DETECTION OF CHANGES IN MATERIAL-SPECIFIC MEMORY FOLLOWING TEMPORAL LOBECTOMY USING THE WECHSLER MEMORY SCALE-REVISED

To determine the utility of the Wechsler Memory Scale-Revised (WMS-R) in measuring material-specific memory changes, within-subject comparis ons of the Verbal-Visual Memory Index discrepancy and discrepancy scor es using short-term and delayed Logical Memory and Visual Reproduction subtests from the WMS-R were studied prior to and following temporal lobectomy among 30 patients with left temporal lobectomy, 30 with righ t temporal lobectomy, and 50 epileptic, nonsurgical controls. The grou ps were matched on age, sex, handedness, age at seizure onset, duratio n of epilepsy, and presurgical Verbal and Performance IQ; the right te mporal group had a higher mean educational level (p < .05). All surgic al patients were left hemisphere dominant for speech; those who had pe rsistent postoperative seizures were excluded from study. On retesting , left temporal lobectomy was associated with a marked change in short -term and delayed memory discrepancy scores primarily due to a drop in verbal memory. Right temporal lobectomy was not associated with a dro p in visual memory, suggesting that the WMS-R appears to reflect decre ments in material-specific memory following left but not right tempora l lobectomy. The nonsurgical controls showed increases in both short-t erm and delayed memory discrepancy scores due to increases in short-te rm and delayed verbal memory. Relative to these controls, the absence of comparable increases in verbal memory among the right temporal pati ents suggests that right temporal lobectomy may be associated with ris k to verbal memory.