World Sleep 2022 | Brain perfusion patterns may predict conversion subtype in iRBD

Shady Rahayel, PhD, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada, discusses how brain perfusion patterns in patients with isolated REM sleep behavior disorder (iRBD) may predict pheno-conversion into Parkinson’s disease (PD) or Lewy body dementia (LBD). Dr Rahayel first gives some background on glucose metabolism in the brains of iRBD patients, and knowledge gaps in this area. While it is known that some patterns in iRBD can predict pheno-conversion to PD and LBD, there are no markers that allow clinicians to differentiate which patients will develop PD, and which patients will develop dementia. Dr Rahayel then discusses a study that was conducted with the aim of using brain perfusion patterns to better predict which of these two neurodegenerative diseases patients would likely develop. Dr Rahayel explains the patient selection process, methodology, and statistical analyses that were conducted, and describes how this study looked at both brain perfusion and clinical features at the same time. Dr Rahayel also details the results of this study, which found that sub-cortical hyper-perfusion and cortical hypo-perfusion play a significant role in iRBD. Following this, Dr Rahayel discusses another component of this study, which found that increased perfusion in the bilateral insula and medial frontal cortex was a pattern associated with iRBD patients who are more likely to develop LBD over PD. To conclude, Dr Rahayel highlights the importance of these findings, as they provide one of the first markers able to predict pheno-conversion into one disease versus another in iRBD patients. This interview took place during the World Sleep Congress 2022 in Rome, Italy.