From Rapid Eye Movement Sleep Behavior Disorder to Parkinson's Disease: Possible Predictive Markers of Conversion

Idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) manifests as unpleasant dreams and dream-enacting behaviors during REM sleep. iRBD is currently recognized as a prodromal stage of Parkinson's disease (PD), and the majority of iRBD patients will develop PD. However, there is an approximately 10 year interval between iRBD onset and established PD, which provides neurologists a window for intervention prior to irreversible neuron damage in prodromal PD patients. In this Review, we summarize possible predictive markers of PD in iRBD on clinical assessment, heredity, neuroimaging, and electrophysiology. We hope this summary can help researchers and clinical physicians better understand the risk factors for conversion from iRBD to PD and indicate directions for neuroprotective strategies and the prediction of disease progression.