Alzheimer’s disease–related atrophy patterns in different definitons of subjective cognitive decline

Abstract

AbstractBackgroundDifferent criteria sets were suggested for better operationalization of subjective cognitive decline. In this study, we aimed to assess structural neuroimaging biomarkers of AD in different definitions of SCD.MethodThe study was conducted at Hacettepe University, Turkey. 101 participants over 55 years of age, with memory complaints and no identifiable impairment in a valid cognitive screening test (Z scores>‐1.5 in the Modified Mini Mental Test 3MS) were included. We evaluated whether (i) using a scale (Subjective Memory Complaints Questionnaire‐SMCQ) rather than a single question assessing the subjective complaint; (ii) utilizing neuropsychological test data in addition to a screening test; (iii) evaluating SCD + criteria (additional qualitative features of the complaint) and (iv) the exclusion of comorbidities that may be associated with memory complaints; would be associated with increased atrophy in AD‐related areas. Three different cortical thickness and two cortical volume patterns based on previous research were determined as the dependent variables. MR images were obtained with a 1.5 Tesla MRI scanner. Cortical thickness and gray matter volumes were estimated using the FreeSurfer Software package version 6.0 on 3D T1‐weighted MRI scans (MP RAGE), in accordance with ADNI‐1 MRI acquisition protocol. The multivariate regression models were performed for evaluating the relationship of each independent variable.ResultResults suggested that age, sex, age of onset of memory complaints, depression or anxiety symptoms and vitamin B12 and vitamin D levels were associated with alterations in the structural markers of AD. Regarding different definitions of SCD; assessment of SCD + criteria, utilizing SMCQ, addition of neuropsychological test data and excluding individuals with comorbidities did not contribute to the validity of SCD in terms of the AD morphology.ConclusionOur findings indicate the importance of psychiatric evaluation in individuals with subjective memory complaints. The presence of depression and anxiety symptoms in a person with SCD may increase the likelihood of AD‐related brain morphological changes. Longitudinal studies, better assessment of the phenotype, inclusion of different diagnostic groups may help to refine the definition of SCD and the addition of criterion which may point to early morphological changes. This study has been funded by TUBITAK 214S048, Hacettepe THD‐2018‐17363.