Estimating premorbid intellectual level in dementia using the National Adult Reading Test: a Canadian study.
Twenty elderly demented subjects were compared with 20 elderly controls using a neuropsychological test battery which included the National Adult Reading Test (NART) and the WAIS-R. Significant differences emerged between the two groups on all of the cognitive measures administered, with the exception of the NART and the Verbal-Performance IQ discrepancy. Models were constructed using the normal controls as subjects where NART errors and WAIS-R Vocabulary age scaled scores were regressed against WAIS-R FSIQ and WAIS-R VIQ. These regression equations were then used to estimate premorbid intelligence levels in the demented sample, and these estimates were compared with the 'current' measures (WAIS-R FSIQ and WAIS-R VIQ). NART estimated IQs were significantly higher than Vocabulary estimated IQs, which in turn were significantly higher than WAIS-R FSIQ and WAIS-R VIQ. These results confirm that the ability to pronounce irregular words correctly remains relatively unimpaired in dementia.
Sharpe
K
K
Department of Psychology, Memorial University of Newfoundland, St. John's, Canada.
O'Carroll
R
R
D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000523:psychology*; D002170:Canada; D015161:Dementia, Multi-Infarct / Q000175:diagnosis* / Q000523:psychology*; D005260:Female; D006801:Humans; D007361:Intelligence Tests / Q000706:statistics & numerical data*; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D011594:Psychometrics; D011932:Reading