The interaction of rate and complexity of stimulus on the performance of adult aphasic subjects.

A need for increased processing of auditory stimuli has been emphasized as a characteristic of aphasic patients. Clinical test performance of aphasics on tasks requiring various levels of communicative abilities was affected by rate of stimulus presentation. Stimuli were subtests of the Minnesota Test for Differential Diagnosis of Aphasia (MTDDA) presented at normal and slowed rates to aphasics grouped according to performance on the Porch Index of Communicative Abilities (PICA). Effect of rate on performance was influenced by severity of the disorder and complexity of the task required. Implications involve the clinician's attention to rate, presentation, and control of complexity of material.