EP 72. Effect of deep brain stimulation on sleep is outcome-dependent in patients with temporal lobe seizures

Abstract

Question In a randomized controlled trial Fisher et al. showed efficacy of deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) for focal epilepsies. In this study the active group complained significantly more often about depression or/and cognitive impairment, both typical symptoms of disturbed sleep (2). Recently, a voltage-dependent effect of ANT-DBS on sleep fragmentation could be demonstrated with polysomnography (PSG): with the reduction of the nightly DBS-voltage the numbers of arousals declined, eventhough the antiictal efficacy remained unchanged (3). In the following, the voltage-dependent effect on arousals was examined in both responders and non-responders of ANT-DBS in a cohort of patients with temporal lobe seizures. Methods In eight patientens a PSG was obtained with standard and voltage-reduced ANT-DBS (monopolar, stimulator case as anode, 0.5 V–6.5 V, pulse width 90 μs; frequency 145 Hz, ON-time 1 min, OFF-time 5 min). The number of arousals during the stimulation ON- and OFF-periods was compared (DBS-arousal-ratio). The results were statistically analysed for the group of ANT-DBS-responders (defined as seizure reduction >50%) and the non-responders. Results The voltage-dependent effect of ANT-DBS on sleep fragmentation was only replicated for our cohort of eight patients (Spearman-Rank-coefficient = 0.546; p Conclusion ANT-DBS seems to have a bigger impact on the sleep quality in patients who respond to ANT-DBS. We recommend an active evaluation of cognitive and mood disturbances in responders and – if necessary – a referral to a sleep laboratory. For confirmation and further understanding of our findings, a controlled trial of a larger patient group is warranted.