Long-term efficacy and cognitive effects of bilateral hippocampal deep brain stimulation in patients with drug-resistant temporal lobe epilepsy.

PURPOSE: Temporal lobe epilepsy patients treated with hippocampal deep brain stimulation (Hip-DBS) have rarely been reported before. Preoperative and postoperative cognitive function is seldom analyzed. METHODS: Seven patients with drug-resistant temporal lobe epilepsy were included in this study. Bilateral Hip-DBS was performed in these patients. The stimulator was activated 1 month after the implantation. Then, the patients returned for further adjustments 4 months after the surgery and reprogramming every year. The seizure frequency, Wechsler Adult Intelligence Scale-IV, and Wechsler memory scale-IV were assessed blindly as the outcomes at each follow-up. RESULTS: After a mean 48-month follow-up, the mean seizure frequency significantly decreased (p = 0.011, paired t test; decrease of 78.1%). One patient (14.3%) was seizure-free by the last follow-up; six of seven (85.7%) patients had reductions in seizure frequency of at least 50%; one patient (14.3%) who did not comply with the antiepileptic drug instructions had a less than 50% reduction in seizure frequency. In addition, there were no significant decreases in intelligence or verbal and visual memory from baseline to the last follow-up (p = 0.736, paired t test; p = 0.380, paired t test, respectively). CONCLUSION: Hip-DBS could provide acceptable long-term efficacy and safety. For patients with drug-resistant temporal lobe epilepsy who are not suitable for resective surgery, Hip-DBS could become a potential therapeutic option.