Cortical vs Subcortical Recordings to Drive Closed-Loop Deep Brain Stimulation in Essential Tremor.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Neurology

Background:

• Essential tremor (ET) is a hyperkinetic disorder characterized by postural and action-kinetic tremor.
• Conventional deep brain stimulation (DBS) may not be optimal for ET management.
• Closed-loop deep brain stimulation (CL-DBS) offers potential benefits including increased battery life, reduced side effects, and mitigation of stimulation tolerance by responding to neuro-markers.

Purpose of the Study:

• To establish patient-specific desynchronization in motor regions as a tremor-tracking surrogate marker for modulating stimulation.
• To evaluate the efficacy and patient experience of CL-DBS for essential tremor.

Main Methods:

• CL-DBS was implemented using a long-term embedded implantable pulse generator in 4 participants.
• Neural activity was recorded from sensorimotor cortical regions and thalamic nuclei.
• Clinical efficacy and patient-reported experiences were assessed over 18 months.

Main Results:

• Sensorimotor cortical regions demonstrated superior and more consistent performance as a biomarker compared to thalamic nuclei.
• CL-DBS maintained clinical efficacy for up to 18 months.
• Patient experiences with home-based CL-DBS were largely positive, with valuable feedback derived from stimulation cessation events.

Conclusions:

• Utilizing a cortical strip to record neural activity remote from the stimulation site is an optimal strategy for CL-DBS in ET.
• Movement signatures are more effective surrogate biomarkers than symptom presence indicators for closed-loop control in ET.
• This approach provides critical real-world feedback for refining future ET therapies.