Auditory processing in individuals with mild aphasia: a study of resource allocation

This study examined the effects of lesion location (frontal vs. posterior) and nature of distraction (nonverbal vs. verbal secondary, competing task) on mildly aphasic individuals' performances of listening tasks that required semantic judgments and lexical decisions under isolation, focused attention, and divided attention conditions. Despite comparable accuracy among all groups during isolation conditions, the aphasic groups responded less accurately and more slowly than the normal control group during focused and divided attention conditions. Generally, the two aphasic groups performed similarly, quantitatively and qualitatively. Demographic characteristics such as time post stroke did not correlate with performance decrements. Independent of group, all individuals showed greater disruption of auditory processing skills when the secondary task was verbal rather than nonverbal. Within a limited-capacity model of attention, the results suggest that aphasic individuals display impairments of attention and resource allocation and that these impairments negatively interact with their auditory processing abilities.