Hemisphere-dependent cognitive performances in epileptic patients.

Short-term memory (STM), long-term memory (LTM), and recency judgment were investigated in 75 right-handed nonaphasic patients without visual deficits who had epileptic foci localized in one of four different regions of the brain: right temporal lobe, left temporal lobe, right frontal lobe, and left frontal lobe. The results led to the following conclusions: (1) left temporal lesions yielded comparatively greater impairment for the verbal LTM task, whereas right temporal lesions were more disruptive for the spatial LTM task; (2) no significant differences between left- and right-brain-damaged patients in STM tasks were obtained; (3) left frontal lesions yielded deficits in a recency task in accordance with hemispheric specialization; (4) only prolonged epileptic syndromes impaired neuropsychological performance in those tests; (5) comparisons between male and female patients and between those with and without clear evidence of a structural lesion did not reach statistical significance.