Cardiac Autonomic Dysfunction Is Associated with Severity of REM Sleep without Atonia in Isolated REM Sleep Behavior Disorder.

Sooyeoun You,Kyoung Sook Won,Keun Tae Kim,Yong Won Cho,Hyang Woon Lee

doi:10.3390/jcm10225414

Abstract

123I-metaiodobenzylguanidine (MIBG) cardiac scintigraphy was performed to assess cardiac autonomic dysfunction and demonstrate its correlation with clinical and polysomnographic characteristics in patients with isolated rapid eye movement (REM) sleep behavior disorder. All subjects including 39 patients with isolated REM sleep behavior disorder and 17 healthy controls underwent MIBG cardiac scintigraphy for cardiac autonomic dysfunction assessment. The isolated REM sleep behavior disorder was confirmed by in-lab overnight polysomnography. A receiver operating curve was constructed to determine the cut-off value of the early and delayed heart-to-mediastinum ratio in patients with isolated REM sleep behavior disorder. Based on each cut-off value, a comparison analysis of REM sleep without atonia was performed by dividing isolated REM sleep behavior disorder patients into two groups. MIBG uptake below the cut-off value was associated with higher REM sleep without atonia. The lower heart-to-mediastinum ratio had significantly higher REM sleep without atonia (%), both with cut-off values of early (11.0 ± 5.6 vs. 29.3 ± 23.2%, p = 0.018) and delayed heart-to-mediastinum ratio (9.1 ± 4.3 vs. 30.0 ± 22.9%, p = 0.011). These findings indicate that reduced MIBG uptake is associated with higher REM sleep without atonia in isolated REM sleep behavior disorder.

Highlights

Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by dream enactment behavior with vivid dreams and REM sleep without atonia (RWA) [1]
There exists a well-established concept to associate REM sleep behavior disorder (RBD) with neurodegenerative diseases caused by alpha-synucleinopathy, such as Parkinson’s disease (PD), multiple system atrophy (MSA), and dementia with Lewy bodies (DLB)
The main aims of our study were (1) to confirm the difference in MIBG scintigraphy results between the normal and isolated RBD (iRBD) groups, (2) to analyze whether there is a correlation between the MIBG scintigraphy results and clinical and PSG data within the iRBD group, and (3) to find out the correlation between REM sleep without atonia as a main polysomnograhic feature of RBD and MIBG scintigraphy results

Summary

Introduction

Rapid eye movement (REM) sleep behavior disorder (RBD) is a parasomnia characterized by dream enactment behavior with vivid dreams and REM sleep without atonia (RWA) [1]. There exists a well-established concept to associate RBD with neurodegenerative diseases caused by alpha-synucleinopathy, such as Parkinson’s disease (PD), multiple system atrophy (MSA), and dementia with Lewy bodies (DLB). More than 50% of patients with RBD had parkinsonian disorders within a decade; between 81 and 90% of patients with RBD develop a neurodegenerative disorder [3,4,5,6]. Recent studies have suggested that ‘isolated RBD (iRBD)’ reflects the early phase of later development of neurodegenerative changes, as the concept of ‘prodromal parkinsonism’ has been suggested to represent an early expression of α-synucleinopathy [7]. According to the results of recently published prospective studies, the phenoconversion rate from iRBD to parkinsonism or dementia are similar [8,9]

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