Effect of White Matter Stimulation on Clinical Outcomes in Thalamic Deep Brain Stimulation for Essential Tremor
Wutt Kyi ’22
Karlo Malaga, Biomedical Engineering
Program for Undergraduate Research (PUR)
Deep brain stimulation (DBS) is a surgical procedure where electrodes are implanted in the brain before stimulating the tissue with electricity. DBS of the ventral intermediate (VIM) nucleus of the thalamus and the subthalamic nucleus (STN) are established treatments for the motor symptoms of essential tremor (ET) and Parkinson disease (PD), respectively. Motor outcomes, such as tremor, rigidity, and bradykinesia, after VIM and STN DBS can vary considerably across patients and strongly depend on the location of stimulation relative to the surgical target. Previous research suggests that stimulation of the white matter (WM) tracts lateral to the VIM, the gray matter (GM) target, results in better DBS outcomes. The objective of this retrospective study is to determine how the spread of stimulation to WM during VIM DBS relates to therapeutic and non-therapeutic outcomes in ET patients. For the first phase of this research, a MATLAB algorithm that can differentiate brain tissues, such as WM, GM, and cerebrospinal fluid, from medical imaging based on tissue anisotropy was developed. Patient-specific tissue anisotropy was derived from diffusion tensor imaging data acquired for individual patients who received DBS (n = 22). To evaluate the performance of the algorithm, it has been trained and tested across both ET and PD patient data sets. This algorithm can be used to differentiate brain tissues in any region of interest. The modeling framework utilized in this study could be used to identify optimal stimulation sites on an individual basis, thereby improving clinical outcomes.