Single cell firing patterns in the anterior thalamic nucleus relate to therapy response in deep brain stimulation for refractory epilepsy
Abstract number :
3.283
Submission category :
9. Surgery
Year :
2015
Submission ID :
2327425
Source :
www.aesnet.org
Presentation date :
12/7/2015 12:00:00 AM
Published date :
Nov 13, 2015, 12:43 PM
Authors :
R. Rouhl, Y. Zhao, G. Wagner, E. Gommer, M. L. Janssen, L. Ackermans, C. Heida, Y. Temel, V. van Kranen-Mastenbroek
Rationale: Patients with medically refractory epilepsy receiving deep brain stimulation (DBS) in the anterior thalamic nucleus (ATN) vary in their therapeutic response. ATN cells in epilepsy patients have a characteristic pattern of firing in bursts, which is, empirically, also highly variable among patients. This led us to hypothesize that the electrophysiological characteristics of the ATN cells may predict the response to DBS.Methods: We included 10 patients with medically refractory epilepsy. The lead trajectory followed an extraventricular approach, ending in the ATN at the top of the mamillothalamic tract (i.e. the target). Along this trajectory we performed microelectrode recordings at 0.5mm intervals to identify the (single unit) neuronal signals of the thalamic nuclei. We assessed preoperative MR images to verify anatomical location of the recordings. We defined therapy response to DBS as a more than 50% reduction in seizure frequency within the first year of treatment and compared signal characteristics at the different depths between responders versus non-responders.Results: We used data from 19 electrode trajectories (in 9 patients bilateral trajectories). We found neurons firing in high-amplitude bursts, usually around the planned target area. Of our patients, 5 responded to the DBS, whereas 5 patients were classified as non-responders. Responders had higher mean firing rates of single cells in regions near the planned target, and profiles of these firing rates along the different depths showed a more clear delineation between the target region and the surrounding area in responders (G1; see Figure) than in non-responders (G2). Correlation with anatomical data did not reveal that electrode trajectories and targets in responders differed significantly from non-responders.Conclusions: We conclude that single unit neuronal activity in the target area of DBS in refractory epilepsy relates to the clinical response. Our study warrants further exploration into the use of electrophysiology in improving the targeting of the ATN.
Surgery