Insights into polysomnography-confirmed rapid eye movement sleep behavior disorder from new prevalence and gender data in the general population

[摘要] The traditional clinical profile of rapid eye movement (REM) sleep behavior disorder (RBD), which was established with the first formal description in five patients [1], and later confirmed in two large series [2, 3], involves predominantly middle-aged and older men with violent, injurious dream-enacting behaviors that prompt clinical referral. (A different clinical profile for RBD in adults aged <50 years old has recently been identified [4].) RBD patients are diagnosed with either “idiopathic” RBD (iRBD) or with symptomatic RBD related to an underlying neurologic disorder (or at times related to medication use). More than 80 per cent of patients with iRBD will eventually develop a parkinsonian (α-synucleinopathy) neurodegenerative disorder, usually Parkinson’s disease (PD) or dementia with Lewy bodies (DLB), with a mean interval from RBD onset to overt neurodegeneration being in the 12- to 14-year range [5, 6]. In a further study by Iranzo et al. [7] involving a cohort 174 patients with iRBD, the risk for emergence of a defined neurodegenerative disorder from the time of iRBD diagnosis was 33 per cent at 5 years, 76 per cent at 10 years, and 91 per cent at 14 years, using the Kaplan–Meier method. These striking long-term outcome data have forced a reconsideration in current thinking insofar as “idiopathic” RBD should now be considered “prodromal parkinsonism,” and thus what was originally called “idiopathic RBD” should now be called “isolated RBD,” as recently advocated by Högl et al. [8], since it implies the eventual transformation of an isolated clinical RBD disorder to overt parkinsonism with RBD. We now know that in iRBD the emergence of REM-sleep-without-atonia (RWA) reflects the damage that the α-synuclein pathology of evolving PD or DLB is doing to the pontine and medullary centers and pathways subserving REM-atonia [9]. This strong association of iRBD with α-synuclein neurodegeneration has spurred interest in developing neuroprotective or disease-modifying agents to be tested in patients with isolated RBD, with the goal being to slow down or halt progression to overt neurodegeneration [10, 11].

[学科分类] 生理学