Risk and predictors of dementia and parkinsonism in idiopathic REM sleep behaviour disorder: a multicentre study

Abstract

See Morris and Weil (doi: ) for a scientific commentary on this article. In a prospective multicentre study involving 1280 patients with idiopathic RBD, Postuma et al. show that approximately 6% of patients each year (>73.5% over 12 years) convert to full neurodegenerative disease. They test the predictive power of 21 prodromal markers of neurodegeneration, providing a template for planning neuroprotective trials.

Prodromal Parkinson's Disease: The Decade Past, the Decade to Come

“…By testing a marker at baseline, then following patients over time as they phenoconverted, the predictive value of markers could be directly measured. Over the last decade, several RBD cohorts confirmed the predictive value of olfactory loss, abnormal color vision, motor symptoms, quantitative motor testing, mild cognitive impairment, constipation, and erectile dysfunction . Numerous other clinical markers were documented on baseline examinations, and their predictive value awaits prospective follow‐up .…”

Prognostic Counseling for Patients With Idiopathic/Isolated Rapid Eye Movement Sleep Behavior Disorder: Should We Tell Them What's Coming? No

“…More recently, a seminal study assessed the neurodegenerative disease risk and predictors of neurodegeneration in the largest worldwide multicenter cohort of iRBD subjects compiled so far . Prospective follow‐up data from 24 centers of the International RBD Study Group were collected, and data from 1,280 subjects with polysomnographically proven iRBD were included.…”

Prognostic Counseling for Patients With Idiopathic/Isolated REM Sleep Behavior Disorder: Should We Tell Them What's Coming? Yes

“…iRBD has been recently demonstrated to be a common neurological disorder in the general population with a prevalence of approximately 1% to 2% . Whether RBD is idiopathic/isolated (iRBD) or symptomatic, RBD is strongly associated with synucleinopathy neurodegenerative disorders, including Parkinson's disease (PD), dementia with Lewy bodies (DLB), and MSA . Even iRBD is strongly associated with symptoms or signs of an underlying covert syncleinopathy, with up to 80% of iRBD patients having nonmotor manifestations of autonomic, cognitive, olfactory, or visual manifestations, or “soft” motor signs insufficient for PD diagnosis of bradykinesia, rigidity, tremor, or postural instability at the time of diagnosis by PSG .…”

“…Whether RBD is idiopathic/isolated (iRBD) or symptomatic, RBD is strongly associated with synucleinopathy neurodegenerative disorders, including Parkinson's disease (PD), dementia with Lewy bodies (DLB), and MSA . Even iRBD is strongly associated with symptoms or signs of an underlying covert syncleinopathy, with up to 80% of iRBD patients having nonmotor manifestations of autonomic, cognitive, olfactory, or visual manifestations, or “soft” motor signs insufficient for PD diagnosis of bradykinesia, rigidity, tremor, or postural instability at the time of diagnosis by PSG . Approximately 70% of iRBD patients develop PD, DLB, or MSA over longitudinal follow‐up of 10 to 15 years, and currently there is no proven beneficial neuroprotective strategy or therapy to prevent the evolution of increasingly devastating neurological deficits .…”

“…Even iRBD is strongly associated with symptoms or signs of an underlying covert syncleinopathy, with up to 80% of iRBD patients having nonmotor manifestations of autonomic, cognitive, olfactory, or visual manifestations, or “soft” motor signs insufficient for PD diagnosis of bradykinesia, rigidity, tremor, or postural instability at the time of diagnosis by PSG . Approximately 70% of iRBD patients develop PD, DLB, or MSA over longitudinal follow‐up of 10 to 15 years, and currently there is no proven beneficial neuroprotective strategy or therapy to prevent the evolution of increasingly devastating neurological deficits . Given this, there is currently prevailing uncertainty about the utility of prognostic counseling for iRBD patients, who are at high risk for future development of a neurodegenerative disorder.…”