Factor-derived categories of chronic aphasia

A large sample of patients with aphasia (N = 118), unselected for etiology, were administered the Porch Index of Communicative Ability more than 6 months after the onset of aphasia. Factor analysis of PICA subtest scores identified five factors which accounted for 83.9% of the total variance. The factors were labeled speaking, writing, comprehension, gesturing, and copying. Cluster analyses of the factor scores yielded five patient categories which differed in the pattern of impairment on the language factors as well as in overall severity of aphasia. A subgroup of the parent sample consisting of 52 patients with localized left-hemisphere CVA had cluster analyses repeated after having first been studied as part of the larger sample. The factor-derived categories for the subgroup were similar to those of the entire group. Discriminant functions of the PICA raw scores of the 52-patient subsample correctly classified all of the patients. When discriminant functions were based upon the factor scores of the 118-patient parent sample, 80.7% of the 52 patients were correctly classified into the five categories.