Relationship Between White Matter Connectivity and Thalamic RNS Responsiveness in Pediatric Patients with Drug Resistant Epilepsy
Abstract number :
1.361
Submission category :
5. Neuro Imaging / 5A. Structural Imaging
Year :
2024
Submission ID :
1352
Source :
www.aesnet.org
Presentation date :
12/7/2024 12:00:00 AM
Published date :
Authors :
Presenting Author: Puck Reeders, PhD – Nicklaus Childrens Hospital
Nathan Schultheiss, PhD – Nicklaus Children's Hospital
Shelly Wang, MD, MPH – University of Miami
Prasanna Jayakar, MD, PhD – Nicklaus Children's Hospital
Matt Lallas, MD – Nicklaus Childrens Hospital
Trevor Resnick, MD – Nicklaus Children's Hospital
Michael Duchowny, MD – Nicklaus Children's Hospital
Marytery Fajardo, MD – Nicklaus Children's Hospital
Rationale:
1.2 million people are living with drug resistant epilepsy (DRE) in the US. Fewer than 20% of patients are candidates for epilepsy surgery due to their onset being bilateral, in eloquent cortex, or multi focal. Responsive NeuroStimulation (RNS) bridges the treatment gap for many DRE patients. RNS delivers therapy with intracranial EEG data to recognize and respond to each patient’s brain pattern, providing personalized stimulation to aim for seizure prevention. RNS therapy often targets the centromedian nucleus of the thalamus (CM) due to its widespread connectivity with the neocortex. However, the relationship between RNS responsiveness and white matter connectivity between the electrode and seizure network are not well understood. One theory is that patients with strong connectivity from the RNS target to the seizure network are more likely to respond to RNS. The current study investigates whether there is a relation between strength of white matter connectivity and RNS responsiveness. We investigated 1) the strength of structural connectivity of the CM (RNS electrode target) to brain regions with predominant peaks in the spatial current density distribution early in the seizure sequence, 2) whether there is a relationship with the connectivity strength and seizure burden reduction 3) whether pulvinar (PuL) and anterior (ANT) thalamic nuclei had stronger connectivity to the epileptogenic brain regions.
Methods:
We performed probabilistic tractography on diffusion weighted imaging using CM of the thalamus as our seed and whole brain cortical and subcortical regions as our targets. We used streamlines from each voxel in the seed region and recorded when those streamlines ended in one of our whole brain target regions. We created a seed-target distribution to investigate the connectivity profile. Next, we identified brain areas with predominant peaks in the spatial current density distribution using Curry sourcing. Then we measured structural connectivity strength from CM to those brain regions. Next, we examined whether connectivity strength is related to RNS responsiveness. Lastly, we repeated this for the PuL and ANT to explore their connectivity profile.
Results:
Out of the 6 CM RNS patients, two patients had the RNS implanted for 12+ months, and four patients 10 months or less. At this time, one patient is a RNS responder (14 months post-surgery) and has shown strongest connectivity between CM and the brain region active earliest in the seizure sequence (Connectivity strength 18354 streamlines) compared to the non-responders (connectivity streamlines ranging from 0 to 421 streamlines). Further analyses, a larger sample size, and more time to allow for RNS programming and neuromodulatory effects to take place are necessary to verify the initial findings.
Conclusions:
These results support a relationship between anatomical connectivity of CM with brain regions involved in early seizure activity, and seizure burden reduction post RNS. This information may aid in candidate selection, and surgical targeting, and outcome prediction.
Funding: Brain Institute Cypen Fund
Neuro Imaging