The Use of Short Versions of the Japanese WAIS-III to Aid in Differentiation Between Alzheimer’s Disease and Dementia with Lewy Bodies

Abstract Objective We examined the cognitive characteristics of patients with Alzheimer’s disease (AD) and dementia with Lewy bodies (DLB) using the Wechsler Adult Intelligent Scale-Third Edition (WAIS-III). In addition, the utility of short versions of WAIS-III for estimating IQ scores and index scores were examined. Methods The subjects were 83 patients with probable AD, 33 patients with probable DLB, and 83 cognitively normal individuals. Results Patients with DLB showed significantly lower scores in Performance IQ and Processing Speed compared with those with AD. The short versions of WAIS-III with Information, Similarities, Arithmetic, Digit Span, Picture Completion, Digit Symbol-Coding, and Block Design demonstrated relatively small amount of error, high correlations, and reliabilities with the full version. Conclusions The results indicated that Performance IQ and Processing Speed in WAIS-III can be an indicator for differentiating AD and DLB in WAIS-III, and a short version obtained by the Similarities, Information, Picture Completion, Block Design, Arithmetic, Digit Span, and Digit-Symbol Coding yields high accuracy and can be used to estimate full-scale IQ scores on the WAIS-III.