Original Research ARTICLE
LOW FREQUENCY MICROSTIMULATION IS LOCALLY EXCITATORY IN PATIENTS WITH EPILEPSY
- 1University Hospital of Geneva, Switzerland
Deep brain stimulation (DBS) could become a palliative treatment for patients with drug-resistant epilepsy for whom surgery cannot be proposed. The objective of this study was to perform microstimulation to measure the effects of DBS in epilepsy locally at the level of a few neurons, with microelectrode recordings, for the first time in patients with epilepsy. Microelectrode recordings were performed before, during and after microstimulation in nineseven patients with refractory epilepsy. Neuronal spikes were successfully extracted from multi-unit recordings with clustering in 6 out of 7 patients during hippocampal and in 1 out of 2 patients during cortical dysplasia microstimulation (1 Hz, charge-balanced biphasic waveform, 60 micros/ph, 25 microA). The firing rates increased in 4 out of the 6 periods of microstimulation that could be analyzed. The firing rates and were found higher than before microstimulation in all 8 periods with increases reaching significance in 6 out of 8 periods. Low-frequency microstimulation was hence sufficient to induce neuronal excitation lasting beyond the stimulation period. No inhibition was observed. This report presents the first evidence that microstimulation performed in epileptic patients produced locally neuronal excitation. Hence neuronal excitation is shown here as the local mechanism of action of DBS. This local excitation is in agreement with epileptogenic effects of low-frequency hippocampal macrostimulation.
Keywords: DBS, Epilepsy, microelectrode, microstimulation, Safety, Hippocampus
Received: 12 May 2017;
Accepted: 26 Feb 2018.
Edited by:Caren Armstrong, Johns Hopkins Children's Center, United States
Reviewed by:Yu-Wei Wu, Stanford University, United States
Daniel Llano, University of Illinois at Urbana–Champaign, United States
Copyright: © 2018 Bartoli, Tyrand, Vargas Gomez, Momjian and Boex. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: PhD. Colette Boex, BOEX., University Hospital of Geneva, rue Gabrielle-Perret Gentil, 4, rue Gabrielle-Perret Gentil, 4, Geneva, 1211, --- Select One ---, Switzerland, Colette.Boex@hcuge.ch