Background: Rapid eye movement (REM) sleep behavior disorder (RBD), a parasomnia, after being diagnosed, can predict the emergence of an alpha-synuclein-associated neurodegenerative disease (NDD) in 20-45% and 92% of patients within 5 and 14 years, respectively. RBD is less common in tauopathies, and the studies to evaluate its association with polyglutamine diseases have been very few. Objective: To revisit our knowledge on the significance of RBD in the emergence of NDDs and to review the recent updates in the potential biomarkers, which can help predict the risk of phenconversion into NDDs in idiopathic RBD (iRBD) patients. We also aimed to look at the potential neuroprotective therapies that can potentially be used earlier in iRBD patients. Methods: We conducted a review of the papers, after selecting them from the PubMed database. After a thorough screening, 51 articles were chosen to be included in this review. Results and Conclusion: The prospective studies showed that the risk of phenoconversion of iRBD into overt NDDs increased over the longer duration of follow up. Magnetic resonance imaging (MRI) findings, Electroencephalographic findings along with subtle motor signs, autonomic dysfunction, impaired olfaction, and color vision, among others, can be used to predict the onset of an NDD in iRBD. Phytocannabinoids showed a possible neuroprotective effect in animal studies. Considering how RBD is the antecedent of NDDs, there is a need for additional studies to better understand the utility of the aforementioned biomarkers and institute potential neuroprotective therapies early in the process.
Background: Rapid eye movement (REM) sleep behavior disorder (RBD), a parasomnia, after being diagnosed, can predict the emergence of an alpha-synuclein-associated neurodegenerative disease (NDD) in 20-45% and 92% of patients within 5 and 14 years, respectively. RBD is less common in tauopathies, and the studies to evaluate its association with polyglutamine diseases have been very few. Objective: To revisit our knowledge on the significance of RBD in the emergence of NDDs and to review the recent updates in the potential biomarkers, which can help predict the risk of phenconversion into NDDs in idiopathic RBD (iRBD) patients. We also aimed to look at the potential neuroprotective therapies that can potentially be used earlier in iRBD patients. Methods: We conducted a review of the papers, after selecting them from the PubMed database. After a thorough screening, 51 articles were chosen to be included in this review. Results and Conclusion: The prospective studies showed that the risk of phenoconversion of iRBD into overt NDDs increased over the longer duration of follow up. Magnetic resonance imaging (MRI) findings, Electroencephalographic findings along with subtle motor signs, autonomic dysfunction, impaired olfaction, and color vision, among others, can be used to predict the onset of an NDD in iRBD. Phytocannabinoids showed a possible neuroprotective effect in animal studies. Considering how RBD is the antecedent of NDDs, there is a need for additional studies to better understand the utility of the aforementioned biomarkers and institute potential neuroprotective therapies early in the process.