Are memory deficits dependent on the presence of aphasia in left brain damaged patients?

While memory deficits in aphasia have been reported in several studies, it has been suggested that these deficits are not due to the presence of aphasia, but rather to the left hemisphere lesion per se. In order to investigate this hypothesis, we tested 64 aphasic and 15 non-aphasic patients with left brain damage on verbal and visuospatial span tasks. Analyses revealed lower than expected performance on all four primary memory tasks for the aphasic, but not for the non-aphasic group. Moreover, comparison of the three lesion-location groups (posterior, anterior, and global) did not reveal statistically significant differences. The present data show that aphasic patients demonstrate memory deficits, which are not specific to the verbal modality, and contradict the notion that primary memory impairment is not due to the presence of aphasia, but rather to a lesion in the left hemisphere per se. Overall our study suggests that verbal and visuospatial, primary memory deficits in patients with left hemisphere lesions are possibly dependent on the presence of aphasia, but not on lesion location or lesion size.