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Summary: Purpose:The technique of selective amygdalohippocampectomy (SAH) was originally developed in epilepsy surgery to spare unaffected brain tissue from surgery, thus minimizing the cognitive consequences of temporal lobe surgery. The results of previous studies, however, are equivocal in this regard. This study evaluated memory after SAH in a large sample of patients with mesial temporal lobe epilepsy.Methods: The 140 patients received material-specific memory tests before and 3 months after unilateral SAH.Results: Significant declines in all aspects of verbal learning and memory were found particularly for the left resected group. With reliability-of-change indices, a high number of patients showed postoperative verbal memory declines, Յ51% in left SAH and Յ32% in right SAH. For left SAH, a higher preoperative verbal memory performance, a lower preoperative nonverbal memory score, an older age at surgery, and a later onset of epilepsy predicted a stronger decline in verbal memory. After right SAH, the risk for a verbal memory decline was slightly increased when patients had surgical complications or a presurgical evaluation with bilateral intrahippocampal depth electrodes. Results concerning nonverbal memory were less clear. Conclusions:The results clearly indicate, that particularly left SAH can lead to a significant decline in memory functions. Predictors of postoperative verbal memory were similar to those reported for temporal lobectomy. Postoperative deteriorations were broader and stronger in our study than in previous studies. We discuss methodologic differences (sample size, retest interval, extent of resection) and other factors as possible reasons. Key Words: Selective amygdalohippocampectomyEpilepsy-Surgery-Memory-Outcome.Approximately 80% of focal epilepsies originate in the temporal lobes, and anterior temporal lobe resections (TLRs) are the most frequently used surgical treatments in medically resistant focal epilepsies. Apart from unexpected complications, decreased memory functions represent the greatest potential neuropsychological morbidity after anterior temporal lobectomy. Verbal memory functions are particularly at risk in patients undergoing left-sided resection (1-3). Identified risk factors for postoperative memory decline after left anterior temporal lobectomy are older age at time of surgery, later age at onset of seizures, male gender, and better preoperative memory performance (4,5). It has also been shown that patients with normal-appearing hippocampi are at greater risk for memory decline after left anterior temporal lobectomy (6-8). The hippocampal formation, one of the most complex and vulnerable brain structures, is recognized as a crucial brain area subserving human long-term memory. Material-specific relations between the left medial temporal lobe and verbal memory (9,10), and between the right medial temporal lobe and visual/ nonverbal memory (11-13) are well described. The relation between verbal memory and the left hippocampus is particularly robust and has been confir...

The purpose of our study is to evaluate whether children recover better than adults from memory deficits as a consequence of temporal lobe surgery. We compared 3 and 12 month outcomes obtained in children and adults with medically refractory epilepsy. Each candidate underwent temporal lobe resection for seizure control and children were matched with regard to pathology, onset of epilepsy, side of surgery and type of surgery with adults (N = 30 for each group, mean age at surgery 13 versus 30 years). Three months after surgery, both left-resected groups displayed a significant decline in verbal learning capacity. During the following 9 months, only the children recovered and were able to reach their preoperative level 1 year after surgery. The left-resected adults remained, for the most part, on their low level and one year after surgery, they were still significantly worse than at the time of their preoperative examination. The right-resected adults experienced a deterioration in visual memory 1 year after surgery relative to the results of the short-term follow-up; the children improved. The children also had a better outcome with regard to attentional functions and, as a trend, a better seizure outcome (Engel Outcome I--1 year after surgery: 63% adults, 80% paediatric patients). Our neuropsychological data provide evidence of greater plasticity and compensational capacity in childhood. The results can be taken as a strong argument for early surgical intervention.

Surgery for the treatment of juvenile TLE is successful and safe, but the resection type may influence outcomes. Results after AHs were disappointing, probably because of difficulties in precise localization of the epileptogenic focus among children. Neuropsychological results demonstrated minimal rates of deterioration and significant improvements in contralateral functions. Surgical treatment of juvenile TLE should be encouraged, but the use of especially left AH should possibly be restricted.

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-