Neurostimulation and sleep in epilepsy

Background Chronic sleep disturbance may affect seizure frequency and efficacy of treatment in epilepsy patients. Vagus nerve stimulation (VNS) and deep brain stimulation (DBS) can both induce sleep disturbance as a side effect.AimThe goal of this review is to provide information and clinical advice about potential interactions between DBS at the anterior nucleus of the thalamus (ANT) and sleep as well as between VNS and sleep.Materials and methodsWe provide an up-to-date overview of the currently available literature, giving insights for diagnostics and therapy based on clinical studies, and experience in two epilepsy centers with longitudinal cohorts of patients under chronic neurostimulation.Results In patients with chronic ANT-DBS and VNS, stimulation-correlated, probably dose-dependent sleep disturbances have been reported in several studies. The reason for this is assumed to be an accidental co-stimulation of the ascending reticular arousal system in the case of DBS, and an indirect effect via induction of sleep-related breathing disorders in the case of VNS. Furthermore, VNS might also influence sleep through modulation of noradrenergic and dopaminergic, arousal-inducing systems in the pons and midbrain. Reduction of stimulation amplitudes, changes in stimulation parameters, and localization of the active stimulation zone are discussed as treatment strategies in DBS. In the case of VNS-induced sleep disturbance, a nocturnal reduction of stimulation (bilevel therapy) can be offered.Conclusion As data are currently still sparse, it seems important to optimize treatment regimens for VNS and DBS in order not to antagonize their potential anticonvulsant effects by inducing sleep fragmentation.