OP-3 Seizure and Neuropsychological Outcome after Surgery for Medial Temporal Lobe Sclerosis

Introduction: The aim of the present study was to evaluate the neuropsychological outcomes of adult patients with drug-resistant unilateral mesial temporal lobe epilepsy (MTLE) due to hippocampal sclerosis (HS) treated by anterio-mesial temporal lobectomy (AMTL).

Methods: This was a prospective study where 34 patients who had undergone surgery for MTLE were evaluated. All patients underwent a detailed neuropsychological evaluation before and 6 months after surgery. The measures of neuropsychological parameters employed included: (1) intelligence: information score, arithmetic score, comprehension score, digit span test, verbal IQ, Koh Block design test, Alexander pass along test, Performance IQ, and mean IQ; (2) attention and working memory: digit vigilance test and mental balance; (3) verbal memory: immediate verbal recall, delayed verbal recall, similar pairs test, and dissimilar pairs test; (4) visual memory: visual retention and visual recognition; (5) recent memory, remote memory, total memory, and memory percentile; (6) perceptual motor functions: Bender Visuomotor Gestalt test, Nahor–Benson test, and Digit symbol substitution test; (7) language function: controlled oral word test for phonemic fluency and animal names test for categorical fluency

Results: Long-term seizure freedom was obtained in 82.3% of patients. There was a statistically significant association of unfavorable outcome with the presence of acute postoperative seizures (p = 0.007). Majority of our patients (91%) did not complain of any decline in cognitive function postoperatively. Postoperative improvement was noted in cognitive domains: verbal IQ (5.9%), performance IQ (20.6%), verbal memory (38.2%), visual memory (11.8%), phonemic fluency (21.9%), and categorical fluency (14.7%). Postoperative verbal memory decline is seen in 29.4% of left MTLS patients and 11.8% of right mesial temporal lobe sclerosis (MTLS) patients. Postoperative visual memory decline was seen in 5.9% of left MTLS patients and 17.6% of right MTLS patients. Postoperative decline in verbal IQ, performance IQ, phonemic fluency, and categorical fluency was seen in 3.1 to 11.8% of patients. In left MTLS group, there were no significant differences between the scores obtained at time 1 (preoperative) and time 2 (postoperative) across all the measures of neuropsychological parameters with the significance threshold of p < 0.05. In, the right MTLS group, there was a significant improvement between the scores obtained at time 1 (preoperative) and time 2 (postoperative) for the Alexander pass along test (Visuo-spatial planning, Performance IQ) [mean ± SD: 94.1 ± 20.7 vs. 105.6 ± 21.8 with p = 0.01] and Controlled Oral word test (Phonemic fluency) [mean ± SD: 5.61 ± 2.33 vs. 6.24 ± 1.8 with p = 0.02] with the significance threshold of p < 0.05.

Conclusion: Resective epilepsy surgery for hippocampal sclerosis is safe and effective in terms of seizure freedom and neuropsychological outcome. The results of our center with noninvasive presurgical evaluation protocol were comparable to the international standard.

Publication History

Article published online:
12 September 2024