Auditory vigilance in aphasic individuals: detecting nonlinguistic stimuli with full or divided attention.

Previous research (LaPointe & Erickson, 1991) has shown that aphasic individuals have difficulty, relative to control subjects, in monitoring for spoken words while performing a secondary task. This finding may indicate that aphasics have fundamental deficits in attention or that their linguistic deficits are simply exacerbated by dividing attention. Twenty subjects, 10 nonfluent aphasic and 10 nonaphasic adults, listened to two 10-min series of nonlinguistic acoustic stimuli across conditions of focused and divided attention. Subjects tried to identify target sounds interspersed with nontarget sounds. As in prior research, aphasic subjects performed less accurately on the auditory vigilance task during the divided attention condition, relative to the undivided attention condition and to control subjects. The findings suggest that deficient cognitive processing, intertwined with linguistic deficit, may underlie auditory comprehension deficits in aphasia and may help explain performance variation within aphasic individuals across tasks.