Structural connectivity predicts the amelioration of postoperative rapid eye movement sleep behavior disorder in Parkinson's disease patients who underwent subthalamic nucleus-deep brain stimulation.

INTRODUCTION

Bilateral subthalamic nucleus (STN)-deep brain stimulation (DBS) has been proven to be effective for treating probable rapid eye movement (REM) sleep behavior disorder (pRBD) symptoms in patients with Parkinson's disease (PD). However, the underlying cortical mechanism has yet to be elucidated.

OBJECTIVES

To investigate the relation of structural connectivity of the STN with fiber tracts and cortical regions to postoperative outcomes of RBD symptoms.

METHODS

Forty PD patients with preoperative pRBD who underwent bilateral STN-DBS were enrolled and divided into a pRBD-group and a pRBD + group according to postoperative scores on the RBD Screening Questionnaire (RBDSQ). The volume of tissue activated (VTA) was calculated for each electrode to locate the sweet spot correlated with the decrease in the RBDSQ score. Tractography was applied to confirm differences in cortico-STN connectivity and to further search for critical fiber tracts and cortical regions associated with treatment effects.

RESULTS

Patients in the pRBD-group showed better improvement on RBDSQ (adjusted P = 0.042), better sleep quality (adjusted P = 0.081) and less restlessness (adjusted P = 0.093) after STN-DBS. VTA analyses revealed a positive correlation between the RBDSQ score decrease and the overlap volume of the left associative subnucleus (adjusted P = 0.090). pRBD-patients were found to have more stimulation scope on VTA-anterior thalamic radiation-9p (adjusted P = 0.096), VTA-dentatorubrothalamic tract (DRTT)-SFL (adjusted P = 0.092), and VTA-superior thalamic radiation-8BL (adjusted P = 0.088) fibers.

CONCLUSION

The effectiveness of STN-DBS for PD-RBD is significantly related to the VTA of electrodes. An appreciable effect may be achieved from VTA circumscribing the STN associative subnucleus, anterior thalamic radiation-9p, DRTT-SFL, and superior thalamic radiation-8BL fibers.