Retinal nerve fiber layer thinning: a window into rapid eye movement sleep behavior disorders in Parkinson's disease.

Purpose: Retinal nerve fiber layer (RNFL) thinning occurs in Parkinson's disease (PD) and other neurodegenerative diseases. Idiopathic RBD (iRBD) is a well-established prodromal hallmark of synucleinopathies and occurs secondary to many neurodegenerative diseases, including PD. The aim of this study is to determine whether or not retinal structures are altered with the onset of rapid eye movement (REM) sleep behavior disorders (RBD).

Rapid Eye Movement Sleep Behavior Disorder Symptoms Correlate with Domains of Cognitive Impairment in Parkinson's Disease.

Background: Rapid eye movement (REM) sleep behavior disorder (RBD) may be a risk factor for cognitive impairment in patients with Parkinson's disease (PD). However, little is known regarding the relation between the severity of RBD and the different domains of cognitive impairment. The aim of this study was: (1) to investigate the domains of cognitive impairment in patients with PD and RBD, and (2) to explore risk factors for PD-mild cognitive impairment (PD-MCI) and the relationship between RBD severity and impairment in different cognitive domains in PD.