Short form of the WAIS-III for use with patients with schizophrenia.

The recent publication of the Wechsler Adult Intelligence Scale (WAIS-III), the most widely used standard test of intelligence, requires the development of a new short form for use with patients with schizophrenia for many clinical and research purposes. We used regression analyses of complete WAIS-III data on 41 outpatients with schizophrenia and 41 education-, and age-matched healthy subjects to determine the best combination of subtests to use as a short form. Excluding three subtests that are time-consuming to administer, and requiring that the solution includes one subtest from each of the four WAIS index scores, the combination that most fully accounted for the variance in full-scale IQ (FSIQ) for both participants with schizophrenia (R(2)=0.90) and healthy controls (R(2)=0.86) included the information, block design, arithmetic, and digit symbol subtests. When the restrictions regarding which subtests could enter were relaxed, the best four-subtest solution included information, block design, comprehension, and similarities. Although the latter explained 95% of the variance in FSIQ for schizophrenia participants and 90% of the variance for healthy controls, it consistently overestimated FSIQ for the schizophrenia group. We recommend the four-factor short form for use in future research and clinical practice in which a quick, accurate IQ estimate is desired.

Effects of contextual processing on visual conditional associative learning in schizophrenia.

BACKGROUND: We adapted visual conditional associative learning paradigms to assess the contextual processing deficit model of schizophrenic cognitive impairment proposed by J.D. Cohen and D. Servan-Schreiber in 1992. In this task subjects learn the associations between four sets of stimuli through the use of feedback. We administered two experimental conditional associative learning conditions: in one, the eight stimuli used to make four pairs were all different; in the other, the pairs were made from different combinations of four identical stimuli, requiring the use of contextual information to mediate correct performance. Two additional associative learning tasks were administered where subjects generated the stimulus pairings or observed the experimenter form the pairs, eliminating the need to learn from feedback. METHODS: We tested 37 patients with schizophrenia and 20 healthy control subjects in each conditional associative learning task condition. RESULTS: Patients demonstrated significant impairments on all four conditional associative learning tasks. The demand to process contextual information did not differentially impact patient performance. Patients were better able to learn associations if they generated or observed the pairings rather than utilized feedback to guide learning. CONCLUSIONS: Patients with schizophrenia demonstrate pronounced deficits in the ability to utilize feedback to guide learning. We found no evidence of an additional deficit in processing of contextual information.

Repeatable battery for the assessment of neuropsychological status as a screening test in schizophrenia I: sensitivity, reliability, and validity.

OBJECTIVE: Cognitive impairment is an important feature of schizophrenia and is correlated with functional outcome. However, psychiatry lacks a screening instrument that can reliably assess the types of cognitive impairment often seen in schizophrenia. The authors assessed the sensitivity, convergent validity, and reliability of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) as well as the relationship of the RBANS to symptoms and employment status. This newly published test takes 25 minutes to administer and was standardized on a U.S.-Census-matched adult population. The test provides a total score and five index scores, each with a mean value of 100 (SD = 15). METHOD: RBANS data were obtained from 129 patients with schizophrenia in the outpatient and inpatient programs of the Maryland Psychiatric Research Center. RBANS data were correlated with WAIS-III and Wechsler Memory Scale, 3rd ed. performance in 38 patients. Reliability data for alternate forms of the RBANS were obtained from 53 patients; symptom ratings were obtained from 48 patients; and employment status was examined in 77 patients. RESULTS: The patients with schizophrenia demonstrated marked impairment on the RBANS (their mean total score was 71.4). The patients' index scores suggested that they had relatively less impairment of language and visual functions than of memory and attention. The RBANS demonstrated high correlations with full-scale IQ and memory measures. The total score demonstrated good reliability. RBANS performance minimally correlated with Brief Psychiatric Rating Scale ratings but was strongly related to employment outcome. CONCLUSIONS: The RBANS appears to be a useful cognitive screening instrument in schizophrenia. The instrument may be a useful prognostic indicator and offers a means of assessing cognitive status.