Deep Brain and Cortical Stimulation for Epilepsy

Summary

A Cochrane review [Abstract] 1 included 12 studies with a total of 374 subjects. Eleven RCTs compared 1 to 3 months of intracranial neurostimulation with sham stimulation. One trial was on anterior thalamic deep brain stimulation (DBS, n = 109; 109 treatment periods); two trials on centromedian thalamic DBS (n = 20; 40 treatment periods), but only one of the trials (n = 7; 14 treatment periods) reported sufficient information for inclusion in the quantitative meta-analysis; 3 trials on cerebellar stimulation (n = 22; 39 treatment periods); 3 trials on hippocampal DBS (n = 15; 21 treatment periods); one trial on nucleus accumbens DBS (n = 4; 8 treatment periods); and one trial on responsive ictal onset zone stimulation (n = 191; 191 treatment periods). In addition, one small RCT (n = 6) compared 6 months of hippocampal DBS vs. sham stimulation. There were no statistically or clinically significant changes in the proportion of patients who were seizure-free or experienced a 50% or greater reduction in seizure frequency after 1 to 3 months of anterior thalamic DBS in (multi)focal epilepsy, responsive ictal onset zone stimulation in (multi)focal epilepsy patients and hippocampal DBS in (medial) temporal lobe epilepsy. However, a significant reduction in seizure frequency was found for anterior thalamic DBS (MD -17.4% vs. sham stimulation; 95% CI -31.2 to -1.0), responsive ictal onset zone stimulation (MD -24.9%; 95% CI -40.1 to -6.0) and hippocampal DBS (MD -28.1%; 95% CI -34.1 to -22.2). Both anterior thalamic DBS and responsive ictal onset zone stimulation do not have a clinically meaningful impact on quality life after 3 months of stimulation.Electrode implantation resulted in postoperative asymptomatic intracranial haemorrhage in 1.6% to 3.7% of the patients included in the two largest trials and 2.0% to 4.5% had postoperative soft tissue infections (9.4% to 12.7% after 5 years); no patient reported permanent symptomatic sequelae. Anterior thalamic DBS was associated with fewer epilepsy-associated injuries (7.4 vs. 25.5%; p = 0.01) but higher rates of self-reported depression (14.8 vs. 1.8%; p = 0.02) and subjective memory impairment (13.8 vs. 1.8%; p = 0.03); there were no significant differences in formal neuropsychological testing results between the groups. Responsive ictal-onset zone stimulation seemed to be well-tolerated with few side effects. The limited number of patients preclude firm statements on safety and tolerability of hippocampal DBS.With regards to centromedian thalamic DBS, nucleus accumbens DBS and cerebellar stimulation, no statistically significant effects could be demonstrated.