Abstracts

Rausch et al. ([italic]Neurology [/italic]2003;60:951-959) have recently underscored the worrisome possibility that resection surgery of the hemisphere associated with speech may be related to an increased risk for late decline in verbal memory beyond that associated with epilepsy or aging.
We evaluated 28 surgical cases (18 with resection surgery on the same side as speech; 10 with resections on the opposite side) before surgery, one month after surgery, one year after sugery, and 10 years after surgery. As a comparison group, we evaluated 28 nonsurgical epilepsy cases once and again at the end of 10 years of medical treatment. All epilepsy cases in this study had partial seizures with or without secondary generalization, all had focal EEGs, and no medically-treated patient had been rejected for epilepsy surgery. In addition, we evaluated 28 normal controls with completely negative neurological histories and tested them initially and again after 10 years. All groups were of adults of similar age, sex, education, and occupational status. Full day testings on each occasion included the complete Wechsler Adult Intelligence Scale (original form), the Wechsler Memory Scale (Form I), and an expanded Halstead-Reitan Battery.
First, considering only the group with surgery on the same side as speech, significant baseline to one month postoperative losses were noted on two of 12 cognitive variables: WMS Logical Memory--immediate ([italic]p [/italic]= .033), WAIS Information ([italic]p [/italic]= .024), and WAIS Vocabulary ([italic]p [/italic]= .025). However, in each of these cases the scores improved over time and the 10 year postoperative scores were actually higher than the one month scores. Also, in comparison with preoperative scores, the group with surgery on the same side as speech had significantly [underline]higher[/underline] values at the end of the study for WAIS Total Verbal Scaled Score ([italic]p [/italic]= .018) and the WAIS Total Performance Scale Scale ([italic]p [/italic]= .037). When the two surgical groups were compared with each other, significant differential changes across the groups were noted on only WMS Logical Memory--immediate ([italic]p [/italic]= .010) and WAIS Information ([italic]p [/italic]= .023) but only at the one month postoperative testing. In each case, the 10 year testings produced scores which were [underline]superior [/underline]to those obtained at the one month testing for the speech side surgery group. When the data from all four patient groups were examined across the 10 year period, significant improvements in WAIS PIQ and FSIQ were noted, especially for the group having surgery on the side of speech..
This study provides no evidence to associate a late loss in memory or general cognitive functioning with surgery on the side of speech or even with surgery at all. Its significance is to suggest that surgery for epilepsy need not be shunned due to potential long term losses in cognition. However, its limitations (only 10 years in duration, absence of measures of delayed memory, no high resolution neuroimagining, etc.) clearly indicate that more work needs to be done before definitive conclusions can be reached.