Effect of deep brain stimulation on brain network and white matter integrity in Parkinson's disease

The effects of subthalamic nucleus (STN)-deep brain stimulation (DBS) on brain topological metrics, functional connectivity (FC), and white matter integrity were studied in levodopa-treated Parkinson's disease (PD) patients before and after DBS.

Clinical assessment, resting-state functional MRI (rs-fMRI), and diffusion tensor imaging (DTI) were performed pre- and post-DBS in 15 PD patients, using a within-subject design. The rs-fMRI identified brain network topological metric and FC changes using graph-theory- and seed-based methods. White matter integrity was determined by DTI and tract-based spatial statistics.

Unified Parkinson's Disease Rating Scale III (UPDRS- III) scores were significantly improved by 35.3% (p < 0.01) after DBS in PD patients, compared with pre-DBS patients without medication. Post-DBS PD patients showed a significant decrease in the graph-theory-based degree and cost in the middle temporal gyrus and temporo-occipital part-Right. Changes in FC were seen in four brain regions, and a decrease in white matter integrity was seen in the left anterior corona radiata. The topological metrics changes were correlated with Beck Depression Inventory II (BDI-II) and the FC changes with UPDRS-III scores.

STN-DBS modulated graph-theoretical metrics, FC, and white matter integrity. Brain connectivity changes observed with multi-modal imaging were also associated with postoperative clinical improvement. These findings suggest that the effects of STN-DBS are caused by brain network alterations.