WAIS-R factor structure in Alzheimer's disease patients: a comparison of alternative models and an assessment of their generalizability.
The WAIS-R is often used in neuropsychological evaluations of individuals with probable Alzheimer's disease (AD), but its factor structure in this population is unknown. Moreover, theories and past research findings make competing predictions concerning its structure. Using confirmatory factor analysis, the authors compared 5 alternative WAIS-R factor models among 516 AD patients: 1-factor (Spearman's g) and 2-factor (Verbal IQ and Performance IQ) models; a 3-factor model including Verbal Comprehension (VC), Perceptual Organization (PO), and Freedom From Distractibility (FD) factors; a 3-factor model in which Digit Symbol loads on PO rather than FD; and a 3-factor model in which Digit Symbol loads on both PO and FD. Results favored the 3-factor model in which Digit Symbol loads on PO rather than FD. Moreover, this model fit the data best among subsamples of patients defined by age, dementia severity, years of education, and gender.
Davis
Robert N
RN
Department of Psychology, University of Houston, USA. rdavis@tcnj.edu
Massman
Paul J
PJ
Doody
Rachelle S
RS
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications / Q000523:psychology*; D004522:Educational Status; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D008960:Models, Psychological; D011594:Psychometrics; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012737:Sex Factors