Olfactory Dysfunction, Olfactory Bulb Volume and Alzheimer’s Disease: Is There a Correlation? A Pilot Study1

Servello, Adriana; Fioretti, Alessandra; Gualdi, Gianfranco; Biasi, C. Di; Pittalis, Angelo; Sollaku, Saadi; Pavaci, Silva; Tortorella, Federica; Fusetti, Marco; Valenti, Marco; Masedu, Francesco; Cacciafesta, Mauro; Marigliano, Vincenzo; Ettorre, Evaristo; Pagliarella, Martina

doi:10.3233/jad-150232

Cited by 24 publications

(16 citation statements)

References 30 publications

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“…In relation to categorical stratification, the identification of odors was measured 40 times, 15 - 52 discrimination 21 times 16 , 21 , 22 , 26 , 29 , 34 , 35 , 37 , 38 , 46 , 53 - 61 and recognition only 6 times, 17 , 18 , 40 , 57 , 62 , 63 representing samples of 3328, 1062 and 244 evaluated individuals, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…Analysis in relation to smoking could not be performed due to insufficient information: only 9 studies 19 , 22 , 26 , 27 , 36 , 42 , 44 , 46 , 47 employed this item as an exclusion criterion and only 5 articles 20 , 21 , 25 , 29 , 34 reported the number of smokers present in the sample. The same situation occurred for onset and duration of symptoms of AD, with insufficient data available.…”

Section: Resultsmentioning

confidence: 99%

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Olfactory dysfunction in Alzheimer’s disease Systematic review and meta-analysis

Silva¹,

Mercer²,

Witt³

et al. 2018

Dement. neuropsychol.

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Alzheimer’s disease (AD), a neurodegenerative condition, is one of the most prevalent kinds of dementia, whose frequency doubles for every 5 years of age in elderly.Objective:To determine the correlation between AD and olfactory alterations, identifying the most affected domains and exploring the utility of olfactory tests for complementing early diagnosis.Methods:Databases were searched using the terms “olfactory OR smell OR olfaction AND alzheimer” for articles related to the proposed theme. The selected studies were categorized and evaluated separately depending on the method of analysis of the olfactory tests: identification of odors, discrimination and recognition, and a meta-analysis was carried out.Results:Fifty-one articles were selected for analysis. The effect size for most studies was large, as were the summary values for each category of individualized olfactory analysis.Conclusion:Among the olfactory domains, except memory, identification appears to be the most altered in AD. The possibility of including tests that specifically evaluate the identification of odors as an item in early diagnostic evaluation should be explored. PROSPERO registration: CRD42018089076.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Olfactory dysfunction in Alzheimer’s disease Systematic review and meta-analysis

Silva¹,

Mercer²,

Witt³

et al. 2018

Dement. neuropsychol.

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“…Several neuroimaging studies have found associations between OI dysfunction and structural abnormities in brain regions that contribute to olfactory processing, such as the olfactory cortex (OC). The OC is the center of olfactory processing and functional and structural anomalies are strongly implicated in OI dysfunction (Thomann et al, 2009b; Servello et al, 2015; Vasavada et al, 2017). Hippocampal atrophy is a well-known pathological feature of AD and MCI (Prestia et al, 2010), and so may also contribute to OI dysfunction in AD and MCI.…”

Section: Introductionmentioning

confidence: 99%

Brain Structural Correlates of Odor Identification in Mild Cognitive Impairment and Alzheimer’s Disease Revealed by Magnetic Resonance Imaging and a Chinese Olfactory Identification Test

Geng

Zhou

et al. 2019

Front. Neurosci.

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Alzheimer’s disease (AD) is a common memory-impairment disorder frequently accompanied by olfactory identification (OI) impairments. In fact, OI is a valuable marker for distinguishing AD from normal age-related cognitive impairment and may predict the risk of mild cognitive impairment (MCI)-to-AD transition. However, current olfactory tests were developed based on Western social and cultural conditions, and are not very suitable for Chinese patients. Moreover, the neural substrate of OI in AD is still unknown. The present study investigated the utility of a newly developed Chinese smell identification test (CSIT) for OI assessment in Chinese AD and MCI patients. We then performed a correlation analysis of gray matter volume (GMV) at the voxel and region-of-interest (ROI) levels to reveal the neural substrates of OI in AD. Thirty-seven AD, 27 MCI, and 30 normal controls (NCs) completed the CSIT and MRI scans. Patients (combined AD plus MCI) scored significantly lower on the CSIT compared to NCs [ F (2,91) = 62.597, p < 0.001)]. Voxel-level GMV analysis revealed strong relationships between CSIT score and volumes of the left precentral gyrus and left inferior frontal gyrus (L-IFG). In addition, ROI-level GMV analysis revealed associations between CSIT score and left amygdala volumes. Our results suggest the following: (1) OI, as measured by the CSIT, is impaired in AD and MCI patients compared with healthy controls in the Chinese population; (2) the severity of OI dysfunction can distinguish patients with cognitive impairment from controls and AD from MCI patients; and (3) the left-precentral cortex and L-IFG may be involved in the processing of olfactory cues.

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“…In human autopsy studies, amyloid and tau, as well as other pathologies such as progranulin and TDP-43 deposition, are found in the olfactory bulb and throughout the olfactory network (including temporal piriform cortex) in patients with AD and other neurodegenerative diseases, and levels of amyloid and tau deposition are associated with the level of olfactory deficits [23] , [24] , [25] , [26] , [27] , [28] , [29] , [34] . The associations of UPSIT performance with neurodegeneration and brain function, measured using magnetic resonance imaging (MRI) or [ 15 O]H 2 O PET, have also been investigated [4] , [14] , [31] , [35] , [36] , [37] , [38] , [39] , [40] , [41] . In vivo imaging studies have shown weak associations between amyloid and olfactory impairments [30] , [31] , [32] .…”

Section: Introductionmentioning

confidence: 99%

Olfactory identification in subjective cognitive decline and mild cognitive impairment: Association with tau but not amyloid positron emission tomography

Risacher

Tallman

West

et al. 2017

Alz & Dem Diag Ass & Dis Mo

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IntroductionWe investigated the association between olfactory identification and Alzheimer's disease biomarkers, including amyloid, tau, and neurodegeneration.MethodsThirty-four older adults, including 19 cognitively normal (CN), 10 subjective cognitive decline (SCD), and 5 mild cognitive impairment, underwent amyloid positron emission tomography, magnetic resonance imaging, and the University of Pennsylvania Smell Identification Test (UPSIT). Twenty-six also underwent tau positron emission tomography. Associations between the UPSIT and regionally sampled amyloid, tau, and temporal atrophy were evaluated. Voxel-wise regression models were also utilized. Analyses were conducted with the full sample and only CN/SCD.ResultsLower UPSIT scores were associated with increased temporal and parietal tau burden in regional and voxel-wise analyses in the full sample and in CN and SCD only. Temporal lobe atrophy was associated with lower UPSIT score. Amyloid was not associated with the UPSIT.DiscussionImpairment on the UPSIT may be a good marker for tau and neurodegeneration in preclinical or prodromal Alzheimer's disease.

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Olfactory Dysfunction, Olfactory Bulb Volume and Alzheimer’s Disease: Is There a Correlation? A Pilot Study1

Abstract: The reduction of OBV does not seem to represent an index of neuronal damage in the earliest stages of AD.

Cited by 24 publications

References 30 publications

Olfactory dysfunction in Alzheimer’s disease Systematic review and meta-analysis

Olfactory dysfunction in Alzheimer’s disease Systematic review and meta-analysis

Brain Structural Correlates of Odor Identification in Mild Cognitive Impairment and Alzheimer’s Disease Revealed by Magnetic Resonance Imaging and a Chinese Olfactory Identification Test

Olfactory identification in subjective cognitive decline and mild cognitive impairment: Association with tau but not amyloid positron emission tomography

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