WAIS-R scatter with psychiatric inpatients: I Intrasubtest scatter

The cognitive structure of higher functioning autism and schizophrenia: a comparative study

The purpose of this study was to examine whether performance on a standard cognitive test-battery can be used to clearly separate higher functioning autism from schizophrenia. Revised Wechsler Intelligence Scale for Children (WISC-R) or Adults (WAIS-R) profiles of 20 autistic and 20 schizophrenic adolescent young adult subjects matched for age, sex, and IQ level were contrasted. On average, autistic individuals had higher values on the subtest "Similarities," while schizophrenic participants scored better on "Comprehension." Discriminant analysis showed that a prognosis of the psychiatric classification can be made with 82.5% accuracy if all subscale data are considered. Even though this finding probably has limited merit for making judgements in clinical practice, it might be of exploratory value in the pursuit of differentiating autism and schizophrenia on a cognitive level.

WAIS--R scatter with psychiatric inpatients: II. Intersubtest scatter

Intersubtest scatter values for the Full, Verbal, and Performance Scales of the WAIS--R were estimated for a sample of 163 psychiatric inpatients and compared with those reported for the WAIS--R standardization group using the normal deviate (z) test. Intersubtest scatter was assessed using the range and the Profile Variability Index. Results were surprising and conflicted with what was expected based on the clinical literature. First, in comparison to the standardization group, the psychiatric inpatients showed significantly more intersubtest scatter on the Verbal Scale only, while Performance Scale values were comparable. Second, the psychiatric inpatient sample, as a group, showed identical amounts of scatter on the Verbal and Performance Scales. Results suggest that the interpretation of intersubtest scatter as a sign of psychopathology should be avoided.