Update on neurodegenerative markers in isolated rapid eye movement sleep behavior disorder

α-synucleinopathy, as represented by Parkinson’s disease and dementia with Lewy bodies, is a group of common neurodegenerative diseases that have insidious onset and irreversible progression. Therefore, identifying markers related to neurodegenerative progression during the prodromal stage is crucial for the early diagnosis and effective treatment of α-synucleinopathy. A distinct parasomnia, isolated rapid eye movement sleep behavior disorder (iRBD), is confirmed as the most specific prodromal phase of α-synucleinopathy, with most of the patients with iRBD eventually converting into a subtype of α-synucleinopathy. Throughout the disease progression of α-synucleinopathy, an array of multidimensional markers, such as clinical, neuroimaging, and neuropathological markers, have been increasingly discovered and validated. These markers may hold potential diagnostic, disease-monitoring, and prognostic values for iRBD. In this review, we summarized the current evidence on the neurodegenerative markers associated with iRBD and discussed their significant role in the diagnosis, monitoring, and prediction of phenoconversion into α-synucleinopathy in iRBD. A better understanding of these markers will facilitate their implementation in risk stratification, population selection for future clinical trials, and monitoring of response to the disease-modifying strategies in iRBD.