Abstracts

Enhancing Thalamic Deep Brain Stimulation Through Real-time Data Streaming

Abstract number : 3.272
Submission category : 3. Neurophysiology / 3E. Brain Stimulation
Year : 2024
Submission ID : 496
Source : www.aesnet.org
Presentation date : 12/9/2024 12:00:00 AM
Published date :

Authors :
Mohammad Taba, MD – University of California, Los Angeles
Ausaf Bari, MD – David Geffen School of Medicine at UCLA
Rajarshi Mazumder, MD – David Geffen School of Medicine at UCLA
John Stern, MD – University of California Los Angeles
Noriko Salamon, MD,PhD – UCLA Mattel Children's Hospital
Presenting Author: Dawn Eliashiv, MD – UCLA


Rationale:
One third of epilepsy patients have Drug Resistant Epilepsy. Neuromodulation like DBS targeting thalamic nuclei is an option for those ineligible for resection surgery. (1) The Percept device captures LFP offering insight into stimulation effects. Real-time LFP streaming of LFP during stimulation titration aids in personalized parameter optimization. (1) The current workflow at our institution is to test stimulation parameters while streaming LFPs. Further, we evaluated the Power Spectrum Density (PSD) in conjunction with time domain data to assess the physiological impact of stimulation. Several patients in our cohort demonstrated suppression in various frequency bands in addition to a reduction in thalamic bursting. In addition, we evaluated the physiological response with stimulation on and off and at various stimulation ramp rates.




Methods:
At UCLA, 24 drug-resistant epilepsy (DRE) cases received bilateral Anterior Nucleus of Thalamus (ANT) (19) or Centromedian Nucleus (CM) (5) DBS implants. Among them,18 patients received the Percept devices. MRI/CT placement was reviewed, and 1-2 contacts were identified in ANT or CM. In clinic LFPs were run to assess the physiological impact of various stimulation parameters, namely amplitude. We stimulated each hemisphere independently from amplitudes of 0mA – 6mA then stimulated hemispheres concurrently at various duty cycles. The physiological impact was evaluated on the tablet in clinic and analyzed in MATLAB.




Results:
The majority of our patients (16, 88.9%) showed baseline thalamic bursting without stimulation, and 67% of patients had a notable Beta/Gamma peak that responded to DBS in a dose dependent manner. Some exhibited suppression of higher frequency bands and thalamic bursting at lower stimulation currents. Conversely, at higher amplitudes several patients in our cohort also demonstrated a re-emergence of thalamic bursting and increased delta activity. We also evaluated various ramp rates and duty cycles. Thalamic activity with stimulation off varied between patients, some had a carry over effect while others showed activity returning immediately. In one case when the ramp rate was 4s there was impact on thalamic bursting which correlated with clinical seizures. When the ramp rate was increased to 8s the was no longer thalamic bursting during stimulation ramp or clinical seizures observed with stimulation.




Conclusions:
This preliminary study reinforces the potential of real-time LFP streaming as a potential marker for DBS optimization in epilepsy patients. Alpha/beta and gamma bands emerge as promising biomarkers for treatment response, supporting previous findings. (1) Further studies validating real time streaming data analysis may contribute to optimization of stimulation parameters to maximize the response to neurostimulation.

References:
1. Chua MMJ, Vissani M, Liu DD, Schaper LWVJ, Warren AEL, Caston R, et al. Initial case series of a novel sensing deep brain stimulation device in drug-resistant epilepsy and consistent identification of alpha/beta oscillatory activity: A feasibility study. Epilepsia 2023; 64: 2586-2603







Funding: Dr. Eliashiv has grant support and honoraria for talks from Medtronic

Neurophysiology