WAIS-R performance following closed-head injury: A comparison of the clinical utility of summary IQs, factor scores, and subtest scatter indices

Abstract

WAIS-R performance can be analyzed at the level of the IQs, factor scores, or subtests. This study exam-ined the relative utility of such analyses in a closed-head-injured (CHI) sample (n = 233). Comparison of the sample with matched controls (n =117) indicated that factor scores may be the most appropriate level of analysis in clinical practice. This conclusion was supported by a series of discriminant function analyses performed on the WAIS-R scores of the CHI sample and 356 healthy controls drawn from the general population. Factor scores achieved a significantly higher classification accuracy than IQs or indices of subtest scatter (all /?s <.001). Combining the scatter indices with the composite measures (i.e., IQs or factor scores) did not produce a significant improvement in discrimination over that achieved by the com-posites alone. Counter to the assumptions underlying the clinical analysis of subtest profiles, CHI partici-pants failed to exhibit significantly greater intraindividual subtest variability in their subtest profiles than the matched control sample. The Wechsler Adult Intelligence Scale-Revised (WAIS-R; Wechsler, 1981) is widely employed in clinical practice to assess the cognitive se-quelae of closed-head injury (CHI) (Lezak,