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Frank C, Albertazzi A, Murphy C. The effect of the apolipoprotein E ε4 allele and olfactory function on odor identification networks. Brain Behav 2024; 14:e3524. [PMID: 38702902 PMCID: PMC11069025 DOI: 10.1002/brb3.3524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 04/11/2024] [Accepted: 04/17/2024] [Indexed: 05/06/2024] Open
Abstract
INTRODUCTION The combination of apolipoprotein E ε4 (ApoE ε4) status, odor identification, and odor familiarity predicts conversion to mild cognitive impairment (MCI) and Alzheimer's disease (AD). METHODS To further understand olfactory disturbances and AD risk, ApoE ε4 carrier (mean age 76.38 ± 5.21) and ε4 non-carrier (mean age 76.8 ± 3.35) adults were given odor familiarity and identification tests and performed an odor identification task during fMRI scanning. Five task-related functional networks were detected using independent components analysis. Main and interaction effects of mean odor familiarity ratings, odor identification scores, and ε4 status on network activation and task-modulation of network functional connectivity (FC) during correct and incorrect odor identification (hits and misses), controlling for age and sex, were explored using multiple linear regression. RESULTS Findings suggested that sensory-olfactory network activation was positively associated with odor identification scores in ε4 carriers with intact odor familiarity. The FC of sensory-olfactory, multisensory-semantic integration, and occipitoparietal networks was altered in ε4 carriers with poorer odor familiarity and identification. In ε4 carriers with poorer familiarity, connectivity between superior frontal areas and the sensory-olfactory network was negatively associated with odor identification scores. CONCLUSIONS The results contribute to the clarification of the neurocognitive structure of odor identification processing and suggest that poorer odor familiarity and identification in ε4 carriers may signal multi-network dysfunction. Odor familiarity and identification assessment in ε4 carriers may contribute to the predictive value of risk for MCI and AD due to the breakdown of sensory-cognitive network integration. Additional research on olfactory processing in those at risk for AD is warranted.
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Affiliation(s)
- Conner Frank
- SDSU/UC San Diego Joint Doctoral Program in Clinical PsychologySan DiegoCaliforniaUSA
| | - Abigail Albertazzi
- Department of PsychologySan Diego State UniversitySan DiegoCaliforniaUSA
| | - Claire Murphy
- Department of PsychologySan Diego State UniversitySan DiegoCaliforniaUSA
- Department of PsychiatryUniversity of California San DiegoLa JollaCaliforniaUSA
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2
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Liu D, Lu J, Wei L, Yao M, Yang H, Lv P, Wang H, Zhu Y, Zhu Z, Zhang X, Chen J, Yang QX, Zhang B. Olfactory deficit: a potential functional marker across the Alzheimer's disease continuum. Front Neurosci 2024; 18:1309482. [PMID: 38435057 PMCID: PMC10907997 DOI: 10.3389/fnins.2024.1309482] [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: 10/08/2023] [Accepted: 02/02/2024] [Indexed: 03/05/2024] Open
Abstract
Alzheimer's disease (AD) is a prevalent form of dementia that affects an estimated 32 million individuals globally. Identifying early indicators is vital for screening at-risk populations and implementing timely interventions. At present, there is an urgent need for early and sensitive biomarkers to screen individuals at risk of AD. Among all sensory biomarkers, olfaction is currently one of the most promising indicators for AD. Olfactory dysfunction signifies a decline in the ability to detect, identify, or remember odors. Within the spectrum of AD, impairment in olfactory identification precedes detectable cognitive impairments, including mild cognitive impairment (MCI) and even the stage of subjective cognitive decline (SCD), by several years. Olfactory impairment is closely linked to the clinical symptoms and neuropathological biomarkers of AD, accompanied by significant structural and functional abnormalities in the brain. Olfactory behavior examination can subjectively evaluate the abilities of olfactory identification, threshold, and discrimination. Olfactory functional magnetic resonance imaging (fMRI) can provide a relatively objective assessment of olfactory capabilities, with the potential to become a promising tool for exploring the neural mechanisms of olfactory damage in AD. Here, we provide a timely review of recent literature on the characteristics, neuropathology, and examination of olfactory dysfunction in the AD continuum. We focus on the early changes in olfactory indicators detected by behavioral and fMRI assessments and discuss the potential of these techniques in MCI and preclinical AD. Despite the challenges and limitations of existing research, olfactory dysfunction has demonstrated its value in assessing neurodegenerative diseases and may serve as an early indicator of AD in the future.
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Affiliation(s)
- Dongming Liu
- Department of Radiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
- Institute of Medical Imaging and Artificial Intelligence, Nanjing University, Nanjing, China
- Medical Imaging Center, The Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Jiaming Lu
- Department of Radiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
- Institute of Medical Imaging and Artificial Intelligence, Nanjing University, Nanjing, China
- Medical Imaging Center, The Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Liangpeng Wei
- Department of Radiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
- Institute of Medical Imaging and Artificial Intelligence, Nanjing University, Nanjing, China
- Medical Imaging Center, The Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Mei Yao
- Department of Radiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
- Institute of Medical Imaging and Artificial Intelligence, Nanjing University, Nanjing, China
- Medical Imaging Center, The Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Huiquan Yang
- Department of Radiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
- Institute of Medical Imaging and Artificial Intelligence, Nanjing University, Nanjing, China
- Medical Imaging Center, The Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Pin Lv
- Department of Radiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
- Institute of Medical Imaging and Artificial Intelligence, Nanjing University, Nanjing, China
- Medical Imaging Center, The Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Haoyao Wang
- Department of Radiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
- Institute of Medical Imaging and Artificial Intelligence, Nanjing University, Nanjing, China
- Medical Imaging Center, The Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Yajing Zhu
- Department of Radiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Zhengyang Zhu
- Department of Radiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Xin Zhang
- Department of Radiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
- Institute of Medical Imaging and Artificial Intelligence, Nanjing University, Nanjing, China
- Medical Imaging Center, The Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Jiu Chen
- Department of Radiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
- Institute of Medical Imaging and Artificial Intelligence, Nanjing University, Nanjing, China
- Medical Imaging Center, The Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Qing X. Yang
- Department of Radiology, Center for NMR Research, Penn State University College of Medicine, Hershey, PA, United States
| | - Bing Zhang
- Department of Radiology, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
- Institute of Medical Imaging and Artificial Intelligence, Nanjing University, Nanjing, China
- Medical Imaging Center, The Affiliated Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, China
- Jiangsu Key Laboratory of Molecular Medicine, Nanjing, China
- Institute of Brain Science, Nanjing University, Nanjing, China
- Jiangsu Provincial Medical Key Discipline (Laboratory), Nanjing, China
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3
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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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GoodSmith MS, Wroblewski KE, Schumm LP, McClintock MK, Pinto JM. Association of APOE ε4 Status With Long-term Declines in Odor Sensitivity, Odor Identification, and Cognition in Older US Adults. Neurology 2023; 101:e1341-e1350. [PMID: 37495381 PMCID: PMC10558172 DOI: 10.1212/wnl.0000000000207659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 06/02/2023] [Indexed: 07/28/2023] Open
Abstract
BACKGROUND AND OBJECTIVES The APOE ε4 allele confers susceptibility to faster decline in odor identification and subsequently to Alzheimer disease (AD). Odor identification requires recognizing and naming odors and detecting them (odor sensitivity). Whether APOE ε4 is associated with decline of odor sensitivity and whether such decline serves as a harbinger of cognitive decline and AD remains unclear. We determined whether and when APOE ε4 affects decline in odor sensitivity, odor identification, and cognition in the National Social Life Health and Aging Project (NSHAP). METHODS We used data from NSHAP, a nationally representative survey study of home-dwelling US older adults. Olfaction was measured over time (odor identification in 2005, 2010, and 2015; odor sensitivity in 2010 and 2015; both using validated tests). Cognition was measured with a modified version of the Montreal Cognitive Assessment in 2010 and 2015. Genotyping was performed using DNA samples collected in 2010. Odor sensitivity and identification were compared among APOE ε4 carriers and noncarriers stratified by age. Relationships between APOE ε4, odor sensitivity, odor identification, and cognition were analyzed in cross-section using ordinal logistic regression and longitudinally using mixed-effects models adjusted for confounders. RESULTS Odor sensitivity was measured in 865 respondents, odor identification in 1,156 respondents, and cognition in 864 respondents; all these respondents had genetic data available. Odor sensitivity deficits in APOE ε4 carriers were apparent at ages 65-69 years, whereas odor identification deficits did not appear until ages 75-79 years. Subsequently, odor sensitivity did not decline more rapidly with aging in APOE ε4 carriers compared with that in noncarriers (carrier status and aging interaction: odds ratio [OR] 1.44, 95% CI 0.94-2.19, p = 0.092), whereas odor identification declined more rapidly in carriers (aging 10 years interaction: OR 0.26, 95% CI 0.13-0.52, p < 0.001). As expected, and in parallel to odor identification, cognition declined more rapidly in APOE ε4 carriers (interaction: OR 0.55, 95% CI 0.34-0.89, p = 0.015). DISCUSSION APOE ε4 affects decline of odor sensitivity earlier than odor identification or cognition. Thus, testing odor sensitivity may be useful to predict future impaired cognitive function. Identifying the mechanism underlying these relationships will elucidate the key role of olfaction in neurodegeneration during aging.
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Affiliation(s)
- Matthew S GoodSmith
- From the Internal Medicine-Pediatrics Residency Program (M.S.G.), Departments of Medicine and Pediatrics, Department of Public Health Sciences (K.E.W., L.P.S.), Department of Psychology and Institute for Mind and Biology (M.K.M.), and Section of Otolaryngology-Head and Neck Surgery (J.M.P.), Department of Surgery, The University of Chicago, IL.
| | - Kristen E Wroblewski
- From the Internal Medicine-Pediatrics Residency Program (M.S.G.), Departments of Medicine and Pediatrics, Department of Public Health Sciences (K.E.W., L.P.S.), Department of Psychology and Institute for Mind and Biology (M.K.M.), and Section of Otolaryngology-Head and Neck Surgery (J.M.P.), Department of Surgery, The University of Chicago, IL
| | - L Philip Schumm
- From the Internal Medicine-Pediatrics Residency Program (M.S.G.), Departments of Medicine and Pediatrics, Department of Public Health Sciences (K.E.W., L.P.S.), Department of Psychology and Institute for Mind and Biology (M.K.M.), and Section of Otolaryngology-Head and Neck Surgery (J.M.P.), Department of Surgery, The University of Chicago, IL
| | - Martha K McClintock
- From the Internal Medicine-Pediatrics Residency Program (M.S.G.), Departments of Medicine and Pediatrics, Department of Public Health Sciences (K.E.W., L.P.S.), Department of Psychology and Institute for Mind and Biology (M.K.M.), and Section of Otolaryngology-Head and Neck Surgery (J.M.P.), Department of Surgery, The University of Chicago, IL
| | - Jayant M Pinto
- From the Internal Medicine-Pediatrics Residency Program (M.S.G.), Departments of Medicine and Pediatrics, Department of Public Health Sciences (K.E.W., L.P.S.), Department of Psychology and Institute for Mind and Biology (M.K.M.), and Section of Otolaryngology-Head and Neck Surgery (J.M.P.), Department of Surgery, The University of Chicago, IL
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5
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Shrestha S, Zhu X, Kamath V, Sullivan KJ, Deal JA, Sharrett AR, Schneider ALC, Palta P, Gottesman RF, Windham BG, Mosley TH, Griswold ME, Chen H. Factors Associated with Poor Olfaction and Olfactory Decline in Older Adults in the ARIC Neurocognitive Study. Nutrients 2023; 15:3641. [PMID: 37630831 PMCID: PMC10459162 DOI: 10.3390/nu15163641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 08/13/2023] [Accepted: 08/18/2023] [Indexed: 08/27/2023] Open
Abstract
Olfactory function has significant implications for human health, but few risk factors for olfactory decline have been identified. We examined the factors associated with olfactory status and decline over five years in the Atherosclerosis Risk in Communities (ARIC) Neurocognitive Study. A 12-item odor identification test was used to assess olfaction in 6053 participants in 2011-2013 (ARIC visit 5, mean age: 75.6, 41% male, 23% Black race) and in 3235 participants in 2016-2017 (visit 6). We used Poisson regression models to examine cross-sectional associations of a range of potential factors with the total odor identification errors (mean errors: 2.8 ± 2.4) in visit 5 participants. We used mixed-effect Poisson regression to examine associations with olfactory decline between visits 5 and 6. We also examined associations with visit 5 anosmia prevalence (847 cases, 14%) and incident anosmia between the two visits (510 cases, 16%) using Poisson models. Older age, male sex, lower education, Black race, APOE ε4 alleles, and diabetes were associated with higher odor identification errors and higher anosmia prevalence, and greater physical activity and hypertension with better olfaction. Age, male sex, lower education, Black race, APOE ε4 allele, and vitamin B12 levels were associated with incident anosmia over 5 years. Older age was associated with faster olfactory decline. Future studies with longer follow-ups are warranted.
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Affiliation(s)
- Srishti Shrestha
- The Memory Impairment and Neurodegenerative Dementia (MIND) Center, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Xiaoqian Zhu
- The Memory Impairment and Neurodegenerative Dementia (MIND) Center, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Vidyulata Kamath
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Kevin J. Sullivan
- The Memory Impairment and Neurodegenerative Dementia (MIND) Center, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Jennifer A. Deal
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - A. Richey Sharrett
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Andrea L. C. Schneider
- Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
- Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Priya Palta
- Department of Neurology, University of North Carolina Chapel Hill, Chapel Hill, NC 27599, USA
| | - Rebecca F. Gottesman
- Stroke Branch, National Institute of Neurological Disorders and Stroke Intramural Research Program, Bethesda, MD 20892, USA
| | - B. Gwen Windham
- The Memory Impairment and Neurodegenerative Dementia (MIND) Center, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Thomas H. Mosley
- The Memory Impairment and Neurodegenerative Dementia (MIND) Center, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Michael E. Griswold
- The Memory Impairment and Neurodegenerative Dementia (MIND) Center, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Honglei Chen
- Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI 48824, USA
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Arsiwala-Scheppach LT, Ramulu PY, Sharrett AR, Kamath V, Deal JA, Guo X, Du S, Garcia Morales EE, Mihailovic A, Chen H, Abraham AG. Associations among Visual, Auditory, and Olfactory Functions in Community-Based Older Adults: The Atherosclerosis Risk in Communities (ARIC) Study. Transl Vis Sci Technol 2022; 11:2. [PMID: 36322079 PMCID: PMC9639698 DOI: 10.1167/tvst.11.11.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
PURPOSE Objective examination of relationships among visual, hearing, and olfactory function may yield mechanistic insights and inform our understanding of the burden of multiple-sensory impairments. METHODS This cross-sectional study capitalized on continuous measures of visual acuity (VA), contrast sensitivity, pure tone audiometry, Quick Speech-in-Noise (QuickSIN), and Sniffin' Sticks from a subset of ARIC participants at two community sites (EyeDOC Study, 2017-2019). Scales of all measures were aligned such that higher values indicated greater impairment. Intersensory bivariate associations were assessed graphically, and correlations assessed using Kendall's tau. Intersensory associations, independent of age, education, smoking, diabetes, and hypertension, were examined using linear regression. Analyses were stratified by community/race (Washington County/White vs Jackson/Black) and sex (men vs women) to explore community-sex heterogeneity. RESULTS We included 834 participants (mean age, 79 years); 39% were from Jackson and 63% females. We found weak intersensory correlations (tau generally ≤0.15). In the demographics-adjusted regression models, results were heterogeneous across communities and sex. Worse near VA, contrast sensitivity, and olfaction were associated with worse QuickSIN and worse near VA was associated with worse olfaction in some but not all community/race-sex groups (e.g., Jackson/Black women, 0.1 logMAR worse near VA was associated with 0.27 units increase in QuickSIN [95% confidence interval, 0.10-0.45]). Associations were modestly attenuated by adjustment for the shared risk factors of smoking, diabetes, and hypertension. CONCLUSIONS Visual dysfunction showed little or no association with hearing or olfaction impairments, suggesting a modest role for shared risk factors. TRANSLATIONAL RELEVANCE Visually impaired individuals have only a modestly higher risk of other sensory impairment.
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Affiliation(s)
| | - Pradeep Y. Ramulu
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, MD, USA,Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - A. Richey Sharrett
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Vidyulata Kamath
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Jennifer A. Deal
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA,Cochlear Center for Hearing and Public Health, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA,Johns Hopkins Center on Aging and Health, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Xinxing Guo
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Simo Du
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Emmanuel E. Garcia Morales
- Cochlear Center for Hearing and Public Health, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Aleksandra Mihailovic
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Honglei Chen
- Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI, USA
| | - Alison G. Abraham
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, MD, USA,Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA,Department of Epidemiology, School of Public Health, University of Colorado, Denver, CO, USA,Department of Ophthalmology, School of Medicine, University of Colorado, Denver, CO, USA
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7
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Olfactory Evaluation in Alzheimer’s Disease Model Mice. Brain Sci 2022; 12:brainsci12050607. [PMID: 35624994 PMCID: PMC9139301 DOI: 10.3390/brainsci12050607] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 04/26/2022] [Accepted: 05/03/2022] [Indexed: 11/17/2022] Open
Abstract
Olfactory dysfunction is considered a pre-cognitive biomarker of Alzheimer’s disease (AD). Because the olfactory system is highly conserved across species, mouse models corresponding to various AD etiologies have been bred and used in numerous studies on olfactory disorders. The olfactory behavior test is a method required for early olfactory dysfunction detection in AD model mice. Here, we review the olfactory evaluation of AD model mice, focusing on traditional olfactory detection methods, olfactory behavior involving the olfactory cortex, and the results of olfactory behavior in AD model mice, aiming to provide some inspiration for further development of olfactory detection methods in AD model mice.
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8
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Lee SJ. Alzheimer’s Disease is a Result of Loss of Full Brain Buoyancy. Med Hypotheses 2022. [DOI: 10.1016/j.mehy.2022.110857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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9
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Cha H, Kim S, Kim H, Kim G, Kwon KY. Effect of intensive olfactory training for cognitive function in patients with dementia. Geriatr Gerontol Int 2021; 22:5-11. [PMID: 34749425 DOI: 10.1111/ggi.14287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 09/06/2021] [Accepted: 09/14/2021] [Indexed: 01/22/2023]
Abstract
AIM Recent evidence has revealed an association between neurodegenerative disorders and olfactory dysfunction. However, whether olfactory training can improve cognitive impairment in patients with dementia requires further study. The present study aimed to resolve this by developing an intensive olfactory training (IOT) protocol and assessing its impact on each of the cognitive domains in patients with dementia. METHODS Patients were prospectively recruited between June 2020 and September 2020. Baseline evaluations included demographic data, olfactory function test, depression scale and detailed cognitive function tests. Thirty-four patients in the experimental group underwent IOT twice a day with a 40-odor set for 15 days, while 31 individuals in the control group received conservative management. Follow-up evaluations using the depression scale and detailed cognitive function tests were performed after IOT. RESULTS Baseline characteristics were not different between the two groups. The IOT group showed significant improvements in depression, attention, memory and language functions, but not global cognition, frontal executive, or visuospatial functions compared with the control group. CONCLUSION This study shows the ability of IOT to alleviate depression and improve some cognitive functions in patients with dementia. These results suggest that IOT may be an effective non-pharmacological approach for improving the symptoms of dementia. Geriatr Gerontol Int ••; ••: ••-•• Geriatr Gerontol Int 2021; ••: ••-••.
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Affiliation(s)
- Hyegyeong Cha
- Department of Nursing, Namseoul University, Cheonan-si, Republic of Korea
| | - Sisook Kim
- Department of Nursing, Namseoul University, Cheonan-si, Republic of Korea
| | - Hansong Kim
- Namgung Hospital, Cheongju-si, Republic of Korea
| | - Gaeyoung Kim
- Department of Nursing, Graduate School of Chung-Ang University, Seoul, Republic of Korea
| | - Kyum-Yil Kwon
- Department of Neurology, Soonchunhyang University Seoul Hospital, Soonchunhyang University School of Medicine, Seoul, Republic of Korea
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10
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Olfactory Measures as Predictors of Conversion to Mild Cognitive Impairment and Alzheimer's Disease. Brain Sci 2021; 11:brainsci11111391. [PMID: 34827390 PMCID: PMC8615615 DOI: 10.3390/brainsci11111391] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 10/11/2021] [Accepted: 10/14/2021] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Early biomarkers of prodromal Alzheimer's disease (AD) are critical both to initiate interventions and to choose participants for clinical trials. Odor threshold, odor identification and odor familiarity are impaired in AD. METHODS We investigated the relative abilities of standard screening (MMSE) and olfactory measures to predict transitions from cognitively normal (CN) to mild cognitive impairment (MCI), from CN to AD, and MCI to AD. The archival sample of 497, from the UCSD ADRC, included participants who were CN, MCI, AD and converters to MCI or AD. Apoe ε4 status, a genetic risk factor, was available for 256 participants, 132 were ε4 carriers. A receiver operating characteristic curve (ROC) curve plots the trade-off between sensitivity and specificity. Area under the ROC curve (AUC) was used to determine diagnostic accuracy. RESULTS Different measures were better predictors at specific stages of disease risk; e.g., odor familiarity, odor identification and the combination showed higher predictive value for converting from MCI to AD in ε4 carriers than the MMSE. Combining odor familiarity and odor identification produced an AUC of 1.0 in ε4 carriers, MMSE alone was 0.58. CONCLUSIONS Olfactory biomarkers show real promise as non-invasive indicators of prodromal AD. The results support the value of combining olfactory measures in assessment of risk for conversion to MCI and to AD.
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11
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Dan X, Wechter N, Gray S, Mohanty JG, Croteau DL, Bohr VA. Olfactory dysfunction in aging and neurodegenerative diseases. Ageing Res Rev 2021; 70:101416. [PMID: 34325072 PMCID: PMC8373788 DOI: 10.1016/j.arr.2021.101416] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 07/22/2021] [Accepted: 07/23/2021] [Indexed: 12/15/2022]
Abstract
Alterations in olfactory functions are proposed to be early biomarkers for neurodegeneration. Many neurodegenerative diseases are age-related, including two of the most common, Parkinson's disease (PD) and Alzheimer's disease (AD). The establishment of biomarkers that promote early risk identification is critical for the implementation of early treatment to postpone or avert pathological development. Olfactory dysfunction (OD) is seen in 90% of early-stage PD patients and 85% of patients with early-stage AD, which makes it an attractive biomarker for early diagnosis of these diseases. Here, we systematically review widely applied smelling tests available for humans as well as olfaction assessments performed in some animal models and the relationships between OD and normal aging, PD, AD, and other conditions. The utility of OD as a biomarker for neurodegenerative disease diagnosis and future research directions are also discussed.
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Affiliation(s)
- Xiuli Dan
- Section on DNA Repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Noah Wechter
- Section on DNA Repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Samuel Gray
- Section on DNA Repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Joy G Mohanty
- Section on DNA Repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Deborah L Croteau
- Section on DNA Repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Vilhelm A Bohr
- Section on DNA Repair, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA; Danish Center for Healthy Aging, University of Copenhagen, 2200 Copenhagen, Denmark.
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12
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Walker IM, Fullard ME, Morley JF, Duda JE. Olfaction as an early marker of Parkinson's disease and Alzheimer's disease. HANDBOOK OF CLINICAL NEUROLOGY 2021; 182:317-329. [PMID: 34266602 DOI: 10.1016/b978-0-12-819973-2.00030-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Olfactory impairment is a common and early sign of Parkinson's disease (PD) and Alzheimer's disease (AD), the two most prevalent neurodegenerative conditions in the elderly. This phenomenon corresponds to pathologic processes emerging in the olfactory system prior to the onset of typical clinical manifestations. Clinically available tests can establish hyposmia through odor identification assessment, discrimination, and odor detection threshold. There are significant efforts to develop preventative or disease-modifying therapies that slow down or halt the progression of PD and AD. Due to the convenience and low cost of its assessment, olfactory impairment could be used in these studies as a screening instrument. In the clinical setting, loss of smell may also help to differentiate PD and AD from alternative causes of Parkinsonism and cognitive impairment, respectively. Here, we discuss the pathophysiology of olfactory dysfunction in PD and AD and how it can be assessed in the clinical setting to aid in the early and differential diagnosis of these disorders.
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Affiliation(s)
- Ian M Walker
- Parkinson's Disease Research, Education and Clinical Center, Michael J. Crescenz, VA Medical Center, Philadelphia, PA, United States; Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Michelle E Fullard
- Department of Neurology, University of Colorado School of Medicine, Aurora, CO, United States
| | - James F Morley
- Parkinson's Disease Research, Education and Clinical Center, Michael J. Crescenz, VA Medical Center, Philadelphia, PA, United States; Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - John E Duda
- Parkinson's Disease Research, Education and Clinical Center, Michael J. Crescenz, VA Medical Center, Philadelphia, PA, United States; Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.
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13
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Analyzing Olfactory Neuron Precursors Non-Invasively Isolated through NADH FLIM as a Potential Tool to Study Oxidative Stress in Alzheimer's Disease. Int J Mol Sci 2021; 22:ijms22126311. [PMID: 34204595 PMCID: PMC8231156 DOI: 10.3390/ijms22126311] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/29/2021] [Accepted: 04/29/2021] [Indexed: 12/22/2022] Open
Abstract
Among all the proposed pathogenic mechanisms to understand the etiology of Alzheimer’s disease (AD), increased oxidative stress seems to be a robust and early disease feature where many of those hypotheses converge. However, despite the significant lines of evidence accumulated, an effective diagnosis and treatment of AD are not yet available. This limitation might be partially explained by the use of cellular and animal models that recapitulate partial aspects of the disease and do not account for the particular biology of patients. As such, cultures of patient-derived cells of peripheral origin may provide a convenient solution for this problem. Peripheral cells of neuronal lineage such as olfactory neuronal precursors (ONPs) can be easily cultured through non-invasive isolation, reproducing AD-related oxidative stress. Interestingly, the autofluorescence of key metabolic cofactors such as reduced nicotinamide adenine dinucleotide (NADH) can be highly correlated with the oxidative state and antioxidant capacity of cells in a non-destructive and label-free manner. In particular, imaging NADH through fluorescence lifetime imaging microscopy (FLIM) has greatly improved the sensitivity in detecting oxidative shifts with minimal intervention to cell physiology. Here, we discuss the translational potential of analyzing patient-derived ONPs non-invasively isolated through NADH FLIM to reveal AD-related oxidative stress. We believe this approach may potentially accelerate the discovery of effective antioxidant therapies and contribute to early diagnosis and personalized monitoring of this devastating disease.
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14
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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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15
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Piccininni K, Barbara F, De Luca C, Mazzatenta A, De Luca L, De Luca G, Zappone C, Ciccarone S. The secretory senescence of the senses of smell and taste. JOURNAL OF GERONTOLOGY AND GERIATRICS 2020. [DOI: 10.36150/2499-6564-486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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16
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Kapoulea EA, Murphy C. Older, non-demented apolipoprotein ε 4 carrier males show hyperactivation and structural differences in odor memory regions: a blood-oxygen-level-dependent and structural magnetic resonance imaging study. Neurobiol Aging 2020; 93:25-34. [PMID: 32447009 PMCID: PMC7605173 DOI: 10.1016/j.neurobiolaging.2020.04.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 04/09/2020] [Accepted: 04/10/2020] [Indexed: 11/18/2022]
Abstract
The current study sought to examine the interaction of sex and Apolipoprotein ε4 status on olfactory recognition memory within non-demented, older individuals. We separated 39 participants into groups based on ε4 status and sex. Each participant completed an olfactory memory recognition task during 2 functional magnetic resonance imaging scans and 1 structural scan. The ε4 carriers had greater functional recruitment of memory regions during false positives relative to ε4 non-carriers. During hits, the male ε4 carriers showed greater functional recruitment compared to female ε4 carriers. The ε4 carriers had larger bilateral putamen volumes relative to ε4 non-carriers. Neuroimaging data were significantly associated with Dementia Rating Scale scores solely in males. Results suggest differential olfactory memory processing in relation to sex and ε4 status. Male ε4 carriers in particular, demonstrated hyperactivation during recognition memory, which we suspect reflects neuronal compensation to maintain functional performance. Future studies should consider examining underlying mechanisms that contribute to these sex differences within ε4 carriers.
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Affiliation(s)
- Eleni A Kapoulea
- Department of Psychology, San Diego State University, San Diego, CA, USA
| | - Claire Murphy
- Department of Psychology, San Diego State University, San Diego, CA, USA; San Diego Joint Doctoral Program in Clinical Psychology, San Diego State University/University of California, San Diego, San Diego, CA, USA; Department of Psychiatry, University of California, San Diego, San Diego, CA, USA.
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17
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Frank C, Murphy C. The Brief Form of the California Odor Learning Test 3. Front Neurosci 2020; 14:173. [PMID: 32265619 PMCID: PMC7105850 DOI: 10.3389/fnins.2020.00173] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/17/2020] [Indexed: 12/15/2022] Open
Abstract
This study explored whether a Brief Form of the California Odor Learning Test 3 (COLT), an olfactory analog of the newly released Brief Form of the California Verbal Learning Test (CVLT 3), could retain the ability of the COLT to detect odor memory dysfunctions observed in normal aging. 52 participants, 28 young (18-30 years old) and 24 old (65 years of age and older), were administered the Brief Forms of the CVLT 3 and the COLT 3. Results indicated poorer performance in immediate and delayed odor recall in older than in younger adults. Poorer odor recognition memory performance in older adults than in younger adults was detected. This study suggests that the Brief Form of the COLT can detect differential odor learning and memory between young and older adults. Thus, the current brief test holds promise as a measure that can be incorporated into studies that demand a brief, non-invasive test capable of detecting impairment in olfactory function.
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Affiliation(s)
- Conner Frank
- Department of Psychology, San Diego State University, San Diego, CA, United States
| | - Claire Murphy
- Department of Psychology, San Diego State University, San Diego, CA, United States
- Department of Psychiatry, University of California, San Diego, San Diego, CA, United States
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18
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Ekström I, Josefsson M, Larsson M, Rönnlund M, Nordin S, Olofsson JK. Subjective Olfactory Loss in Older Adults Concurs with Long-Term Odor Identification Decline. Chem Senses 2020; 44:105-112. [PMID: 30544138 DOI: 10.1093/chemse/bjy079] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Olfactory impairments may provide early indications of future health outcomes in older adults. Thus, an important question concerns whether these impairments can be self-assessed. Previous findings of cross-sectional studies indicate low correlations between self-reported olfactory function and objective olfactory performance. On the other hand, subjective olfactory impairments predict future dementia and mortality in longitudinal settings. No previous study has assessed the relationship between subjectively and objectively measured decline in olfaction over time. Based on data for 903 older adults derived from the Betula Study, a Swedish population-based prospective study, we tested whether rate-of-change in odor identification could be predicted from subjective olfactory decline over a time span of 10 years during which subjective and objective odor functions were assessed on 2 or 3 test occasions. Indeed, we found that participants who experienced subjective olfactory decline over the study period also had significantly steeper rates of decline in odor identification, even after adjusting for demographic, cognitive, and genetic factors that previously have been associated with performance in odor identification. This association was, however, not present in a subsample with baseline cognitive impairment. We interpret these results as evidence that when asked about whether they have an olfactory impairment or not, older persons are assessing intraindividual olfactory changes, rather than interindividual differences. Our results indicate that subjective olfactory loss reflects objective olfactory decline in cognitively intact older adults. This association might be harnessed to predict health outcomes and highlights the need to develop effective olfactory self-assessments.
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Affiliation(s)
- Ingrid Ekström
- Gösta Ekman Laboratory, Stockholm University, Stockholm, Sweden.,Department of Psychology, Stockholm University, Stockholm, Sweden
| | - Maria Josefsson
- Center for Demographic and Ageing Research, Umeå University, Umeå, Sweden.,Center for Functional Brain Imaging, Umeå, Sweden
| | - Maria Larsson
- Gösta Ekman Laboratory, Stockholm University, Stockholm, Sweden.,Department of Psychology, Stockholm University, Stockholm, Sweden
| | | | - Steven Nordin
- Department of Psychology, Umeå University, Umeå, Sweden
| | - Jonas K Olofsson
- Gösta Ekman Laboratory, Stockholm University, Stockholm, Sweden.,Department of Psychology, Stockholm University, Stockholm, Sweden
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19
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Devanand D, Lee S, Luchsinger JA, Andrews H, Goldberg T, Huey ED, Schupf N, Manly J, Stern Y, Kreisl WC, Mayeux R. Intact global cognitive and olfactory ability predicts lack of transition to dementia. Alzheimers Dement 2020; 16:326-334. [PMID: 31676234 PMCID: PMC7007828 DOI: 10.1016/j.jalz.2019.08.200] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
INTRODUCTION Odor identification deficits characterize Alzheimer's disease and other dementias. We examined if intact performance on brief cognitive and odor identification tests predicts lack of transition to dementia. METHODS In an urban community, 1037 older adults without dementia completed the 40-item University of Pennsylvania Smell Identification Test, which includes the 12-item Brief Smell Identification Test (B-SIT). Data from 749 participants followed up for 4 years were analyzed. RESULTS In covariate-adjusted survival analyses, impairment on the Blessed Orientation Memory Concentration Test and B-SIT each predicted dementia (n = 109), primarily Alzheimer's disease (n = 101). Among participants with intact olfactory (B-SIT ≥ 11/12 correct) and cognitive (Blessed Orientation Memory Concentration Test ≤ 5/28 incorrect) ability, 3.4% (4/117) transitioned to dementia during follow-up with no transitions in the 70-75 and 81-83 years age group quartiles. DISCUSSION Odor identification testing adds value to global cognitive testing, and together can identify individuals who rarely transition to dementia, thereby avoiding unnecessary diagnostic investigation.
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Affiliation(s)
- D.P. Devanand
- Division of Geriatric Psychiatry, New York State Psychiatric Institute, New York, NY, USA
- Department of Psychiatry, Columbia University Medical Center, New York, NY, USA
| | - Seonjoo Lee
- Research Foundation for Mental Hygiene and the Department of Biostatics, College of Physicians and Surgeons, Columbia University, New York City, New York, United States of America
| | - Jose A. Luchsinger
- Department of Medicine, Columbia University Medical Center, New York, NY, USA
| | - Howard Andrews
- Department of Biostatistics, Mailman School of Public Health, Columbia University Medical Center, New York, NY, USA
| | - Terry Goldberg
- Division of Geriatric Psychiatry, New York State Psychiatric Institute, New York, NY, USA
- Department of Psychiatry, Columbia University Medical Center, New York, NY, USA
| | - Edward D. Huey
- Department of Psychiatry, Columbia University Medical Center, New York, NY, USA
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, United States
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, United States
| | - Nicole Schupf
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, United States
- Department of Neurology Columbia University and the New York Presbyterian Hospital, New York, NY, USA
- Department of Epidemiology, Mailman School of Public Health, Columbia University Medical Center, New York, NY, USA
| | - Jennifer Manly
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, United States
- Department of Neurology Columbia University and the New York Presbyterian Hospital, New York, NY, USA
- The Gertrude H. Sergievsky Center, Columbia University, New York,NY, USA
| | - Yaakov Stern
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, United States
| | - William C. Kreisl
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, United States
| | - Richard Mayeux
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, United States
- The Gertrude H. Sergievsky Center, Columbia University, New York,NY, USA
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20
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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: 48] [Impact Index Per Article: 9.6] [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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21
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Odor Identification in Rats: Behavioral and Electrophysiological Evidence of Learned Olfactory-Auditory Associations. eNeuro 2019; 6:ENEURO.0102-19.2019. [PMID: 31362955 PMCID: PMC6709214 DOI: 10.1523/eneuro.0102-19.2019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 06/28/2019] [Accepted: 07/15/2019] [Indexed: 12/31/2022] Open
Abstract
The ability to recognize and identify a smell is highly dependent on multisensory context and expectation, for example, hearing the name of the odor source. Here, we develop a novel auditory-odor association task in rats, wherein the animal learns that a specific auditory tone, when associated with a specific odor, predicts reward (Go signal), whereas the same tone associated with a different odor, or vice versa, is not (No-Go signal). The tone occurs prior to the onset of the odor, allowing physiological analyses of sensory-evoked local field potential (LFP) activity to each stimulus in primary auditory cortex and anterior piriform cortex (aPCX). In trained animals that have acquired the task, both auditory and subsequent olfactory cues activate β band oscillations in both the auditory cortex and PCX, suggesting multisensory integration. Naive animals show no such multisensory responses, suggesting the response is learned. In addition to the learned multisensory evoked responses, functional connectivity between auditory cortex and PCX, as assessed with spectral coherence and phase lag index (PLI), is enhanced. Importantly, both the multi-sensory evoked responses and the functional connectivity are context-dependent. In trained animals, the same auditory stimuli presented in the home cage evoke no responses in auditory cortex or PCX, and functional connectivity between the sensory cortices is reduced. Together, the results demonstrate how learning and context shape the expression of multisensory cortical processing. Given that odor identification impairment is associated with preclinical dementia in humans, the mechanisms suggested here may help develop experimental models to assess effects of neuropathology on behavior.
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22
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Bower ES, Szajer J, Murphy C. Effect of Worry Level on Recall Memory for Odors in ApoE-ε4 Carriers and Non-Carriers. J Int Neuropsychol Soc 2019; 25:546-556. [PMID: 30987686 PMCID: PMC6534430 DOI: 10.1017/s1355617719000158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Increased levels of worry, age, and presence of the apolipoprotein-E (ApoE)-ε4 allele are associated with the risk of developing cognitive declines and Alzheimer's disease (AD). Odor memory performance has been shown to vary as a function of age and ApoE genotype, and odor memory tests are sensitive to preclinical AD. Worry is known to influence verbal memory; however, its effects on odor memory are unknown. This study aimed to assess the relationships between worry, age, and ε4 status on odor memory. METHOD Worry was evaluated for young (n = 53) and older (n = 45) adults using the Penn State Worry Questionnaire. Odor memory was assessed using the California Odor Learning Test, an olfactory analogue to the California Verbal Learning Test. RESULTS A significant main effect of worry on long-delay free recall was found, such that increasing worry was associated with better recall across age and ε4 status. A significant interaction effect between ε4 status and worry on both short-and long-delay cued recall was found, such that across age, higher worry was associated with increased cued recall scores among ε4-negative adults, and decreased scores among ε4-positive adults. CONCLUSIONS Findings demonstrated that worry influences odor memory and exerts a particular effect on cued recall among ε4 carriers who are at a greater risk of developing AD. Worry is a modifiable predictor of cognitive decline and risk of dementia in aging. Future studies on the effects of treatments aimed at reducing worry (e.g., cognitive behavioral therapies for anxiety) on changes in cognitive functioning are warranted.
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Affiliation(s)
- Emily S Bower
- Department of Psychology,San Diego State University,San Diego, California 92182,USA
| | - Jacquelyn Szajer
- SDSU/UCSD Joint Doctoral Program in Clinical Psychology,San Diego, California 92120,USA
| | - Claire Murphy
- Department of Psychology,San Diego State University,San Diego, California 92182,USA
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23
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Prediger RD, Schamne MG, Sampaio TB, Moreira ELG, Rial D. Animal models of olfactory dysfunction in neurodegenerative diseases. HANDBOOK OF CLINICAL NEUROLOGY 2019; 164:431-452. [PMID: 31604561 DOI: 10.1016/b978-0-444-63855-7.00024-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Olfactory dysfunction seems to occur earlier than classic motor and cognitive symptoms in many neurodegenerative diseases, including Parkinson's disease (PD) and Alzheimer's disease (AD). Thus, the use of the olfactory system as a 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. The use of genetic and neurotoxin animal models has contributed to the understanding of the mechanisms underlying olfactory dysfunction in a number of neurodegenerative diseases. In this chapter, we provide an overview of behavioral and neurochemical alterations observed in animal models of different neurodegenerative diseases (such as genetic and Aβ infusion models for AD and neurotoxins and genetic models of PD), in which olfactory dysfunction has been described.
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Affiliation(s)
- Rui D Prediger
- Department of Pharmacology, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, Brazil.
| | - Marissa G Schamne
- Department of Pharmacology, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Tuane B Sampaio
- Department of Pharmacology, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Eduardo L G Moreira
- Department of Physiological Sciences, Center of Biological Sciences¸ Federal University of Santa Catarina, Florianópolis, Brazil
| | - Daniel Rial
- Department of Pharmacology, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, Brazil
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25
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Abstract
Disturbances in both the ability to smell and to taste are common in older persons. Such disturbances influence nutrition, safety, quality of life, and psychological and physical health. The anatomic and physiologic causes of age-related disturbances are multiple and interacting, and depend on genetic and environmental factors. Frank losses of function, distortions, and hallucinations are common. Most distortions resolve over time, although this can take months or even years. Olfactory dysfunction occurs during the earliest stages of several neurologic disorders, most notably Alzheimer's disease and Parkinson's disease, likely heralding the onset of the underlying pathologies.
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Affiliation(s)
- Richard L Doty
- Smell and Taste Center, Department of Otorhinolaryngology, Head and Neck Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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26
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Misiak MM, Hipolito MS, Ressom HW, Obisesan TO, Manaye KF, Nwulia EA. Apo E4 Alleles and Impaired Olfaction as Predictors of Alzheimer's Disease. CLINICAL AND EXPERIMENTAL PSYCHOLOGY 2017; 3:169. [PMID: 29423459 PMCID: PMC5800509 DOI: 10.4172/2471-2701.1000169] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Alzheimer's disease (AD) is the most common form of dementia that affects more than 5 million Americans. It is the only disease among the 10 causes of death that cannot be slowed or cured, thus raising the need for identification of early preclinical markers that could be the focus of preventative efforts. Although evidence is escalating that abnormalities in olfactory structure and function precede AD development and early cognitive impairments by one or more decades, the importance of olfaction is largely overlooked in AD, and such testing is not routinely performed in neurology clinics. Nevertheless, research using the olfactory model, has begun to advance our understanding of the preclinical pathophysiology of AD. Notably, an interesting series of studies is beginning to illuminate the relationship between Apolipoprotein E (ApoE) ε4 polymorphism and olfactory dysfunction and late-onset Alzheimer's disease. In this article, we reviewed present research on the significance of ApoE and olfaction to AD, summarized current studies on the associations and mechanisms of ApoE and olfactory dysfunction, and highlighted important gaps for future work to further advance the translational application of the olfactory paradigm to early, preclinical diagnosis and treatment of AD.
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Affiliation(s)
- Magdalena M Misiak
- Department of Psychiatry and Behavioral Sciences, Howard University, Washington DC, USA
- Department of Physiology, Howard University, Washington DC, USA
| | - MariaMananita S Hipolito
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
| | - Habtom W Ressom
- Department of Medicine, Howard University, Washington DC, USA
| | | | | | - Evaristus A Nwulia
- Department of Psychiatry and Behavioral Sciences, Howard University, Washington DC, USA
- Department of Oncology, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
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Josefsson M, Larsson M, Nordin S, Adolfsson R, Olofsson J. APOE-ɛ4 effects on longitudinal decline in olfactory and non-olfactory cognitive abilities in middle-aged and old adults. Sci Rep 2017; 7:1286. [PMID: 28455505 PMCID: PMC5430873 DOI: 10.1038/s41598-017-01508-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 03/28/2017] [Indexed: 11/29/2022] Open
Abstract
Characterizing aging-related decline trajectories in mental abilities, and relationships of the ɛ4 allele of the Apolipoprotein gene, helps to identify individuals at high risk for dementia. However, longitudinal changes in olfactory and non-olfactory cognitive abilities have not been investigated in relation to the ɛ4 allele. In the present study, participants from a large population-based study (657 middle-aged and 556 old) were tested over 10 years on their performance on an odor identification task and three non-olfactory cognitive tasks; MMSE, episodic memory, and semantic memory. Our key finding is that in middle-aged participants, odor identification declined twice as fast for ɛ4/4 homozygotes, compared to non-carriers. However, in old participants, the ɛ4/4 homozygotes showed an impaired odor identification ability, but they declined at a similar rate as the non-carriers. Furthermore, in old participants all assessments displayed aging-related declines, but exaggerated declines in ɛ4-carriers were found only in MMSE and episodic memory assessments. In sum, we present evidence that odor identification ability starts to decline already in middle-aged, and that carriers of ɛ4/4, who are at highest risk of developing dementia, decline twice as fast. Our results may have implications for use of odor identification assessment in detection of early-stage dementia.
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Affiliation(s)
- Maria Josefsson
- Centre for Demographic and Ageing Research, Umeå University, Umeå, Sweden.
| | - Maria Larsson
- Gösta Ekman Laboratory, Department of Psychology, Stockholm University, Stockholm, Sweden
| | - Steven Nordin
- Department of Psychology, Umeå University, Umeå, Sweden
| | - Rolf Adolfsson
- Department of Clinical Sciences, Psychiatry, Umeå University Hospital, Umeå, Sweden
| | - Jonas Olofsson
- Gösta Ekman Laboratory, Department of Psychology, Stockholm University, Stockholm, Sweden.,Swedish Collegium for Advanced Study, Uppsala, Sweden
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Abstract
Object recognition is a crucial component of both visual and auditory perception. It is also critical for olfaction. Most odours are composed of 10s or 100s of volatile components, yet they are perceived as unitary perceptual events against a continually shifting olfactory background (ie figure—ground segregation). We argue here that this occurs by rapid central adaptation to background odours combined with a pattern-matching system to recognise discrete sets of spatial and temporal olfactory features—an odour object. We present supporting neuropsychological, learning, and developmental evidence and then describe the neural circuitry which underpins this. The vagaries of an object-recognition approach are then discussed, with emphasis on the putative importance of memory, multimodal representations, and top—down processing.
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Affiliation(s)
| | - Donald A Wilson
- Department of Zoology, University of Oklahoma, Norman, OK 73019, USA
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DelGaudio JM, Panella NJ. Presbynasalis. Int Forum Allergy Rhinol 2016; 6:1083-1087. [DOI: 10.1002/alr.21787] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 03/10/2016] [Accepted: 03/15/2016] [Indexed: 11/07/2022]
Affiliation(s)
- John M. DelGaudio
- Division of Rhinology and Sinus Surgery; Emory University; Atlanta GA
- Department of Otolaryngology-Head and Neck Surgery; Emory University; Atlanta GA
| | - Nicholas J. Panella
- Department of Otolaryngology-Head and Neck Surgery; Emory University; Atlanta GA
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Olofsson JK, Josefsson M, Ekström I, Wilson D, Nyberg L, Nordin S, Nordin Adolfsson A, Adolfsson R, Nilsson LG, Larsson M. Long-term episodic memory decline is associated with olfactory deficits only in carriers of ApoE-є4. Neuropsychologia 2016; 85:1-9. [DOI: 10.1016/j.neuropsychologia.2016.03.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 03/03/2016] [Accepted: 03/04/2016] [Indexed: 02/06/2023]
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Daulatzai MA. Olfactory dysfunction: its early temporal relationship and neural correlates in the pathogenesis of Alzheimer’s disease. J Neural Transm (Vienna) 2015; 122:1475-97. [DOI: 10.1007/s00702-015-1404-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 04/29/2015] [Indexed: 12/18/2022]
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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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At the interface of sensory and motor dysfunctions and Alzheimer's disease. Alzheimers Dement 2015; 11:70-98. [PMID: 25022540 PMCID: PMC4287457 DOI: 10.1016/j.jalz.2014.04.514] [Citation(s) in RCA: 370] [Impact Index Per Article: 41.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 03/13/2014] [Accepted: 04/09/2014] [Indexed: 11/21/2022]
Abstract
Recent evidence indicates that sensory and motor changes may precede the cognitive symptoms of Alzheimer's disease (AD) by several years and may signify increased risk of developing AD. Traditionally, sensory and motor dysfunctions in aging and AD have been studied separately. To ascertain the evidence supporting the relationship between age-related changes in sensory and motor systems and the development of AD and to facilitate communication between several disciplines, the National Institute on Aging held an exploratory workshop titled "Sensory and Motor Dysfunctions in Aging and AD." The scientific sessions of the workshop focused on age-related and neuropathologic changes in the olfactory, visual, auditory, and motor systems, followed by extensive discussion and hypothesis generation related to the possible links among sensory, cognitive, and motor domains in aging and AD. Based on the data presented and discussed at this workshop, it is clear that sensory and motor regions of the central nervous system are affected by AD pathology and that interventions targeting amelioration of sensory-motor deficits in AD may enhance patient function as AD progresses.
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Devanand DP, Lee S, Manly J, Andrews H, Schupf N, Doty RL, Stern Y, Zahodne LB, Louis ED, Mayeux R. Olfactory deficits predict cognitive decline and Alzheimer dementia in an urban community. Neurology 2014; 84:182-9. [PMID: 25471394 DOI: 10.1212/wnl.0000000000001132] [Citation(s) in RCA: 225] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To determine the predictive utility of baseline odor identification deficits for future cognitive decline and the diagnosis of Alzheimer disease (AD) dementia. METHODS In a multiethnic community cohort in North Manhattan, NY, 1,037 participants without dementia were evaluated with the 40-item University of Pennsylvania Smell Identification Test (UPSIT). In 757 participants, follow-up occurred at 2 years and 4 years. RESULTS In logistic regression analyses, lower baseline UPSIT scores were associated with cognitive decline (relative risk 1.067 per point interval; 95% confidence interval [CI] 1.040, 1.095; p < 0.0001), and remained significant (relative risk 1.065 per point interval; 95% CI 1.034, 1.095; p < 0.0001) after including covariates. UPSIT, but not Selective Reminding Test-total immediate recall, predicted cognitive decline in participants without baseline cognitive impairment. During follow-up, 101 participants transitioned to AD dementia. In discrete time survival analyses, lower baseline UPSIT scores were associated with transition to AD dementia (hazard ratio 1.099 per point interval; 95% CI 1.067, 1.131; p < 0.0001), and remained highly significant (hazard ratio 1.072 per point interval; 95% CI 1.036, 1.109; p < 0.0001) after including demographic, cognitive, and functional covariates. CONCLUSIONS Impairment in odor identification was superior to deficits in verbal episodic memory in predicting cognitive decline in cognitively intact participants. The findings support the cross-cultural use of a relatively inexpensive odor identification test as an early biomarker of cognitive decline and AD dementia. Such testing may have the potential to select/stratify patients in treatment trials of cognitively impaired patients or prevention trials in cognitively intact individuals.
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Affiliation(s)
- D P Devanand
- From the Division of Geriatric Psychiatry, Department of Psychiatry (D.P.D.), Department of Neurology and the Gertrude H. Sergievsky Center and the Taub Institute for Research on Alzheimer's Disease and the Aging Brain (J.M., H.A., N.S., Y.S., L.B.Z., E.D.L., R.M.), College of Physicians and Surgeons, Columbia University, New York; Division of Biostatistics (S.L.), New York State Psychiatric Institute and Columbia University, New York; and University of Pennsylvania (R.L.D.), Philadelphia.
| | - Seonjoo Lee
- From the Division of Geriatric Psychiatry, Department of Psychiatry (D.P.D.), Department of Neurology and the Gertrude H. Sergievsky Center and the Taub Institute for Research on Alzheimer's Disease and the Aging Brain (J.M., H.A., N.S., Y.S., L.B.Z., E.D.L., R.M.), College of Physicians and Surgeons, Columbia University, New York; Division of Biostatistics (S.L.), New York State Psychiatric Institute and Columbia University, New York; and University of Pennsylvania (R.L.D.), Philadelphia
| | - Jennifer Manly
- From the Division of Geriatric Psychiatry, Department of Psychiatry (D.P.D.), Department of Neurology and the Gertrude H. Sergievsky Center and the Taub Institute for Research on Alzheimer's Disease and the Aging Brain (J.M., H.A., N.S., Y.S., L.B.Z., E.D.L., R.M.), College of Physicians and Surgeons, Columbia University, New York; Division of Biostatistics (S.L.), New York State Psychiatric Institute and Columbia University, New York; and University of Pennsylvania (R.L.D.), Philadelphia
| | - Howard Andrews
- From the Division of Geriatric Psychiatry, Department of Psychiatry (D.P.D.), Department of Neurology and the Gertrude H. Sergievsky Center and the Taub Institute for Research on Alzheimer's Disease and the Aging Brain (J.M., H.A., N.S., Y.S., L.B.Z., E.D.L., R.M.), College of Physicians and Surgeons, Columbia University, New York; Division of Biostatistics (S.L.), New York State Psychiatric Institute and Columbia University, New York; and University of Pennsylvania (R.L.D.), Philadelphia
| | - Nicole Schupf
- From the Division of Geriatric Psychiatry, Department of Psychiatry (D.P.D.), Department of Neurology and the Gertrude H. Sergievsky Center and the Taub Institute for Research on Alzheimer's Disease and the Aging Brain (J.M., H.A., N.S., Y.S., L.B.Z., E.D.L., R.M.), College of Physicians and Surgeons, Columbia University, New York; Division of Biostatistics (S.L.), New York State Psychiatric Institute and Columbia University, New York; and University of Pennsylvania (R.L.D.), Philadelphia
| | - Richard L Doty
- From the Division of Geriatric Psychiatry, Department of Psychiatry (D.P.D.), Department of Neurology and the Gertrude H. Sergievsky Center and the Taub Institute for Research on Alzheimer's Disease and the Aging Brain (J.M., H.A., N.S., Y.S., L.B.Z., E.D.L., R.M.), College of Physicians and Surgeons, Columbia University, New York; Division of Biostatistics (S.L.), New York State Psychiatric Institute and Columbia University, New York; and University of Pennsylvania (R.L.D.), Philadelphia
| | - Yaakov Stern
- From the Division of Geriatric Psychiatry, Department of Psychiatry (D.P.D.), Department of Neurology and the Gertrude H. Sergievsky Center and the Taub Institute for Research on Alzheimer's Disease and the Aging Brain (J.M., H.A., N.S., Y.S., L.B.Z., E.D.L., R.M.), College of Physicians and Surgeons, Columbia University, New York; Division of Biostatistics (S.L.), New York State Psychiatric Institute and Columbia University, New York; and University of Pennsylvania (R.L.D.), Philadelphia
| | - Laura B Zahodne
- From the Division of Geriatric Psychiatry, Department of Psychiatry (D.P.D.), Department of Neurology and the Gertrude H. Sergievsky Center and the Taub Institute for Research on Alzheimer's Disease and the Aging Brain (J.M., H.A., N.S., Y.S., L.B.Z., E.D.L., R.M.), College of Physicians and Surgeons, Columbia University, New York; Division of Biostatistics (S.L.), New York State Psychiatric Institute and Columbia University, New York; and University of Pennsylvania (R.L.D.), Philadelphia
| | - Elan D Louis
- From the Division of Geriatric Psychiatry, Department of Psychiatry (D.P.D.), Department of Neurology and the Gertrude H. Sergievsky Center and the Taub Institute for Research on Alzheimer's Disease and the Aging Brain (J.M., H.A., N.S., Y.S., L.B.Z., E.D.L., R.M.), College of Physicians and Surgeons, Columbia University, New York; Division of Biostatistics (S.L.), New York State Psychiatric Institute and Columbia University, New York; and University of Pennsylvania (R.L.D.), Philadelphia
| | - Richard Mayeux
- From the Division of Geriatric Psychiatry, Department of Psychiatry (D.P.D.), Department of Neurology and the Gertrude H. Sergievsky Center and the Taub Institute for Research on Alzheimer's Disease and the Aging Brain (J.M., H.A., N.S., Y.S., L.B.Z., E.D.L., R.M.), College of Physicians and Surgeons, Columbia University, New York; Division of Biostatistics (S.L.), New York State Psychiatric Institute and Columbia University, New York; and University of Pennsylvania (R.L.D.), Philadelphia
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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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Doty RL, Kamath V. The influences of age on olfaction: a review. Front Psychol 2014; 5:20. [PMID: 24570664 PMCID: PMC3916729 DOI: 10.3389/fpsyg.2014.00020] [Citation(s) in RCA: 336] [Impact Index Per Article: 33.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 01/08/2014] [Indexed: 12/21/2022] Open
Abstract
Decreased olfactory function is very common in the older population, being present in over half of those between the ages of 65 and 80 years and in over three quarters of those over the age of 80 years. Such dysfunction significantly influences physical well-being and quality of life, nutrition, the enjoyment of food, as well as everyday safety. Indeed a disproportionate number of the elderly die in accident gas poisonings each year. As described in this review, multiple factors contribute to such age-related loss, including altered nasal engorgement, increased propensity for nasal disease, cumulative damage to the olfactory epithelium from viral and other environmental insults, decrements in mucosal metabolizing enzymes, ossification of cribriform plate foramina, loss of selectivity of receptor cells to odorants, changes in neurotransmitter and neuromodulator systems, and neuronal expression of aberrant proteins associated with neurodegenerative disease. It is now well established that decreased smell loss can be an early sign of such neurodegenerative diseases as Alzheimer's disease and sporadic Parkinson's disease. In this review we provide an overview of the anatomy and physiology of the aging olfactory system, how this system is clinically evaluated, and the multiple pathophysiological factors that are associated with its dysfunction.
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Affiliation(s)
- Richard L. Doty
- Department of Otorhinolaryngology: Head and Neck Surgery, Smell and Taste Center, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, USA
| | - Vidyulata Kamath
- Department of Otorhinolaryngology: Head and Neck Surgery, Smell and Taste Center, Perelman School of Medicine, University of PennsylvaniaPhiladelphia, PA, USA
- Division of Medical Psychology, Department of Psychiatry and Behavioral Sciences, The Johns Hopkins University School of MedicineBaltimore, MD, USA
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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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Aliani M, Udenigwe CC, Girgih AT, Pownall TL, Bugera JL, Eskin MNA. Aroma and taste perceptions with Alzheimer disease and stroke. Crit Rev Food Sci Nutr 2013; 53:760-9. [PMID: 23638935 DOI: 10.1080/10408398.2011.559557] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Chemosensory disorders of smell or taste in humans have been attributed to various physiological and environmental factors including aging and disease conditions. Aroma and taste greatly condition our food preference, selection and, consumption; the decreased appetite in patients with known neurodegenerative diseases may lead to dietary restrictions that could negatively impact nutritional and health status. The decline in olfactory and gustatory systems in patients with Alzheimer disease and various types of stroke are described.
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Affiliation(s)
- Michel Aliani
- Human Nutritional Sciences, Faculty of Human Ecology, University of Manitoba, Winnipeg, Manitoba, Canada.
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Hussain A, Luong M, Pooley A, Nathan BP. Isoform-specific effects of apoE on neurite outgrowth in olfactory epithelium culture. J Biomed Sci 2013; 20:49. [PMID: 23845000 PMCID: PMC3717083 DOI: 10.1186/1423-0127-20-49] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 07/08/2013] [Indexed: 11/10/2022] Open
Abstract
Background The apolipoprotein E4 (apoE4) genotype is a major risk factor for developing late-onset Alzheimer’s disease (AD). Inheritance of apoE4 is also associated with impairments in olfactory function in early stages of AD. In this project we examined the effects of the three common isoforms of human apoE (apoE2, apoE3, and apoE4) on neuronal differentiation and neurite outgrowth in explant cultures of mouse olfactory epithelium (OE). Results The OE cultures derived from apoE-deficient/knockout (KO) mice have significantly fewer neurons with shorter neurite outgrowth than cultures from wild-type (WT) mice. Treatment of the apoE KO culture with either purified human apoE2 or with human apoE3 significantly increased neurite outgrowth. In contrast, treatment with apoE4 did not have an effect on neurite outgrowth. The differential effects of human apoE isoforms on neurite outgrowth were abolished by blocking the low-density lipoprotein receptor-related protein (LRP) with lactoferrin and receptor-associated protein (RAP). Conclusion ApoE2 and apoE3 stimulate neurite outgrowth in OE cultures by interacting with the lipoprotein receptor, LRP. ApoE4, the isoform associated with AD, failed to promote neurite outgrowth, suggesting a potential mechanism whereby apoE4 may lead to olfactory dysfunction in AD patients.
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Affiliation(s)
- Aseem Hussain
- Department of Biological Sciences, Eastern Illinois University, 600 Lincoln Avenue, Charleston, IL 61920, USA
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Bower E, Szajer J, Mattson SN, Riley EP, Murphy C. Impaired odor identification in children with histories of heavy prenatal alcohol exposure. Alcohol 2013; 47:275-8. [PMID: 23683527 DOI: 10.1016/j.alcohol.2013.03.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 03/21/2013] [Accepted: 03/21/2013] [Indexed: 11/29/2022]
Abstract
Prenatal alcohol exposure can lead to behavioral and cognitive impairments across multiple domains. Many of the brain regions impacted by prenatal alcohol exposure are also linked with olfactory processing, and odor identification deficits have been documented in certain neurological disorders associated with these brain regions. As odor identification following prenatal alcohol exposure is not well studied, we compared odor identification in children with prenatal exposure to alcohol (AE) to typically developing controls (CON) (N = 16/group). It was hypothesized that children in the AE group would perform more poorly than children in the CON group on the San Diego Odor Identification Test, an identification test of 8 common household odorants. Children exposed to alcohol during prenatal development were significantly impaired in olfactory identification (M = 5.95, SE = 0.37) compared to typically developing controls (M = 7.24, SE = 0.37). These findings confirmed the hypothesis that prenatal exposure to alcohol is associated with odor identification deficits, and suggest that further research is warranted to identify the mechanisms underlying these deficits, the integrity of brain areas that are involved, and to determine whether olfactory performance might contribute to better identification of children at risk for behavioral and cognitive deficits.
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Affiliation(s)
- Emily Bower
- San Diego State University/University of California, San Diego Joint Doctoral Program in Clinical Psychology, San Diego, CA 92120-4913, USA
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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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Morgan CD, Murphy C. Individuals at risk for Alzheimer's disease show differential patterns of ERP brain activation during odor identification. BEHAVIORAL AND BRAIN FUNCTIONS : BBF 2012; 8:37. [PMID: 22849610 PMCID: PMC3542023 DOI: 10.1186/1744-9081-8-37] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Accepted: 06/15/2012] [Indexed: 11/17/2022]
Abstract
BACKGROUND Studies suggest that older adults at risk of developing Alzheimer's disease may show olfactory processing deficits before other signs of dementia appear. METHODS We studied 60 healthy non-demented individuals, half of whom were positive for the genetic risk factor the Apolipoprotein E ε4 allele, in three different age groups. Event-related potentials to visual and olfactory identification tasks were recorded and analyzed for latency and amplitude differences, and plotted via topographical maps. RESULTS Varying patterns of brain activation were observed over the post-stimulus epoch for ε4- versus ε4+ individuals on topographical maps. Individuals with the ε4 allele demonstrated different ERP peak latencies during identification of olfactory but not visual stimuli. High correct ApoE classification rates were obtained utilizing the olfactory ERP. CONCLUSIONS Olfactory ERPs demonstrate functional decline in individuals at risk for Alzheimer's disease at much earlier ages than previously observed, suggesting the potential for pre-clinical detection of AD at very early stages.
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Affiliation(s)
- Charlie D Morgan
- Department of Psychology, San Diego State University, San Diego, CA, 92120, USA
| | - Claire Murphy
- Department of Psychology, San Diego State University, San Diego, CA, 92120, USA
- University of California San Diego Medical Center, San Diego, CA, 92120, USA
- SDSU/UCSD Joint Doctoral Program, 6363 Alvarado Ct., Suite 101, San Diego, CA, 92120-4913, USA
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Nathan BP, Tonsor M, Struble RG. Long-term effects of estradiol replacement in the olfactory system. Exp Neurol 2012; 237:1-7. [PMID: 22691461 DOI: 10.1016/j.expneurol.2012.06.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2012] [Revised: 05/27/2012] [Accepted: 06/01/2012] [Indexed: 01/09/2023]
Abstract
Olfactory dysfunction often precedes other clinical symptoms in chronic neurodegenerative diseases like Alzheimer's disease and Parkinson's disease. Estrogen deficiency and apoE genotype are known risk factors in these diseases and these factors also affect olfaction. Therefore we examined the effects of estradiol replacement following ovariectomy on expression of apoE and markers of cell proliferation, neuronal maturation, synaptogenesis and reactive gliosis in the primary olfactory pathway of wild-type (WT) and apoE knockout (KO) mice. Estradiol replacement increased apoE staining in the olfactory nerve and glomerular layers. Estradiol increased astrocyte density and olfactory epithelium (OE) thickness regardless of the genotype. In addition estradiol treatment increased the number of mature neurons in the OE and glomerular synaptophysin in both genotypes, but the magnitude of increase was greater in the WT than in the KO mice. These data suggest that estrogen and apoE act synergistically to minimize the loss of mature sensory neurons and synapses following ovariectomy.
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Affiliation(s)
- Britto P Nathan
- Department of Biological Sciences, Eastern Illinois University, 600 Lincoln Avenue, Charleston, IL 61920, USA.
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Corby K, Morgan CD, Murphy C. Abnormal event-related potentials in young and middle-aged adults with the ApoE ε4 allele. Int J Psychophysiol 2012; 83:276-81. [PMID: 22100309 PMCID: PMC4343300 DOI: 10.1016/j.ijpsycho.2011.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2011] [Revised: 06/23/2011] [Accepted: 11/03/2011] [Indexed: 11/23/2022]
Abstract
The largest genetic susceptibility factor for Alzheimer's disease is the Apolipoprotein E (ApoE) ε4 allele. Cognitive decline and olfactory impairment are greater in those positive for the ε4 allele. This study sought to determine if the olfactory event-related potential (OERP), compared to the visual ERP, would be sensitive to these subtle declines. Participants included 40 individuals from two age groups, half of each group were ε4 allele positive and half were ε4 negative. Visual ERPs did not demonstrate significant differences between ApoE groups. OERPs demonstrated robust age by ApoE interactions. P3 latencies were significantly longer in ε4 young and middle age participants. These findings suggest that very early olfactory and cognitive changes related to ApoE status are detectible via the OERP.
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Affiliation(s)
- Krystin Corby
- San Diego State University, Department of Psychology, San Diego, CA, 92120, USA
| | - Charlie D. Morgan
- San Diego State University, Department of Psychology, San Diego, CA, 92120, USA
| | - Claire Murphy
- San Diego State University, Department of Psychology, San Diego, CA, 92120, USA
- University of California Medical Center, San Diego, CA, 92120, USA
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Olfactory ERPs in an odor/visual congruency task differentiate ApoE ε4 carriers from non-carriers. Brain Res 2011; 1442:55-65. [PMID: 22305338 DOI: 10.1016/j.brainres.2011.12.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 12/13/2011] [Indexed: 11/21/2022]
Abstract
Alzheimer's disease (AD) is a progressive, neurodegenerative disorder that impairs memory and semantic processing. AD patients and MCI patients at risk for AD show altered N400 ERP responses to incongruent visual and verbal stimuli. AD patients exhibit neuropathology in olfactory brain areas before cognitive symptoms, suggesting the potential for olfactory processing to reflect early pathology. Despite this, odor congruency has not been examined. We investigated odor-image congruency in older adults at genetic risk for AD. ApoE ε4 carriers and non-carriers were screened for anosmia, severe hyposmia, and dementia. Olfactory ERPs were measured 600-1300 ms following odor-image pairs. Odors were each presented once congruently and once incongruently via an olfactometer. Pz amplitude significantly decreased on incongruent trials in e4 carriers. Pz amplitude differences on congruous and incongruous trials were larger in non carriers. Regression indicated that congruency showed very high sensitivity and specificity for correctly classifying ε4 carriers from non-carriers.
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Haase L, Wang M, Green E, Murphy C. Functional connectivity during recognition memory in individuals genetically at risk for Alzheimer's disease. Hum Brain Mapp 2011; 34:530-42. [PMID: 22102296 DOI: 10.1002/hbm.21451] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 07/03/2011] [Accepted: 08/08/2011] [Indexed: 11/10/2022] Open
Abstract
The medial temporal lobes (MTL) and frontal cortex have been shown to subserve memory processes. Neurodegenerative diseases, such as Alzheimer's disease (AD), disrupt the neuronal networks that underlie memory processing. The ε4 allele of the apolipoprotein E gene is a genetic risk factor for AD and is associated with decrements in memory and in olfactory function. The present study utilized EQS, a structural equation modeling software program, to examine differences in the neuronal networks between non-demented ε4 carriers and ε4 noncarriers during a cross-modal olfactory recognition memory paradigm. Prior to fMRI scanning, participants were presented with 16 odors. During two scans, participants discriminated between names of odors presented before scanning (targets) or not presented (foils). The results indicate significant connections between bilateral frontal lobes and MTL for ε4 carriers when they misidentified a foil as a target. When ε4 noncarriers correctly identified a target, there were greater associations between the amygdala, MTL, and right frontal lobe; these associations also modeled the brain's response when ε4 noncarriers misidentified a foil as a target. During memory retrieval, affective cues may facilitate retrieval in ε4 noncarriers relative to ε4 carriers. Last, no model was found that best represented the functional network used by ε4 carriers when they correctly identified a target, which may reflect variability of neuronal recruitment within this population.
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Affiliation(s)
- Lori Haase
- Joint Doctoral Program in Clinical Psychology, San Diego State University/University of California San Diego, San Diego, CA, USA
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Wilson RS, Yu L, Schneider JA, Arnold SE, Buchman AS, Bennett DA. Lewy bodies and olfactory dysfunction in old age. Chem Senses 2011; 36:367-73. [PMID: 21257733 PMCID: PMC3073534 DOI: 10.1093/chemse/bjq139] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/02/2010] [Indexed: 11/14/2022] Open
Abstract
As part of a clinical-pathologic project, older people completed a standard odor identification test at study entry. During a mean of 3.5 years of observation, 201 people died and underwent brain autopsy and neuropathologic examination (6 with a history of Parkinson's disease were excluded). Lewy bodies were identified with antibodies to alpha-synuclein and classified as nigral, limbic, or neocortical based on their distribution in 6 brain regions. Plaques and tangles in 5 regions were summarized with a previously established composite measure, and neuron loss in the substantia nigra was rated on 6-point scale. Odor identification scores ranged from 0 to 12 correct (mean = 8.0, standard deviation = 2.6). On neuropathologic examination, 26 persons had Lewy bodies (13 neocortical, 9 limbic, and 4 nigral). In an analysis adjusted for age, sex, education, and time from olfactory testing to death, limbic (estimate = -2.47, standard error [SE] = 0.73, P < 0.001) and neocortical (estimate = -4.36, SE = 0.63, P < 0.001) Lewy body subgroups were associated with impaired olfaction. Results were comparable in analyses that controlled for dementia or parkinsonism during the study or postmortem measures of plaques and tangles or nigral cell loss. A final set of analyses suggested that impaired olfactory performance may aid detection of underlying Lewy body disease. The findings indicate that Lewy body disease impairs late life olfactory function even in otherwise asymptomatic individuals.
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Affiliation(s)
- Robert S Wilson
- Rush Alzheimer's Disease Center, Rush University Medical Center, 600 South Paulina Avenue, Chicago, IL 60612, USA.
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Abstract
The association of olfactory dysfunction with mortality was examined in 1162 older persons without dementia or Parkinson's disease. They completed a standard 12-item test of odor identification and then were followed for a mean of 4.2 years (standard deviation [SD] = 2.6, range: 0-9) during which 321 individuals died (27.6%). The relation of olfactory score to risk of death was assessed in a series of proportional hazards models adjusted for age, sex, education, and other covariates. Olfactory scores ranged from 0 to 12 correct (mean = 9.0, SD = 2.2). In an initial analysis, risk of death decreased by about 6% for each additional odor correctly identified (hazard ratio = 0.94; 95% confidence interval: 0.90, 0.98). Thus, mortality risk was about 36% higher with a low score (6, 10th percentile) compared with a high score (11, 90th percentile). The association persisted in subsequent analyses that controlled for naming ability, disability, cerebrovascular disease, characteristic patterns of leisure activity, depressive symptoms, and apolipoprotein E genotype. The results indicate that difficulty identifying familiar odors in old age is associated with increased risk of death.
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Affiliation(s)
- Robert S Wilson
- Rush Alzheimer's Disease Center, Rush University Medical Center, 600 South Paulina Avenue, Suite 1038, Chicago, IL 60612, USA.
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Schmitt AL, Livingston RB, Reese EM, Davis KM. The Relationship Between the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and Olfaction in Patients Referred for a Dementia Evaluation. ACTA ACUST UNITED AC 2010; 17:163-71. [DOI: 10.1080/09084281003715667] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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