title: Idiopathic REM sleep behavior disorder and neurodegenerative risk: To tell or not to tell to the patient? How to minimize the risk?
abstract: Most people with idiopathic REM sleep behavior disorder (iRBD) have an underlying synucleinopathy, mainly Parkinson's disease (PD) or dementia with Lewy bodies, with median conversion time of 4-9 y from iRBD diagnosis and of 11-16 y from symptom onset. Subtle signs and imaging tests indicate concomitant neurodegeneration in widespread brain areas. Risk factor studies suggest that iRBD patients may have prior head injury, occupational farming, pesticide exposure, low education level and possibly more frequent family history of dream-enactment behavior (but not of PD), plus unexpected risk factors (smoking, ischemic heart disease and inhaled corticosteroid use). Unlike PD, caffeine and smoking appear not to have a protective role. Prior depression and antidepressant use may be early neurodegenerative signs rather than exclusively causative factors. Age, hyposmia, impaired color vision, abnormal dopaminergic imaging, mild cognitive impairment and possibly sleepiness, may identify patients at greater risk of more rapid conversion. The consensus is to generally disclose the neurodegenerative risk to patients (with the caveat that phenoconversion and its temporal course remain uncertain in individuals without "soft neurodegenerative signs" and those under 50 y of age), to suggest a healthy lifestyle and to take part in prospective cohort studies in anticipation of eventual neuroprotective trials.
authors.affiliation: Clinical Neurology, Department of Neuroscience (DINOGMI), University of Genoa, Italy.
authors.forename: Dario
authors.initials: D
authors.lastname: Arnaldi
authors.affiliation: Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Antelmi
authors.affiliation: Mayo Center for Sleep Medicine, Departments of Neurology and Medicine, Mayo Clinic and Foundation, Rochester, MN, USA.
authors.forename: Erik K
authors.initials: EK
authors.lastname: St Louis
authors.affiliation: Department of Neurology, Montreal General Hospital, Montreal, Quebec, Canada.
authors.forename: Ronald B
authors.initials: RB
authors.lastname: Postuma
authors.affiliation: Sleep Disorder Unit, Pitie-Salpetriere Hospital, APHP, Pierre and Marie Curie University, Paris, France. Electronic address: isabelle.arnulf@aphp.fr.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Arnulf
mesh_terms: D003071:Cognition; D003863:Depression; D004298:Dopamine; D006801:Humans; D019636:Neurodegenerative Diseases; D020734:Parkinsonian Disorders / Q000209:etiology*; D020187:REM Sleep Behavior Disorder / Q000175:diagnosis*; D012307:Risk Factors; D013997:Time Factors
chemical_list: D004298:Dopamine
keywords: Dementia; Dopamine; Exercise; Hyposmia; Lifestyle; Neurodegeneration; Parkinsonism; REM sleep behavior disorder; Synucleinopathy