warranted.
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Affiliation(s)
- Conner Frank
- SDSU/UC San Diego Joint Doctoral Program in Clinical PsychologySan DiegoCaliforniaUSA
| | - Abigail Albertazzi
- Department of PsychologySan Diego State UniversitySan DiegoCaliforniaUSA
| | - Claire Murphy
- Department of PsychologySan Diego State UniversitySan DiegoCaliforniaUSA
- Department of PsychiatryUniversity of California San DiegoLa JollaCaliforniaUSA
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Crossley CA, Omoluabi T, Torraville SE, Duraid S, Maziar A, Hasan Z, Rajani V, Ando K, Hell JW, Yuan Q. Hippocampal hyperphosphorylated tau-induced deficiency is rescued by L-type calcium channel blockade. Brain Commun 2024; 6:fcae096. [PMID: 38562310 PMCID: PMC10984573 DOI: 10.1093/braincomms/fcae096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 01/07/2024] [Accepted: 03/19/2024] [Indexed: 04/04/2024] Open
Abstract
Aging and Alzheimer's disease are associated with chronic elevations in neuronal calcium influx via L-type calcium channels. The hippocampus, a primary memory encoding structure in the brain, is more vulnerable to calcium dysregulation in Alzheimer's disease. Recent research has suggested a link between L-type calcium channels and tau hyperphosphorylation. However, the precise mechanism of L-type calcium channel-mediated tau toxicity is not understood. In this study, we seeded a human tau pseudophosphorylated at 14 amino acid sites in rat hippocampal cornu ammonis 1 region to mimic soluble pretangle tau. Impaired spatial learning was observed in human tau pseudophosphorylated at 14 amino acid sites-infused rats as early as 1-3 months and worsened at 9-10 months post-infusion. Rats infused with wild-type human tau exhibited milder behavioural deficiency only at 9-10 months post-infusion. No tangles or plaques were observed in all time points examined in both human tau pseudophosphorylated at 14 amino acid sites and human tau-infused brains. However, human tau pseudophosphorylated at 14 amino acid sites-infused hippocampus exhibited a higher amount of tau phosphorylation at S262 and S356 than the human tau-infused rats at 3 months post-infusion, paralleling the behavioural deficiency observed in human tau pseudophosphorylated at 14 amino acid sites-infused rats. Neuroinflammation indexed by increased Iba1 in the cornu ammonis 1 was observed in human tau pseudophosphorylated at 14 amino acid sites-infused rats at 1-3 but not 9 months post-infusion. Spatial learning deficiency in human tau pseudophosphorylated at 14 amino acid sites-infused rats at 1-3 months post-infusion was paralleled by decreased neuronal excitability, impaired NMDA receptor-dependent long-term potentiation and augmented L-type calcium channel-dependent long-term potentiation at the cornu ammonis 1 synapses. L-type calcium channel expression was elevated in the soma of the cornu ammonis 1 neurons in human tau pseudophosphorylated at 14 amino acid sites-infused rats. Chronic L-type calcium channel blockade with nimodipine injections for 6 weeks normalized neuronal excitability and synaptic plasticity and rescued spatial learning deficiency in human tau pseudophosphorylated at 14 amino acid sites-infused rats. The early onset of L-type calcium channel-mediated pretangle tau pathology and rectification by nimodipine in our model have significant implications for preclinical Alzheimer's disease prevention and intervention.
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Affiliation(s)
- Chelsea A Crossley
- Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1B 3V6, Canada
| | - Tamunotonye Omoluabi
- Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1B 3V6, Canada
| | - Sarah E Torraville
- Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1B 3V6, Canada
| | - Sarah Duraid
- Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1B 3V6, Canada
| | - Aida Maziar
- Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1B 3V6, Canada
| | - Zia Hasan
- Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1B 3V6, Canada
| | - Vishaal Rajani
- Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1B 3V6, Canada
| | - Kanae Ando
- Department of Biological Sciences, School of Science, Tokyo Metropolitan University, Tokyo, 192-0397, Japan
| | - Johannes W Hell
- Department of Pharmacology, School of Medicine, University of California at Davis, Davis, CA 95616, USA
| | - Qi Yuan
- Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John’s, NL A1B 3V6, Canada
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Zhou C, Yang C, Ai Y, Fang X, Zhang A, Wang Y, Hu H. Valid olfactory impairment tests can help identify mild cognitive impairment: an updated meta-analysis. Front Aging Neurosci 2024; 16:1349196. [PMID: 38419646 PMCID: PMC10900519 DOI: 10.3389/fnagi.2024.1349196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 01/29/2024] [Indexed: 03/02/2024] Open
Abstract
Background Olfactory testing is emerging as a potentially effective screening method for identifying mild cognitive impairment in the elderly population. Objective Olfactory impairment is comorbid with mild cognitive impairment (MCI) in older adults but is not well-documented in subdomains of either olfactory or subtypes of cognitive impairments in older adults. This meta-analysis was aimed at synthesizing the differentiated relationships with updated studies. Methods A systematic search was conducted in seven databases from their availability to April 2023. A total of 38 publications were included, including 3,828 MCI patients and 8,160 healthy older adults. Two investigators independently performed the literature review, quality assessment, and data extraction. The meta-analyses were conducted with Stata to estimate the average effects and causes of the heterogeneity. Results Compared to normal adults, MCI patients had severe impairments in olfactory function and severe deficits in specific domains of odor identification and discrimination. Olfactory impairment was more severe in patients with amnestic mild cognitive impairment than in patients with non-amnestic MCI. Diverse test instruments of olfactory function caused large heterogeneity in effect sizes. Conclusion Valid olfactory tests can be complementary tools for accurate screening of MCI in older adults.
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Affiliation(s)
- Chunyi Zhou
- School of Nursing, Hubei University of Chinese Medicine, Wuhan, China
| | - Chongming Yang
- Research Support Center, College of Family, Home, and Social Sciences, Brigham Young University, Provo, UT, United States
| | - Yating Ai
- School of Nursing, Hubei University of Chinese Medicine, Wuhan, China
| | - Xueling Fang
- School of Nursing, Hubei University of Chinese Medicine, Wuhan, China
| | - Ailin Zhang
- School of Nursing, Hubei University of Chinese Medicine, Wuhan, China
| | - Yuncui Wang
- School of Nursing, Hubei University of Chinese Medicine, Wuhan, China
- Engineering Research Center of TCM Protection Technology and New Product Development for the Elderly Brain Health, Ministry of Education, Wuhan, China
- Hubei Shizhen Laboratory, Wuhan, China
| | - Hui Hu
- School of Nursing, Hubei University of Chinese Medicine, Wuhan, China
- Engineering Research Center of TCM Protection Technology and New Product Development for the Elderly Brain Health, Ministry of Education, Wuhan, China
- Hubei Shizhen Laboratory, Wuhan, China
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Alotaibi M, Lessard-Beaudoin M, Busch K, Loudghi A, Gaudreau P, Graham RK. Olfactory Dysfunction Associated with Cognitive Decline in an Elderly Population. Exp Aging Res 2024; 50:1-16. [PMID: 36545820 DOI: 10.1080/0361073x.2022.2160597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022]
Abstract
BACKGROUND In many neurological disorders, including Alzheimer disease, early olfactory dysfunction is observed. OBJECTIVE In order to determine if deficits in olfactory memory are present in the elderly and if olfactory dysfunction correlates with cognitive impairment in the aging population, olfactory testing has been done on seniors from the NuAge cohort accepting to participate in the Olfactory Response Cognition and Aging (ORCA) secondary sub-study. The t-Mini Mental Statement Examination and the Telephone Interview for Cognitive Status tests were done to assess cognition levels. RESULTS Overall, 94% of the ORCA cohort displayed olfactory dysfunction. Deficits in olfactory memory were also present. A correlation was observed between olfactory function and cognitive test scores. Moreover, in women who smoked, there was an association between olfactory memory and cognitive scores. CONCLUSION Our results suggest that olfactory dysfunction may predict impending cognitive decline and highlights the need for olfactory training in seniors to improve olfaction and overall well-being.
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Affiliation(s)
- Majed Alotaibi
- King Abdullah International Medical Research Center, KSAU-HS, Riyadh, Saudi Arabia
- Department of Neuroscience, The University of Sheffield, Sheffiled, UK
- Research Centre on Aging CIUSSS de l'Estrie - CHUS, Sherbrooke, Quebec, Canada
| | - Melissa Lessard-Beaudoin
- Research Centre on Aging CIUSSS de l'Estrie - CHUS, Sherbrooke, Quebec, Canada
- Department of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Canada
| | - Kate Busch
- Research Centre on Aging CIUSSS de l'Estrie - CHUS, Sherbrooke, Quebec, Canada
| | - Amal Loudghi
- Research Centre on Aging CIUSSS de l'Estrie - CHUS, Sherbrooke, Quebec, Canada
- Department of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Canada
| | - Pierrette Gaudreau
- Department of Medicine, University of Montreal, Quebec, Canada
- Department of Biochemistry and Molecular Medicine, Centre Hospitalier de l'Université de Montréal Research Center, Montreal, Quebec, Canada
| | - Rona K Graham
- Research Centre on Aging CIUSSS de l'Estrie - CHUS, Sherbrooke, Quebec, Canada
- Department of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Canada
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Yu SE, Athni TS, Mitchell MB, Zhou X, Chiang S, Lee SE. The Impact of Ambient and Wildfire Air Pollution on Rhinosinusitis and Olfactory Dysfunction. Curr Allergy Asthma Rep 2023; 23:665-673. [PMID: 38047993 DOI: 10.1007/s11882-023-01110-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2023] [Indexed: 12/05/2023]
Abstract
PURPOSE OF REVIEW With increasing industrialization, exposure to ambient and wildfire air pollution is projected to increase, necessitating further research to elucidate the complex relationship between exposure and sinonasal disease. This review aims to summarize the role of ambient and wildfire air pollution in chronic rhinosinusitis (CRS) and olfactory dysfunction and provide a perspective on gaps in the literature. RECENT FINDINGS Based on an emerging body of evidence, exposure to ambient air pollutants is correlated with the development of chronic rhinosinusitis in healthy individuals and increased symptom severity in CRS patients. Studies have also found a robust relationship between long-term exposure to ambient air pollutants and olfactory dysfunction. Ambient air pollution exposure is increasingly recognized to impact the development and sequelae of sinonasal pathophysiology. Given the rising number of wildfire events and worsening impacts of climate change, further study of the impact of wildfire-related air pollution is a crucial emerging field.
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Affiliation(s)
- Sophie E Yu
- Division of Otolaryngology-Head & Neck Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Tejas S Athni
- Division of Otolaryngology-Head & Neck Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Margaret B Mitchell
- Division of Otolaryngology-Head & Neck Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Department of Otolaryngology-Head & Neck Surgery, Massachusetts Eye & Ear, Boston, USA
| | - Xiaodan Zhou
- Department of Statistics, North Carolina State University, Raleigh, NC, USA
| | - Simon Chiang
- Division of Otolaryngology-Head & Neck Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Stella E Lee
- Division of Otolaryngology-Head & Neck Surgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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Papadatos Z, Phillips NA. Olfactory function reflects episodic memory performance and atrophy in the medial temporal lobe in individuals at risk for Alzheimer's disease. Neurobiol Aging 2023; 128:33-42. [PMID: 37146503 DOI: 10.1016/j.neurobiolaging.2023.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 03/29/2023] [Accepted: 04/02/2023] [Indexed: 05/07/2023]
Abstract
We examined cognitive domains and brain regions associated with olfactory performance in cognitively unimpaired older adults (CU-OAs) and individuals with or at risk for Alzheimer's Disease (AD). We compared CU-OAs (N = 55), individuals with subjective cognitive decline (SCD, N = 55), mild cognitive impairment (MCI, N = 101), and AD (N = 45) on measures of olfactory function (Brief Smell Identification Test), cognition (episodic and semantic memory), and medial temporal lobe thickness and volume. Analyses controlled for age, sex, education, and total intracranial volume. Olfactory function decreased from SCD to MCI to AD. CU-OAs outperformed all groups except SCDs on tests of cognition and olfaction. Although these measures did not differ between the CU-OAs and SCDs, olfactory function correlated with episodic memory tests and with entorhinal cortex atrophy only in the SCD group. Olfactory function also correlated with hippocampal volume and right-hemisphere entorhinal cortex thickness in the MCI group. Olfactory dysfunction reflects medial temporal lobe integrity and memory performance in a group at risk for AD with normal cognition and olfaction.
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Affiliation(s)
- Zoe Papadatos
- Department of Psychology, Concordia University, Montréal, Quebec, Canada
| | - Natalie A Phillips
- Department of Psychology, Concordia University, Montréal, Quebec, Canada; Center for Research in Human Development (CRDH), Concordia University, Montréal, Quebec, Canada; Centre for Research on Brain, Language & Music (CRBLM), McGill University, Montréal, Quebec, Canada; Bloomfield Centre for Research in Aging, Lady Davis Institute for Medical Research/Jewish General Hospital/McGill University, Montréal, Quebec, Canada.
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Woo CC, Miranda B, Sathishkumar M, Dehkordi-Vakil F, Yassa MA, Leon M. Overnight olfactory enrichment using an odorant diffuser improves memory and modifies the uncinate fasciculus in older adults. Front Neurosci 2023; 17:1200448. [PMID: 37554295 PMCID: PMC10405466 DOI: 10.3389/fnins.2023.1200448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 07/07/2023] [Indexed: 08/10/2023] Open
Abstract
OBJECTIVE Cognitive loss in older adults is a growing issue in our society, and there is a need to develop inexpensive, simple, effective in-home treatments. This study was conducted to explore the use of olfactory enrichment at night to improve cognitive ability in healthy older adults. METHODS Male and female older adults (N = 43), age 60-85, were enrolled in the study and randomly assigned to an Olfactory Enriched or Control group. Individuals in the enriched group were exposed to 7 different odorants a week, one per night, for 2 h, using an odorant diffuser. Individuals in the control group had the same experience with de minimis amounts of odorant. Neuropsychological assessments and fMRI scans were administered at the beginning of the study and after 6 months. RESULTS A statistically significant 226% improvement was observed in the enriched group compared to the control group on the Rey Auditory Verbal Learning Test and improved functioning was observed in the left uncinate fasciculus, as assessed by mean diffusivity. CONCLUSION Minimal olfactory enrichment administered at night produces improvements in both cognitive and neural functioning. Thus, olfactory enrichment may provide an effective and low-effort pathway to improved brain health.
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Affiliation(s)
- Cynthia C. Woo
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
| | - Blake Miranda
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
- Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, United States
| | - Mithra Sathishkumar
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
- Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, United States
| | | | - Michael A. Yassa
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
- Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, United States
| | - Michael Leon
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA, United States
- Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, United States
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA, United States
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Hummel T, Power Guerra N, Gunder N, Hähner A, Menzel S. Olfactory Function and Olfactory Disorders. Laryngorhinootologie 2023; 102:S67-S92. [PMID: 37130532 PMCID: PMC10184680 DOI: 10.1055/a-1957-3267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The sense of smell is important. This became especially clear to patients with infection-related olfactory loss during the SARS-CoV-2 pandemic. We react, for example, to the body odors of other humans. The sense of smell warns us of danger, and it allows us to perceive flavors when eating and drinking. In essence, this means quality of life. Therefore, anosmia must be taken seriously. Although olfactory receptor neurons are characterized by regenerative capacity, anosmia is relatively common with about 5 % of anosmic people in the general population. Olfactory disorders are classified according to their causes (e. g., infections of the upper respiratory tract, traumatic brain injury, chronic rhinosinusitis, age) with the resulting different therapeutic options and prognoses. Thorough history taking is therefore important. A wide variety of tools are available for diagnosis, ranging from short screening tests and detailed multidimensional test procedures to electrophysiological and imaging methods. Thus, quantitative olfactory disorders are easily assessable and traceable. For qualitative olfactory disorders such as parosmia, however, no objectifying diagnostic procedures are currently available. Therapeutic options for olfactory disorders are limited. Nevertheless, there are effective options consisting of olfactory training as well as various additive drug therapies. The consultation and the competent discussion with the patients are of major importance.
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Affiliation(s)
- T Hummel
- Interdisziplinäres Zentrum Riechen und Schmecken, HNO Klinik, TU Dresden
| | - N Power Guerra
- Rudolf-Zenker-Institut für Experimentelle Chirurgie, Medizinische Universität Rostock, Rostock
| | - N Gunder
- Universitäts-HNO Klinik Dresden, Dresden
| | - A Hähner
- Interdisziplinäres Zentrum Riechen und Schmecken, HNO Klinik, TU Dresden
| | - S Menzel
- Interdisziplinäres Zentrum Riechen und Schmecken, HNO Klinik, TU Dresden
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Camara G, Alotaibi M, Lessard-Beaudoin M, Busch K, Gendron L, Graham RK. Specific olfactory deficit patterns observed in seniors and associated with cognitive decline. Prog Neuropsychopharmacol Biol Psychiatry 2023; 126:110775. [PMID: 37120003 DOI: 10.1016/j.pnpbp.2023.110775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 04/20/2023] [Accepted: 04/21/2023] [Indexed: 05/01/2023]
Abstract
Olfactory dysfunction is a common symptom in neurodegenerative disorders and is regarded as a potential early predictor of impending cognitive decline. This study was undertaken in order to determine if olfactory dysfunction observed in the elderly is due to a general loss of smell or the inability to detect specific odours, and if misidentification of odours correlates with cognitive scores. Seniors for the Olfactory Response and Cognition in Aging (ORCA) sub-study were recruited from the Quebec Nutrition and Successful Aging (NuAge) cohort. The University of Pennsylvania smell identification test (UPSIT) was performed to measure olfactory function and the telephone Mini Mental State Examination (t-MMSE) and the French version of the Telephone Interview for Cognitive Status Modified (F-TICS-m) for cognitive status. The results demonstrate that seniors exhibit specific olfactory loss and had severe difficulty in particular in identifying lemon, pizza, fruit punch, cheddar cheese and lime. Furthermore, there was a significant difference in the ability to detect certain odours between the sexes. Results also showed that misidentification of certain scents was associated with cognitive scores, and when the sexes were assessed separately sex-specific misidentification of cognitive-associated odours was observed. The relationship between the cognitive scores and scent misidentification suggests that impending cognitive decline may be highlighted by the inability to smell specific odours. Our study provides additional support for the testing of olfactory function in the elderly and suggests that loss of smell for particular scents may become a useful diagnostic tool.
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Affiliation(s)
- Gemma Camara
- Research Centre on Aging CIUSSS de l'Estrie - CHUS, Canada; Dept of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Canada
| | - Majed Alotaibi
- Medical Genomics Research Department, King Abdullah International Medical Research Center, United States of America; King Saud Bin Abdulaziz University for Health and Science, Riyadh, Kingdom of Saudi Arabia
| | - Melissa Lessard-Beaudoin
- Research Centre on Aging CIUSSS de l'Estrie - CHUS, Canada; Dept of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Canada
| | - Kate Busch
- Research Centre on Aging CIUSSS de l'Estrie - CHUS, Canada
| | - Louis Gendron
- Dept of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Canada
| | - Rona K Graham
- Research Centre on Aging CIUSSS de l'Estrie - CHUS, Canada; Dept of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Canada.
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11
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Hummel T, T. Liu D, A. Müller C, A. Stuck B, Welge-Lüssen A, Hähner A. Olfactory Dysfunction: Etiology, Diagnosis, and Treatment. DEUTSCHES ARZTEBLATT INTERNATIONAL 2023; 120:146-154. [PMID: 36647581 PMCID: PMC10198165 DOI: 10.3238/arztebl.m2022.0411] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 06/03/2022] [Accepted: 12/21/2022] [Indexed: 01/18/2023]
Abstract
BACKGROUND Disorders of the sense of smell have received greater attention because of the frequency with which they occur as a symptom of SARS-CoV-2 infection. Olfactory dysfunction can lead to profound reduction in quality of life and may arise from many different causes. METHODS A selective literature review was conducted with consideration of the current version of the guideline issued by the Association of the Scientific Medical Societies in Germany. RESULTS The cornerstones of diagnosis are the relevant medical history and psychophysical testing of olfactory function using standardized validated tests. Modern treatment strategies are oriented on the cause of the dysfunction. While treatment of the underlying inflammation takes precedence in patients with sinunasal dysosmia, olfactory training is the primary treatment option for other forms of the disorder. The prognosis is determined not only by the cause of the olfactory dysfunction and the patient's age, but also by the olfactory performance as measured at the time of diagnosis. CONCLUSION Options for the treatment of olfactory dysfunction are available but limited, depending on the cause. It is therefore important to carry out a detailed diagnostic work-up and keep the patient informed of the expected course and prognosis.
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Affiliation(s)
- Thomas Hummel
- Interdisciplinary Center for Smell and Taste, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden
| | - David T. Liu
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna General Hospital, Austria
| | - Christian A. Müller
- Department of Otorhinolaryngology, Head and Neck Surgery, Medical University of Vienna, Vienna General Hospital, Austria
| | - Boris A. Stuck
- Department of Otorhinolaryngology, Head and Neck Surgery, Giessen and Marburg University Hospital Ltd., Marburg
| | - Antje Welge-Lüssen
- Interdisciplinary Center for Smell and Taste, Department of Otorhinolaryngology, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden
| | - Antje Hähner
- Department of Otorhinolaryngology, Basel University Hospital, Switzerland
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Flynn CM, Yuan Q. Probiotic supplement as a promising strategy in early tau pathology prevention: Focusing on GSK-3β? Front Neurosci 2023; 17:1159314. [PMID: 37034173 PMCID: PMC10073452 DOI: 10.3389/fnins.2023.1159314] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 03/07/2023] [Indexed: 04/11/2023] Open
Abstract
Neurofibrillary tangles (NFT) is one of the hallmarks of Alzheimer's disease (AD). Recent research suggests that pretangle tau, the soluble precursor of NFT, is an initiator for AD pathogenesis, thus targeting pretangle tau pathology may be a promising early intervention focus. The bidirectional communications between the gut and the brain play a crucial role in health. The compromised gut-brain axis is involved in various neurodegenerative diseases including AD. However, most research on the relationship between gut microbiome and AD have focused on amyloid-β. In this mini review, we propose to target preclinical pretangle tau stages with gut microbiota interventions such as probiotic supplementation. We discuss the importance of targeting pretangle tau that starts decades before the onset of clinical symptoms, and potential intervention focusing on probiotic regulation of tau hyperphosphorylation. A particular focus is on GSK-3β, a protein kinase that is at the interface between tau phosphorylation, AD and diabetes mellitus.
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Casares N, Alfaro M, Cuadrado-Tejedor M, Lasarte-Cia A, Navarro F, Vivas I, Espelosin M, Cartas-Cejudo P, Fernández-Irigoyen J, Santamaría E, García-Osta A, Lasarte JJ. Improvement of cognitive function in wild-type and Alzheimer´s disease mouse models by the immunomodulatory properties of menthol inhalation or by depletion of T regulatory cells. Front Immunol 2023; 14:1130044. [PMID: 37187754 PMCID: PMC10175945 DOI: 10.3389/fimmu.2023.1130044] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 04/13/2023] [Indexed: 05/17/2023] Open
Abstract
A complex network of interactions exists between the olfactory, immune and central nervous systems. In this work we intend to investigate this connection through the use of an immunostimulatory odorant like menthol, analyzing its impact on the immune system and the cognitive capacity in healthy and Alzheimer's Disease Mouse Models. We first found that repeated short exposures to menthol odor enhanced the immune response against ovalbumin immunization. Menthol inhalation also improved the cognitive capacity of immunocompetent mice but not in immunodeficient NSG mice, which exhibited very poor fear-conditioning. This improvement was associated with a downregulation of IL-1β and IL-6 mRNA in the brain´s prefrontal cortex, and it was impaired by anosmia induction with methimazole. Exposure to menthol for 6 months (1 week per month) prevented the cognitive impairment observed in the APP/PS1 mouse model of Alzheimer. Besides, this improvement was also observed by the depletion or inhibition of T regulatory cells. Treg depletion also improved the cognitive capacity of the APPNL-G-F/NL-G-F Alzheimer´s mouse model. In all cases, the improvement in learning capacity was associated with a downregulation of IL-1β mRNA. Blockade of the IL-1 receptor with anakinra resulted in a significant increase in cognitive capacity in healthy mice as well as in the APP/PS1 model of Alzheimer´s disease. These data suggest an association between the immunomodulatory capacity of smells and their impact on the cognitive functions of the animals, highlighting the potential of odors and immune modulators as therapeutic agents for CNS-related diseases.
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Affiliation(s)
- Noelia Casares
- Immunology and Immunotherapy Program, Center for Applied Medical Research (CIMA), University of Navarra, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
- *Correspondence: Juan José Lasarte, ; Noelia Casares,
| | - María Alfaro
- Immunology and Immunotherapy Program, Center for Applied Medical Research (CIMA), University of Navarra, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Mar Cuadrado-Tejedor
- Gene Therapy for Neurological Disease Program, Center for Applied Medical Research (CIMA), University of Navarra, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
- Department of Pathology, Anatomy and Physiology, School of Medicine, University of Navarra, Pamplona, Spain
| | - Aritz Lasarte-Cia
- Immunology and Immunotherapy Program, Center for Applied Medical Research (CIMA), University of Navarra, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Flor Navarro
- Immunology and Immunotherapy Program, Center for Applied Medical Research (CIMA), University of Navarra, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Isabel Vivas
- Department of Radiology, Clínica Universidad de Navarra, University of Navarra, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - María Espelosin
- Gene Therapy for Neurological Disease Program, Center for Applied Medical Research (CIMA), University of Navarra, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Paz Cartas-Cejudo
- Clinical Neuroproteomics Unit, Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Joaquín Fernández-Irigoyen
- Clinical Neuroproteomics Unit, Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Enrique Santamaría
- Clinical Neuroproteomics Unit, Navarrabiomed, Hospital Universitario de Navarra (HUN), Universidad Pública de Navarra (UPNA), Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Ana García-Osta
- Gene Therapy for Neurological Disease Program, Center for Applied Medical Research (CIMA), University of Navarra, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
| | - Juan José Lasarte
- Immunology and Immunotherapy Program, Center for Applied Medical Research (CIMA), University of Navarra, Instituto de Investigación Sanitaria de Navarra (IdiSNA), Pamplona, Spain
- *Correspondence: Juan José Lasarte, ; Noelia Casares,
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Verification of the association between cognitive decline and olfactory dysfunction using a DEmentia screening kit in subjects with Alzheimer's dementia, mild cognitive impairment, and normal cognitive function (DESK study): A multicenter, open-label, interventional study. eNeurologicalSci 2022; 29:100439. [DOI: 10.1016/j.ensci.2022.100439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 11/10/2022] [Accepted: 11/27/2022] [Indexed: 12/05/2022] Open
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Pusswald G, Ocak S, Stögmann E, Lehrner J. Neurocognitive testing in predicting conversion to Alzheimer's disease. CHEMOSENS PERCEPT 2022. [DOI: 10.1007/s12078-022-09306-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Abstract
Introduction
Alzheimer’s disease (AD) is a neurodegenerative disorder that affects memory, thinking, attention, and emotion or AD. Smelling problems are frequent symptoms of dementia. The aim of this study was to evaluate whether it is possible to predict if someone with anosmia or hyposmia has a higher risk of getting dementia or even AD.
Methods
This study was a retrospective longitudinal study, and the data used were part of a larger research project, the Vienna Conversion to Dementia Study. The 173 participants were divided into four groups based on cognitive features such as healthy control (HC), subjective cognitive decline (SCD), non-amnestic mild cognitive impairment (naMCI), and amnestic mild cognitive impairment (aMCI). Olfactory assessment and neurocognitive assessment were administered.
Results
We found that 30.5% of aMCI patients converted into AD after an average of about two years. The corresponding ROC analyses for olfactory testing showed that Sniffin’ Sticks revealed significant results regarding the conversion to AD, whereas the Assessment of Self-Reported Olfactory Functioning and olfaction-related quality of life (ASOF) inventory using the Subjective Olfactory Capability (SOC) subscale, the Smell-Related Problems (SRP) subscale, and the Olfaction-Related Quality of life (ORQ) did not. A logistic regression showed that among the olfactory test procedures, only the Sniffin’ Sticks enabled a relevant prognosis. Including neurocognitive measures in the model, only VSRT and the Trail Making Test-B. The other predictors did not contribute to the prediction of conversion to AD.
Conclusion
Unlike self-reporting of olfactory functioning, olfactory testing using standardized tests may have potential for predicting dementia, especially AD. However, olfactory tests have lower predictive power than neurocognitive tests such as verbal memory and divided attention tests.
Implications
Diagnostic tools for predicting dementia as accurately and early as possible are important. Olfactory assessment, compared to neurocognitive tests for verbal memory and divided attention, is inferior in predicting the prognosis of AD.
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Seneviratne R, Weinborn M, Badcock DR, Gavett BE, Laws M, Taddei K, Martins RN, Sohrabi HR. The Western Australia Olfactory Memory Test: Reliability and Validity in a Sample of Older Adults. Arch Clin Neuropsychol 2022; 37:1720-1734. [DOI: 10.1093/arclin/acac048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Abstract
Objective
The Western Australia Olfactory Memory Test (WAOMT) is a newly developed test designed to meet a need for a comprehensive measure of olfactory episodic memory (OEM) for clinical and research applications.
Method
This study aimed to establish the psychometric properties of the WAOMT in a sample of 209 community-dwelling older adults. An independent sample of 27 test-naïve participants were recruited to assess test retest reliability (between 7 and 28 days). Scale psychometric properties were examined using item response theory methods, combined samples (final N = 241). Convergent validity was assessed by comparing performance on the WAOMT with a comprehensive neuropsychological battery of domains (verbal and visual episodic memory, and odor identification), as well as other neuropsychological skills. Based on previous literature, it was predicted that the WAOMT would be positively correlated with conceptually similar cognitive domains.
Results
The WAOMT is a psychometrically sound test with adequate reliability properties and demonstrated convergent validity with tests of verbal and episodic memory and smell identification. Patterns of performance highlight learning and memory characteristics unique to OEM (e.g., learning curves, cued and free recall).
Conclusion
Clinical and research implications include streamlining future versions of the WAOMT to ease patient and administrative burden, and the potential to reliably detect early neuropathological changes in healthy older adults with nonimpaired OEM abilities.
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Affiliation(s)
- Rasangi Seneviratne
- School of Psychological Science, University of Western Australia , Crawley, WA , Australia
| | - Michael Weinborn
- School of Psychological Science, University of Western Australia , Crawley, WA , Australia
- Australian Alzheimer's Research Foundation , Nedlands, Western Australia , Australia
- School of Medical and Health Sciences, Edith Cowan University , Joondalup, Western Australia , Australia
| | - David R Badcock
- School of Psychological Science, University of Western Australia , Crawley, WA , Australia
| | - Brandon E Gavett
- School of Psychological Science, University of Western Australia , Crawley, WA , Australia
| | - Manuela Laws
- Australian Alzheimer's Research Foundation , Nedlands, Western Australia , Australia
- School of Medical and Health Sciences, Edith Cowan University , Joondalup, Western Australia , Australia
| | - Kevin Taddei
- Australian Alzheimer's Research Foundation , Nedlands, Western Australia , Australia
- School of Medical and Health Sciences, Edith Cowan University , Joondalup, Western Australia , Australia
| | - Ralph N Martins
- Australian Alzheimer's Research Foundation , Nedlands, Western Australia , Australia
- School of Medical and Health Sciences, Edith Cowan University , Joondalup, Western Australia , Australia
- Department of Biomedical Sciences, Macquarie University , Macquarie Park, New South Wales , Australia
| | - Hamid R Sohrabi
- Australian Alzheimer's Research Foundation , Nedlands, Western Australia , Australia
- School of Medical and Health Sciences, Edith Cowan University , Joondalup, Western Australia , Australia
- Department of Biomedical Sciences, Macquarie University , Macquarie Park, New South Wales , Australia
- Centre for Healthy Ageing , College of Science, Health, Engineering, and Education, , Murdoch, Western Australia , Australia
- Murdoch University , College of Science, Health, Engineering, and Education, , Murdoch, Western Australia , Australia
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Haehner A, Chen B, Espin M, Haussmann R, Matthes C, Desser D, Loessner L, Brandt MD, Donix M, Hummel T. Training with Odors Impacts Hippocampal Thickness in Patients with Mild Cognitive Impairment. J Alzheimers Dis 2022; 88:743-755. [DOI: 10.3233/jad-220248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Background: The olfactory system is affected early in Alzheimer’s disease and olfactory loss can already be observed in patients with mild cognitive impairment (MCI). Olfactory training is effective for improving olfactory and cognitive function by stimulating the olfactory pathway, but its effect on patients with MCI remains unclear. Objective: The aim of this randomized, prospective, controlled, blinded study was to assess whether a 4-month period of olfactory training (frequent short-term sniffing various odors) may have an effect on olfactory function, cognitive function, and morphology of medial temporal lobe (MTL) subregions and olfactory bulb in MCI patients. Methods: A total of thirty-seven MCI patients were randomly assigned to the training group or a placebo group, which were performed twice a day for 4 months. Olfactory assessments, cognitive tests and magnetic resonance imaging were performed at the baseline and follow-up period. Results: After the training, there was an increase in odor discrimination, and increased cortical thickness of bilateral hippocampus (CA23DG and CA1) and mean MTL. Additionally, the change of olfactory score was positively associated with change of volume of olfactory bulb and hippocampus; the change of global cognition was positively associated with change of cortical thickness of hippocampus, entorhinal cortex and mean MTL; the change of cortical thickness of entorhinal cortex was positively associated with change of executive function. Conclusion: Olfactory training was associated with an increase in cortical thickness of the hippocampus but not olfactory bulb volume in patients with MCI. Olfactory training may serve as an early intervention of preventing hippocampal atrophy.
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Affiliation(s)
| | - Ben Chen
- Smell & Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany
- Memory Clinic, Department of Geriatric Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong Province, China
| | - Melanie Espin
- Smell & Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany
| | | | | | - Dmitriy Desser
- Smell & Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany
| | | | - Moritz D. Brandt
- Department of Neurology, TU Dresden, Dresden, Germany
- German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany
| | - Markus Donix
- Department of Psychiatry, TU Dresden, Dresden, Germany
- German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany
| | - Thomas Hummel
- Smell & Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany
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18
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Patel ZM, Holbrook EH, Turner JH, Adappa ND, Albers MW, Altundag A, Appenzeller S, Costanzo RM, Croy I, Davis GE, Dehgani-Mobaraki P, Doty RL, Duffy VB, Goldstein BJ, Gudis DA, Haehner A, Higgins TS, Hopkins C, Huart C, Hummel T, Jitaroon K, Kern RC, Khanwalkar AR, Kobayashi M, Kondo K, Lane AP, Lechner M, Leopold DA, Levy JM, Marmura MJ, Mclelland L, Miwa T, Moberg PJ, Mueller CA, Nigwekar SU, O'Brien EK, Paunescu TG, Pellegrino R, Philpott C, Pinto JM, Reiter ER, Roalf DR, Rowan NR, Schlosser RJ, Schwob J, Seiden AM, Smith TL, Soler ZM, Sowerby L, Tan BK, Thamboo A, Wrobel B, Yan CH. International consensus statement on allergy and rhinology: Olfaction. Int Forum Allergy Rhinol 2022; 12:327-680. [PMID: 35373533 DOI: 10.1002/alr.22929] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 01/01/2021] [Accepted: 11/19/2021] [Indexed: 12/11/2022]
Abstract
BACKGROUND The literature regarding clinical olfaction, olfactory loss, and olfactory dysfunction has expanded rapidly over the past two decades, with an exponential rise in the past year. There is substantial variability in the quality of this literature and a need to consolidate and critically review the evidence. It is with that aim that we have gathered experts from around the world to produce this International Consensus on Allergy and Rhinology: Olfaction (ICAR:O). METHODS Using previously described methodology, specific topics were developed relating to olfaction. Each topic was assigned a literature review, evidence-based review, or evidence-based review with recommendations format as dictated by available evidence and scope within the ICAR:O document. Following iterative reviews of each topic, the ICAR:O document was integrated and reviewed by all authors for final consensus. RESULTS The ICAR:O document reviews nearly 100 separate topics within the realm of olfaction, including diagnosis, epidemiology, disease burden, diagnosis, testing, etiology, treatment, and associated pathologies. CONCLUSION This critical review of the existing clinical olfaction literature provides much needed insight and clarity into the evaluation, diagnosis, and treatment of patients with olfactory dysfunction, while also clearly delineating gaps in our knowledge and evidence base that we should investigate further.
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Affiliation(s)
- Zara M Patel
- Otolaryngology, Stanford University School of Medicine, Stanford, California, USA
| | - Eric H Holbrook
- Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, USA
| | - Justin H Turner
- Otolaryngology, Vanderbilt School of Medicine, Nashville, Tennessee, USA
| | - Nithin D Adappa
- Otolaryngology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mark W Albers
- Neurology, Harvard Medical School, Boston, Massachusetts, USA
| | - Aytug Altundag
- Otolaryngology, Biruni University School of Medicine, İstanbul, Turkey
| | - Simone Appenzeller
- Rheumatology, School of Medical Sciences, University of Campinas, São Paulo, Brazil
| | - Richard M Costanzo
- Physiology and Biophysics and Otolaryngology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
| | - Ilona Croy
- Psychology and Psychosomatic Medicine, TU Dresden, Dresden, Germany
| | - Greg E Davis
- Otolaryngology, Proliance Surgeons, Seattle and Puyallup, Washington, USA
| | - Puya Dehgani-Mobaraki
- Associazione Naso Sano, Umbria Regional Registry of Volunteer Activities, Corciano, Italy
| | - Richard L Doty
- Smell and Taste Center, Otolaryngology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Valerie B Duffy
- Allied Health Sciences, University of Connecticut, Storrs, Connecticut, USA
| | | | - David A Gudis
- Otolaryngology, Columbia University Irving Medical Center, New York, USA
| | - Antje Haehner
- Smell and Taste, Otolaryngology, TU Dresden, Dresden, Germany
| | - Thomas S Higgins
- Otolaryngology, University of Louisville School of Medicine, Louisville, Kentucky, USA
| | - Claire Hopkins
- Otolaryngology, Guy's and St. Thomas' Hospitals, London Bridge Hospital, London, UK
| | - Caroline Huart
- Otorhinolaryngology, Cliniques universitaires Saint-Luc, Institute of Neuroscience, Université catholgique de Louvain, Brussels, Belgium
| | - Thomas Hummel
- Smell and Taste, Otolaryngology, TU Dresden, Dresden, Germany
| | | | - Robert C Kern
- Otolaryngology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Ashoke R Khanwalkar
- Otolaryngology, Stanford University School of Medicine, Stanford, California, USA
| | - Masayoshi Kobayashi
- Otorhinolaryngology-Head and Neck Surgery, Mie University Graduate School of Medicine, Mie, Japan
| | - Kenji Kondo
- Otolaryngology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Andrew P Lane
- Otolaryngology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Matt Lechner
- Otolaryngology, Barts Health and University College London, London, UK
| | - Donald A Leopold
- Otolaryngology, University of Vermont Medical Center, Burlington, Vermont, USA
| | - Joshua M Levy
- Otolaryngology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Michael J Marmura
- Neurology Thomas Jefferson University School of Medicine, Philadelphia, Pennsylvania, USA
| | - Lisha Mclelland
- Otolaryngology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK
| | - Takaki Miwa
- Otolaryngology, Kanazawa Medical University, Ishikawa, Japan
| | - Paul J Moberg
- Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | | | - Sagar U Nigwekar
- Division of Nephrology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Erin K O'Brien
- Otolaryngology, Mayo Clinic Rochester, Rochester, Minnesota, USA
| | - Teodor G Paunescu
- Division of Nephrology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | | | - Carl Philpott
- Otolaryngology, University of East Anglia, Norwich, UK
| | - Jayant M Pinto
- Otolaryngology, University of Chicago, Chicago, Illinois, USA
| | - Evan R Reiter
- Otolaryngology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
| | - David R Roalf
- Psychiatry, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Nicholas R Rowan
- Otolaryngology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Rodney J Schlosser
- Otolaryngology, Medical University of South Carolina, Mt Pleasant, South Carolina, USA
| | - James Schwob
- Biomedical Sciences, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Allen M Seiden
- Otolaryngology, University of Cincinnati School of Medicine, Cincinnati, Ohio, USA
| | - Timothy L Smith
- Otolaryngology, Oregon Health and Sciences University, Portland, Oregon, USA
| | - Zachary M Soler
- Otolaryngology, Medical University of South Carolina, Mt Pleasant, South Carolina, USA
| | - Leigh Sowerby
- Otolaryngology, University of Western Ontario, London, Ontario, Canada
| | - Bruce K Tan
- Otolaryngology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Andrew Thamboo
- Otolaryngology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Bozena Wrobel
- Otolaryngology, Keck School of Medicine, USC, Los Angeles, California, USA
| | - Carol H Yan
- Otolaryngology, School of Medicine, UCSD, La Jolla, California, USA
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Goodwin GR, Bestwick JP, Noyce AJ. The potential utility of smell testing to screen for neurodegenerative disorders. Expert Rev Mol Diagn 2022; 22:139-148. [PMID: 35129037 DOI: 10.1080/14737159.2022.2037424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Loss of smell is a common early feature of neurodegenerative diseases including Alzheimer's and Parkinson's disease. Identifying these conditions in their early stages is important to understand more about early pathophysiological events and the development of disease modifying therapies. Smell testing may be an effective future tool for screening large populations for early neurodegeneration. AREAS COVERED : In this review, we appraise the evidence for, and discuss the likelihood of, the use of smell testing in large screening programs to detect early neurodegeneration. We evaluate the predictive power of smell tests for neurodegenerative disease, compare performance to other established screening programs, and discuss ethical and practical considerations and limitations. EXPERT OPINION : Even if disease modifying therapies were available for neurodegenerative disease, smell tests alone are unlikely to have high enough predictive power to be used in a future screening program. However, we believe they could be a valuable component of a short battery of tests or part of a stepwise process that together could more accurately identify early neurodegeneration in large populations.
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Affiliation(s)
- Gregory R Goodwin
- Preventive Neurology Unit, Wolfson Institute of Preventive Medicine, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, E1 4NS, UK
| | - Jonathan P Bestwick
- Preventive Neurology Unit, Wolfson Institute of Preventive Medicine, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, E1 4NS, UK
| | - Alastair J Noyce
- Preventive Neurology Unit, Wolfson Institute of Preventive Medicine, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, E1 4NS, UK
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Shao Y, Wang Z, Ji B, Qi H, Hao S, Li G, Zhang Y, Xi Q. Diffusion Tensor Imaging Study of Olfactory Identification Deficit in Patients With Mild Cognitive Impairment. Front Aging Neurosci 2021; 13:765432. [PMID: 34887745 PMCID: PMC8649768 DOI: 10.3389/fnagi.2021.765432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 11/01/2021] [Indexed: 11/13/2022] Open
Abstract
Objective: To explore the relationship between white matter changes and olfactory ability among patients with mild cognitive impairment (MCI) and to develop a tool to predict the development of Alzheimer's disease among patients with MCI. Methods: The Montreal Cognitive Assessment (MoCA) was used for cognitive assessments, and the 70% isopropanol test paper was used to evaluate olfactory function. Tract-based spatial statistics, based on the diffusion tensor imaging technology, were used to obtain relevant parameters, and behavioral and imaging results were compared between patients with MCI (n = 36) and healthy older adults (n = 32). Results: The olfactory ability of MCI patients was lower overall, which was positively correlated with the MoCA score. Fractional anisotropy (FA) changes significantly of all parameters. Lower FA regions were mainly located in the corpus callosum, the orbitofrontal gyrus, and the left occipital lobe. The olfactory score was significantly correlated with the FA value of the orbitofrontal gyrus. Fibrous connections in several brain regions, such as the entorhinal cortex, were stronger in patients with MCI. Conclusion: The olfactory ability of MCI patients in our group was positively correlated with the neuropsychological scale results. Impairment in olfactory function was superior to memory deficits for predicting cognitive decline among cognitively intact participants. The fibrous connections in several brain regions, such as the entorhinal cortex, were higher in patients with MCI, which suggested that there may be a compensatory mechanism in the olfactory pathway in MCI patients. The decline in olfactory function may be a significant and useful indicator of neuropathological changes in MCI patients and an effective marker for the development of cognitive decline and dementia.
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Affiliation(s)
- Yongjia Shao
- Department of Radiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Zijian Wang
- School of Computer Science and Technology, Donghua University, Shanghai, China
| | - Bin Ji
- Department of Radiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Hang Qi
- Department of Radiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Shangci Hao
- Department of Radiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Gang Li
- Department of Neurology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yue Zhang
- Department of Neurology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Qian Xi
- Department of Radiology, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
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21
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Yan Y, Aierken A, Wang C, Song D, Ni J, Wang Z, Quan Z, Qing H. A potential biomarker of preclinical Alzheimer's disease: The olfactory dysfunction and its pathogenesis-based neural circuitry impairments. Neurosci Biobehav Rev 2021; 132:857-869. [PMID: 34810025 DOI: 10.1016/j.neubiorev.2021.11.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 10/26/2021] [Accepted: 11/07/2021] [Indexed: 01/24/2023]
Abstract
The olfactory dysfunction can signal and act as a potential biomarker of preclinical AD. However, the precise regulatory mechanism of olfactory function on the neural pathogenesis of AD is still unclear. The impairment of neural networks in olfaction system has been shown to be tightly associated with AD. As key brain regions of the olfactory system, the olfactory bulb (OB) and the piriform cortex (PCx) have a profound influence on the olfactory function. Therefore, this review will explore the mechanism of olfactory dysfunction in preclinical AD in the perspective of abnormal neural networks in the OB and PCx and their associated brain regions, especially from two aspects of aberrant oscillations and synaptic plasticity damages, which help better understand the underlying mechanism of olfactory neural network damages related to AD.
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Affiliation(s)
- Yan Yan
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Ailikemu Aierken
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Chunjian Wang
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Da Song
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Junjun Ni
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing, 100081, China
| | - Zhe Wang
- Advanced Innovation Center for Human Brain Protection, Capital Medical University, The National Clinical Research Center for Geriatric Disease, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Zhenzhen Quan
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing, 100081, China.
| | - Hong Qing
- Key Laboratory of Molecular Medicine and Biotherapy, School of Life Science, Beijing Institute of Technology, Beijing, 100081, China.
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22
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Marín-Pardo D, Giménez-Llort L. Olfactory Signatures in the Food Finding Test in Mice With Normal and Alzheimer's Disease-Pathological Aging With Special Concerns on the Effects of Social Isolation. Front Neurosci 2021; 15:733984. [PMID: 34675767 PMCID: PMC8523944 DOI: 10.3389/fnins.2021.733984] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/31/2021] [Indexed: 12/17/2022] Open
Abstract
The temporal course and the severity of the involution of sensory systems through aging can be critical since they ensure the ability to perceive and recognize the world. In older people, sensory impairments significantly increase their risk of biological, psychological, and social impoverishment. Besides this, olfactory loss is considered an early biomarker in Alzheimer’s disease (AD) neurodegenerative process. Here we studied olfactory ethograms in middle-aged male and female gold-standard C57BL/6 mice and 3xTg-AD mice, a genetic model of AD that presents cognitive dysfunction and a conspicuous neuropsychiatric-like phenotype. A paradigm involving 1-day food deprivation was used to investigate the ethological patterns shown in the olfactory inspection of a new cage and the sniffing, finding, and eating of hidden food pellets. The sniffing–find–eat temporal patterns were independent of the loss of weight and unveiled (fast) olfactory signatures in Alzheimer’s disease, differing from those (slow progressive) in normal aging. Male 3xTg-AD mice exhibited an early signature than female mice, opposite to animals with normal aging. The sequence of actions was correlated in male and female 3xTg-AD mice in contrast to control mice. Social isolation, naturally occurring in male 3xTg-AD due to the death of cage mates, emphasized their olfactory patterns and disrupted the behavioral correlates. The paradigm provided distinct contextual, sex, and genotype olfactory ethogram signatures useful to investigate olfactory function in normal and AD-pathological aging. Isolation had an impact on enhancing the changes in the olfactory signature here described, for the first time, in the 3xTg-AD model of Alzheimer’s disease.
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Affiliation(s)
- Daniela Marín-Pardo
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain.,Department of Psychiatry and Forensic Medicine, School of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Lydia Giménez-Llort
- Institut de Neurociències, Universitat Autònoma de Barcelona, Barcelona, Spain.,Department of Psychiatry and Forensic Medicine, School of Medicine, Universitat Autònoma de Barcelona, Barcelona, Spain
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23
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Lessard-Beaudoin M, M Gonzalez L, AlOtaibi M, Chouinard-Watkins R, Plourde M, Calon F, Graham RK. Diet enriched in omega-3 fatty acids alleviates olfactory system deficits in APOE4 transgenic mice. Eur J Neurosci 2021; 54:7092-7108. [PMID: 34549475 DOI: 10.1111/ejn.15472] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 09/10/2021] [Accepted: 09/14/2021] [Indexed: 11/30/2022]
Abstract
Olfactory dysfunction is observed in several neurological disorders including Mild Cognitive Impairment (MCI) and Alzheimer disease (AD). These deficits occur early and correlate with global cognitive performance, depression and degeneration of olfactory regions in the brain. Despite extensive human studies, there has been little characterization of the olfactory system in models of AD. In order to determine if olfactory structural and/or molecular phenotypes are observed in a model expressing a genetic risk factor for AD, we assessed the olfactory bulb (OB) in APOE4 transgenic mice. A significant decrease in OB weight was observed at 12 months of age in APOE4 mice concurrent with inflammation and decreased NeuN expression. In order to determine if a diet rich in omega-3s may alleviate the olfactory system phenotypes observed, we assessed WT and APOE4 mice on a docosahexaenoic acid (DHA) diet. APOE4 mice on a DHA diet did not present with atrophy of the OB, and the alterations in NeuN and IBA-1 expression were alleviated. Furthermore, alterations in caspase mRNA and protein expression in the APOE4 OB were not observed with a DHA diet. Similar to the human AD condition, OB atrophy is an early phenotype in the APOE4 mice and concurrent with inflammation. These data support a link between the structural olfactory brain region atrophy and the olfactory dysfunction observed in AD and suggest that inflammation and cell death pathways may contribute to the olfactory deficits observed. Furthermore, the results suggest that diets enriched in DHA may provide benefit to APOE4 allele carriers.
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Affiliation(s)
- Melissa Lessard-Beaudoin
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Laura M Gonzalez
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Majed AlOtaibi
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Quebec, Canada.,Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Raphaël Chouinard-Watkins
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Medicine, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Melanie Plourde
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Medicine, University of Sherbrooke, Sherbrooke, Quebec, Canada
| | - Frederic Calon
- Faculty of Pharmacy, Centre de Recherche du CHU de Québec, Université Laval, Quebec City, Quebec, Canada
| | - Rona K Graham
- Research Center on Aging, CIUSSS de L'Estrie - CHUS, Sherbrooke, Quebec, Canada.,Department of Pharmacology and Physiology, University of Sherbrooke, Sherbrooke, Quebec, Canada
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24
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Wang Q, Chen B, Zhong X, Zhou H, Zhang M, Mai N, Wu Z, Huang X, Haehner A, Chen X, Auber LA, Peng Q, Hummel T, Ning Y. Olfactory Dysfunction Is Already Present with Subjective Cognitive Decline and Deepens with Disease Severity in the Alzheimer's Disease Spectrum. J Alzheimers Dis 2021; 79:585-595. [PMID: 33361601 DOI: 10.3233/jad-201168] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND Odor identification dysfunction occurs early in Alzheimer's disease (AD) and is considered a preclinical symptom along with subjective cognitive decline (SCD). Nevertheless, whether subjects with SCD are co-symptomatic with odor identification dysfunction remains unclear. OBJECTIVE To compare the degree of odor identification dysfunction and assess the relation between odor identification and cognitive performance in the AD spectrum (including SCD, mild cognitive impairment (MCI), and AD). METHODS Patients (84 SCD, 129 MCI, 52 AD) and 35 controls underwent the Sniffin' Sticks Screen 16 test and comprehensive neuropsychological examination. RESULTS Odor identification scores were progressively lower moving from normal older adult to SCD, MCI, and AD. Additionally,the proportion of odor identification dysfunction were increasingly higher in the AD spectrum (p for trend <0.001), but no significant difference was found in the proportion of subjective olfactory dysfunction. No significant correlation was found between odor identification and cognition in the normal older adults and SCD subjects, but odor identification correlated with global cognition in the MCI (r = 0.199, p = 0.033) and in the AD (r = 0.300, p = 0.036) patients. Multiple linear regression showed that odor identification dysfunction was most strongly associated with memory among different cognitive subdomains and was most strongly associated with immediate verbal recall among different memory subdomains. CONCLUSION Odor identification dysfunction is already present with SCD and deepens with disease severity in the AD spectrum, and it may contribute to predicting cognitive decline and identifying SCD subjects who are at risk of developing AD.
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Affiliation(s)
- Qiang Wang
- Memory Clinic, Department of Geriatric Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong Province, China.,Department of Geriatric Psychiatry, The Second People's Hospital of Dali Bai Autonomous Prefecture, Dali, Yunnan Province, China
| | - Ben Chen
- Memory Clinic, Department of Geriatric Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong Province, China
| | - Xiaomei Zhong
- Memory Clinic, Department of Geriatric Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong Province, China
| | - Huarong Zhou
- Memory Clinic, Department of Geriatric Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong Province, China
| | - Min Zhang
- Memory Clinic, Department of Geriatric Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong Province, China
| | - Naikeng Mai
- Department of Neurology, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong Province, China
| | - Zhangying Wu
- Memory Clinic, Department of Geriatric Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong Province, China
| | - Xingxiao Huang
- Memory Clinic, Department of Geriatric Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong Province, China
| | - Antje Haehner
- Smell and Taste Clinic, Department of Otorhinolaryngology, Technische Universität Dresden, Germany
| | - Xinru Chen
- Memory Clinic, Department of Geriatric Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong Province, China
| | - Lavinia Alberi Auber
- Department of Medicine, University of Fribourg, Fribourg, Switzerland.,Swiss Integrative Center of Human Health, Fribourg, Switzerland
| | - Qi Peng
- Memory Clinic, Department of Geriatric Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong Province, China
| | - Thomas Hummel
- Smell and Taste Clinic, Department of Otorhinolaryngology, Technische Universität Dresden, Germany
| | - Yuping Ning
- Memory Clinic, Department of Geriatric Psychiatry, The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), Guangzhou, Guangdong Province, China.,The first School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong Province, China.,Guangdong Engineering Technology Research Center for Translational Medicine of Mental Disorders, Guangzhou, China
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25
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Jobin B, Zahal R, Bussières EL, Frasnelli J, Boller B. Olfactory Identification in Subjective Cognitive Decline: A Meta-Analysis. J Alzheimers Dis 2021; 79:1497-1507. [PMID: 33459721 DOI: 10.3233/jad-201022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Recently, subjective cognitive decline (SCD) has been considered to be one of the first signs of Alzheimer's disease (AD). Since this potential early marker is sensitive but not specific to AD, combining it with other markers could ensure higher accuracy when predicting which persons with SCD will convert to AD. Since olfactory dysfunction is observable in both AD and mild cognitive impairment (MCI), it is a promising marker that could help improve the early diagnosis of AD. OBJECTIVE The aim of this meta-analysis was to verify whether the presence of SCD is associated with a decrease in olfactory identification ability. METHODS We collected articles from the following databases: PsychNet, PubMed, Ebsco, and ProQuest using the keywords: "SCD", "subjective cognitive decline", "subjective cognitive impairment", "subjective memory impairment", "subjective memory decline", "cognitive complaints", "memory complaints", "cognitive concerns", "memory concerns", "olfac*" and "smell". We included articles according to the following criteria: 1) participants aged 50 and over; 2) presence of an SCD group or a conceptual equivalent; 3) presence of a healthy control group with the same age range; and 4) assessment of olfactory identification ability. RESULTS Five studies met the inclusion criteria. Small and homogeneous effects were observed for olfactory identification alteration in individuals with SCD relative to controls (g = -0.16, 95% CI [-0.46, 0.14]). CONCLUSION Despite the low number of studies included, the findings suggest that odor identification is slightly altered in SCD compared to healthy older adults. This alteration in individuals with SCD could be an early marker of AD.
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Affiliation(s)
- Benoît Jobin
- Department of Psychology, Université du Québec à Trois-Rivières, QC, Canada.,Research Centre of the Hôpital du Sacré-Cœur de Montréal, QC, Canada.,Research Centre of the Institut Universitaire de Gériatrie de Montréal, QC, Canada
| | - Rayane Zahal
- Research Centre of the Hôpital du Sacré-Cœur de Montréal, QC, Canada.,Department of Psychology, Université de Montréal, QC, Canada
| | - Eve-Line Bussières
- Department of Psychology, Université du Québec à Trois-Rivières, QC, Canada
| | - Johannes Frasnelli
- Research Centre of the Hôpital du Sacré-Cœur de Montréal, QC, Canada.,Department of Anatomy, Université du Québec à Trois-Rivières, QC, Canada
| | - Benjamin Boller
- Department of Psychology, Université du Québec à Trois-Rivières, QC, Canada.,Research Centre of the Institut Universitaire de Gériatrie de Montréal, QC, Canada
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26
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Yi JS, Hura N, Roxbury CR, Lin SY. Magnetic Resonance Imaging Findings Among Individuals With Olfactory and Cognitive Impairment. Laryngoscope 2021; 132:177-187. [PMID: 34383302 DOI: 10.1002/lary.29812] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 06/25/2021] [Accepted: 07/25/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVES The underlying mechanism of the association between olfactory impairment and dementia may be explained by neurodegenerative changes detected on magnetic resonance imaging (MRI). The purpose of this systematic review is to describe neurodegenerative changes on MRI in patients with olfactory impairment and mild cognitive impairment (MCI) or dementia. STUDY DESIGN Systematic review. METHODS A literature search encompassing PubMed, Embase, Cochrane Library, Web of Science, Scopus, and Google Scholar for studies with MRI and olfactory testing among participants diagnosed with MCI or dementia was performed. Sample size, study design, cognitive impairment type, olfactory testing, and MRI findings were abstracted. Two investigators independently reviewed all articles. RESULTS The search yielded 556 nonduplicate abstracts, from which 86 articles were reviewed and 24 were included. Seventeen (71%) of 24 studies reported hippocampal volume findings, with 14 studies reporting a relationship between hippocampal volume and olfactory performance. Two (50%) of four prospective studies reported the potential utility of baseline hippocampal volume as a marker of dementia conversion from MCI. Five (21%) of 24 studies reporting olfactory functional MRI (fMRI) findings highlighted the utility of olfactory fMRI to identify individuals in the early stages of cognitive decline. CONCLUSION Current evidence suggests hippocampal volume correlates with olfactory performance in individuals with cognitive impairment, and that olfactory fMRI may improve early detection of AD. However, the predictive utility of these imaging markers is limited in prospective studies. MRI may be a useful modality for selecting patients at high risk of future cognitive decline for enrollment in early treatment trials. Laryngoscope, 2021.
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Affiliation(s)
- Julie S Yi
- Johns Hopkins University School of Medicine, Baltimore, Maryland, U.S.A
| | - Nanki Hura
- Johns Hopkins University School of Medicine, Baltimore, Maryland, U.S.A
| | - Christopher R Roxbury
- Department of Otolaryngology-Head and Neck Surgery, The University of Chicago Medical Center, Chicago, Illinois, U.S.A
| | - Sandra Y Lin
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, U.S.A
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27
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Jobin B, Boller B, Frasnelli J. Volumetry of Olfactory Structures in Mild Cognitive Impairment and Alzheimer's Disease: A Systematic Review and a Meta-Analysis. Brain Sci 2021; 11:1010. [PMID: 34439629 PMCID: PMC8393728 DOI: 10.3390/brainsci11081010] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 11/25/2022] Open
Abstract
Olfactory decline is an early symptom of Alzheimer's disease (AD) and is a predictor of conversion from mild cognitive impairment (MCI) to AD. Olfactory decline could reflect AD-related atrophy of structures related to the sense of smell. The aim of this study was to verify whether the presence of a clinical diagnosis of AD or MCI is associated with a volumetric decrease in the olfactory bulbs (OB) and the primary olfactory cortex (POC). We conducted two systematic reviews, one for each region and a meta-analysis. We collected articles from PsychNet, PubMed, Ebsco, and ProQuest databases. Results showed large and heterogeneous effects indicating smaller OB volumes in patients with AD (k = 6, g = -1.21, 95% CI [-2.19, -0.44]) and in patients with MCI compared to controls. There is also a trend for smaller POC in patients with AD or MCI compared to controls. Neuroanatomical structures involved in olfactory processing are smaller in AD and these volumetric reductions could be measured as early as the MCI stage.
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Affiliation(s)
- Benoît Jobin
- Department of Psychology, Université du Québec à Trois-Rivières, Trois-Rivieres, QC G8Z 4M3, Canada;
- Research Centre of the Institut Universitaire de Gériatrie de Montréal, Montréal, QC H3W 1W5, Canada
- Research Centre of the CIUSSS du Nord-de-l’île-de-Montréal, Montréal, QC H4J 1C5, Canada;
| | - Benjamin Boller
- Department of Psychology, Université du Québec à Trois-Rivières, Trois-Rivieres, QC G8Z 4M3, Canada;
- Research Centre of the Institut Universitaire de Gériatrie de Montréal, Montréal, QC H3W 1W5, Canada
| | - Johannes Frasnelli
- Research Centre of the CIUSSS du Nord-de-l’île-de-Montréal, Montréal, QC H4J 1C5, Canada;
- Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivieres, QC G8Z 4M3, Canada
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28
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Affiliation(s)
- Melissa Tam
- Food, Nutrition, Dietetics and Health Kansas State University Manhattan Kansas USA
| | - Kadri Koppel
- Food, Nutrition, Dietetics and Health Kansas State University Manhattan Kansas USA
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29
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A novel olfactory threshold test for screening cognitive decline among elderly people. PLoS One 2021; 16:e0254357. [PMID: 34252091 PMCID: PMC8274884 DOI: 10.1371/journal.pone.0254357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 06/24/2021] [Indexed: 11/20/2022] Open
Abstract
Olfactory impairment is associated with dementia and is a potential early biomarker of cognitive decline. We developed a novel olfactory threshold test called Sniff Bubble using rose odor-containing beads made with 2-phenylethyl alcohol. We aimed to define cut-off scores for this tool to help identify cognitive decline among elderly people. In total, 162 elderly people (mean age ± SD: 73.04 ± 8.73 years) were administered olfactory threshold and neurocognitive tests. For analyses, we divided the participants into two groups based on cognitive functioning, namely cognitive decline (n = 44) and normal cognition (n = 118) groups. The Sniff Bubble and YSK olfactory function test for olfactory threshold and the Structured Clinical Interview for DSM-5 Disorders-Clinician Version and Korean version of the Consortium to Establish a Registry for Alzheimer’s Disease assessment packet for neurocognitive functioning were used. We used K-means cluster analyses and receiver operating characteristic (ROC) analyses to identify the most appropriate cut-off value. We established a positive correlation between the Sniff Bubble and neurocognitive function test scores (r = 0.431, p < 0.001). We defined the cut-off score, using the ROC curve analyses for Sniff Bubble scores, at 3 and higher with an area under the curve of 0.759 (p < 0.001). The Sniff Bubble test can adequately detect cognitive decline in elderly people and may be used clinically as the first step in the screening process.
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30
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Handgrip strength as a moderator of the influence of age on olfactory impairment in US adult population ≥ 40 years of age. Sci Rep 2021; 11:14085. [PMID: 34238956 PMCID: PMC8266868 DOI: 10.1038/s41598-021-93355-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 06/21/2021] [Indexed: 11/16/2022] Open
Abstract
The aim of this study was to determine whether handgrip strength attenuates the negative relationship between age and olfactory function in a representative US population sample 40 years old and over. A cross-sectional study was performed with 2861 adults from the US National Health and Nutrition Examination Survey NHANES (2013–2014). An 8-item odor identification test was applied to determine olfactory function. Muscle strength was determined through a handgrip dynamometer (defined as the sum of the largest handgrip strength reading from right and left hands). Moderation analysis was performed to test whether the association between age and olfactory impairment was moderated by handgrip strength. Moderation analysis highlighted two regions of significance: the first region was found at < 56.6 kg, indicating that the adverse influence of age on olfactory function may be greater for the participants in this area; the second region was found at ≥ 56.6 kg, indicating that the negative impact of age on olfactory function disappeared for adults who were above this estimate point. In conclusion, handgrip strength, a general indicator of muscle strength, moderates the relationship between age and olfactory ability in a US adult population aged 40 years and older. Our findings are clinically relevant, since they emphasize the importance of muscular fitness in adulthood and old age by diminishing the deleterious effect of aging on olfactory performance.
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31
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Olofsson JK. Olfaction and Aging: A Review of the Current State of Research and Future Directions. Iperception 2021; 12:20416695211020331. [PMID: 34249327 PMCID: PMC8239976 DOI: 10.1177/20416695211020331] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 04/21/2021] [Indexed: 11/16/2022] Open
Abstract
Olfaction, the sense of smell, is characterized by a notable age-dependency such that aging individuals are more likely to have poor olfactory abilities. These impairments are considered to be mostly irreversible and as having potentially profound effects on quality of life and food behavior, as well as constituting warning signs of mortality, cognitive dysfunction, and dementia. Here, we review the current state of research on aging and olfaction, focusing on five topics which we regard to be of particular relevance for the field: nutrition and health, cognition and dementia, mortality, environment and genetics, and training-based enhancement. Under each of these headlines, we provide a state-of-the-art overview and discuss gaps in our knowledge which might be filled by further research. Understanding how olfactory abilities are diminished in aging, and how they may be alleviated or recovered, involves a set of challenging tasks for researchers in the years to come.
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Affiliation(s)
- Jonas K. Olofsson
- Gösta Ekman Laboratory, Stockholm University, Stockholm, Sweden; Department of Psychology, Stockholm University, Stockholm, Sweden
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32
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Su B, Bleier B, Wei Y, Wu D. Clinical Implications of Psychophysical Olfactory Testing: Assessment, Diagnosis, and Treatment Outcome. Front Neurosci 2021; 15:646956. [PMID: 33815048 PMCID: PMC8012732 DOI: 10.3389/fnins.2021.646956] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Accepted: 03/01/2021] [Indexed: 11/13/2022] Open
Abstract
Purpose of Review Olfactory dysfunction dramatically impairs quality of life with a prevalence of 20% in the general adult population. Psychophysical olfactory testing has been widely used to evaluate the ability to smell due to its validated utility and feasibility in clinic. This review summarizes the current literature regarding psychophysical olfactory testing and the clinical relevance of the olfactory testing with different components. Furthermore, the review highlights the diagnosis and treatment value of olfactory subtests in patients with olfactory dysfunction. Recent Findings With the accumulation of studies of psychophysical olfactory testing in olfactory disorders, the clinical relevance of olfactory testing with different components is expanding. Different olfactory domains present with distinct olfactory processing and cortical activity. Psychophysical assessment of olfaction with three domains reveals different levels of olfactory processing and might assist with analyzing the pathophysiologic mechanism of the various olfactory disorders. Furthermore, olfactory thresholds provided the largest amount of non-redundant information to the olfactory diagnosis. Sinonasal olfactory dysfunction and non-sinonasal-related olfactory dysfunction are emerging classifications of smell disorders with certain characteristics of olfactory impairment and different responses to the therapy including steroids, sinus surgery, and olfactory training. Summary These recent advancements should promote the understanding of psychophysical olfactory testing, the association between individual subcomponents and neurophysiological processes, and pave the way for precision assessment and treatment of the olfactory dysfunction.
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Affiliation(s)
- Baihan Su
- Department of Otolaryngology, Smell and Taste Center, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Benjamin Bleier
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, United States
| | - Yongxiang Wei
- Department of Otolaryngology, Smell and Taste Center, Beijing Anzhen Hospital, Capital Medical University, Beijing, China.,Department of Otorhinolaryngology Head and Neck Surgery, Capital Institute of Pediatrics, Beijing, China
| | - Dawei Wu
- Department of Otolaryngology, Smell and Taste Center, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
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33
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Zhou G, Olofsson JK, Koubeissi MZ, Menelaou G, Rosenow J, Schuele SU, Xu P, Voss JL, Lane G, Zelano C. Human hippocampal connectivity is stronger in olfaction than other sensory systems. Prog Neurobiol 2021; 201:102027. [PMID: 33640412 DOI: 10.1016/j.pneurobio.2021.102027] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/20/2021] [Accepted: 02/21/2021] [Indexed: 12/17/2022]
Abstract
During mammalian evolution, primate neocortex expanded, shifting hippocampal functional networks away from primary sensory cortices, towards association cortices. Reflecting this rerouting, human resting hippocampal functional networks preferentially include higher association cortices, while those in rodents retained primary sensory cortices. Research on human visual, auditory and somatosensory systems shows evidence of this rerouting. Olfaction, however, is unique among sensory systems in its relative structural conservation throughout mammalian evolution, and it is unknown whether human primary olfactory cortex was subject to the same rerouting. We combined functional neuroimaging and intracranial electrophysiology to directly compare hippocampal functional networks across human sensory systems. We show that human primary olfactory cortex-including the anterior olfactory nucleus, olfactory tubercle and piriform cortex-has stronger functional connectivity with hippocampal networks at rest, compared to other sensory systems. This suggests that unlike other sensory systems, olfactory-hippocampal connectivity may have been retained in mammalian evolution. We further show that olfactory-hippocampal connectivity oscillates with nasal breathing. Our findings suggest olfaction might provide insight into how memory and cognition depend on hippocampal interactions.
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Affiliation(s)
- Guangyu Zhou
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
| | - Jonas K Olofsson
- Department of Psychology, Stockholm University, Stockholm, Sweden; Emotional Brain Institute, Nathan S. Kline Institute, Orangeburg, NY, USA; Department of Child and Adolescent Psychiatry, New York University School of Medicine, New York, NY, USA
| | | | | | - Joshua Rosenow
- Department of Neurosurgery, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Stephan U Schuele
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Pengfei Xu
- Beijing Key Laboratory of Applied Experimental Psychology, Faculty of Psychology, Beijing Normal University, Beijing, China; Center for Neuroimaging, Shenzhen Institute of Neuroscience, Shenzhen, China; Guangdong-Hong Kong-Macao Greater Bay Area Research Institute for Neuroscience and Neurotechnologies, Kwun Tong, Hong Kong, China
| | - Joel L Voss
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; Department of Medical Social Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, USA; Department of Psychiatry and Behavioral Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Gregory Lane
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Christina Zelano
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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Delgado-Losada ML, Bouhaben J, Delgado-Lima AH. Development of the Spanish Version of Sniffin's Sticks Olfactory Identification Test: Normative Data and Validity of Parallel Measures. Brain Sci 2021; 11:216. [PMID: 33578970 PMCID: PMC7916642 DOI: 10.3390/brainsci11020216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/04/2021] [Accepted: 02/06/2021] [Indexed: 12/22/2022] Open
Abstract
The Sniffin' Sticks Olfactory Identification Test is a tool for measurement of olfactory performance developed in Germany and validated in several countries. This research aims to develop the Spanish version of the Sniffin' Sticks Olfactory Identification Test and obtain normative values for the Spanish population. The parameters are free recall and subjective intensity of odorants are included. The influence of possible demographic covariates such as sex, age, smoking, or educational level are analyzed, and the items that best discriminate are studied. In addition, the internal structure validity of the blue and purple versions is studied as a parallel measure, and a cultural adaptation of the purple version is carried out. For this, three independent samples of normosmic healthy volunteers were studied. To obtain normative values, the sample was of 417 participants (18-89 years). For the internal structure validity study of both versions, the sample was 226 (18-70 years), and for familiarity of the purple version, the sample was 75 participants (21-79 years). Results indicated that men and women and smokers and non-smokers perform equally. However, differences were found as age progresses, being more pronounced after 60 years old in all three measurements of the identification test. This research also provides the items that best discriminate in the blue version and a cultural adaptation for the purple version. In conclusion, the Sniffin' Sticks Odor Identification Test is a suitable tool for olfactory assessment in the Spanish population. The instrument has been expanded with two new scores, and normative data as a function of age are provided. Its parallel version also seems appropriate for testing, as items have been culturally adapted and evidence of internal structure validity for both versions is reported.
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Affiliation(s)
- María Luisa Delgado-Losada
- Experimental Psychology, Cognitive Processes and Speech Therapy Department, Faculty of Psychology, Complutense University of Madrid, Campus de Somosaguas, 28223 Pozuelo de Alarcón, Spain; (J.B.); (A.H.D.-L.)
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Martínez-García I, Hernández-Soto R, Villasana-Salazar B, Ordaz B, Peña-Ortega F. Alterations in Piriform and Bulbar Activity/Excitability/Coupling Upon Amyloid-β Administration in vivo Related to Olfactory Dysfunction. J Alzheimers Dis 2021; 82:S19-S35. [PMID: 33459655 DOI: 10.3233/jad-201392] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Deficits in odor detection and discrimination are premature symptoms of Alzheimer's disease (AD) that correlate with pathological signs in the olfactory bulb (OB) and piriform cortex (PCx). Similar olfactory dysfunction has been characterized in AD transgenic mice that overproduce amyloid-β peptide (Aβ), which can be prevented by reducing Aβ levels by immunological and pharmacological means, suggesting that olfactory dysfunction depends on Aβ accumulation and Aβ-driven alterations in the OB and/or PCx, as well as on their activation. However, this possibility needs further exploration. OBJECTIVE To characterize the effects of Aβ on OB and PCx excitability/coupling and on olfaction. METHODS Aβ oligomerized solution (containing oligomers, monomers, and protofibrils) or its vehicle were intracerebroventricularlly injected two weeks before OB and PCx excitability and synchrony were evaluated through field recordings in vivo and in brain slices. Synaptic transmission from the OB to the PCx was also evaluated in slices. Olfaction was assessed through the habituation/dishabituation test. RESULTS Aβ did not affect lateral olfactory tract transmission into the PCx but reduced odor habituation and cross-habituation. This olfactory dysfunction was related to a reduction of PCx and OB network activity power in vivo. Moreover, the coherence between PCx-OB activities was also reduced by Aβ. Finally, Aβ treatment exacerbated the 4-aminopyridine-induced excitation in the PCx in slices. CONCLUSION Our results show that Aβ-induced olfactory dysfunction involves a complex set of pathological changes at different levels of the olfactory pathway including alterations in PCx excitability and its coupling with the OB. These pathological changes might contribute to hyposmia in AD.
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Affiliation(s)
- Ignacio Martínez-García
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
| | - Rebeca Hernández-Soto
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
| | - Benjamín Villasana-Salazar
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
| | - Benito Ordaz
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
| | - Fernando Peña-Ortega
- Departamento de Neurobiología del Desarrollo y Neurofisiología, Instituto de Neurobiología, UNAM-Campus Juriquilla, México
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Ni W, Zhang Z, Zhang B, Zhang W, Cheng H, Miao Y, Chen W, Liu J, Zhu D, Bi Y. Connecting Peripheral to Central Neuropathy: Examination of Nerve Conduction Combined with Olfactory Tests in Patients with Type 2 Diabetes. Diabetes Metab Syndr Obes 2021; 14:3097-3107. [PMID: 34267530 PMCID: PMC8276992 DOI: 10.2147/dmso.s312021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 06/14/2021] [Indexed: 12/11/2022] Open
Abstract
AIM Few studies have investigated the associations between diabetic peripheral neuropathy (DPN) and cognitive decline. Olfactory impairment is related to neurodegenerative diseases and type 2 diabetes mellitus (T2DM); however, the cognitive alterations of patients with DPN and the role of olfactory function in DPN are not known. We explored alterations in cognition with DPN and the associations of neuropathy parameters with cognition and olfaction. METHODS Healthy controls (HCs) and patients with T2DM underwent nerve-conduction tests, detailed cognitive assessment, olfactory-behavior tests, and odor-induced functional magnetic resonance imaging (fMRI). T2DM patients were divided into two groups (non-DPN [NDPN] and DPN). Olfactory brain regions showing different activation between the two groups were selected for functional connectivity (FC) analyses. A structural equation model (SEM) was also generated to demonstrate the association among cognition, olfactory, and neuropathy parameters. RESULTS One hundred individuals (36 HCs, 36 NDPN, and 28 DPN) were matched for age, sex, and educational level. Compared with the NDPN group, the DPN group had significantly lower scores for memory and processing speed, as well as lower olfactory identification and memory scores, decreased activation of the left frontal lobe, and reduced seed-based functional connectivity in the right insula. The nerve conduction velocity in patients with T2DM was associated with cognitive functions. The association between nerve conduction and executive function was mediated by olfactory behavior. CONCLUSION Patients with DPN had worse cognition than the NDPN patients in the domains of memory and processing speed. Cognitive dysfunction could be predicted by olfactory-behavior tests and electrophysiological examination.
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Affiliation(s)
- Wenyu Ni
- Department of Endocrinology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, People’s Republic of China
| | - Zhou Zhang
- Department of Endocrinology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, People’s Republic of China
| | - Bing Zhang
- Department of Radiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, People’s Republic of China
| | - Wen Zhang
- Department of Radiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, People’s Republic of China
| | - Haiyan Cheng
- Department of Endocrinology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, People’s Republic of China
| | - Yingwen Miao
- Department of Endocrinology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, People’s Republic of China
| | - Wei Chen
- Department of Endocrinology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, People’s Republic of China
| | - Jiani Liu
- Department of Radiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, People’s Republic of China
| | - Dalong Zhu
- Department of Endocrinology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, People’s Republic of China
| | - Yan Bi
- Department of Endocrinology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, People’s Republic of China
- Correspondence: Yan Bi Department of Endocrinology, Drum Tower Hospital, Affiliated to Nanjing University Medical School, No. 321, Zhongshan Road, Nanjing, 210008, People’s Republic of ChinaTel +86 25-83304616-61431Fax +86 25-83304616-61431 Email
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Abstract
Age-related olfactory dysfunction, or presbyosmia, is a common sensory impairment in aging adults. People in this demographic group with comorbid conditions or exposure to viral, traumatic, or environmental insults remain at the greatest risk for impairment. Several methods for assessing olfaction exist, but they are only available in special settings and require consideration of age, sex, ancestry, and cognition. Perhaps most importantly, olfactory dysfunction has been suggested as an early sign of Alzheimer's and Parkinson's disease and therefore may serve as a tool in the diagnosis and prognosis of these neurodegenerative conditions. Outside of this context, olfactory loss also impacts nutrition, safety, and social relationships, and even predicts mortality itself. This review covers the detection and manifestations of olfactory decline in aging individuals and the myriad ways in which olfactory impairment is connected to their health and well-being.
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Affiliation(s)
- Emily J Papazian
- Pritzker School of Medicine, The University of Chicago, Chicago, IL, USA
- Department of Otorhinolaryngology-Head and Neck Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Jayant M Pinto
- Section of Otolaryngology-Head and Neck Surgery, Department of Surgery, The University of Chicago Medicine, Chicago, IL, USA
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Al-Otaibi M, Lessard-Beaudoin M, Castellano CA, Gris D, Cunnane SC, Graham RK. Volumetric MRI demonstrates atrophy of the olfactory cortex in AD. Curr Alzheimer Res 2020; 17:904-915. [PMID: 33327913 DOI: 10.2174/1567205017666201215120909] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 10/02/2020] [Accepted: 11/05/2020] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Alzheimer disease (AD) is a chronic neurodegenerative disorder that affects millions of individuals worldwide. Symptoms include memory dysfunction and deficits in attention, planning, language, and overall cognitive function. Olfactory dysfunction is a common symptom of AD and evidence supports that it is an early marker. Furthermore, olfactory bulb and entorhinal cortex atrophy are well described in AD. However, in AD, no studies have assessed the olfactory cortex as a whole and if sex effects are observed. METHODS Magnetic Resonance Imaging was used to scan 39 participants with an average age of 72 years and included men and women. AAL Single-Subject Atlas (implemented in PNEURO tool - PMOD 3.8) was used to determine the volume of the olfactory cortex and the hippocampus. Olfactory cortex volume was lower in both men and women AD cases compared with controls. This decrease was more apparent in the left olfactory cortex and was influenced by age. As expected, hippocampal volume was also significantly reduced in AD. However, this was only observed in the male cohort. A significant correlation was observed between levels of education and hippocampal volume in controls that were not detected in the AD participants. Asymmetry was observed in the olfactory cortex volume when comparing left and right volumes in both the control and AD participants, which was not observed in the hippocampus. RESULTS These data highlight the importance of the role of olfactory cortical atrophy in the pathogenesis of AD and the interplay between the olfactory deficits and degeneration of olfactory regions in the brain.
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Affiliation(s)
| | | | | | - Denis Gris
- Department of Pediatrics, University of Sherbrooke, Sherbrooke, QC, Canada
| | - Stephen C Cunnane
- Research Center on Aging, CIUSSS-IUGS de l'Estrie-CHUS, Sherbrooke, QC, Canada
| | - Rona K Graham
- Research Center on Aging, CIUSSS-IUGS de l'Estrie-CHUS, Sherbrooke, QC, Canada
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Spanish Validation for Olfactory Function Testing Using the Sniffin' Sticks Olfactory Test: Threshold, Discrimination, and Identification. Brain Sci 2020; 10:brainsci10120943. [PMID: 33297359 PMCID: PMC7762307 DOI: 10.3390/brainsci10120943] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 12/04/2020] [Accepted: 12/04/2020] [Indexed: 12/14/2022] Open
Abstract
The assessment of olfactory function is becoming increasingly relevant, especially in cases of cognitive decline (i.e., neurodegenerative diseases), where olfactory alterations may be relevant as potential early biomarkers. The Sniffin' Sticks Olfactory Test, developed in Germany and validated in several countries, is an objective measure of olfactory performance. This study aims to validate this test in a Spanish sample. This study included 209 healthy normosmic volunteers (154 females and 55 males) aged between 20 to 79 years (mean age = 50.11 ± 15.18 years) as the normative sample. From this group, 22 participants were retested in order to obtain test-retest reliability evidence. Odor familiarity for descriptors in the olfactory identification test was also studied on an independent healthy sample (n = 69), and required cultural modifications were applied. Results indicate that men and women, as well as smokers and non-smokers, performed equally in every test. However, significant differences were found between age groups in every score. The general trend is that olfactory function progressively decreases as a function of age, the elderly group (+60 years) being the one with the lowest scores. In conclusion, this normative data, in addition to the test's cultural modifications, allows the Sniffin' Sticks Olfactory Test to be administered on a Spanish population.
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Kim SM, Kim HR, Min HJ, Kim KS, Ga H, Lee SH, Han DH. Impaired Odor Identification of Culturally Familiar Odorants Associated with Dementia in South Korean Older Adults. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17228441. [PMID: 33202663 PMCID: PMC7696462 DOI: 10.3390/ijerph17228441] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 01/31/2023]
Abstract
Among olfactory functions, odor identification is the most studied predictor of dementia. We aimed to verify whether patients with dementia are less aware of specific odors than cognitively normal individuals using an odor identification test, which includes odorants that are culturally familiar to South Koreans. We divided 139 older adults aged 57–79 years into the dementia and normal cognition groups. Odor identification function was assessed in all participants. We conducted hierarchical logistic regression analyses with the diagnosis of dementia as a dependent variable and three demographic characteristics, as well as 12 odor identification items, as independent variables. Impaired odor identification for herbal medicine (odds ratio (OR) = 9.420; p = 0.012) and Korean grilled meat (OR = 5.361; p = 0.019) and older age (OR = 1.176; p = 0.005) were significant predictors of dementia. Impaired odor identification of culturally familiar odorants was associated with dementia risk. This may be explained by the fact that compared with culturally non-specific universal odorants, familiar odorants are more related to episodic memory, which is impaired in the early stages of dementia. Thus, an optimal combination of odor identification items should be used for screening individuals with cognitive decline requiring further neurocognitive function tests.
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Affiliation(s)
- Sun Mi Kim
- Department of Psychiatry, Chung-Ang University College of Medicine, Seoul 06974, Korea; (S.M.K.); (H.R.K.)
| | - Hye Ri Kim
- Department of Psychiatry, Chung-Ang University College of Medicine, Seoul 06974, Korea; (S.M.K.); (H.R.K.)
| | - Hyun Jin Min
- Department of Otorhinolaryngology-Head and Neck Surgery, Chung-Ang University College of Medicine, Seoul 06974, Korea; (H.J.M.); (K.S.K.)
| | - Kyung Soo Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Chung-Ang University College of Medicine, Seoul 06974, Korea; (H.J.M.); (K.S.K.)
| | - Hyuk Ga
- Department of Family Medicine, Institute of Geriatric Medicine, Incheon Eun-Hye Hospital, Incheon 22711, Korea;
| | - Sang Hoon Lee
- Department of Psychiatry, Eun-Hye Hospital, Incheon 22711, Korea;
| | - Doug Hyun Han
- Department of Psychiatry, Chung-Ang University College of Medicine, Seoul 06974, Korea; (S.M.K.); (H.R.K.)
- Correspondence: ; Tel.: +82-2-6299-3132
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Ding D, Liang X, Xiao Z, Wu W, Zhao Q, Cao Y. Can dementia be predicted using olfactory identification test in the elderly? A Bayesian network analysis. Brain Behav 2020; 10:e01822. [PMID: 32864870 PMCID: PMC7667339 DOI: 10.1002/brb3.1822] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/13/2020] [Accepted: 08/12/2020] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Previous studies suggest that olfactory dysfunction is associated with cognitive decline or dementia. OBJECTIVE To find a potential association between the olfactory identification (OI) and dementia onset, and build a prediction model for dementia screening in the older population. METHODS Nine hundred and forty-seven participants from the Shanghai Aging Study were analyzed. The participants were dementia-free and completed OI test using the Sniffin' Sticks Screening Test-12 at baseline. After an average of 4.9-year follow-up, 75 (8%) of the participants were diagnosed with incident dementia. Discrete Bayesian network (DBN) and multivariable logistic regression (MLR) models were used to explore the dependencies of the incident dementia on the baseline demographics, lifestyles, and OI test results. RESULTS In DBN analysis, odors of orange, cinnamon, peppermint, and pineapple, combined with age and Mini-mental State Examination (MMSE), achieved a high predictive ability for incident dementia, with an area under the receiver operating characteristic curve (AUC) larger than 0.8. The odor cinnamon showed the highest AUC of 0.838 (95% CI: 0.731-0.946) and a high accuracy of 0.867. The DBN incorporating age, MMSE, and one odor test had an accuracy (0.760-0.872 vs. 0.835) comparable to that of the MLR model and revealed the dependency between the variables. CONCLUSION The DBN using OI test may have predictive ability comparable to MLR analysis and suggest potential causal relationship for further investigation. Identification of odor cinnamon might be a useful indicator for dementia screening and deserve further investigation.
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Affiliation(s)
- Ding Ding
- Institute of Neurology, Huashan Hospital, Fudan University, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiaoniu Liang
- Institute of Neurology, Huashan Hospital, Fudan University, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Zhenxu Xiao
- Institute of Neurology, Huashan Hospital, Fudan University, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Wanqing Wu
- Institute of Neurology, Huashan Hospital, Fudan University, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Qianhua Zhao
- Institute of Neurology, Huashan Hospital, Fudan University, Shanghai, China.,National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, Shanghai, China
| | - Yang Cao
- Clinical Epidemiology and Biostatistics, School of Medical Sciences, Örebro University, Örebro, Sweden
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Kim HR, Kim SM, Seong W, Min HJ, Kim KS, Ga H, Han DH. Cut-Off Scores of an Olfactory Function Test for Mild Cognitive Impairment and Dementia. Psychiatry Investig 2020; 17:1021-1030. [PMID: 33059394 PMCID: PMC7596283 DOI: 10.30773/pi.2020.0203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 09/01/2020] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE We aimed to find the optimal cut-off scores for screening of odor detection threshold, odor discrimination, and odor identification tests for detection of mild cognitive impairment (MCI) and dementia in Korean elderly. METHODS A total of 195 elderly people were divided into three groups: the normal cognition (NC), MCI, and dementia groups. All participants underwent neurocognitive and olfactory function tests. We used k-means cluster analysis and receiver operating characteristic (ROC) analysis to identify the most appropriate cut-off value. RESULTS To distinguish the MCI from NC groups, odor identification [area under the curve (AUC)=0.670, p<0.007] with a cut-off point of 7 showed greater validity for screening (sensitivity/specificity=0.462/0.837) than did other olfactory function tests. To distinguish the MCI and dementia from NC as well, odor identification (AUC=0.817, p=0.002) with a cut-off point of 7 showed the highest validity for screening (0.785/0.654). To distinguish MCI from AD, an odor detection threshold (AUC=0.722, p=0.001) with a cut-off point of 2 showed the highest validity for screening (0.785/0.654). CONCLUSION Olfactory function tests may be a useful screening tool for cognitive decline before clinical symptoms of dementia have completely developed. This tool can be used as a supplementary tool to enhance the sensitivity of traditional cognitive tests to screen for dementia.
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Affiliation(s)
- Hye Ri Kim
- Department of Psychiatry, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - Sun Mi Kim
- Department of Psychiatry, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - Wonshik Seong
- Department of Psychiatry, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - Hyun Jin Min
- Department of Otorhinolaryngology, Head and Neck Surgery, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - Kyung Soo Kim
- Department of Otorhinolaryngology, Head and Neck Surgery, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - Hyuk Ga
- Institute of Geriatric Medicine, Incheon Eun-Hye Hospital, Incheon, Republic of Korea
| | - Doug Hyun Han
- Department of Psychiatry, Chung-Ang University College of Medicine, Seoul, Republic of Korea
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Functional Alterations in the Olfactory Neuronal Circuit Occur before Hippocampal Plasticity Deficits in the P301S Mouse Model of Tauopathy: Implications for Early Diagnosis and Translational Research in Alzheimer's Disease. Int J Mol Sci 2020; 21:ijms21155431. [PMID: 32751531 PMCID: PMC7432464 DOI: 10.3390/ijms21155431] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/18/2020] [Accepted: 07/24/2020] [Indexed: 02/06/2023] Open
Abstract
Alzheimer's disease (AD) is characterized by neuronal loss and impaired synaptic transmission, ultimately leading to cognitive deficits. Early in the disease, the olfactory track seems most sensitive to tauopathy, while most plasticity studies focused on the hippocampal circuits. Functional network connectivity (FC) and long-term potentiation (LTP), considered as the plasticity substrate of learning and memory, were longitudinally assessed in mice of the P301S model of tauopathy following the course (time and location) of progressively neurodegenerative pathology (i.e., at 3, 6, and 9 months of age) and in their wild type (WT) littermates. Using in vivo local field potential (LFP) recordings, early (at three months) dampening in the gamma oscillatory activity and impairments in the phase-amplitude theta-gamma coupling (PAC) were found in the olfactory bulb (OB) circuit of P301S mice, which were maintained through the whole course of pathology development. In contrast, LFP oscillatory activity and PAC indices were normal in the entorhinal cortex, hippocampal CA1 and CA3 nuclei. Field excitatory postsynaptic potential (fEPSP) recordings from the Shaffer collateral (SC)-CA1 hippocampal stratum pyramidal revealed a significant altered synaptic LTP response to high-frequency stimulation (HFS): at three months of age, no significant difference between genotypes was found in basal synaptic activity, while signs of a deficit in short term plasticity were revealed by alterations in the fEPSPs. At six months of age, a slight deviance was found in basal synaptic activity and significant differences were observed in the LTP response. The alterations in network oscillations at the OB level and impairments in the functioning of the SC-CA1 pyramidal synapses strongly suggest that the progression of tau pathology elicited a brain area, activity-dependent disturbance in functional synaptic transmission. These findings point to early major alterations of neuronal activity in the OB circuit prior to the disturbance of hippocampal synaptic plasticity, possibly involving tauopathy in the anomalous FC. Further research should determine whether those early deficits in the OB network oscillations and FC are possible mechanisms that potentially promote the emergence of hippocampal synaptic impairments during the progression of tauopathy.
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Baek MS, Cho H, Lee HS, Lee JH, Ryu YH, Lyoo CH. Effect of A/T/N imaging biomarkers on impaired odor identification in Alzheimer's disease. Sci Rep 2020; 10:11556. [PMID: 32665636 PMCID: PMC7360607 DOI: 10.1038/s41598-020-68504-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Accepted: 06/11/2020] [Indexed: 11/30/2022] Open
Abstract
Odor identification ability may serve as an important diagnostic biomarker in Alzheimer’s disease (AD). The aim of the study is to investigate the contribution of A/T/N neuroimaging biomarkers to impaired odor identification ability in the Alzheimer’s disease spectrum. In 127 participants, we compared A/T/N neuroimaging biomarkers between normosmia and hyposmia groups, and performed correlation analysis between the biomarkers and Cross-Cultural Smell Identification Test (CCSIT) scores. Additionally, path analysis for odor identification ability was performed using cognitive function as a mediator. In between-group comparison, individuals with hyposmia showed higher frequency of amyloid-β (Aβ) positivity, and lower neuropsychological test performance than those with normosmia. After correction for covariates including total cognition scores, there was no difference in the Aβ or tau burden between the normosmia and hyposmia groups, and no correlation between CCSIT scores and Aβ or tau burden. Meanwhile, cortical volumes in the lateral and medial temporal cortices were smaller in the hyposmia group and decreased with the worsening of CCSIT scores. Path analysis showed that only neurodegeneration had a direct effect on odor identification, while Aβ and tau burden contributed to odor identification with the mediation of cognition. In the Alzheimer’s disease spectrum, impaired odor identification ability may be attributable to neurodegeneration rather than the direct effect of Aβ or tau burden.
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Affiliation(s)
- Min Seok Baek
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Hanna Cho
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Hye Sun Lee
- Biostatistics Collaboration Unit, Yonsei University College of Medicine, Seoul, South Korea
| | - Jae Hoon Lee
- Department of Nuclear Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Young Hoon Ryu
- Department of Nuclear Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Chul Hyoung Lyoo
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
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45
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Woods NI, Stefanini F, Apodaca-Montano DL, Tan IMC, Biane JS, Kheirbek MA. The Dentate Gyrus Classifies Cortical Representations of Learned Stimuli. Neuron 2020; 107:173-184.e6. [PMID: 32359400 DOI: 10.1016/j.neuron.2020.04.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 03/16/2020] [Accepted: 03/31/2020] [Indexed: 10/24/2022]
Abstract
Animals must discern important stimuli and place them onto their cognitive map of their environment. The neocortex conveys general representations of sensory events to the hippocampus, and the hippocampus is thought to classify and sharpen the distinctions between these events. We recorded populations of dentate gyrus granule cells (DG GCs) and lateral entorhinal cortex (LEC) neurons across days to understand how sensory representations are modified by experience. We found representations of odors in DG GCs that required synaptic input from the LEC. Odor classification accuracy in DG GCs correlated with future behavioral discrimination. In associative learning, DG GCs, more so than LEC neurons, changed their responses to odor stimuli, increasing the distance in neural representations between stimuli, responding more to the conditioned and less to the unconditioned odorant. Thus, with learning, DG GCs amplify the decodability of cortical representations of important stimuli, which may facilitate information storage to guide behavior.
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Affiliation(s)
- Nicholas I Woods
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA; Medical Scientist Training Program, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Fabio Stefanini
- Center for Theoretical Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | | | - Isabelle M C Tan
- Department of Psychiatry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Jeremy S Biane
- Department of Psychiatry, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Mazen A Kheirbek
- Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Psychiatry, University of California, San Francisco, San Francisco, CA 94158, USA; Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94158, USA; Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA.
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46
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Windon MJ, Kim SJ, Oh ES, Lin SY. Predictive value of olfactory impairment for cognitive decline among cognitively normal adults. Laryngoscope 2020; 130:840-847. [DOI: 10.1002/lary.28166] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 05/20/2019] [Accepted: 06/13/2019] [Indexed: 12/22/2022]
Affiliation(s)
- Melina J. Windon
- Department of Otolaryngology–Head and Neck SurgeryJohns Hopkins University School of Medicine Baltimore Maryland U.S.A
| | - Sun Joo Kim
- Department of Otolaryngology–Head and Neck SurgeryJohns Hopkins University School of Medicine Baltimore Maryland U.S.A
| | - Esther S. Oh
- Division of Geriatric Medicine and Gerontology, Psychiatry and Behavioral Sciences and NeuropathologyJohns Hopkins University School of Medicine Baltimore Maryland U.S.A
| | - Sandra Y. Lin
- Department of Otolaryngology–Head and Neck SurgeryJohns Hopkins University School of Medicine Baltimore Maryland U.S.A
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47
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Van Regemorter V, Hummel T, Rosenzweig F, Mouraux A, Rombaux P, Huart C. Mechanisms Linking Olfactory Impairment and Risk of Mortality. Front Neurosci 2020; 14:140. [PMID: 32153360 PMCID: PMC7046549 DOI: 10.3389/fnins.2020.00140] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/04/2020] [Indexed: 12/16/2022] Open
Abstract
Olfaction is a sense involved in a complex set of tasks, influencing eating behavior, increasing awareness of environmental hazards and affecting social communication. Surprisingly, smell disorders are very frequent, especially in the elderly population. Several recent studies conducted mostly in older subjects have demonstrated a strong association between olfactory impairment and overall mortality risk, with anosmia being even more predictive of 5 years mortality risk than cardiovascular disease. Presently, the underlying pathophysiology linking olfactory impairment to mortality remains unknown and only putative mechanisms are suggested. This review aims to examine the link between olfactory impairment and mortality and to discuss existing ideas on underlying existing mechanisms including, (1) the effect of olfactory loss on nutrition, life-threatening situations and social interactions, (2) associated neurodegenerative diseases, (3) accelerated brain aging, and (4) reflection of general health status being reflected in olfactory function.
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Affiliation(s)
- Victoria Van Regemorter
- Department of Anesthesiology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Thomas Hummel
- Smell and Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany
| | - Flora Rosenzweig
- Department of Otorhinolaryngology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - André Mouraux
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Philippe Rombaux
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
- Department of Otorhinolaryngology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Caroline Huart
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
- Department of Otorhinolaryngology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
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48
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Zuo LJ, Guo P, Liu L, Yu SY, Lian TH, Yu QJ, Hu Y, Jin Z, Wang RD, Piao YS, Li LX, Wang YJ, Wang XM, Zhang W. Analyses of Clinical Features and Investigations on Potential Mechanisms in Patients with Alzheimer's Disease and Olfactory Dysfunction. J Alzheimers Dis 2019; 66:789-799. [PMID: 30347619 DOI: 10.3233/jad-180425] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND OD is common in patients with Alzheimer's disease (AD). However, the relationship between OD and clinical symptoms and the potential mechanisms of OD in AD patients are still unknown. OBJECTIVE To explore the relationship between OD and clinical symptoms and the potential mechanisms of OD in AD patients. METHODS We evaluated OD using the Hyposmia Rating Scale (HRS), classified patients into AD with OD (AD-OD) and AD with no OD (AD-NOD) groups, and detected the levels of free radicals and inflammatory factors, including hydroxyl radical (•OH), hydrogen peroxide (H2O2), nitric oxide, interleukin-1β, interleukin-6, tumor necrosis factor-α, and prostaglandin E2 in serum from AD patients. RESULTS It was shown that the scores of the Mini-Mental State Examination, Animal Fluency Test, Boston Naming Test (BNT), and Auditory Verbal Learning Test-delayed recall were all significantly lower and the score of overall activity of daily living (ADL) and instrumental ADL were significantly higher in AD-OD group than those in AD-NOD group. Compared with AD-NOD group, •OH level in serum was prominently elevated, and H2O2 level was dramatically declined in AD-OD group. In the correlation analysis, HRS score was significantly and positively correlated with the score of BNT, and negatively correlated with •OH level in serum. CONCLUSIONS AD-OD patients suffered from severe cognitive impairment in the domain of language. Oxidative stress might be correlated with AD-OD featured by the drastically increased •OH level in serum.
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Affiliation(s)
- Li-Jun Zuo
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Peng Guo
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Li Liu
- Department of Internal Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Shu-Yang Yu
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Teng-Hong Lian
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Qiu-Jin Yu
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yang Hu
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Zhao Jin
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Rui-Dan Wang
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Ying-Shan Piao
- Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Li-Xia Li
- Department of Internal Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Ya-Jie Wang
- Core Laboratory for Clinical Medical Research, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xiao-Min Wang
- Department of Physiology, Capital Medical University, Beijing, China
| | - Wei Zhang
- Center for Cognitive Neurology, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,China National Clinical Research Center for Neurological Diseases, Beijing, China.,Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, Capital Medical University, Beijing, China.,Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Beijing, China.,Beijing Key Laboratory on Parkinson's Disease, Beijing, China
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49
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Tebrügge S, Winkler A, Gerards D, Weimar C, Moebus S, Jöckel KH, Erbel R, Jokisch M. Olfactory Function is Associated with Cognitive Performance: Results of the Heinz Nixdorf Recall Study. J Alzheimers Dis 2019; 63:319-329. [PMID: 29578482 DOI: 10.3233/jad-170863] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND There is strong evidence for an association of olfactory dysfunction and neurodegenerative diseases. Studies on the association of olfaction and cognition in the general population are rare. OBJECTIVE To evaluate gender- and age-specific associations of olfactory function and cognitive performance in a well characterized population-based study sample. METHODS At the third examination of the Heinz Nixdorf Recall study (n = 3,087), 2,640 participants (48% men; 68.2±7.2 years) underwent Sniffin' Sticks Screening Test measuring olfactory function on a scale of 0-12 points. Olfactory function was rated as anosmic, hyposmic, or normosmic (≤6, 7-10 or ≥11 points, respectively). All participants performed eight validated cognitive subtests. Age- (55-64 years, 65-74 years, 75-86 years) and gender-stratified multivariate analysis of covariance was used to evaluate group differences in cognitive performance. RESULTS Women showed better olfactory function than men (p < 0.001). For middle-aged participants, olfactory groups differed in almost all cognitive subtests. The analyses revealed no gender effects, although associations were slightly greater for women than for men. Anosmics showed the worst cognitive performance and normosmics showed the best cognitive performance. In the young- and old-aged groups, a quantitative association was found for anosmics in all subtests and for normosmics and hyposmics in almost all subtests. CONCLUSION This is the first study reporting on age-specific associations of olfactory function and cognitive performance in the general population. The association found in middle-aged participants (65-74 years) may serve as a marker to improve identification of persons at high risk for cognitive decline and dementia.
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Affiliation(s)
- Sarah Tebrügge
- Department of Neurology, University Hospital of Essen, University of Duisburg-Essen, Germany
| | - Angela Winkler
- Department of Neurology, University Hospital of Essen, University of Duisburg-Essen, Germany
| | - Diana Gerards
- Department of Neurology, University Hospital of Essen, University of Duisburg-Essen, Germany
| | - Christian Weimar
- Department of Neurology, University Hospital of Essen, University of Duisburg-Essen, Germany
| | - Susanne Moebus
- Institute for Medical Informatics, Biometry and Epidemiology, University Hospital of Essen, University Duisburg-Essen, Germany
| | - Karl-Heinz Jöckel
- Institute for Medical Informatics, Biometry and Epidemiology, University Hospital of Essen, University Duisburg-Essen, Germany
| | - Raimund Erbel
- Institute for Medical Informatics, Biometry and Epidemiology, University Hospital of Essen, University Duisburg-Essen, Germany
| | - Martha Jokisch
- Department of Neurology, University Hospital of Essen, University of Duisburg-Essen, Germany
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50
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Ghosh A, Torraville SE, Mukherjee B, Walling SG, Martin GM, Harley CW, Yuan Q. An experimental model of Braak's pretangle proposal for the origin of Alzheimer's disease: the role of locus coeruleus in early symptom development. ALZHEIMERS RESEARCH & THERAPY 2019; 11:59. [PMID: 31266535 PMCID: PMC6607586 DOI: 10.1186/s13195-019-0511-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 06/06/2019] [Indexed: 12/22/2022]
Abstract
Background The earliest brain pathology related to Alzheimer’s disease (AD) is hyperphosphorylated soluble tau in the noradrenergic locus coeruleus (LC) neurons. Braak characterizes five pretangle tau stages preceding AD tangles. Pretangles begin in young humans and persist in the LC while spreading from there to other neuromodulatory neurons and, later, to the cortex. While LC pretangles appear in all by age 40, they do not necessarily result in AD prior to death. However, with age and pretangle spread, more individuals progress to AD stages. LC neurons are lost late, at Braak stages III–IV, when memory deficits appear. It is not clear if LC hyperphosphorylated tau generates the pathology and cognitive changes associated with preclinical AD. We use a rat model expressing pseudohyperphosphorylated human tau in LC to investigate the hypothesis that LC pretangles generate preclinical Alzheimer pathology. Methods We infused an adeno-associated viral vector carrying a human tau gene pseudophosphorylated at 14 sites common in LC pretangles into 2–3- or 14–16-month TH-Cre rats. We used odor discrimination to probe LC dysfunction, and we evaluated LC cell and fiber loss. Results Abnormal human tau was expressed in LC and exhibited somatodendritic mislocalization. In rats infused at 2–3 months old, 4 months post-infusion abnormal LC tau had transferred to the serotonergic raphe neurons. After 7 months, difficult similar odor discrimination learning was impaired. Impairment was associated with reduced LC axonal density in the olfactory cortex and upregulated β1-adrenoceptors. LC infusions in 14–16-month-old rats resulted in more severe outcomes. By 5–6 months post-infusion, rats were impaired even in simple odor discrimination learning. LC neuron number was reduced. Human tau appeared in the microglia and cortical neurons. Conclusions Our animal model suggests, for the first time, that Braak’s hypothesis that human AD originates with pretangle stages is plausible. LC pretangle progression here generates both preclinical AD pathological changes and cognitive decline. The odor discrimination deficits are similar to human odor identification deficits seen with aging and preclinical AD. When initiated in aged rats, pretangle stages progress rapidly and cause LC cell loss. These age-related outcomes are associated with a severe learning impairment consistent with memory decline in Braak stages III–IV. Electronic supplementary material The online version of this article (10.1186/s13195-019-0511-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Abhinaba Ghosh
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, A1B 3V6, Canada
| | - Sarah E Torraville
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, A1B 3V6, Canada.,Department of Psychology, Faculty of Science, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada
| | - Bandhan Mukherjee
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, A1B 3V6, Canada
| | - Susan G Walling
- Department of Psychology, Faculty of Science, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada
| | - Gerard M Martin
- Department of Psychology, Faculty of Science, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada
| | - Carolyn W Harley
- Department of Psychology, Faculty of Science, Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada.
| | - Qi Yuan
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, A1B 3V6, Canada.
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