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Verbal fluency associated with tau accumulation and not amyloid deposition in the Alzheimer’s disease spectrum
Author(s) -
Rahmouni Nesrine,
Stevenson Alyssa,
Stevenson Jenna,
Tissot Cécile,
Lussier Firoza Z,
Bezgin Gleb,
Therriault Joseph,
Chamoun Mira,
Kang Min Su,
Pascoal Tharick A.,
Gauthier Serge,
Benedet Andréa Lessa,
RosaNeto Pedro
Publication year - 2021
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.056671
Subject(s) - psychology , verbal fluency test , audiology , precuneus , standardized uptake value , neuropsychology , alzheimer's disease , cognition , neuroscience , pathology , cognitive psychology , disease , medicine , positron emission tomography
Abstract Background Recent studies have shown that pathological amyloid deposition and tau accumulation, hallmarks of the Alzheimer's disease, are closely related to cognitive deficits in older individuals. The present study evaluates the associations between the Alzheimer's disease hallmarks and verbal fluency and lexical speed access impairment. Method The study was conducted in a population of 262 individuals (162 cognitively unimpaired individuals (CU), 100 cognitively impaired individuals (CI; 61 MCI and 39 AD). The verbal Letter Fluency test was used to assess the vocabulary size and lexical speed access. Individuals underwent an MRI, a [18F]AZD4694 amyloid‐PET scan and a [18F]MK6240 tau‐PET scan. [18F]AZD4694 and [18F]MK6240 standardized uptake value ratio (SUVRs) were calculated between 40 to 70 min and 90 to 110 min post‐injection, respectively, using cerebellum grey matter as the reference region. A voxel‐based regression model evaluated the relationship between the cognitive scoring and the PET markers [18F]AZD4694 and [18F]MK6240, correcting for age, sex, education, APOE, diagnosis and RFT was used to account for multiple comparisons Result Negative correlations were found between Letter Fluency scores and tau accumulation. The associated regions were medial frontal, superior temporal, medial occipital lobes and precuneus area. No associations were found between the Letter Fluency scoring and amyloid deposition. Conclusion Our results suggest that tau accumulation is associated with lower vocabulary size and lexical speed access, whereas amyloid deposition does not influence this neuropsychological field.