Authors :
Presenting Author: Zachary Sanger, MS – University of Minnesota Medical Center
Thomas Lisko, BS – Department of Neurosurgery, University of Minnesota
Hafsa Farooqi, PhD – University of Minnesota
Robert McGovern III, MD – University of Minnesota Medical Center
Theoden Netoff, PhD – University of Minnesota
Rationale:
Deep Brain Stimulation (DBS) is FDA approved for the treatment of drug resistant epilepsy. While the SANTE trial (Fisher et al, 2010) demonstrated the anterior nucleus of the thalamus (ANT) as an efficacious brain target for the therapy, some patients did not achieve seizure freedom and neurostimulators did not have the capability of recording neural activity while simultaneously stimulating. Modern implantable pulse generators (IPG), like Neuropace RNS and Medtronic’s Percept, allow for local field potential (LFP) recordings which may inform clinicians about the patient state at location of implant and during therapy delivery.
Methods:
Utilizing Percept PC, we recorded LFP during stim on and off conditions under multiple stimulation parameters as part of an Institutional Review Board (IRB) approved clinical study (#NCT05493722) at the University of Minnesota (N=14). LFPs were transformed into the frequency domain using slepian multitaper analysis and 1/F detrended using an adjusted FOOOF method (Donoghue et al, 2020). Patient responses to stim on/off were compared within a visit and across visits.
Results:
In patients where low gamma oscillations (30-45Hz) were observed, multiple stimulation parameters, including the standard clinical setting (145Hz, 90μs pulse width), statistically significantly reduced gamma activity. Power spectral density morphology changed and baseline low gamma oscillations decreased in power across visits.
Conclusions:
Low gamma oscillations have been observed in multiple ANT DBS implanted refractory epilepsy patients. Stimulation can effectively reduce this oscillation within the same visit and over time. Because stimulation of the thalamus suppresses these oscillations, it suggests that stimulation may either block incoming oscillations originating from another source, or that the thalamus may be involved in or the origin of these rhythms. Additionally, Low gamma band activity in the ANT may be a biomarker that can be used to identify responders and optimize stimulation settings.
Funding:
NIH U01NS124616
MnDrive Brain Conditions Fellow: Research reported in this presentation was supported by the University of Minnesota’s MnDRIVE
(Minnesota’s Discovery, Research and Innovation Economy) initiative.