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.