Schizophrenia Bulletin Advance Access published online on September 23, 2009
Schizophrenia Bulletin, doi:10.1093/schbul/sbp095
A Brief Cognitive Assessment Tool for Schizophrenia: Construction of a Tool for Clinicians
2 Department of Behavioral Health, Philadelphia VA Medical Center, Rm 7A-113 Mail Code 116, PA 19104
3 Department of Psychiatry, University of Pennsylvania, Philadelphia, PA
4 Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine at University of California at Los Angeles (UCLA), Los Angeles, CA
5 Department of Psychiatry, VA Greater Los Angeles Healthcare System, Los Angeles, CA
6 Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC
7 Department of Psychology, UCLA, Los Angeles, CA
1 To whom correspondence should be addressed; tel: 215-823-4055; fax: 215-823-4040, e-mail: ihurford{at}upenn.edu.
Cognitive impairment in schizophrenia is often severe, enduring, and contributes significantly to chronic disability. But clinicians have difficulty in assessing cognition due to a lack of brief instruments. We evaluated whether a brief battery of cognitive tests derived from larger batteries could generate a summary score representing global cognitive function. Using data from 3 previously published trials, we calculated the corrected item-total correlations (CITCs) or the correlation of each test with the battery total score. We computed the proportion of variance that each test shares with the global score excluding that test (R
=CITC2) and the variance explained per minute of administration time for each test (R/min). The 3 tests with the highest R/min were selected for the brief battery. The composite score from the trail making test B, category fluency, and digit symbol correlated .86 with the global score of the larger battery in 2 of the studies and correlated between .73 and .82 with the total battery scores excluding these 3 tests. A Brief Cognitive Assessment Tool for Schizophrenia (B-CATS) using the above 3 tests can be administered in 10–11 min. The full batteries of the larger studies have administration times ranging from 90 to 210 min. Given prior research suggesting that a single factor of global cognition best explains the pattern of cognitive deficit in schizophrenia, an instrument like B-CATS can provide clinicians with meaningful data regarding their patients’ cognitive function. It can also serve researchers who want an estimate of global cognitive function without requiring a full neuropsychological battery.
Keywords: schizophrenia / cognition / cognitive assessment / neurocognitive battery / clinical assessment