Verbal learning and memory following stroke.

OBJECTIVE The research examined whether verbal learning and memory impairment previously observed 1 year after left hemisphere stroke endures over a longer period and whether stroke sufferers compensate for their impairments using working memory. METHODOLOGY Twenty-one persons with left hemisphere lesions; 20 with right hemisphere lesions only and 41 matched controls completed the Hopkins Verbal Learning Test-Revised (HVLT-R), a working memory test (Letter-Number Sequencing, LNS) and the Boston Naming Test (BNT). RESULTS Persons with left hemisphere damage performed more poorly on HVLT-R than controls. They showed poorer immediate recall, delayed recall, recognition and learning, but intact retention, suggesting an encoding impairment. BNT and LNS scores predicted recall in this group. HVLT-R performance of persons with right hemisphere lesions only was comparable to controls. BNT (not LNS) predicted recall in these groups. CONCLUSIONS Persons with left hemisphere damage relied more on working memory and recruited diverse left hemisphere regions to compensate for their impaired encoding. IMPLICATIONS Tasks requiring verbal encoding and memory are effortful following left hemisphere stroke. This should be recognized and accommodated.