Premium
[P2–476]: LACK OF SELF‐AWARENESS OF COGNITIVE DEFICITS IN ALZHEIMER's DISEASE IS RELATED TO DECREASED METABOLISM IN THE POSTERIOR CINGULATE CORTEX
Author(s) -
Therriault Joseph,
Pascoal Tharick A.,
Ng Kok Pin,
Mathotaarachchi Sulantha S.,
Kang Min Su,
Shin Monica,
Struyfs Hanne,
Gauthier Serge,
Nair Vasavan,
RosaNeto Pedro
Publication year - 2017
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 - 10.1016/j.jalz.2017.06.1133
Subject(s) - posterior cingulate , cognition , neuroimaging , alzheimer's disease , psychology , cognitive decline , cognitive reserve , disease , positron emission tomography , neuroscience , dementia , medicine , cognitive impairment
Background:Subjective cognitive decline (SCD) could be a potential harbinger of AD. People with SCD often experience word-finding problems, but these are difficult to objectifywith neuropsychological or linguistic assessments and it is unknown whether they are related to underlying Alzheimer pathology. We aim to investigate whether semantic complexity, determined from spontaneous speech is reduced in SCD patients with preclinical AD.Methods:We included 61 cognitively normal patients with SCD (age 6468, 41% female, MMSE 2961), available amyloid status, and spontaneous speech recordings (minimum 300 words) from the ongoing SCIENCe cohort. Spontaneous speech was recorded using descriptions of the cookie theft figure, an abstract painting and an open-ended question (describe your regular Sunday). Speech recordings were transcribed verbatim and the following a priori defined linguistic parameters were extracted using the computational linguistics package software package T-scan and in-house developed python scripts: abstract nouns (proportion), content words (1000 most frequent), nouns referring to complex human characteristics (density), nouns referring to concrete events (density), lemma (frequency), content words (density), Type Token Ratio content words (TTR), D-level, word length and fillers (frequency). Amyloid positivity (yes/no) was determined based on visual reading of florbetapir or florbetaben PET scans (n1⁄453), or AB1-42 CSF (n1⁄48). The effects of amyloid (independent variable) on the different measures of language complexity (dependent variable) were investigated using linear regression adjusted for education and age. Results: Twenty (33%) SCD patients were amyloid positive. Age, education, gender, MMSE and depressive symptoms were comparable between groups. Adjusted for age and education, amyloid positivity was related to less use of specific words referring to human characteristics (stdb1⁄4 -.31, p1⁄4.02), and less use of concrete nouns referring events (stdb1⁄4 -.29, p1⁄4.03). There were no differences between groups on other types of non-specific words, syntactic complexity, word length, or information density. Conclusions:Preclinical AD in SCDwas associatedwith a lower proportion of specificwords, but not to estimates of syntactic complexity or information density. Spontaneous speech recordings could be a promising way to reveal subtle Alzheimerrelated language deficiencies in cognitively normal individuals.