Voxel-based magnetic resonance imaging study of structural brain changes in patients with idiopathic REM sleep behavior disorder

Purpose: Rapid eye movement (REM) sleep behavior disorder (RBD) is considered to result from dysfunction of the brain stem structures that regulate REM sleep. In this study, we investigated structural brain changes using magnetic resonance imaging (MRI) in patients with idiopathic RBD (iRBD) to determine structural brain alterations associated with the disorder. Methods: Voxel-based MRI morphometry was applied to 20 patients with iRBD and findings were compared with those from 18 age-matched controls. Results: Compared with the controls, the patients with iRBD had significant gray matter volume reduction in the anterior lobes of the right and left cerebellum, tegmental portion of the pons, and left parahippocampal gyrus. Conclusion: The present study provides invivo evidence suggesting that structural lesions of the brain stem are responsible for the occurrence of iRBD. In addition, the pattern of gray matter loss is consistent with morphological changes commonly observed in patients with Lewy body disease and multiple system atrophy, indicating that iRBD can share a common morphological abnormality with alpha-synucleinopathies.