Memory Outcome after Selective Amygdalohippocampectomy in Patients with Temporal Lobe Epilepsy: One‐year Follow‐up

Abstract

Summary:Purpose: In a previous study we reported clinically significant memory declines 3 months after selective amygdalohippocampectomy (SAH) in 140 patients with mesial temporal lobe epilepsy, particularly if the resection was left-sided. We supposed that the observed postoperative impairments might have reflected acute effects of surgery. Therefore we evaluated in the present study whether a recovery can be found 1 year after surgery.Methods: Verbal and nonverbal memory functions were assessed in 115 patients before and 3 and 12 months after unilateral SAH.Results: No recovery of postoperative verbal memory declines was found in the left-SAH group. Clinically meaningful losses were still evident in 33 to 50% of patients. In right-SAH patients, a recovery of verbal memory was indicated, and effects of surgical complications were no longer evident. One year after surgery, the corresponding preoperative performance was the only significant predictor of a postoperative change in the left-SAH group.Conclusions: Verbal memory decline observed 3 months after left SAH is persistent 1 year after surgery. Declines in verbal memory, which were observed in some right-SAH patients at the short-term follow-up, seem to be temporary. Key Words: Selective amygdalohippocampectomyEpilepsy-Surgery-Memory-Outcome.Cognitive effects of selective amygdalohippocampectomy (SAH) are not unequivocal (1-7). Although several studies indicated a relatively better outcome than after standard anterior temporal lobectomy (2-4,7), it is not clear to what extent SAH also can lead to a significant memory decline, because some studies reported significant verbal memory decreases after left SAH (3-6), but others did not (1,7). Most of these studies referred to relatively small samples. Therefore we recently investigated the effects of lateralized SAH on memory and determinants of memory outcome in a very large sample of 140 patients (8). Our results indicated relatively broad and strong declines in verbal memory 3 months after left SAH, and we supposed that the observed impairments might reflect immediate effects of surgery that could recover in the later course. This was supported by the observation that memory decline was particularly reported in studies with short retest intervals of 1 to 4 months (3,5,6), whereas studies that found no declines had longer retest intervals of 1 to 4 years after surgery (1,7). We now evaluated for a subgroup of 115 patients whether a recovery is indicated 1 year af-

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