Neuroimaging-evident lesional pathology associated with REM sleep behavior disorder

Background/Rationale: Rapid eye movement (REM) sleep behavior disorder (RBD) is a potentially injurious parasomnia characterized by dream enactment behavior and polysomnographic REM sleep without atonia (RSWA). Recently, RBD not only has been shown to be strongly associated with synucleinopathy neurodegeneration but has also been rarely reported to be associated with structural lesions involving the brainstem or limbic system. The aim of this study was to describe the clinical, neuroimaging, and outcome characteristics in a case series of patients with lesional RBD. Methods: This is a retrospective case series from a tertiary care referral center. Results: A total of 10 patients with lesional RBD were identified. Seven (70%) were men, with an average age of sleep symptom onset of 53.7 ± 17.0 years. Structural pathology evident on neuroimaging included four extraaxial (three meningiomas and one basilar fusiform aneurysm with brainstem compression) and six intraaxial (encephalomalacia, multiple sclerosis, vasculitis, autoimmune limbic encephalitis, and leukodystrophy) lesions. No patient developed parkinsonian features or cognitive impairment suggestive of synucleinopathy over an average of 45.4 ± 35.2 months of follow-up. Conclusions: RBD is rarely associated with non-synuclein structural lesions affecting the pons, medulla, or limbic system. The spectrum of lesional RBD comprises tumors, aneurysms, leukodystrophy, and autoimmune/inflammatory/demyelinating brain lesions.