Characteristics of idiopathic REM sleep behavior disorder and that associated with MSA and PD

TLDR

To compare the clinical and video‑polysomnographic characteristics of idiopathic REM sleep behavior disorder with those seen in multiple system atrophy and Parkinson disease. Clinical features and VPSG measures were evaluated in 110 nondemented subjects (26 MSA, 45 PD, 39 idiopathic RBD) over five years with an average follow‑up of 26.9 ± 21.3 months. Across idiopathic RBD, MSA, and PD, symptom quality, PSG variables, abnormal behaviors, and clonazepam response were similar, yet MSA patients had shorter disease duration, higher REM‑without‑atonia %, higher periodic leg movement index, and less total sleep time compared to PD, while idiopathic RBD patients were more often male, reported greater RBD severity, and were more aware of their behaviors; overall RBD‑related symptoms and neurophysiologic features were qualitatively similar, with polysomnographic abnormalities more pronounced in MSA than PD, indicating greater REM sleep modulation dysfunction.

Abstract

<b>Objective: </b> To compare the clinical and video-polysomnographic (VPSG) characteristics of idiopathic REM sleep behavior disorder (RBD) vs the RBD seen in multiple system atrophy (MSA) and Parkinson disease (PD). <b>Methods: </b> Clinical features and VPSG measures were evaluated in 110 consecutive nondemented subjects (26 MSA, 45 PD, and 39 idiopathic RBD) free of psychoactive medications referred for suspected RBD to our sleep unit over a 5-year period, with extended follow-up (mean 26.9 ± 21.3 months). <b>Results: </b> Across the three groups studied, logistic regression analysis demonstrated that there were no differences in the quality of RBD symptoms (e.g., nature of unpleasant dream recall or behaviors witnessed by bed partners), most PSG variables, abnormal behaviors captured by VPSG, and clinical response to clonazepam. When compared to subjects with PD, however, patients with MSA had a significantly shorter duration of disease, a higher REM sleep without atonia percentage, a greater periodic leg movement index, and less total sleep time. Subjects with idiopathic RBD, as compared to those with either MSA or PD, were more often male, had greater self-reported clinical RBD severity, and were more often aware of their abnormal sleep behaviors. <b>Conclusions: </b> REM sleep behavior disorder (RBD)-related symptoms and neurophysiologic features are qualitatively similar in RBD subjects with the idiopathic form, multiple system atrophy (MSA), and Parkinson disease (PD). Polysomnographic abnormalities associated with RBD in the setting of MSA are greater than in PD, suggesting a more severe dysfunction in the structures that modulate REM sleep.