Abstracts

RATIONALE: In seizure patients and other patients with lateralized brain lesions, assessments of verbal and nonverbal memory are frequently done for clinical and research purposes. Of specific interest is the association between the laterality of the lesion and the different types of memory. Currently, the most recent revision of the Wechsler Memory Scale (WMS-III) is commonly used in neuropsychological investigations of patients with lateralized brain pathology. This study examined the relationship between lateralized brain pathology and the summary scores for nonverbal and verbal memory of the WMS-III.
METHODS: The sample consisted of 61 right-handed adult patients who were administered the WMS-III as part of a full neuropsychological evaluation. All patients had lateralized structural lesions, verified through neuroimaging. Using t-tests, comparisons were made between patients with right hemisphere lesions (N = 22) and left hemisphere (N = 39) lesions on four summary scores from the WMS-III: Visual Immediate and Delayed, Auditory Immediate and Delayed. In addition, to assess the disparity between a patient[ssquote]s verbal and nonverbal memory, difference scores were computed for immediate and for delayed recall by subtracting Visual Memory from Auditory Memory.
RESULTS: The means for the four WMS-III summary scores were in the average range. For Visual Memory Immediate and Delayed, there were no differences between the right and left hemisphere groups. For Auditory Memory, there was no difference in Immediate memory. However, at Delayed recall, the left hemisphere patients had lower auditory memory scores than the right hemisphere patients ( p = .046). Analyses of the difference scores showed a tendency for the right-lesioned patients to have a larger discrepancy between nonverbal and verbal memory at Immediate recall (p = .09), with nonverbal memory stronger than verbal memory. For Delayed recall, this discrepancy reached significance (p = .032).
CONCLUSIONS: In this study, the summary scores for Visual Memory from the WMS-III did not distinguish between patients with right and left hemisphere lesions. For the Auditory Memory scores, differences were obtained for delayed recall only, with patients with left hemisphere pathology having weaker performances. The difference scores showed that patients with right hemisphere lesions had a greater disparity between nonverbal and verbal memory, with the latter being stronger. These results suggest that the ability to distinguish between right and left hemisphere lesions on the basis of the summary scores for Auditory and Visual Memory of the WMS-III is limited. However, a within-patient comparison between verbal and nonverbal memory, based on these scores, is more likely to be associated with lesion laterality.