THE COMPARABILITY OF THE WRAT-R READING TEST AND NAART AS ESTIMATES OF PREMORBID INTELLIGENCE IN NEUROLOGICALLY IMPAIRED PATIENTS

A study by Wiens, Bryan, and Crossen (1993) suggests the Wide Range Ac hievement Test-Revised (WRAT-R) Reading subtest and North American Adu lt Reading Test (NAART) are adequate predictors of Wechsler Adult Inte lligence Scale-Revised (WAIS-R) IQ scores for a normal population. Alt hough it is common practice to use reading scores to estimate premorbi d IQ in clinical populations, the WRAT-R and NAART have not been compa red using individuals with brain dysfunction The current study cross-v alidated the Wiens et al. (1993) study using neurologically impaired p opulations: traumatic brain injury (n = 118), dementia (n = 37), and o ther neurologic impairments (n = 77). The results were generally consi stent across all three groups: (a) the WRAT-R and NAART were equivalen t and accurate estimates of average VIQ levels; (b) the WRAT-R and NAA RT were equivalent but underestimates of higher intelligence ranges: a nd (c) the WRAT-R is a more accurate estimate for lower VIQ ranges, al though both are overestimates. This third finding is in contrast to Wi ens et al.'s (1993) results that suggest the WRAT-R is an accurate est imate of lower Ie ranges for normals. It is concluded that the WRAT-R is the preferred measure of premorbid verbal intelligence for psychome tric and clinical reasons.