Intrasubtest scatter on the WAIS-III information subtest and psychometrically defined retrieval deficits

Milberg, et al. (1996) postulated that significant intrasubtest scatter on the Wechsler Information subtest reflects impaired retrieval. From a pool of 205 male referrals at a VA medical center with complete WAIS-III and WMS-III protocols, 28 participants with impaired retrieval (Group I) defined by a high Retrieval Composite score were identified. A sample (Group II) without similar evidence of impaired retrieval was matched to Group I on age, education, Full Scale IQ, race, and diagnosis. Intrasubtest scatter on the Information subtest was the same across groups (Group I M = 6.3, SD = 2.7; Group II M = 6.9, SD = 3.4). A second study identified impaired retrieval using the WMS-III Word Lists subtest. 21 participants (Group III) had impaired retrieval indicated by a Recognition scaled score being > or = 4 points higher than the Delayed Recall scaled score. A matched sample (Group IV) of VA patients without similar evidence of impaired retrieval was constituted. Intrasubtest scatter on the Information subtest did not differ across groups (Group III M = 6.6, SD = 2.4; Group IV M = 6.0, SD = 2.5). Evaluations of the retrieval deficit hypothesis should be based on responses of participants whose Information performance is characterized by abnormal amounts of intrasubtest scatter. It is possible that a specific amount of response variability must be present within the subtest before retrieval problems can be detected.