This study shows that cognitive impairment in nondemented patients with Parkinson disease (PD) is closely related to the presence of REM sleep behavior disorder, a sleep disturbance that was not controlled for in previous studies assessing cognitive deficits in PD.

The presence of altered motor subtypes in PD with RBD suggests that patients with PD and RBD may have a different underlying pattern of neurodegeneration than PD patients without RBD.

Background: Over 50% of persons with idiopathic REM sleep behavior disorder (RBD) will develop

No abstract