VALIDATION OF THE WECHSLER MEMORY SCALE-REVISED IN A SAMPLE OF PEOPLEWITH INTRACTABLE TEMPORAL-LOBE EPILEPSY

Purpose: The Wechsler Memory Scale-Revised (WMS-R) is used routinely f or presurgical assessment of memory for patients considering elective resection of the temporal lobe and/or hippocampus for the relief of in tractable temporal lobe epilepsy (TLE). We investigated the validity o f the WMS-R in a population of people with TLE. Methods: The sample co nsisted of 138 patients with a diagnosis of TLE in which the epileptog enic focus was clearly and exclusively lateralized to either the right or left hemisphere. They underwent a complete neuropsychological exam ination as a routine part of their investigation for epilepsy surgery. Psychometric scores included in this study were: Wechsler Adult Intel ligence Scale-Revised (WAIS-R) LQ. scores, National Adult Reading Test Revised (NART-R) predicted-Lq. scores, and WMS-R Memory Index and sub test scores. Results: Multiple univariate analyses were performed. The group with left temporal focus had significantly lower Verbal Memory Index, Logical memory (both immediate and delayed), and Digit Span sco res. Visual/verbal discrepancy scores incorrectly identified most pati ents with right temporal focus. Analyses of a total group of people wi th epilepsy (i.e., mixed temporal, frontal, occipital and unknown foci ) as compared with the normative sample indicated that the patient gro up scored significantly lower across all memory index scores and most memory subtests. Conclusions: Our results confirm that the WMS-R is ca pable of lateralizing to left hemispheric impairment but is more probl ematic in the assessment of right hemispheric impairment. The Visual/v erbal Memory Index discrepancy has questionable validity. People with epilepsy performed less well on the WMS-R than did the normative sampl e. The need for reliable and valid nonverbal tests of memory is theref ore warranted.