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Comparison of sub‐tests in working memory index among posterior cortical atrophy, Alzheimer’s disease and age‐associated memory impairment
Author(s) -
Sarutikriangkri Yuthachai,
Chokesuwattanaskul Anthipa,
Phanthumchinda Kammant,
Likitjaroen Yuttachai
Publication year - 2020
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.044360
Subject(s) - memory span , clinical dementia rating , wechsler adult intelligence scale , working memory , audiology , atrophy , dementia , neurocognitive , medicine , psychology , disease , cognition , psychiatry
Background Posterior cortical atrophy (PCA) is a rare syndrome of Dementia. Typically, the main symptoms is visuoperceptual impairment. However, working memory impairment has also been reported. This study aimed reveal the pattern of working memory index impairment in PCA by comparing to Alzheimer’s disease patients (AD) and Age‐associated Memory Impairment subjects (AAMI). Method Patients were recruited from Neurocognitive Clinic, King Chulalongkorn Memorial Hospital. Working Memory Index (WMI) in Wechsler Adult Intelligence Scale – Fourth Edition (WAIS‐IV) was used to assess working memory. WMI is composed of 2 subtests which are Digit Span (DS) and Arithmetic (AR). DS is divided into 3 tasks including Digit Span Forward (DSF), Digit Span Backward (DSB), and Digit Span Sequencing (DSS). The score of WMI and all subtests were converted to standard score by age‐matched group. Descriptive statistics, One‐way ANOVA, and Wilcoxon Sign Test were used to analyze. Result There were 7 PCA, 19 AD, and 22 AAMI. WMI score of PCA, AD, and AAMI were 65.86, 91.63, and 99.50 respectively. WMI score of PCA were significantly less than AD (p<0.001) and AAMI (p<0.001). For each subtest scaled score of WMI revealed PCA had DS and AR significantly less than AD (p=0.001) and AAMI (p<0.001). Regarding the scaled score of PCA patients, DS was 4.57 (DSF=7.86, DSB=5.29, and DSS=3.57) and AR was 3.57. DSB and DSS were significantly less than DSF (p≤0.05). Conclusion Working memory in PCA patients was extremely low compared to AD and AAMI patients. PCA patients were more impaired in mental manipulation and calculation compared to attention. We should consider PCA as a differential diagnosis in dementia patients who score very low on WMI.