When a client has cognitive impairment resulting from cerebral dysfunction (CD) that goes undiagnosed and, therefore, untreated, psychotherapy and rehabilitation outcome is likely to be impacted negatively. Due primarily to managed care, screening for CD has reduced substantially. Master's level counselors need a cost-efficient way to detect possible CD and, thus, justify referral for neuropsychological evaluation. This study examined the Wechsler Abbreviated Scale of Intelligence (WASI) instrument's ability to screen for possible CD by examining the relationship between a) WASI Performance IQ (PIQ) and Verbal IQ (VIQ) scores and neuropsychological test scores, and b) the VIQ-PIQ discrepancy and the severity of disability. In this retrospective study, test scores were extrapolated from neuropsychological assessments conducted between 2001 and 2004 on 73 CD-diagnosed adults at a CARF accredited rehabilitation facility. Disability severity ratings of mild, moderate, and severe were assigned based on clinical judgment and interrater agreement. The assessment battery included the WASI and several neuropsychological tests: Halstead-Reitan TPT, TMT-A and B, and FOT; WMS-III VR-I and 2, LM-1 and 2, and MC; McCarron-Dial HVDT; SDMT; and SCT. Based upon a multitrait-multimethod matrix, mild to moderate convergent and discriminant validity was found with the WASI VIQ and PIQ traits among neuropsychological verbal and performance measures. Statistically, the SCT, TMT-A, and HVDT-right shape were most predictive of the PIQ, and the WMS-III LM-2 and MC were most predictive of the VIQ. VIQ-PIQ discrepancy did not predict severity of disability, but IQ means and subtest scores between the mild and severe groups were significantly different. Results indicated that WASI VIQ-PIQ discrepancy did not detect CD. However, WASI subtest scores of 40 or lower may justify further evaluation of potential CD. Contrary to the WASI manual, Similarities and Block Design rather than Vocabulary and Matrix Reasoning subtest scores may be more predictive of CD. This author suggested that counselors administer the WASI, SCT, and TMT-A as a time efficient screening method for CD.
