Deep brain stimulation for intractabile epilepsy

INTRODUCTION: Deep brain stimulation (DBS) is currently considered a promising neuromodulation therapy for refractory epilepsy not suitable for resective surgery. Several anatomical targets and different stimulation approaches have been proposed in order to obtain satisfactory seizures reduction. As expected, according with different patterns of neural pathways involvement, the efficacy of each anatomical target stimulation in reducing seizure frequency varies among the different epileptic syndromes. EVIDENCE ACQUISITION: We reviewed the current literature on this topic to provide an overview of the clinical efficacy of the main stimulation targets (anterior nucleus of the thalamus [ANT], hippocampus formation [HF] and centromedian nucleus of the thalamus [CMT]) related to the different epileptic syndromes. We also summarized the available data concerning side effects, neuropsychological outcome, quality of life and future perspective of DBS in intractable epilepsy. EVIDENCE SYNTHESIS: Encouraging results were reported for each target stimulation. However, only in ANT and responsive neurostimulation (RNS) the efficacy and safety were tested on large series of patients and achieving class I evidence level. CONSLUSIONS: We concluded that responsive stimulation could be more appropriate in focal epilepsy, while ANT stimulation could be properly performed also in multifocal seizures with predominant limbic involvement. Despite the small samples size, HF stimulation reduces seizure frequency in (bi) temporal lobe epilepsy, as well as CMT stimulation is able to reduce, seizure frequency, in generalized epilepsy.