Correlation Between Electrode Location and Clinical Efficacy of Deep Brain Stimulation of the Subthalamic Nucleus in Isolated Generalized Dystonia

Background: Isolated Generalized Dystonia (IGD) severely reduces quality of life. Deep brain stimulation of the subthalamic nucleus (STN-DBS) is effective for refractory IGD, but the factors influencing efficacy remain unclear. Methods: Twelve IGD patients treated with bilateral STN-DBS (2016–2021) were retrospectively analyzed. Clinical outcomes (BFMDRS, HAMA, HAMD, MOCA, MMSE) were evaluated at baseline and the last follow-up (12–60 months). The electrode position and volume of tissue activated (VTA) in STN subregions were analyzed using Lead-DBS V3.0. Results: STN-DBS significantly improved BFMDRS-M and BFMDRS-D scores (p < 0.001) without cognitive or mood deterioration. BFMDRS-M improvement correlated positively with the VTA of the whole STN and motor subregion (p < 0.05) but not with associative/limbic subregions. The preoperative HAMD score was negatively associated with motor improvement (p = 0.002). Conclusions: STN-DBS safely improves motor function in IGD. Efficacy depends on the VTA within the STN sensorimotor subregion. The preoperative HAMD score may predict the long-term outcome, helping guide patient selection and surgical planning.