Spoken language of individuals with mild fluent aphasia under focused and divided-attention conditions

The spoken language of individuals with mild aphasia and age-matched control subjects was studied under conditions of isolation, focused attention, and divided attention. A picture-description task was completed alone and in competition with a tone-discrimination task. Regardless of condition, individuals with aphasia performed more poorly on most morphosyntactic, lexical, and pragmatic measures of spoken language than control subjects. Increasing condition complexity resulted in little quantitative or qualitative change in the spoken language of the control group. In contrast, the individuals with aphasia showed dual-task interference; as they shifted from isolation to divided-attention conditions, they produced fewer syntactically complete and complex utterances, fewer words, and poorer word-finding accuracy. In pragmatic terms, their communication was considered less successful and less efficient. These results suggest that decrements of attentional capacity or its allocation may negatively affect the quantity and quality of the spoken language of individuals with mild aphasia.