Differences in neuropsychological performance in psychiatric, anterior- and posterior-cerebral dysfunctioning groups

The neuropsychological performance of psychiatric, anterior- and posterior-cerebral dysfunctioning groups was compared using both raw scores and scores statistically adjusted for the effects of age, education, gender, and overall level of intellectual functioning. Between 5% and 37% of the variance of the subtests of the WAIS-R and between 9% and 58% of the variance associated with the neuropsychological variables was accounted for by the demographic variables. Using raw scores, ten of the twenty-five tests showed significant overall differences among the groups, while only five of the contrast using adjusted scores were significant. Anterior- and posterior-cerebral dysfunctioning groups generally were significantly more impaired than the psychiatric group. Memory and problem-solving variables were the most sensitive to the removal of demographic variance, while psychomotor test scores were the most robust. Differences among cerebrally impaired and psychiatric groups may be obscured by demographic variables or levels of general intellectual functioning.