1. Introduction - Tractography is emerging as a precise and more personalized approach for DBS targeting and programming, especially given the evolving understanding of the physiological mechanisms underlying the therapeutic benefits of DBS. The advances in imaging and post-processing software have further influenced the interest in exploring the role of tractography. We plan to investigate the role of tractography in defining the DBS target, its correlation with the conventional targeting techniques and finally deciding if one is better than the other. 

Different regions of the cortex connect differently to the target nuclei, and though there is a good amount of conformity, there is also significant variability in the areas connected. This, in turn, influences the clinical responses in the patient seen during programming. We plan to investigate the preoperative tractography-based information and use it to perform postoperative programming, especially in difficult cases of dystonia, psychiatric disorders, or Parkinson’s disease. Lastly, we intend to advocate for precision-targeting with evidence from a cohort of Indian patients.

Methodology - Patients with Parkinson’s Disease, Dystonia, Depression, Obsessive-Compulsive Disorder, and Tourette Syndrome, eligible for Deep Brain Stimulation (based on standard guidelines), will be enrolled in the study. Two investigators will independently locate direct and tractography-based targets. Attempts will be made to include both targets in the trajectory. If not, the electrode will be implanted as per the direct target. Each patient’s pacemaker will then be programmed as per clinical assessment and tracking based on one month, each with regular clinical assessments. The outcome between the two methods would be compared.