California Verbal Learning Test indicators of suboptimal performance in a sample of head-injury litigants

Cutoff scores suggested by Millis, Putnam, Adams, and Ricker (1995) for det ecting suboptimal performance on indices from the California Verbal Learnin g Test (CVLT) were evaluated using data from 193 compensation-seeking parti cipants. All participants claimed to have suffered a blow to the head in an accident causing subsequent deterioration in cognitive function. The parti cipants were divided into those with negligible or possible mild brain inju ries and those with clear evidence of moderate to severe brain injuries. In addition to the CVLT, all participants were administered the Computerized Assessment of Response Bias (CARB), a two-alternative forced choice test of recognition memory that is used to detect feigned cognitive impairment. Fo r all CVLT indices, the distributions of outcome (valid vs. suboptimal perf ormance) was unrelated to age and brain injury severity, and only weakly as sociated with education. However, a significantly higher proportion of male s than females obtained scores in the suboptimal performance range. The CVL T indices were not fully redundant with each other with respect to binary p articipant classifications; substantial disagreement between pairwise class ifications was found among those participants who obtained at least one sco re in the suboptimal performance range. CVLT index classifications were als o found to be non-redundant with classifications based on CARB scores. The CVLT may thus add useful data over and above that obtained from symptom val idity testing. However, the data suggest that the use of the strategy where any one or more below-cutoff CVLT scores are considered a positive indicat or of suboptimal performance may be associated with a higher than acceptabl e false-positive error rate.