Intellectual evaluation of brain-damaged patients with a WAIS short form.

Abstract

The routine usage of intellecmal tests in research and diagnosis makes a short-form test desirable. However, recent criticisms of short forms have been made (Kramer & Francis, 1965; Silverstein, 1965). The purpose of this study was to give consideration to these criticisms and ro develop a short form of the WAIS for the evaluation of patients with organic brain damage. The standard form WAIS (11 subtests) was administered to 142 patients with organic brain damage (100 males, 42 females). Their age range was 16 to 72 yr. (M = 48.05, SD = 16.93). The Full Scale IQ range was 56 to 139 (M = 92.48, SD = 16.05). Brain damage was determined by standard neurological and neurosurgical techniques. Two short forms were developed. The four-subtest form consisted of Similarities and Vocabulary from the verbal scale and Block Design and Picture Arrangement from the performance scale. The six-subtest form included Information, Similarities, and Vocabulary from the verbal scale and Picture Completion, Block Design, and Picmre Arrangement from the performance scale. The scaled scores from each of the short forms were prorated to provide estimates of the standard form. The intraclass correlation, R, was used (Haggard, 1958). Next the short forms were compared with the standard form for agreement as to intellectual classification. Finally, a frequency distribution was worked out for the differences between the short forms and standard form IQ scores. The correlations between the four-subtest form and the standard form were: Verbal IQ .92, Performance IQ 92, Full Scale IQ .95. The correlations between the six-subtest form and the standard form were: Verbal IQ 96, Performance IQ .96, Full Scale IQ .97. The four-subtest form, in comparison to the standard form, misclassified as follows: Verbal 1Q 3796, Performance IQ 3796, Full Scale IQ 32%. The six-subtest form, in cornparlson to the standard form, misclassified as follows: Verbal IQ 2876, Performance IQ 21 C/o, Full Scale IQ 18%. With regard to deviation of the short-form IQs from the standard form IQs, the four-subtest form required a 20-point range, and the six-subtest form required a 14-point range to encompass 95% of the scores. The present evidence tends to support the position that a short-form WAIS is a valid instrument for evaluating intellecrual functioning of patients with organic brain damage, especially where time limits are imposed.