A screening procedure for estimating premorbid intelligence in the elderly

Abstract

WAIS-R IQs were estimated using the National Adult Reading Test (NART) in a sample of 126 normal elderly. Linear regression equations to predict WAIS-R IQs from NART error scores were generated for a development sample of 85 subjects. Correlations between reading errors and Verbal, Performance, and Full Scale IQs were -.78, -.56, and -.74, respectively. Cross-validation on 41 elderly subjects yielded significant correlations between earned IQ and the NART that ranged from -.40 to - .83. Mean earned and estimated IQs for the normal elderly cross-validation sample were the same. Additional cross-validation on a sample of 20 neurologically impaired subjects revealed significant overestimation of the actual WAIS-R IQs by the NART estimated IQs. Thus, the NART estimated IQs adequately demonstrated intellectual deterioration in a brain-damaged sample.