Stimulation-induced side effects in the posterior subthalamic area: distribution, characteristics and visualization.

Area of Science:

• Neurosurgery
• Neurology
• Stereotactic Surgery

Background:

• The posterior subthalamic area (PSA) is an emerging target for deep brain stimulation (DBS) in tremor treatment.
• Further exploration of the PSA is needed to understand its functional anatomy and optimize DBS therapy.

Purpose of the Study:

• To investigate the spatial distribution of stimulation-induced side effects within the PSA.
• To characterize the nature of these side effects and their relationship to specific anatomical structures.

Main Methods:

• Evaluation of 33 DBS electrodes in 28 essential tremor (ET) patients one year post-surgery.
• Systematic testing of each electrode contact to identify stimulation-induced side effects.
• Plotting side effect locations on stereotactic atlases and creating a 3D model for visualization.

Main Results:

• Identical stimulation-induced responses were elicited from various points within and around the PSA.
• Muscular and cerebellar symptoms, including dysarthria, were not consistently linked to the internal capsule.
• Paresthesias occurred across the PSA without a discernible somatotopic pattern.

Conclusions:

• Attributing specific side effects to distinct anatomical areas in the PSA proved challenging due to response variability.
• The study could not establish a meaningful somatotopic map for stimulation-induced side effects in the PSA.
• Further research is needed to refine DBS targeting within the PSA for tremor management.