Improved spatial targeting with directionally segmented deep brain stimulation leads for treating essential tremor.

Area of Science:

• Neuroscience
• Biomedical Engineering
• Computational Modeling

Background:

• Deep brain stimulation (DBS) in the ventral intermediate nucleus of thalamus (Vim) effectively treats essential tremor (ET).
• Leads near the Vim's caudal border risk stimulating the ventral caudal (Vc) nucleus, causing paresthesia side effects.
• Optimizing DBS requires understanding modulated neuronal pathways and exploring advanced electrode designs.

Purpose of the Study:

• To investigate neuronal pathways affected by different deep brain stimulation (DBS) settings in essential tremor (ET) patients.
• To compare standard DBS leads with directionally segmented DBS (dDBS) leads for improved therapeutic outcomes.
• To determine the potential benefits of dDBS in achieving tremor suppression without paresthesia.

Main Methods:

• Developed multi-compartment neuron models of thalamocortical, cerebellothalamic, and medial lemniscal pathways.
• Simulated patient-specific anatomies, lead placements, and programming parameters from three ET patients.
• Utilized computational models to analyze neuronal activation patterns for therapeutic and side-effect-inducing DBS settings.

Main Results:

• Therapeutic tremor suppression correlated with activating ~62% of cerebellothalamic input to Vim.
• Paresthesias were linked to activating ~35% of the medial lemniscal tract input to Vc thalamus.
• Directionally segmented DBS (dDBS) showed superior targeting of the cerebello-thalamo-cortical pathway, particularly with misaligned leads.

Conclusions:

• Directionally segmented DBS (dDBS) offers enhanced precision for targeting therapeutic pathways in the thalamus.
• dDBS enables better current sculpting to maximize tremor suppression while minimizing paresthesia side effects.
• This technology holds promise for more consistent and effective essential tremor management.