Attention impairments in individuals with aphasia due to anterior versus posterior left hemisphere lesions.

Abstract

A growing body of literature has documented attention impairments in individuals with aphasia. This study extended that literature by examining the effects of lesion location (anterior versus posterior left hemisphere lesion) and nature of distractor task (nonverbal versus verbal) on aphasic individuals' performances of a variety of listening and speaking tasks under isolation, focused and divided attention conditions. Across tasks, conditions, and experiments, both anterior and posterior groups of aphasic individuals demonstrated greater disruption of language skills than a group of healthy individuals. Although it was initially hypothesized that the anterior group would display greater attention impairments than the posterior group, few differences were found; generally, the two aphasic groups performed similarly, both quantitatively and qualitatively. Independent of group, all individuals showed greater disruption of listening and speaking skills when the distractor task was verbal rather than nonverbal in nature. Performance decrements on most tasks were poorly predicted by severity of language impairment, time post-onset and other demographic characteristics of the aphasic individuals. Within a capacity framework of attention, the results of this study suggest that the attention impairments of aphasic individuals may reflect one or a combination of the following: decreased attentional capacity, inefficient attention allocation, or poor task-demand evaluation.