Original articleInsights into REM sleep behavior disorder pathophysiology in brainstem-predominant Lewy body disease
Introduction
Rapid eye movement (REM) sleep behavior disorder (RBD) is characterized by loss of normal skeletal muscle atonia during REM sleep with prominent motor activity and dreaming [1], [2]. There is ample data from animal and human studies that dysfunction of brainstem structures and networks are likely involved, but which specific neuronal networks are involved in RBD pathogenesis has not yet been determined [1], [3]. To date, fewer than 25 cases of polysomnographically (PSG) proven RBD cases have undergone neuropathologic examination [3], and only one case of idiopathic RBD has undergone autopsy, in which “incidental Lewy body disease” was found [4]. We report herein another case of idiopathic RBD associated with Lewy body disease (LBD), but with degenerative changes topographically different from those previously reported.
Section snippets
Subject and methods
The patient was followed longitudinally at Mayo Clinic Rochester, and written consent was provided for autopsy. Evaluation of antemortem and pathologic data for research purposes on patients with RBD has also been approved by the Mayo Foundation Institutional Review Board.
All available clinical, laboratory, and PSG data were analyzed and summarized. PSG included surface electromyographic (EMG) monitoring of the submental, anterior tibial, and wrist extensor muscles. Neuropathologic examination
Antemortem features
This right-handed retired male physician began exhibiting dream enactment behavior at the age of 57. His wife observed numerous episodes of flailing and thrashing his limbs while vocalizing. She had been struck and bitten several times. The patient would describe the dreams associated with this activity as nightmares in which he was being chased or attacked, and he bolted out of bed on several occasions while attempting to evade the attackers. The frequency and severity of these episodes
Discussion
RBD has been associated with several etiologies, including medications, autoimmune/limbic encephalitis, narcolepsy, structural lesions in the brainstem, and neurodegenerative disease [1], [2], [9], [10], [11]. The few cases which have been studied with magnetic resonance imaging (MRI) have shown lesions in the dorsal pons [10], [11], yet the specific neuronal networks involved in human RBD pathogenesis have not been identified with certainty. Although ubiquitin and α-synuclein
Acknowledgment
This study was supported by Grants P50 NS40256, P50 AG16574, and RO1 AG15866.
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