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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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2
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Chao LL. Olfactory and cognitive decrements in 1991 Gulf War veterans with gulf war illness/chronic multisymptom illness. Environ Health 2024; 23:14. [PMID: 38291474 PMCID: PMC10825982 DOI: 10.1186/s12940-024-01058-2] [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: 12/09/2023] [Accepted: 01/26/2024] [Indexed: 02/01/2024]
Abstract
BACKGROUND Gulf War illness (GWI)/Chronic Multisymptom Illness (CMI) is a disorder related to military service in the 1991 Gulf War (GW). Prominent symptoms of GWI/CMI include fatigue, pain, and cognitive dysfunction. Although anosmia is not a typical GWI/CMI symptom, anecdotally some GW veterans have reported losing their sense smell shortly after the war. Because olfactory deficit is a prodromal symptom of neurodegenerative diseases like Parkinson's and Alzheimer's disease, and because we previously reported suggestive evidence that deployed GW veterans may be at increased risk for Mild Cognitive Impairment (MCI) and dementia, the current study examined the relationship between olfactory and cognitive function in deployed GW veterans. METHODS Eighty deployed GW veterans (mean age: 59.9 ±7.0; 4 female) were tested remotely with the University of Pennsylvania Smell Identification Test (UPSIT) and the Montreal Cognitive Assessment (MoCA). Veterans also completed self-report questionnaires about their health and deployment-related exposures and experiences. UPSIT and MoCA data from healthy control (HC) participants from the Parkinson's Progression Markers Initiative (PPMI) study were downloaded for comparison. RESULTS GW veterans had a mean UPSIT score of 27.8 ± 6.3 (range 9-37) and a mean MoCA score of 25.3 ± 2.8 (range 19-30). According to age- and sex-specific normative data, 31% of GW veterans (vs. 8% PPMI HCs) had UPSIT scores below the 10th percentile. Nearly half (45%) of GW veterans (vs. 8% PPMI HCs) had MoCA scores below the cut-off for identifying MCI. Among GW veterans, but not PPMI HCs, there was a positive correlation between UPSIT and MoCA scores (Spearman's ρ = 0.39, p < 0.001). There were no significant differences in UPSIT or MoCA scores between GW veterans with and without history of COVID or between those with and without Kansas GWI exclusionary conditions. CONCLUSIONS We found evidence of olfactory and cognitive deficits and a significant correlation between UPSIT and MoCA scores in a cohort of 80 deployed GW veterans, 99% of whom had CMI. Because impaired olfactory function has been associated with increased risk for MCI and dementia, it may be prudent to screen aging, deployed GW veterans with smell identification tests so that hypo- and anosmic veterans can be followed longitudinally and offered targeted neuroprotective therapies as they become available.
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Affiliation(s)
- Linda L Chao
- Departments of Radiology & Biomedical Imaging and Psychiatry & Behavioral Science, University of Calfiornia, 505 Parnassus Avenue, San Francisco, CA, 94143, USA.
- San Francisco Veterans Affairs Health Care System, 4150 Clement Street, San Francisco, CA, 94121, USA.
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3
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Liu S, Jiang Z, Zhao J, Li Z, Li R, Qiu Y, Peng H. Disparity of smell tests in Alzheimer's disease and other neurodegenerative disorders: a systematic review and meta-analysis. Front Aging Neurosci 2023; 15:1249512. [PMID: 37744388 PMCID: PMC10512741 DOI: 10.3389/fnagi.2023.1249512] [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: 06/28/2023] [Accepted: 08/21/2023] [Indexed: 09/26/2023] Open
Abstract
Background There are discrepancies of olfactory impairment between Alzheimer's disease (AD) and other neurodegenerative disorders. Olfactory deficits may be a potential marker for early and differential diagnosis of AD. We aimed to assess olfactory functions in patients with AD and other neurodegenerative disorders, to further evaluate the smell tests using subgroup analysis, and to explore moderating factors affecting olfactory performance. Methods Cross-sectional studies relating to olfactory assessment for both AD and other neurodegenerative disorders published before 27 July 2022 in English, were searched on PubMed, Embase and Cochrane. After literature screening and quality assessment, meta-analyses were conducted using stata14.0 software. Results Forty-two articles involving 12 smell tests that evaluated 2,569 AD patients were included. It was revealed that smell tests could distinguish AD from mild cognitive impairment (MCI), Lewy body disease (LBD), depression, and vascular dementia (VaD), but not from diseases such as frontotemporal dementia (FTD). Our finding indicated that in discriminating AD from MCI, the University of Pennsylvania Smell Identification Test (UPSIT) was most frequently used (95%CI: -1.12 to -0.89), while the Brief Smell Identification Test (B-SIT), was the most widely used method in AD vs. LBD group. Further subgroup analyses indicated that the methods of smell test used contributed to the heterogeneity in olfactory threshold and discrimination scores in group AD vs. MCI. While the moderating variables including age, MMSE scores, education years in AD vs. LBD, were account for heterogeneity across studies. Conclusion Our finding suggests smell tests have potential value in early differential diagnosis of AD. UPSIT and its simplified variant, B-SIT, are widely used methods in the analyses. Systematic Review Registration https://www.crd.york.ac.uk/PROSPERO/display_record.php? RecordID = 357970 (PROSPERO, registration number CRD42022357970).
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Affiliation(s)
- Silin Liu
- Department of Otolaryngology Head and Neck Surgery, General Hospital of Southern Theater Command, Guangzhou, China
- The First School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Zhihui Jiang
- Department of Pharmacy, General Hospital of Southern Theater Command, Guangzhou, China
- School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Jing Zhao
- Department of Otolaryngology Head and Neck Surgery, General Hospital of Southern Theater Command, Guangzhou, China
- Graduate School, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Zhensheng Li
- Department of Neurology, General Hospital of Southern Theater Command, Guangzhou, China
| | - Ruixin Li
- The First School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Yunyi Qiu
- The First School of Clinical Medicine, Southern Medical University, Guangzhou, China
| | - Hua Peng
- Department of Otolaryngology Head and Neck Surgery, General Hospital of Southern Theater Command, Guangzhou, China
- The First School of Clinical Medicine, Southern Medical University, Guangzhou, China
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4
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Carnemolla S, Kumfor F, Liang CT, Foxe D, Ahmed R, Piguet O. Olfactory Bulb Integrity in Frontotemporal Dementia and Alzheimer’s Disease. J Alzheimers Dis 2022; 89:51-66. [DOI: 10.3233/jad-220080] [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: Olfactory dysfunction is highly prevalent in dementia syndromes, including Alzheimer’s disease (AD) and frontotemporal dementia (FTD). The structural integrity of the olfactory bulb (OB) is thought to play a critical role in odor detection and identification, but no MRI study has measured OB volume in FTD, or measured OB volume longitudinally in AD. Objective: To measure OB volume in FTD and AD patients longitudinally using MRI. Methods: This study measured OB volumes using MRI in patients diagnosed with behavioral-variant FTD (n = 55), semantic dementia (n = 34), progressive non-fluent aphasia (n = 30), AD (n = 50), and healthy age-matched controls (n = 55) at their first visit to a dementia research clinic (‘baseline’). Imaging data in patients 12-months later were analyzed where available (n = 84) for longitudinal assessment. Volumes of subcortical and cortical olfactory regions (‘olfactory network’) were obtained via surface-based morphometry. Results: Results revealed that in AD and FTD at baseline, OB volumes were similar to controls, whereas volumes of olfactory network regions were significantly reduced in all patient groups except in progressive non-fluent aphasia. Longitudinal data revealed that OB volume became significantly reduced (10–25% volume reduction) in all dementia groups with disease progression. Conclusion: Olfactory dysfunction is common in patients diagnosed with AD or FTD, but our results indicate that there is no detectable volume loss to the OBs upon first presentation to the clinic. Our findings indicate that the OBs become detectably atrophied later in the disease process. OB atrophy indicates the potential usefulness for OBs to be targeted in interventions to improve olfactory function.
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Affiliation(s)
- Sarah Carnemolla
- University of Sydney, School of Psychology, Sydney, New South Wales, Australia
- University of Sydney, Brain & Mind Centre, Sydney, New South Wales, Australia
| | - Fiona Kumfor
- University of Sydney, School of Psychology, Sydney, New South Wales, Australia
- University of Sydney, Brain & Mind Centre, Sydney, New South Wales, Australia
| | - Cheng Tao Liang
- University of Sydney, School of Psychology, Sydney, New South Wales, Australia
- University of Sydney, Brain & Mind Centre, Sydney, New South Wales, Australia
| | - David Foxe
- University of Sydney, School of Psychology, Sydney, New South Wales, Australia
- University of Sydney, Brain & Mind Centre, Sydney, New South Wales, Australia
| | - Rebekah Ahmed
- University of Sydney, Brain & Mind Centre, Sydney, New South Wales, Australia
- Memory and Cognition Clinic, Department of Clinical Neurosciences, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
- University of Sydney, Central Sydney Medical School, Sydney, New South Wales, Australia
| | - Olivier Piguet
- University of Sydney, School of Psychology, Sydney, New South Wales, Australia
- University of Sydney, Brain & Mind Centre, Sydney, New South Wales, Australia
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5
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"On the nose" - could olfactory testing be a reliable bedside marker of prodromal DLB? Int Psychogeriatr 2022; 34:523-527. [PMID: 35510296 DOI: 10.1017/s104161022200045x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Novotny D, Stögmann E, Lehrner J. Long-term Olfactory Functions in Patients with Subjective Cognitive Decline and Mild Cognitive Impairment. CHEMOSENS PERCEPT 2022. [DOI: 10.1007/s12078-022-09298-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Abstract
Introduction
Olfactory function is known to be impaired in patients with Alzheimer’s disease (AD) as well as in subjective cognitive decline (SCD) and mild cognitive impairment (MCI), which are generally considered at-risk states for developing AD. The aim of the study at hand was to identify predictors of self-reported olfaction capability (SOC), self-reported capability of perceiving specific odors (SRP), olfaction-related quality of life (ORQ), and odor identification (OIT) in patients with SCD, naMCI, and aMCI.
Methods
The sample consisted of 33 patients with SCD, 88 with naMCI, and 43 with aMCI who consulted the Department of Neurology, Medical University of Vienna, due to memory complaints between January 2001 and May 2018. Olfactory function was assessed objectively by means of the Sniffin’ Sticks odor identification test (OIT) and subjectively by means of the ASOF-scores SOC, SRP, and ORQ at two to three points in time, with an average time interval of 39 months between the first and second examination, and 24 months between the second and third examination. Linear mixed models were used in order to identify clinical and demographic variables as predictors of mean SOC, SRP, ORQ, and OIT throughout the observation period.
Results
There was a statistically significant — albeit small — time-related decline of SOC and ORQ in the SCD group but not in other groups. Throughout the observation period, estimated ORQ was significantly higher in the SCD group than in the naMCI and estimated OIT was significantly higher in the naMCI group than in the aMCI group after adjusting for time of measurement and other covariates. Positive relationships between OIT and all three ASOF-scores, negative relationships between BDI-II and SOC and ORQ, and a positive relationship between WST-IQ and SRP were identified.
Conclusion
There is a statistically significant, albeit small, time-related decline of uncertain clinical relevance in subjective measures of olfactory capability and olfaction-related quality of life in patients with SCD.
Implications
In all subgroups, objectively measured odor-identification scores have a significant impact on subjective scores over time. The study at hand confirms previous observations regarding the negative influence of depression on subjective perception of olfactory capabilities known from cross-sectional studies.
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7
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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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Ziegler-Waldkirch S, Friesen M, Loreth D, Sauer JF, Kemna S, Hilse A, Erny D, Helm C, d´Errico P, Prinz M, Bartos M, Meyer-Luehmann M. Seed-induced Aβ deposition alters neuronal function and impairs olfaction in a mouse model of Alzheimer's disease. Mol Psychiatry 2022; 27:4274-4284. [PMID: 35869271 PMCID: PMC9718674 DOI: 10.1038/s41380-022-01686-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/22/2022] [Accepted: 06/27/2022] [Indexed: 02/07/2023]
Abstract
Alzheimer's disease (AD) is characterized by the accumulation of amyloid-β (Aβ) which ultimately forms plaques. These Aβ deposits can be induced in APP transgenic mouse models by prion-like seeding. It has been widely accepted that anosmia and hyposmia occur during the early stages of AD, even before cognitive deficits are present. In order to determine the impact of seed-induced Aβ deposits on olfaction, we performed intracerebral injections of seed-competent brain homogenate into the olfactory bulb of young pre-depositing APP transgenic mice. Remarkably, we observed a dramatic olfactory impairment in those mice. Furthermore, the number of newborn neurons as well as the activity of cells in the mitral cell layer was decreased. Notably, exposure to an enriched environment reduced Aβ seeding, vivified neurogenesis and most importantly reversed olfactory deficits. Based on our findings, we conclude that altered neuronal function as a result of induced Aβ pathology might contribute to olfactory dysfunction in AD.
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Affiliation(s)
- Stephanie Ziegler-Waldkirch
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Marina Friesen
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Faculty of Biology, University of Freiburg, 79110 Freiburg, Germany
| | - Desirée Loreth
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.13648.380000 0001 2180 3484Institute of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Jonas-Frederic Sauer
- grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, 79104 Freiburg, Germany
| | - Solveig Kemna
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Alexandra Hilse
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Faculty of Biology, University of Freiburg, 79110 Freiburg, Germany
| | - Daniel Erny
- grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Institute of Neuropathology, University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Berta-Ottenstein-Programme, Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Christina Helm
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Paolo d´Errico
- grid.7708.80000 0000 9428 7911Department of Neurology, Medical Center – University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany
| | - Marco Prinz
- grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Institute of Neuropathology, University of Freiburg, 79106 Freiburg, Germany ,grid.5963.9Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Signalling Research Centres BIOSS and CIBSS, University of Freiburg, 79104 Freiburg, Germany
| | - Marlene Bartos
- grid.5963.9Faculty of Medicine, University of Freiburg, 79110 Freiburg, Germany ,grid.5963.9Institute for Physiology I, Systemic and Cellular Neurophysiology, University of Freiburg, 79104 Freiburg, Germany ,grid.5963.9Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine University of Freiburg, 79110 Freiburg, Germany
| | - Melanie Meyer-Luehmann
- Department of Neurology, Medical Center - University of Freiburg, 79106, Freiburg, Germany. .,Faculty of Medicine, University of Freiburg, 79110, Freiburg, Germany. .,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine University of Freiburg, 79110, Freiburg, Germany.
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9
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Touliou K, Maglaveras N, Bekiaris E. Olfactory Decline in Older Adults with Mild Cognitive Impairment with and without Comorbidities. Diagnostics (Basel) 2021; 11:diagnostics11122228. [PMID: 34943465 PMCID: PMC8700609 DOI: 10.3390/diagnostics11122228] [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: 10/03/2021] [Revised: 11/08/2021] [Accepted: 11/24/2021] [Indexed: 12/03/2022] Open
Abstract
Over the past two decades, several studies have measured olfactory performance in Mild Cognitive Impairment (MCI). Deficits are observed in multiple olfactory domains, including odour detection threshold, identification, discrimination, and memory. In this study, the psychophysiological Sniffin’ Sticks smell screening test was administered to examine olfactory functioning in 145 older adults with MCI, a group with MCI and chronic comorbid conditions, and a healthy age-matched comparison group. We hypothesised that olfactory performance will deteriorate in the two MCI groups compared to the control group, even after assessing the known contributions of age and gender. The higher olfactory deterioration in the group with the MCI and the comorbidities in the first year disappeared in the second. This could mean that early consideration of the potential effect of other comorbidities that might affect olfaction should be taken and addressed, as they could easily mask the effect of cognitive decline and/or contribute to it. This study also found higher deterioration in smell identification in participants with MCI, as has been found repeatedly in similar research. Olfactory identification seems to be a more robust marker for discriminating people with MCI and without, and even discriminating between those with MCI and having other health problems.
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Affiliation(s)
- Katerina Touliou
- Center for Research and Technology Hellas, Hellenic Institute of Transportation, 57001 Thessaloniki, Greece; (K.T.); (E.B.)
| | - Nicos Maglaveras
- Laboratory of Computing, Medical Informatics and Biomedical Imaging Technologies, Medical School, Aristotle University of Thessaloniki, 57001 Thessaloniki, Greece
- Correspondence:
| | - Evangelos Bekiaris
- Center for Research and Technology Hellas, Hellenic Institute of Transportation, 57001 Thessaloniki, Greece; (K.T.); (E.B.)
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10
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Grieco F, Bernstein BJ, Biemans B, Bikovski L, Burnett CJ, Cushman JD, van Dam EA, Fry SA, Richmond-Hacham B, Homberg JR, Kas MJH, Kessels HW, Koopmans B, Krashes MJ, Krishnan V, Logan S, Loos M, McCann KE, Parduzi Q, Pick CG, Prevot TD, Riedel G, Robinson L, Sadighi M, Smit AB, Sonntag W, Roelofs RF, Tegelenbosch RAJ, Noldus LPJJ. Measuring Behavior in the Home Cage: Study Design, Applications, Challenges, and Perspectives. Front Behav Neurosci 2021; 15:735387. [PMID: 34630052 PMCID: PMC8498589 DOI: 10.3389/fnbeh.2021.735387] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 08/27/2021] [Indexed: 12/14/2022] Open
Abstract
The reproducibility crisis (or replication crisis) in biomedical research is a particularly existential and under-addressed issue in the field of behavioral neuroscience, where, in spite of efforts to standardize testing and assay protocols, several known and unknown sources of confounding environmental factors add to variance. Human interference is a major contributor to variability both within and across laboratories, as well as novelty-induced anxiety. Attempts to reduce human interference and to measure more "natural" behaviors in subjects has led to the development of automated home-cage monitoring systems. These systems enable prolonged and longitudinal recordings, and provide large continuous measures of spontaneous behavior that can be analyzed across multiple time scales. In this review, a diverse team of neuroscientists and product developers share their experiences using such an automated monitoring system that combines Noldus PhenoTyper® home-cages and the video-based tracking software, EthoVision® XT, to extract digital biomarkers of motor, emotional, social and cognitive behavior. After presenting our working definition of a "home-cage", we compare home-cage testing with more conventional out-of-cage tests (e.g., the open field) and outline the various advantages of the former, including opportunities for within-subject analyses and assessments of circadian and ultradian activity. Next, we address technical issues pertaining to the acquisition of behavioral data, such as the fine-tuning of the tracking software and the potential for integration with biotelemetry and optogenetics. Finally, we provide guidance on which behavioral measures to emphasize, how to filter, segment, and analyze behavior, and how to use analysis scripts. We summarize how the PhenoTyper has applications to study neuropharmacology as well as animal models of neurodegenerative and neuropsychiatric illness. Looking forward, we examine current challenges and the impact of new developments. Examples include the automated recognition of specific behaviors, unambiguous tracking of individuals in a social context, the development of more animal-centered measures of behavior and ways of dealing with large datasets. Together, we advocate that by embracing standardized home-cage monitoring platforms like the PhenoTyper, we are poised to directly assess issues pertaining to reproducibility, and more importantly, measure features of rodent behavior under more ethologically relevant scenarios.
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Affiliation(s)
| | - Briana J Bernstein
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, United States
| | | | - Lior Bikovski
- Myers Neuro-Behavioral Core Facility, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- School of Behavioral Sciences, Netanya Academic College, Netanya, Israel
| | - C Joseph Burnett
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Jesse D Cushman
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, United States
| | | | - Sydney A Fry
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, United States
| | - Bar Richmond-Hacham
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Judith R Homberg
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands
| | - Martien J H Kas
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
| | - Helmut W Kessels
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | | | - Michael J Krashes
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Vaishnav Krishnan
- Laboratory of Epilepsy and Emotional Behavior, Baylor Comprehensive Epilepsy Center, Departments of Neurology, Neuroscience, and Psychiatry & Behavioral Sciences, Baylor College of Medicine, Houston, TX, United States
| | - Sreemathi Logan
- Department of Rehabilitation Sciences, College of Allied Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Maarten Loos
- Sylics (Synaptologics BV), Amsterdam, Netherlands
| | - Katharine E McCann
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, United States
| | | | - Chaim G Pick
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- The Dr. Miriam and Sheldon G. Adelson Chair and Center for the Biology of Addictive Diseases, Tel Aviv University, Tel Aviv, Israel
| | - Thomas D Prevot
- Centre for Addiction and Mental Health and Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Gernot Riedel
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Lianne Robinson
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Mina Sadighi
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, VU University Amsterdam, Amsterdam, Netherlands
| | - William Sonntag
- Department of Biochemistry & Molecular Biology, Center for Geroscience, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | | | | | - Lucas P J J Noldus
- Noldus Information Technology BV, Wageningen, Netherlands
- Department of Biophysics, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
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11
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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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12
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Pálsdóttir AM, Spendrup S, Mårtensson L, Wendin K. Garden Smellscape-Experiences of Plant Scents in a Nature-Based Intervention. Front Psychol 2021; 12:667957. [PMID: 34290648 PMCID: PMC8288369 DOI: 10.3389/fpsyg.2021.667957] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/19/2021] [Indexed: 12/29/2022] Open
Abstract
This study explores how participants suffering from stress-related mental disorders describe their perception, interaction, and lived experience of garden smellscape during their nature-based rehabilitation. Natural elements, and especially nature smells, have been found to have a profound effect on stress reduction, suggesting an interesting link between odor in nature and stress reduction. The study was conducted as a longitudinal case-study, running over a period of 5 years, investigating participants' perceptions of a garden smellscape, after completing a 12-weeks nature-based rehabilitation in Alnarp Rehabilitation Garden, Sweden. All participants were treated for stress-related mental disorders. Data were collected through retrospective semi-structured individual interviews and analyzed according to interpretative phenomenological analysis. The results revealed in what way nature odor (odor in nature) evoked associations, emotions, and physical reactions and provide examples of how nature scents function as a catalyst for sensory awareness and memories. Findings supported the understanding that experiencing the smell of plants, especially pelargonium, may facilitate stress reduction and support mental recovery in a real-life context. The results of the study can be used for several purposes; thus, they are relevant for actors within the development of nature-based therapy, as well as stakeholders within the horticultural industry.
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Affiliation(s)
- Anna María Pálsdóttir
- Department of People and Society, Swedish University of Agricultural Sciences, Lomma, Sweden
| | - Sara Spendrup
- Department of People and Society, Swedish University of Agricultural Sciences, Lomma, Sweden
| | - Lennart Mårtensson
- Faculty of Natural Sciences, Kristianstad University, Kristianstad, Sweden
| | - Karin Wendin
- Faculty of Natural Sciences, Kristianstad University, Kristianstad, Sweden.,Department of Food Science, University of Copenhagen, Frederiksberg, Denmark
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13
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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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14
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Parvand M, Rankin CH. Is There a Shared Etiology of Olfactory Impairments in Normal Aging and Neurodegenerative Disease? J Alzheimers Dis 2021; 73:1-21. [PMID: 31744002 DOI: 10.3233/jad-190636] [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: 12/19/2022]
Abstract
As we age, our olfactory function declines. In addition to occurring in normal aging, more rapid decrement of olfactory decline has been associated with several neurodegenerative diseases including Alzheimer's disease (AD) and Parkinson's disease (PD). It has been argued that since olfactory deficits occur less frequently or are absent in diseases such as progressive supranuclear palsy, corticobasal degeneration, and multiple system atrophy, olfactory deficits can be used for differential diagnoses of AD and PD. The purpose of this review is to provide a survey of current knowledge about the molecular bases and differential patterns of olfactory deficits present in normal aging, AD, and PD. As substantial research has been conducted in this area, the majority of the content of this review focuses on articles published in the past decade. We hypothesize that olfactory deficits in normal aging, AD, and PD may have different underlying causes, and propose the use of model organisms with small, tractable nervous systems and/or easy to manipulate genomes to further investigate the cellular mechanisms responsible for these deficits.
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Affiliation(s)
- Mahraz Parvand
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Catharine H Rankin
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.,Department of Psychology, University of British Columbia, Vancouver, BC, Canada
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15
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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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16
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Aging Alters Olfactory Bulb Network Oscillations and Connectivity: Relevance for Aging-Related Neurodegeneration Studies. Neural Plast 2020; 2020:1703969. [PMID: 32774353 PMCID: PMC7396091 DOI: 10.1155/2020/1703969] [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: 12/06/2019] [Revised: 01/27/2020] [Accepted: 02/12/2020] [Indexed: 11/18/2022] Open
Abstract
The aging process eventually cause a breakdown in critical synaptic plasticity and connectivity leading to deficits in memory function. The olfactory bulb (OB) and the hippocampus, both regions of the brain considered critical for the processing of odors and spatial memory, are commonly affected by aging. Using an aged wild-type C57B/6 mouse model, we sought to define the effects of aging on hippocampal plasticity and the integrity of cortical circuits. Specifically, we measured the long-term potentiation of high-frequency stimulation (HFS-LTP) at the Shaffer-Collateral CA1 pyramidal synapses. Next, local field potential (LFP) spectra, phase-amplitude theta-gamma coupling (PAC), and connectivity through coherence were assessed in the olfactory bulb, frontal and entorhinal cortices, CA1, and amygdala circuits. The OB of aged mice showed a significant increase in the number of histone H2AX-positive neurons, a marker of DNA damage. While the input-output relationship measure of basal synaptic activity was found not to differ between young and aged mice, a pronounced decline in the slope of field excitatory postsynaptic potential (fEPSP) and the population spike amplitude (PSA) were found in aged mice. Furthermore, aging was accompanied by deficits in gamma network oscillations, a shift to slow oscillations, reduced coherence and theta-gamma PAC in the OB circuit. Thus, while the basal synaptic activity was unaltered in older mice, impairment in hippocampal synaptic transmission was observed only in response to HFS. However, age-dependent alterations in neural network appeared spontaneously in the OB circuit, suggesting the neurophysiological basis of synaptic deficits underlying olfactory processing. Taken together, the results highlight the sensitivity and therefore potential use of LFP quantitative network oscillations and connectivity at the OB level as objective electrophysiological markers that will help reveal specific dysfunctional circuits in aging-related neurodegeneration studies.
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17
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Oleszkiewicz A, Kunkel F, Larsson M, Hummel T. Consequences of undetected olfactory loss for human chemosensory communication and well-being. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190265. [PMID: 32306872 DOI: 10.1098/rstb.2019.0265] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Olfactory perception has implications for human chemosensory communication and in a broader context, it affects well-being. However, most of the studies investigating the consequences of olfactory loss have recruited patients who have already been categorized as having a dysfunctional sense of smell and sought help in an ENT clinic. We revisit these findings by distinguishing subjects with olfactory impairment from a group of subjects who all declared a normal sense of smell when enrolling for this study. In the initial sample of 203 individuals, we found 59 to have impaired olfaction and four with marginal olfactory performance, not useful in daily life. Interestingly, we found a significant between-group difference in cognitive functioning, further supporting the notion of the relationship between cognition and olfactory performance. However, their chemosensory communication and well-being appeared not to be different from subjects with normosmia. Impaired olfactory function certainly has a severe impact on daily life but more so in individuals who are bothered with it and decide to seek treatment. The limited-to-no olfactory perception in the fraction of subjects who neither complain about it nor seek help in ENT clinics does not seem to have a major effect on their social, cognitive, emotional and health functioning. This article is part of the Theo Murphy meeting issue 'Olfactory communication in humans'.
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Affiliation(s)
- A Oleszkiewicz
- Smell and Taste Clinic, Technische Universität Dresden, 01307 Dresden, Germany.,Institute of Psychology, University of Wroclaw, 50527 Wroclaw, Poland
| | - F Kunkel
- Smell and Taste Clinic, Technische Universität Dresden, 01307 Dresden, Germany
| | - M Larsson
- Gösta Ekmans Laboratory, Stockholm University, 11419 Stockholm, Sweden
| | - T Hummel
- Smell and Taste Clinic, Technische Universität Dresden, 01307 Dresden, Germany
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18
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Wearable Sensors to Characterize the Autonomic Nervous System Correlates of Food-Like Odors Perception: A Pilot Study. ELECTRONICS 2019. [DOI: 10.3390/electronics8121481] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Background: The sense of smell has been recently recognized as one of the most important sensory features in the human being, representing a reliable biomarker for a number of clinical conditions. The relationship between olfactory function and the person’s attitude towards food has frequently been investigated, often using questionnaires. The administration of minimally invasive methods for characterizing autonomic nervous system (ANS) functionality could help in objectivizing such measurements. Methods: The present study assessed ANS activation through the analysis of the electrocardiogram (ECG) and galvanic skin response (GSR) signals, in response to olfactory stimuli using non-invasive wearable devices. The ANS activation was also studied with respect to the odor familiarity, as well as with other olfactory and food dimensions (e.g., odor identification, odor pleasantness, food neophobia). Results: We demonstrated a significant activation of the ANS, in particular of its sympathetic branch, during the olfactory stimulation, with the ECG signal seen as more sensitive to detect ANS response to moderate olfactory stimuli rather than the GSR. Conclusions: When applied to a greater number of subjects, or to specific groups of patients, this methodology could represent a promising, reliable addition to diagnostic methods currently used in clinical settings.
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19
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Bathini P, Brai E, Auber LA. Olfactory dysfunction in the pathophysiological continuum of dementia. Ageing Res Rev 2019; 55:100956. [PMID: 31479764 DOI: 10.1016/j.arr.2019.100956] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 07/29/2019] [Accepted: 08/26/2019] [Indexed: 12/21/2022]
Abstract
Sensory capacities like smell, taste, hearing, vision decline with aging, but increasing evidence show that sensory dysfunctions are one of the early signs diagnosing the conversion from physiological to pathological brain state. Smell loss represents the best characterized sense in clinical practice and is considered as one of the first preclinical signs of Alzheimer's and Parkinson's disease, occurring a decade or more before the onset of cognitive and motor symptoms. Despite the numerous scientific reports and the adoption in clinical practice, the etiology of sensory damage as prodromal of dementia remains largely unexplored and more studies are needed to resolve the mechanisms underlying sensory network dysfunction. Although both cognitive and sensory domains are progressively affected, loss of sensory experience in early stages plays a major role in reducing the autonomy of demented people in their daily tasks or even possibly contributing to their cognitive decline. Interestingly, the chemosensory circuitry is devoid of a blood brain barrier, representing a vulnerable port of entry for neurotoxic species that can spread to the brain. Furthermore, the exposure of the olfactory system to the external environment make it more susceptible to mechanical injury and trauma, which can cause degenerative neuroinflammation. In this review, we will summarize several findings about chemosensory impairment signing the conversion from healthy to pathological brain aging and we will try to connect those observations to the promising research linking environmental influences to sporadic dementia. The scientific body of knowledge will support the use of chemosensory diagnostics in the presymptomatic stages of AD and other biomarkers with the scope of finding treatment strategies before the onset of the disease.
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Affiliation(s)
- Praveen Bathini
- Department of Medicine, University of Fribourg, Fribourg, Switzerland
| | - Emanuele Brai
- VIB-KU Leuven Center for Brain & Disease Research, Laboratory for the Research of Neurodegenerative Diseases, Leuven, Belgium
| | - Lavinia Alberi Auber
- Department of Medicine, University of Fribourg, Fribourg, Switzerland; Swiss Integrative Center of Human Health, Fribourg, Switzerland.
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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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Tahmasebi R, Zehetmayer S, Stögmann E, Lehrner J. Awareness of Olfactory Dysfunction in Subjective Cognitive Decline, Mild Cognitive Decline, and Alzheimer’s Disease. CHEMOSENS PERCEPT 2019. [DOI: 10.1007/s12078-019-09267-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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22
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Olfactory bulb atrophy and caspase activation observed in the BACHD rat models of Huntington disease. Neurobiol Dis 2019; 125:219-231. [DOI: 10.1016/j.nbd.2019.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 12/14/2018] [Accepted: 02/04/2019] [Indexed: 01/08/2023] Open
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Abstract
PURPOSE OF REVIEW The sense of smell is today one of the focuses of interest in aging and neurodegenerative disease research. In several neurodegenerative diseases, such as Parkinson's disease and Alzheimer's disease, the olfactory dysfunction is one of the initial symptoms appearing years before motor symptoms and cognitive decline, being considered a clinical marker of these diseases' early stages and a marker of disease progression and cognitive decline. Overall and under the umbrella of precision medicine, attention to olfactory function may help to improve chances of success for neuroprotective and disease-modifying therapeutic strategies. RECENT FINDINGS The use of olfaction, as clinical marker for neurodegenerative diseases is helpful in the characterization of prodromal stages of these diseases, early diagnostic strategies, differential diagnosis, and potentially prediction of treatment success. Understanding the mechanisms underlying olfactory dysfunction is central to determine its association with neurodegenerative disorders. Several anatomical systems and environmental factors may underlie or contribute to olfactory loss associated with neurological diseases, although the direct biological link to each disorder remains unclear and, thus, requires further investigation. In this review, we describe the neurobiology of olfaction, and the most common olfactory function measurements in neurodegenerative diseases. We also highlight the evidence for the presence of olfactory dysfunction in several neurodegenerative diseases, its value as a clinical marker for early stages of the diseases when combined with other clinical, biological, and neuroimage markers, and its role as a useful symptom for the differential diagnosis and follow-up of disease. The neuropathological correlations and the changes in neurotransmitter systems related with olfactory dysfunction in the neurodegenerative diseases are also described.
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Silva MDME, Mercer PBS, Witt MCZ, Pessoa RR. Olfactory dysfunction in Alzheimer's disease Systematic review and meta-analysis. Dement Neuropsychol 2018; 12:123-132. [PMID: 29988355 PMCID: PMC6022986 DOI: 10.1590/1980-57642018dn12-020004] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Alzheimer’s disease (AD), a neurodegenerative condition, is one of the most prevalent kinds of dementia, whose frequency doubles for every 5 years of age in elderly.
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Affiliation(s)
| | | | | | - Renata Ramina Pessoa
- MD. Hospital da Cruz Vermelha Filial do Paraná. Neurology Department. Curitiba, PR, Brazil
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25
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Van der Jeugd A, D'Hooge R. Assessment of Social Transmission of Food Preferences Behaviors. J Vis Exp 2018. [PMID: 29443064 DOI: 10.3791/57029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Olfactory recognition deficits are suggested to be able to serve as clinical marker to differentiate Alzheimer's disease (AD) subjects from healthy aging groups. For example, olfactory dysfunction in AD can present as impairment in olfactory recognition, emerging during early stages of the disease and worsening while the disease progresses. The social transmission of food preferences (STFP) task is based on a rudimentary form of communication between rodents concerning distant foods dependent on the transmission of olfactory cues. Healthy wild-type mice would prefer to eat a novel, flavored food that was previously cued by a conspecific, and this food preference would be hampered in transgenic AD mice, such as the APP/PS1 model. Indeed, a strong preference for the cued food in C57Bl6/J mice of 3 months of age was found, and this was reduced in 3 months old transgenic APP/PS1 mice. In summary, STFP task could be a powerful measure to be integrated in present subclinical detection assays of AD.
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Adams DR, Kern DW, Wroblewski KE, McClintock MK, Dale W, Pinto JM. Olfactory Dysfunction Predicts Subsequent Dementia in Older U.S. Adults. J Am Geriatr Soc 2017; 66:140-144. [PMID: 28944467 DOI: 10.1111/jgs.15048] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVES To investigate the relationship between olfactory dysfunction and subsequent diagnosis of dementia. DESIGN Longitudinal study of a population representative of U.S. older adults. SETTING Home interviews (National Social Life, Health, and Aging Project). PARTICIPANTS Men and women aged 57 to 85 (N = 2,906). MEASUREMENTS Objective odor identification ability was measured at baseline using a validated five-item test. Five years later, the respondent, or a proxy if the respondent was too sick to interview or had died, reported physician diagnosis of dementia. The association between baseline olfactory dysfunction and an interval dementia diagnosis was tested using multivariate logistic regression, controlling for age, sex, race and ethnicity, education, comorbidities (modified Charlson Comorbidity Index), and cognition at baseline (Short Portable Mental Status Questionnaire). RESULTS Older adults with olfactory dysfunction had more than twice the odds of having developed dementia 5 years later (odds ratio = 2.13, 95% confidence interval = 1.32-3.43), controlling for the above covariates. Having more odor identification errors was associated with greater probability of an interval dementia diagnosis (P = .04, 1-degree of freedom linear-trend test). CONCLUSION We show for the first time in a nationally representative sample that home-dwelling older adults with normal cognition and difficulty identifying odors face higher odds of being diagnosed with dementia 5 years later, independent of other significant risk factors. This validated five-item odor identification test is an efficient, low-cost component of the physical examination that can provide useful information while assessing individuals' risk of dementia. Use of such testing may provide an opportunity for early interventions to reduce the attendant morbidity and public health burden of dementia.
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Affiliation(s)
- Dara R Adams
- Section of Otolaryngology-Head and Neck Surgery, University of Chicago, Chicago, Illinois
| | - David W Kern
- Department of Psychology, Northeastern Illinois University, Chicago, Illinois
| | | | - Martha K McClintock
- Department of Comparative Human Development, University of Chicago, Chicago, Illinois.,Institute for Mind and Biology, University of Chicago, Chicago, Illinois
| | - William Dale
- Section of Geriatrics and Palliative Medicine, Department of Medicine, University of Chicago, Chicago, Illinois
| | - Jayant M Pinto
- Section of Otolaryngology-Head and Neck Surgery, University of Chicago, Chicago, Illinois
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Savage SA, Butler CR, Milton F, Han Y, Zeman AZ. On the nose: Olfactory disturbances in patients with transient epileptic amnesia. Epilepsy Behav 2017; 66:113-119. [PMID: 28038387 PMCID: PMC6197428 DOI: 10.1016/j.yebeh.2016.09.043] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 09/29/2016] [Accepted: 09/30/2016] [Indexed: 11/17/2022]
Abstract
OBJECTIVE While olfactory hallucinations are relatively rare in epilepsy, a high prevalence (up to 42%) has been reported in one form - Transient Epileptic Amnesia (TEA). TEA is characterized by recurring amnestic seizures and is commonly associated with persistent interictal memory deficits. Despite reports of changes in smell, olfactory ability has not been objectively assessed in this group. The aim of this study was to measure olfactory ability in patients with TEA and explore whether olfactory symptoms relate to other clinical variables. METHODS Fifty-five participants with TEA were recruited from The Impairment of Memory in Epilepsy project database. The presence of olfactory symptoms was obtained via case notes and clinical interview. Participants completed questionnaires to evaluate their olfaction and memory function subjectively. Olfactory ability was measured using the University of Pennsylvania Smell Identification Test (UPSIT). TEA participants' performance was compared to 50 matched healthy control participants. A subset of TEA participants (n=26) also completed a battery of memory tests including standard neuropsychological measures, and assessment of accelerated long-term forgetting and autobiographical memory. RESULTS Olfactory hallucinations were reported in 55% of patients with TEA. A significant reduction in smell identification (UPSIT) was found between patients with TEA and healthy controls (p<0.001). Epilepsy variables, including history of olfactory hallucinations, were not predictive of olfactory ability. Patients reported ongoing memory difficulties and performed below normative values on objective tests. While no correlation was found between objective measures of memory and olfactory performance, subjective complaints of route finding difficulty was associated with UPSIT score. CONCLUSIONS Impairments in odor identification are common in patients with TEA and exceed changes that occur in normal aging. Olfactory hallucinations occurs in approximately half of patients with TEA, but do not always coincide with reduced sense of smell. Olfactory impairment and interictal memory problems both occur frequently in TEA but are not closely associated.
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Affiliation(s)
- Sharon A. Savage
- Cognitive & Behavioural Neurology, University of Exeter Medical School, College House, St Luke’s Campus, Exeter, EX1 2LU, UK,corresponding author:
| | - Christopher R. Butler
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, John Radcliffe Hospital, OX3 9DU, UK
| | - Fraser Milton
- Discipline of Psychology, University of Exeter, Washington Singer Laboratories, Exeter, EX4 4QG, UK
| | - Yang Han
- Health Statistics, University of Exeter Medical School, South Cloisters, St Luke’s Campus, Exeter, EX1 2LU, UK
| | - Adam Z. Zeman
- Cognitive & Behavioural Neurology, University of Exeter Medical School, College House, St Luke’s Campus, Exeter, EX1 2LU, UK
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28
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Affiliation(s)
- Ji-Eun Lee
- Department of Otorhinolaryngology, Chosun University College of Medicine, Gwangju, Korea
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29
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Ward AM, Calamia M, Thiemann E, Dunlap J, Tranel D. Association between olfaction and higher cortical functions in Alzheimer's disease, mild cognitive impairment, and healthy older adults. J Clin Exp Neuropsychol 2016; 39:646-658. [PMID: 27868477 DOI: 10.1080/13803395.2016.1253667] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Neural regions important for smell are proximal and closely connected to cortical areas that have been strongly implicated in higher order functions of value-based decision making and emotional memory. The integrity of these neural regions are affected in aging and neurodegenerative conditions. Two specific predictions follow from these neuroanatomical arrangements-namely, that olfaction would be associated with value-based decision making and with emotional memory. METHOD To test these predictions, we measured these different capacities in participants with presumed varying degrees of integrity of the relevant brain structures: specifically, 13 patients with Alzheimer's disease, 8 patients with mild cognitive impairment, and 20 healthy older adults. The participants completed detailed tests of olfaction, value-based decision making, emotional memory, and general cognitive ability. RESULTS Olfactory functioning was significantly associated with emotional and nonemotional memory. The association was especially strong and consistent for memory recall with olfaction, explaining as much as 10% additional variance over and above general cognition. Olfactory functioning was not strongly or consistently associated with decision making over and above general cognition. CONCLUSION Olfaction is a strong predictor of memory recall. These findings may contribute to a better understanding of olfaction and specific cognitive domains known to be affected by aging and implicated in neurodegenerative disease.
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Affiliation(s)
- Amanda M Ward
- a Department of Psychological and Brain Sciences , University of Iowa , Iowa City , IA , USA
| | - Matthew Calamia
- b Department of Psychology , Louisiana State University , Baton Rouge , LA , USA
| | - Erin Thiemann
- a Department of Psychological and Brain Sciences , University of Iowa , Iowa City , IA , USA
| | - Jamie Dunlap
- a Department of Psychological and Brain Sciences , University of Iowa , Iowa City , IA , USA
| | - Daniel Tranel
- a Department of Psychological and Brain Sciences , University of Iowa , Iowa City , IA , USA.,c Department of Neurology , University of Iowa Carver College of Medicine , Iowa City , IA , USA
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Metacognitive knowledge of olfactory dysfunction in Parkinson's disease. Brain Cogn 2016; 104:1-6. [PMID: 26867087 DOI: 10.1016/j.bandc.2016.01.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 01/12/2016] [Accepted: 01/13/2016] [Indexed: 11/20/2022]
Abstract
It is well known that patients with Parkinson's Disease (PD) suffer from olfactory impairments, but it is not clear whether patients are aware of their level of deficit in olfactory functioning. Since PD is a neurodegenerative disorder and its progression may be correlated with olfactory loss (Ansari & Johnson, 1975; but see also Doty, Deems, & Stellar, 1988), it is possible that these patients would be subject to metacognitive errors of over-estimation of olfactory ability (White & Kurtz, 2003). Nineteen non-demented PD patients and 19 age-matched controls were each given an objective measure of olfactory identification (the UPSIT, Doty, Shaman, Kimmelman, & Dann, 1984) and a subjective measure involving a questionnaire that asked them to self-rate both their olfactory function generally and their ability to smell each of 20 odors, 12 of which were assessed on the UPSIT. All of the PD patients showed impaired olfactory ability, as did 7 of the controls, according to the UPSIT norms. Self-rated and performance-based olfactory ability scores were significantly correlated in controls (r=.49, p=.03) but not in patients with PD (r=.20, p=.39). When the 12 odors common to both the self-rated questionnaire and UPSIT were compared, PD patients were less accurate than controls (t(36)=-4.96, p<.01) at estimating their own ability and the number of over-estimation errors was significantly higher (tone-tailed(29)=1.80, p=.04) in PD patients than in the control group, showing less metacognitive awareness of their ability than controls. These results support the idea that olfactory metacognition is often impaired in PD, as well as in controls recruited for normosmic ability (Wehling, Nordin, Espeseth, Reinvang, & Lundervold, 2011), and indicate that people with PD generally exhibit over-estimation of their olfactory ability at a rate that is higher than controls. These findings imply that PD patients, unaware of their olfactory deficit, are at greater risk of harm normally detected through olfaction, such as smoke or spoiled foods.
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Abstract
Alzheimer's disease (AD) is a common neurodegenerative disorder with the earliest clinical symptom of olfactory dysfunction, which is a potential clinical marker for AD severity and progression. However, many questions remain unanswered. This article reviews relevant research on olfactory dysfunction in AD and evaluates the predictive value of olfactory dysfunction for the epidemiological, pathophysiological, and clinical features of AD, as well as for the conversion of cognitive impairment to AD. We summarize problems of existing studies and provide a useful reference for further studies in AD olfactory dysfunction and for clinical applications of olfactory testing.
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Affiliation(s)
- Yong-Ming Zou
- Department of Neurology, Tianjin Huanhu Hospital, Tianjin, People's Republic of China
| | - Da Lu
- Department of Neurology, Tianjin Huanhu Hospital, Tianjin, People's Republic of China
| | - Li-Ping Liu
- Department of Neurology, Tianjin Huanhu Hospital, Tianjin, People's Republic of China
| | - Hui-Hong Zhang
- Department of Neurology, Tianjin Huanhu Hospital, Tianjin, People's Republic of China
| | - Yu-Ying Zhou
- Department of Neurology, Tianjin Huanhu Hospital, Tianjin, People's Republic of China
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Franks KH, Chuah MI, King AE, Vickers JC. Connectivity of Pathology: The Olfactory System as a Model for Network-Driven Mechanisms of Alzheimer's Disease Pathogenesis. Front Aging Neurosci 2015; 7:234. [PMID: 26696886 PMCID: PMC4678206 DOI: 10.3389/fnagi.2015.00234] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 11/30/2015] [Indexed: 11/24/2022] Open
Abstract
The pathogenesis of Alzheimer’s disease (AD) has been postulated to preferentially impact specific neural networks in the brain. The olfactory system is a well-defined network that has been implicated in early stages of the disease, marked by impairment in olfaction and the presence of pathological hallmarks of the disease, even before clinical presentation. Discovering the cellular mechanisms involved in the connectivity of pathology will provide insight into potential targets for treatment. We review evidence from animal studies on sensory alteration through denervation or enrichment, which supports the notion of using the olfactory system to investigate the implications of connectivity and activity in the spread of pathology in AD.
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Affiliation(s)
- Katherine H Franks
- Faculty of Health, Wicking Dementia Research and Education Centre, University of Tasmania , Hobart, TAS , Australia
| | - Meng Inn Chuah
- Faculty of Health, Wicking Dementia Research and Education Centre, University of Tasmania , Hobart, TAS , Australia
| | - Anna E King
- Faculty of Health, Wicking Dementia Research and Education Centre, University of Tasmania , Hobart, TAS , Australia
| | - James C Vickers
- Faculty of Health, Wicking Dementia Research and Education Centre, University of Tasmania , Hobart, TAS , Australia
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Xie AJ, Liu EJ, Huang HZ, Hu Y, Li K, Lu Y, Wang JZ, Zhu LQ. Cnga2 Knockout Mice Display Alzheimer’s-Like Behavior Abnormities and Pathological Changes. Mol Neurobiol 2015; 53:4992-9. [DOI: 10.1007/s12035-015-9421-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Accepted: 09/02/2015] [Indexed: 10/23/2022]
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Yoon JH, Kim M, Moon SY, Yong SW, Hong JM. Olfactory function and neuropsychological profile to differentiate dementia with Lewy bodies from Alzheimer's disease in patients with mild cognitive impairment: A 5-year follow-up study. J Neurol Sci 2015; 355:174-9. [PMID: 26076880 DOI: 10.1016/j.jns.2015.06.013] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 06/05/2015] [Accepted: 06/08/2015] [Indexed: 12/13/2022]
Abstract
BACKGROUND Mild cognitive impairment (MCI) is a well-known precursor of Alzheimer's disease (AD) but often also precedes dementia with Lewy bodies (DLB). The early differentiation of DLB from AD is important to delay disease progression. Olfactory dysfunction is a well-known early sign of both AD and Lewy body disorders, including Parkinson's disease (PD) and DLB. Thus, the aim of the present study was to determine whether olfactory and neuropsychological tests can aid in the differentiation of DLB from AD at the MCI stage. METHODS The present study included 122 MCI patients who were monitored until they developed dementia or until their condition stabilized; the follow-up period averaged 4.9 years (range: 3.9-6.2 years). Baseline olfactory function as measured with the Cross-Cultural Smell Identification (CCSI) test and neuropsychological data were compared. RESULTS During the follow-up period, 32 subjects developed probable AD (MCI-AD), 18 had probable DLB (MCI-DLB), 45 did not convert to dementia (MCI-stable), and eight developed a non-AD/DLB dementia. The mean CCSI score (95% confidence interval [CI]) in patients with MCI-DLB (4.6; 95% CI: 4.0-5.3) was significantly lower than that of MCI-AD patients (6.4; 95% CI: 6.0-6.7, p<0.001) and MCI-stable patients (7.3; 95% CI: 6.9-7.8, p<0.001). The area under the curve of the receiver operating characteristic to discriminate MCI-DLB from MCI-AD using CCSI scores was (0.84; 95% CI: 0.72-0.97). Frontal-executive function and visuospatial ability was worse in patients with MCI-DLB, while verbal recognition memory impairment was greater in those with MCI-AD. CONCLUSION Olfactory and neuropsychological tests can help predict conversion to DLB or AD in patients with MCI.
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Affiliation(s)
- Jung Han Yoon
- Department of Neurology, Ajou University School of Medicine, Suwon, South Korea.
| | - Min Kim
- Department of Neurology, Ajou University School of Medicine, Suwon, South Korea
| | - So Young Moon
- Department of Neurology, Ajou University School of Medicine, Suwon, South Korea
| | - Seok Woo Yong
- Department of Neurology, Ajou University School of Medicine, Suwon, South Korea
| | - Ji Man Hong
- Department of Neurology, Ajou University School of Medicine, Suwon, South Korea
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Growdon ME, Schultz AP, Dagley AS, Amariglio RE, Hedden T, Rentz DM, Johnson KA, Sperling RA, Albers MW, Marshall GA. Odor identification and Alzheimer disease biomarkers in clinically normal elderly. Neurology 2015; 84:2153-60. [PMID: 25934852 DOI: 10.1212/wnl.0000000000001614] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 02/12/2015] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES Our objective was to investigate cross-sectional associations between odor identification ability and imaging biomarkers of neurodegeneration and amyloid deposition in clinically normal (CN) elderly individuals, specifically testing the hypothesis that there may be an interaction between amyloid deposition and neurodegeneration in predicting odor identification dysfunction. METHODS Data were collected on 215 CN participants from the Harvard Aging Brain Study. Measurements included the 40-item University of Pennsylvania Smell Identification Test and neuropsychological testing, hippocampal volume (HV) and entorhinal cortex (EC) thickness from MRI, and amyloid burden using Pittsburgh compound B (PiB) PET. A linear regression model with backward elimination (p < 0.05 retention) evaluated the cross-sectional association between the University of Pennsylvania Smell Identification Test and amyloid burden, HV, and EC thickness, assessing for effect modification by PiB status. Covariates included age, sex, premorbid intelligence, APOE ε4 carrier status, and Boston Naming Test. RESULTS In unadjusted univariate analyses, worse olfaction was associated with decreased HV (p < 0.001), thinner EC (p = 0.003), worse episodic memory (p = 0.03), and marginally associated with greater amyloid burden (binary PiB status, p = 0.06). In the multivariate model, thinner EC in PiB-positive individuals (interaction term) was associated with worse olfaction (p = 0.02). CONCLUSIONS In CN elderly, worse odor identification was associated with markers of neurodegeneration. Furthermore, individuals with elevated cortical amyloid and thinner EC exhibited worse odor identification, elucidating the potential contribution of olfactory testing to detect preclinical AD in CN individuals.
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Affiliation(s)
- Matthew E Growdon
- From Harvard Medical School (M.E.G., R.E.A., T.H., D.M.R., K.A.J., R.A.S., M.W.A., G.A.M.) and Harvard T.H. Chan School of Public Health (M.E.G.), Boston, MA; Athinoula A. Martinos Center for Biomedical Imaging (A.P.S., A.S.D., T.H., R.A.S., M.W.A.), Massachusetts General Hospital, Charlestown; Departments of Neurology (A.P.S., A.S.D., R.E.A., D.M.R., R.A.S., M.W.A., G.A.M.), Psychiatry (A.P.S., A.S.D.), and Radiology (T.H., K.A.J.), MassGeneral Institute of Neurodegenerative Disease (M.W.A.), Massachusetts General Hospital, Boston; and Center for Alzheimer Research and Treatment (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.) and Department of Neurology (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.), Brigham and Women's Hospital, Boston, MA
| | - Aaron P Schultz
- From Harvard Medical School (M.E.G., R.E.A., T.H., D.M.R., K.A.J., R.A.S., M.W.A., G.A.M.) and Harvard T.H. Chan School of Public Health (M.E.G.), Boston, MA; Athinoula A. Martinos Center for Biomedical Imaging (A.P.S., A.S.D., T.H., R.A.S., M.W.A.), Massachusetts General Hospital, Charlestown; Departments of Neurology (A.P.S., A.S.D., R.E.A., D.M.R., R.A.S., M.W.A., G.A.M.), Psychiatry (A.P.S., A.S.D.), and Radiology (T.H., K.A.J.), MassGeneral Institute of Neurodegenerative Disease (M.W.A.), Massachusetts General Hospital, Boston; and Center for Alzheimer Research and Treatment (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.) and Department of Neurology (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.), Brigham and Women's Hospital, Boston, MA
| | - Alexander S Dagley
- From Harvard Medical School (M.E.G., R.E.A., T.H., D.M.R., K.A.J., R.A.S., M.W.A., G.A.M.) and Harvard T.H. Chan School of Public Health (M.E.G.), Boston, MA; Athinoula A. Martinos Center for Biomedical Imaging (A.P.S., A.S.D., T.H., R.A.S., M.W.A.), Massachusetts General Hospital, Charlestown; Departments of Neurology (A.P.S., A.S.D., R.E.A., D.M.R., R.A.S., M.W.A., G.A.M.), Psychiatry (A.P.S., A.S.D.), and Radiology (T.H., K.A.J.), MassGeneral Institute of Neurodegenerative Disease (M.W.A.), Massachusetts General Hospital, Boston; and Center for Alzheimer Research and Treatment (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.) and Department of Neurology (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.), Brigham and Women's Hospital, Boston, MA
| | - Rebecca E Amariglio
- From Harvard Medical School (M.E.G., R.E.A., T.H., D.M.R., K.A.J., R.A.S., M.W.A., G.A.M.) and Harvard T.H. Chan School of Public Health (M.E.G.), Boston, MA; Athinoula A. Martinos Center for Biomedical Imaging (A.P.S., A.S.D., T.H., R.A.S., M.W.A.), Massachusetts General Hospital, Charlestown; Departments of Neurology (A.P.S., A.S.D., R.E.A., D.M.R., R.A.S., M.W.A., G.A.M.), Psychiatry (A.P.S., A.S.D.), and Radiology (T.H., K.A.J.), MassGeneral Institute of Neurodegenerative Disease (M.W.A.), Massachusetts General Hospital, Boston; and Center for Alzheimer Research and Treatment (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.) and Department of Neurology (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.), Brigham and Women's Hospital, Boston, MA
| | - Trey Hedden
- From Harvard Medical School (M.E.G., R.E.A., T.H., D.M.R., K.A.J., R.A.S., M.W.A., G.A.M.) and Harvard T.H. Chan School of Public Health (M.E.G.), Boston, MA; Athinoula A. Martinos Center for Biomedical Imaging (A.P.S., A.S.D., T.H., R.A.S., M.W.A.), Massachusetts General Hospital, Charlestown; Departments of Neurology (A.P.S., A.S.D., R.E.A., D.M.R., R.A.S., M.W.A., G.A.M.), Psychiatry (A.P.S., A.S.D.), and Radiology (T.H., K.A.J.), MassGeneral Institute of Neurodegenerative Disease (M.W.A.), Massachusetts General Hospital, Boston; and Center for Alzheimer Research and Treatment (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.) and Department of Neurology (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.), Brigham and Women's Hospital, Boston, MA
| | - Dorene M Rentz
- From Harvard Medical School (M.E.G., R.E.A., T.H., D.M.R., K.A.J., R.A.S., M.W.A., G.A.M.) and Harvard T.H. Chan School of Public Health (M.E.G.), Boston, MA; Athinoula A. Martinos Center for Biomedical Imaging (A.P.S., A.S.D., T.H., R.A.S., M.W.A.), Massachusetts General Hospital, Charlestown; Departments of Neurology (A.P.S., A.S.D., R.E.A., D.M.R., R.A.S., M.W.A., G.A.M.), Psychiatry (A.P.S., A.S.D.), and Radiology (T.H., K.A.J.), MassGeneral Institute of Neurodegenerative Disease (M.W.A.), Massachusetts General Hospital, Boston; and Center for Alzheimer Research and Treatment (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.) and Department of Neurology (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.), Brigham and Women's Hospital, Boston, MA
| | - Keith A Johnson
- From Harvard Medical School (M.E.G., R.E.A., T.H., D.M.R., K.A.J., R.A.S., M.W.A., G.A.M.) and Harvard T.H. Chan School of Public Health (M.E.G.), Boston, MA; Athinoula A. Martinos Center for Biomedical Imaging (A.P.S., A.S.D., T.H., R.A.S., M.W.A.), Massachusetts General Hospital, Charlestown; Departments of Neurology (A.P.S., A.S.D., R.E.A., D.M.R., R.A.S., M.W.A., G.A.M.), Psychiatry (A.P.S., A.S.D.), and Radiology (T.H., K.A.J.), MassGeneral Institute of Neurodegenerative Disease (M.W.A.), Massachusetts General Hospital, Boston; and Center for Alzheimer Research and Treatment (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.) and Department of Neurology (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.), Brigham and Women's Hospital, Boston, MA
| | - Reisa A Sperling
- From Harvard Medical School (M.E.G., R.E.A., T.H., D.M.R., K.A.J., R.A.S., M.W.A., G.A.M.) and Harvard T.H. Chan School of Public Health (M.E.G.), Boston, MA; Athinoula A. Martinos Center for Biomedical Imaging (A.P.S., A.S.D., T.H., R.A.S., M.W.A.), Massachusetts General Hospital, Charlestown; Departments of Neurology (A.P.S., A.S.D., R.E.A., D.M.R., R.A.S., M.W.A., G.A.M.), Psychiatry (A.P.S., A.S.D.), and Radiology (T.H., K.A.J.), MassGeneral Institute of Neurodegenerative Disease (M.W.A.), Massachusetts General Hospital, Boston; and Center for Alzheimer Research and Treatment (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.) and Department of Neurology (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.), Brigham and Women's Hospital, Boston, MA
| | - Mark W Albers
- From Harvard Medical School (M.E.G., R.E.A., T.H., D.M.R., K.A.J., R.A.S., M.W.A., G.A.M.) and Harvard T.H. Chan School of Public Health (M.E.G.), Boston, MA; Athinoula A. Martinos Center for Biomedical Imaging (A.P.S., A.S.D., T.H., R.A.S., M.W.A.), Massachusetts General Hospital, Charlestown; Departments of Neurology (A.P.S., A.S.D., R.E.A., D.M.R., R.A.S., M.W.A., G.A.M.), Psychiatry (A.P.S., A.S.D.), and Radiology (T.H., K.A.J.), MassGeneral Institute of Neurodegenerative Disease (M.W.A.), Massachusetts General Hospital, Boston; and Center for Alzheimer Research and Treatment (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.) and Department of Neurology (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.), Brigham and Women's Hospital, Boston, MA
| | - Gad A Marshall
- From Harvard Medical School (M.E.G., R.E.A., T.H., D.M.R., K.A.J., R.A.S., M.W.A., G.A.M.) and Harvard T.H. Chan School of Public Health (M.E.G.), Boston, MA; Athinoula A. Martinos Center for Biomedical Imaging (A.P.S., A.S.D., T.H., R.A.S., M.W.A.), Massachusetts General Hospital, Charlestown; Departments of Neurology (A.P.S., A.S.D., R.E.A., D.M.R., R.A.S., M.W.A., G.A.M.), Psychiatry (A.P.S., A.S.D.), and Radiology (T.H., K.A.J.), MassGeneral Institute of Neurodegenerative Disease (M.W.A.), Massachusetts General Hospital, Boston; and Center for Alzheimer Research and Treatment (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.) and Department of Neurology (R.E.A., D.M.R., K.A.J., R.A.S., G.A.M.), Brigham and Women's Hospital, Boston, MA.
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Abstract
PURPOSE OF REVIEW To provide an update of the recent studies on the olfactory function in Alzheimer's disease, with a focus on the olfactory identification function. RECENT FINDINGS The studies reviewed here confirm previous reports on the poor olfactory function in Alzheimer's disease compared to health normal controls and also as a marker for conversion from mild cognitive impairment to Alzheimer's disease. Olfactory identification function has been associated with severity of illness, non-cognitive neuropsychiatric symptoms, and structural and functional MRI measures. There is a possible interaction of apolipoprotein E genotype with olfactory performance in Alzheimer's disease patients and those at risk for Alzheimer's disease. Usefulness of smell identification function in differentiating Alzheimer's disease patients from other types of dementia needs to be established. SUMMARY The need for simple, inexpensive and non-invasive procedures for aiding in the diagnosis and understanding of Alzheimer's disease has led to theories and procedures examining the role of olfactory functions in Alzheimer's disease. Although there is increasing evidence for olfactory dysfunction in general and impaired odour identification in particular in Alzheimer's disease, additional larger and methodologically sound research is needed for testing its clinical utility in day-to-day clinical practice for early, accurate and differential diagnosis of Alzheimer's disease.
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Xu W, Fitzgerald S, Nixon RA, Levy E, Wilson DA. Early hyperactivity in lateral entorhinal cortex is associated with elevated levels of AβPP metabolites in the Tg2576 mouse model of Alzheimer's disease. Exp Neurol 2015; 264:82-91. [PMID: 25500142 PMCID: PMC4324092 DOI: 10.1016/j.expneurol.2014.12.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 11/14/2014] [Accepted: 12/07/2014] [Indexed: 12/27/2022]
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder which is the most common cause of dementia in the elderly today. One of the earliest symptoms of AD is olfactory dysfunction. The present study investigated the effects of amyloid β precursor protein (AβPP) metabolites, including amyloid-β (Aβ) and AβPP C-terminal fragments (CTF), on olfactory processing in the lateral entorhinal cortex (LEC) using the Tg2576 mouse model of human AβPP over-expression. The entorhinal cortex is an early target of AD related neuropathology, and the LEC plays an important role in fine odor discrimination and memory. Cohorts of transgenic and age-matched wild-type (WT) mice at 3, 6, and 16months of age (MO) were anesthetized and acute, single-unit electrophysiology was performed in the LEC. Results showed that Tg2576 exhibited early LEC hyperactivity at 3 and 6MO compared to WT mice in both local field potential and single-unit spontaneous activity. However, LEC single-unit odor responses and odor receptive fields showed no detectable difference compared to WT at any age. Finally, the very early emergence of olfactory system hyper-excitability corresponded not to detectable Aβ deposition in the olfactory system, but rather to high levels of intracellular AβPP-CTF and soluble Aβ in the anterior piriform cortex (aPCX), a major afferent input to the LEC, by 3MO. The present results add to the growing evidence of AβPP-related hyper-excitability, and further implicate both soluble Aβ and non-Aβ AβPP metabolites in its early emergence.
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Affiliation(s)
- Wenjin Xu
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Child & Adolescent Psychiatry, New York University School of Medicine, New York, NY 10016, USA
| | - Shane Fitzgerald
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Ralph A Nixon
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA; Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
| | - Efrat Levy
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA; Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Donald A Wilson
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA; Department of Child & Adolescent Psychiatry, New York University School of Medicine, New York, NY 10016, USA; Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA.
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Activation of Glycogen Synthase Kinase-3 Mediates the Olfactory Deficit-Induced Hippocampal Impairments. Mol Neurobiol 2014; 52:1601-1617. [DOI: 10.1007/s12035-014-8953-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Accepted: 10/20/2014] [Indexed: 01/04/2023]
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Changes of olfactory abilities in relation to age: odor identification in more than 1400 people aged 4 to 80 years. Eur Arch Otorhinolaryngol 2014; 272:1937-44. [PMID: 25238811 PMCID: PMC4473282 DOI: 10.1007/s00405-014-3263-4] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 08/28/2014] [Indexed: 12/21/2022]
Abstract
The currently presented large dataset (n = 1,422) consists of results that have been assembled over the last 8 years at science fairs using the 16-item odor identification part of the “Sniffin’ Sticks”. In this context, the focus was on olfactory function in children; in addition before testing, we asked participants to rate their olfactory abilities and the patency of the nasal airways. We reinvestigated some simple questions, e.g., differences in olfactory odor identification abilities in relation to age, sex, self-ratings of olfactory function and nasal patency. Three major results evolved: first, consistent with previously published reports, we found that identification scores of the youngest and the oldest participants were lower than the scores obtained by people aged 20–60. Second, we observed an age-related increase in the olfactory abilities of children. Moreover, the self-assessed olfactory abilities were related to actual performance in the smell test, but only in adults, and self-assessed nasal patency was not related to the “Sniffin’ Sticks” identification score.
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Xu W, Lopez-Guzman M, Schoen C, Fitzgerald S, Lauer SL, Nixon RA, Levy E, Wilson DA. Spared piriform cortical single-unit odor processing and odor discrimination in the Tg2576 mouse model of Alzheimer's disease. PLoS One 2014; 9:e106431. [PMID: 25181487 PMCID: PMC4152226 DOI: 10.1371/journal.pone.0106431] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 07/29/2014] [Indexed: 11/23/2022] Open
Abstract
Alzheimer's disease is a neurodegenerative disorder that is the most common cause of dementia in the elderly today. One of the earliest reported signs of Alzheimer's disease is olfactory dysfunction, which may manifest in a variety of ways. The present study sought to address this issue by investigating odor coding in the anterior piriform cortex, the primary cortical region involved in higher order olfactory function, and how it relates to performance on olfactory behavioral tasks. An olfactory habituation task was performed on cohorts of transgenic and age-matched wild-type mice at 3, 6 and 12 months of age. These animals were then anesthetized and acute, single-unit electrophysiology was performed in the anterior piriform cortex. In addition, in a separate group of animals, a longitudinal odor discrimination task was conducted from 3-12 months of age. Results showed that while odor habituation was impaired at all ages, Tg2576 performed comparably to age-matched wild-type mice on the olfactory discrimination task. The behavioral data mirrored intact anterior piriform cortex single-unit odor responses and receptive fields in Tg2576, which were comparable to wild-type at all age groups. The present results suggest that odor processing in the olfactory cortex and basic odor discrimination is especially robust in the face of amyloid β precursor protein (AβPP) over-expression and advancing amyloid β (Aβ) pathology. Odor identification deficits known to emerge early in Alzheimer's disease progression, therefore, may reflect impairments in linking the odor percept to associated labels in cortical regions upstream of the primary olfactory pathway, rather than in the basic odor processing itself.
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Affiliation(s)
- Wenjin Xu
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York, United States of America
- Department of Child and Adolescent Psychiatry, New York University School of Medicine, New York, New York, United States of America
| | - Mirielle Lopez-Guzman
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York, United States of America
| | - Chelsea Schoen
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York, United States of America
| | - Shane Fitzgerald
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York, United States of America
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York, United States of America
| | - Stephanie L. Lauer
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York, United States of America
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York, United States of America
| | - Ralph A. Nixon
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York, United States of America
- Department of Psychiatry, New York University School of Medicine, New York, New York, United States of America
- Department of Cell Biology, New York University School of Medicine, New York, New York, United States of America
| | - Efrat Levy
- Center for Dementia Research, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York, United States of America
- Department of Psychiatry, New York University School of Medicine, New York, New York, United States of America
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, United States of America
| | - Donald A. Wilson
- Emotional Brain Institute, Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York, United States of America
- Department of Child and Adolescent Psychiatry, New York University School of Medicine, New York, New York, United States of America
- Department of Neuroscience and Physiology, New York University School of Medicine, New York, New York, United States of America
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Wehling E, Lundervold AJ, Nordin S. Does it Matter How We Pose the Question "How is Your Sense of Smell?". CHEMOSENS PERCEPT 2014; 7:103-107. [PMID: 25485033 PMCID: PMC4250572 DOI: 10.1007/s12078-014-9171-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 07/11/2014] [Indexed: 11/26/2022]
Abstract
There is a rather large, and unfortunate, discrepancy in the outcome between self-reported and standardized assessment of olfactory function. Questions for self-evaluation are commonly used that provide no information of with what to compare (comparison target) one’s olfactory function. We therefore investigated whether responses differed between an unspecific question and two questions providing comparison targets. Ninety-six healthy community-dwelling individuals (62.5 % women) aged 49–80 years evaluated their odor identification ability, followed by standardized assessment of odor identification ability. Results revealed that response patterns varied significantly depending on comparison target. While 81 % reported normal function when no further comparison target was presented, 69 % reported normal function when referring to age-related olfactory changes in identification ability. In turn, sensitivity of the accuracy of self-reported reduced odor identification ability (with standardized assessment as reference) increased from 11 to 37 %, whereas specificity decreased from 86 to 71 % when providing a comparison target. Accuracy of self-reported olfactory function can be increased by including a comparison target. However, standardized assessment is to be preferred over self-reported assessment, irrespective of how the question is formulated.
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Affiliation(s)
- Eike Wehling
- />Department of Biological and Medical Psychology, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway
- />Kavli Research Centre for Aging and Dementia, Haraldsplass Hospital, Bergen, Norway
| | - Astri J. Lundervold
- />Department of Biological and Medical Psychology, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway
- />Kavli Research Centre for Aging and Dementia, Haraldsplass Hospital, Bergen, Norway
| | - Steven Nordin
- />Department of Psychology, Umeå University, Umeå, Sweden
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Schofield PW, Finnie S, Yong YM. The Role of Olfactory Challenge Tests in Incipient Dementia and Clinical Trial Design. Curr Neurol Neurosci Rep 2014; 14:479. [DOI: 10.1007/s11910-014-0479-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Caminiti F, De Salvo S, De Cola MC, Russo M, Bramanti P, Marino S, Ciurleo R. Detection of olfactory dysfunction using olfactory event related potentials in young patients with multiple sclerosis. PLoS One 2014; 9:e103151. [PMID: 25047369 PMCID: PMC4105616 DOI: 10.1371/journal.pone.0103151] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 06/26/2014] [Indexed: 11/18/2022] Open
Abstract
Background Several studies reported olfactory dysfunction in patients with multiple sclerosis. The estimate of the incidence of olfactory deficits in multiple sclerosis is uncertain; this may arise from different testing methods that may be influenced by patients' response bias and clinical, demographic and cognitive features. Aims To evaluate objectively the olfactory function using Olfactory Event Related Potentials. Materials and Methods We tested the olfactory function of 30 patients with relapsing remitting multiple sclerosis (mean age of 36.03±6.96 years) and of 30 age, sex and smoking–habit matched healthy controls by using olfactory potentials. A selective and controlled stimulation of the olfactory system to elicit the olfactory event related potentials was achieved by a computer-controlled olfactometer linked directly with electroencephalograph. Relationships between olfactory potential results and patients' clinical characteristics, such as gender, disability status score, disease-modifying therapy, and disease duration, were evaluated. Results Seven of 30 patients did not show olfactory event related potentials. Sixteen of remaining 23 patients had a mean value of amplitude significantly lower than control group (p<0.01). The presence/absence of olfactory event related potentials was associated with dichotomous expanded disability status scale (p = 0.0433), as well as inversely correlated with the disease duration (r = −0.3641, p = 0.0479). Conclusion Unbiased olfactory dysfunction of different severity found in multiple sclerosis patients suggests an organic impairment which could be related to neuroinflammatory and/or neurodegenerative processes of olfactory networks, supporting the recent findings on neurophysiopathology of disease.
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Affiliation(s)
| | | | | | | | | | - Silvia Marino
- IRCCS Centro Neurolesi “Bonino-Pulejo”, Messina, Italy
- Department of Biomedical Sciences and Morphological and Functional Imaging, University of Messina, Messina, Italy
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Farooqui T. Oxidative stress and age-related olfactory memory impairment in the honeybee Apis mellifera. Front Genet 2014; 5:60. [PMID: 24723939 PMCID: PMC3971156 DOI: 10.3389/fgene.2014.00060] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 03/11/2014] [Indexed: 11/30/2022] Open
Affiliation(s)
- Tahira Farooqui
- Department of Entomology, The Ohio State University Columbus, OH, USA
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Olfactory impairment and subjective olfactory complaints independently predict conversion to dementia: a longitudinal, population-based study. J Int Neuropsychol Soc 2014; 20:209-17. [PMID: 24451436 DOI: 10.1017/s1355617713001409] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
We examined whether conversion to dementia can be predicted by self-reported olfactory impairment and/or by an inability to identify odors. Common forms of dementia involve an impaired sense of smell, and poor olfactory performance predicts cognitive decline among the elderly. We followed a sample of 1529 participants, who were within a normal range of overall cognitive function at baseline, over a 10-year period during which 159 were classified as having a dementia disorder. Dementia conversion was predicted from demographic variables, Mini-Mental State Examination score, and olfactory assessments. Self-reported olfactory impairment emerged as an independent predictor of dementia. After adjusting for effects of other predictors, individuals who rated their olfactory sensitivity as "worse than normal" were more likely to convert to dementia than those who reported normal olfactory sensitivity (odds ratio [OR] = 2.17; 95% confidence interval [CI] [1.40, 3.37]). Additionally, low scores on an odor identification test also predicted conversion to dementia (OR per 1 point increase = 0.89; 95% CI [0.81, 0.98]), but these two effects were additive. We suggest that assessing subjective olfactory complaints might supplement other assessments when evaluating the risk of conversion to dementia. Future studies should investigate which combination of olfactory assessments is most useful in predicting dementia conversion.
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Abstract
The olfactory system has a rich cortical representation, including a large archicortical component present in most vertebrates, and in mammals neocortical components including the entorhinal and orbitofrontal cortices. Together, these cortical components contribute to normal odor perception and memory. They help transform the physicochemical features of volatile molecules inhaled or exhaled through the nose into the perception of odor objects with rich associative and hedonic aspects. This chapter focuses on how olfactory cortical areas contribute to odor perception and begins to explore why odor perception is so sensitive to disease and pathology. Odor perception is disrupted by a wide range of disorders including Alzheimer's disease, Parkinson's disease, schizophrenia, depression, autism, and early life exposure to toxins. This olfactory deficit often occurs despite maintained functioning in other sensory systems. Does the unusual network of olfactory cortical structures contribute to this sensitivity?
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Abstract
BACKGROUND Olfactory dysfunction, impaired smell identification in particular, is known as a diagnostic and a marker of conversion in Alzheimer's disease (AD). We aimed to evaluate the associations of olfactory identification impairments with cognition, illness severity, and progression in AD patients. METHODS Fifty-seven outpatients with late onset mild to moderate AD and 24 elderly non-demented controls (NDC) were assessed, at baseline and after three months, for Mini-Mental State Examination (MMSE), University of Pennsylvania Smell Identification Test (UPSIT), and Bristol Activities of Daily Living and Neuropsychiatry Inventory. AD participants were classified as Rapid Cognitive Decliners (RCD) defined on a priori with a loss of ≥2 points in MMSE within the previous six months. RESULTS AD participants had lower olfactory scores than NDC. RCD had lower olfaction scores compared with Non-Rapid Cognitive Decliners (NRCD). Although the baseline UPSIT scores were associated with baseline MMSE scores, it did not interact significantly with change in MMSE over the follow-up period. Using a median split for olfactory scores, the AD participants were classified as Rapid Olfactory Progressors (ROP) (UPSIT ≤ 15) and Slow Olfactory Progressors correlating significantly with RCD/NRCD groups. The ROP group with higher olfactory impairment indicated more symptomatic illness or severity, i.e. lower cognition, higher functional dependence, and presence of behavioral symptoms. CONCLUSIONS Our study supports association of smell identification function with cognition and its utility as an adjunct clinical measure to assess severity in AD. Further work, including larger longitudinal studies, is needed to explore its value in predicting AD progression.
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Conti MZ, Vicini-Chilovi B, Riva M, Zanetti M, Liberini P, Padovani A, Rozzini L. Odor Identification Deficit Predicts Clinical Conversion from Mild Cognitive Impairment to Dementia Due to Alzheimer's Disease. Arch Clin Neuropsychol 2013; 28:391-9. [DOI: 10.1093/arclin/act032] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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The olfactory system in Alzheimer’s disease: Pathology, pathophysiology and pathway for therapy. Transl Neurosci 2013. [DOI: 10.2478/s13380-013-0108-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
AbstractOlfaction is frequently mentioned as a “neglected sense”, although the olfactory system has several interesting and unique anatomical and physiological features. Olfactory involvement is present in several degenerative disorders, especially in Alzheimer’s disease (AD). The peripheral and central parts of the olfactory system are damaged even in the early stages of AD, manifesting in profound olfactory deficits. Besides the early pathology, the olfactory system may be involved in the pathogenesis of AD by providing a route of entry for pathological agents still unknown. In contrast to this olfactory vector hypothesis, the olfactory system can be used to deliver therapeutic agents in AD, such as nerve growth factor and insulin, by decreasing the side-effects of the therapy or providing a non-invasive method of delivery.
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Pusswald G, Auff E, Lehrner J. Development of a Brief Self-Report Inventory to Measure Olfactory Dysfunction and Quality of Life in Patients with Problems with the Sense of Smell. CHEMOSENS PERCEPT 2012. [DOI: 10.1007/s12078-012-9127-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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