Clinical characteristics, surgical and neuropsychological outcomes in drug resistant tumoral temporal lobe epilepsy

Abstract

Introduction: Glioneuronal tumors are found in nearly one third patients who undergo surgery for pharmacoresistant epilepsy with temporal lobe being the most common location. Few studies, however have concentrated on the neurological and neuropsychological outcomes after surgery, hitherto none from India.

Methods: We studied 34 patients with temporal lobe tumors and drug resistant epilepsy. These patients underwent anterior temporal lobectomy or lesionectomy based on the involvement of the hippocampus and mesial temporal structures. The clinical history, EEG, neuropsychology profile and MRI were compared. Seizure outcome was categorized using Engel's classification.

Results: At a mean follow up of 62 months, 85.29% of the patients were seizure free (Engel's Class I). All 8 patients with intraoperative electrocorticography (ECoG) guided resection were seizure free.

Discussion: Presence of a residual lesion was significantly associated with persistence of seizures post surgery (p = 0.002). Group analysis revealed no significant shifts in IQ and memory scores postoperatively. There was a significant improvement in the quality of life scores (total and across all subdomains) in all patients (p < 0.001). Postoperative EEG abnormalities predicted unfavorable ​seizure outcome.

Conclusion: Surgery for temporal lobe tumors and refractory epilepsy offers complete seizure freedom in majority. Complete surgical excision of the epileptogenic zone is of paramount importance in achieving seizure freedom. Intraoperative electrocorticography (EcoG) is a useful adjunct to ensure complete removal of epileptogenic zone, thus achieving optimal seizure freedom. There is a significant improvement in the quality of life scores (p < 0.001) with no negative impact of surgery on memory and intelligence. Even the patients who are not seizure free can achieve worthwhile improvement post surgery.

Keywords: Amygdalahippocampectomy; Anterior temporal lobectomy (ATL); Drug resistant epilepsy; Electrocorticography (ECoG); Neuropsychological outcomes; Temporal lobe tumors.