Directional deep brain stimulation of the centromedian thalamic nucleus reduces DBS-induced ataxia and dysarthria in Lennox-Gastaut Syndrome: A single case study

Background: We present a case of a 46-year-old man with Lennox-Gastaut syndrome and drug-resistant epilepsy. An adjunctive neurostimulation therapy strategy was implemented involving bilateral deep brain stimulation (DBS) of the centromedian thalamic nucleus (CMT).

Methods: Robotically assisted implantation of bilateral DBS directional lead system with 8 contacts in the CMT was performed. The clinical course was assessed in repeated in-patient follow-ups.

Results: Initial DBS stimulation resulted in progressive ataxia and dysarthria significantly beyond the level seen before surgery. Deactivation of DBS coincided with improvement of dysarthria. A DBS stimulation paradigm with reduction of lateral and superior stimulation resulted in improvement and eventually complete resolution of the stimulation side effect.

Discussion: This case suggests that stimulation-induced dysarthria in DBS can be improved by targeted reduction of lateral and/or superior thalamic stimulation. When dysarthria and ataxia occur during DBS, directed stimulation to medial thalamic structures and more inferior electrode contacts offers a promising strategy to reduce side effects while maintaining positive effects.