We aim to compare effects of thalamic Deep Brain Stimulator (DBS) and responsive neurostimulator (RNS) device therapy on seizure burden in drug-resistant epilepsy patients. 

Intractable epilepsy unamenable to cortical resection is often treated with a device, either RNS or DBS provides intracranial stimulation. The devices are thought to reduce seizure frequency by reducing synchronization of cortical activity. The RNS provides more localized stimulation while the DBS does this by stimulating the anterior nucleus of the thalamus. At our institution a small number of patients have also undergone thalamic stimulation by using the RNS.

We performed retrospective analysis on seizure frequency pre-implant and at most recent follow-up for our cohort, 12 DBS and 6 RNS patients.  

Average age of RNS implantation was 30 years (range 19-41) vs 42 years (range 18-66) for DBS.

Thirteen (9 DBS, 4 RNS) of the 18 patients had stereo-EEG (SEEG) evaluation before device placement, SEEG ictal onset was broad or multifocal in all (DBS: 7 – bilateral and 2 – unilateral, RNS: 3 bilateral, 1 unilateral). Three out of five patients who did not have invasive EEG evaluation before device placement had suspected (2) or confirmed (1) genetic etiology, all five had non-localizing, non-lateralizing scalp ictal EEG.

The electrodes were placed to the anterior nucleus of thalamus bilaterally in all DBS and four RNS patients, two RNS patients had centromedian nucleus of thalamus sampling.

Twelve of our 18 patients (8 out of 12 DBS and 4 out of 6 RNS) were shown to be responders, achieving 50% or greater reduction in seizure frequency. The average follow-up duration for RNS was 22 months (range 3-36), for DBS 13.5 months (range 2-29).

This analysis demonstrates the potency of thalamic neuromodulation, both RNS and DBS, as therapies capable of seizure relief in wide breadths of epilepsy presentations.