# Prevalence and Impact of Probable REM Sleep Behavior Disorder in Essential Tremor: A Multicenter Cross‐Sectional Study

## TL;DR

This study finds that about 11.6% of essential tremor patients have probable REM sleep behavior disorder, which is linked to older age, later tremor onset, and more non-motor symptoms.

## Contribution

The study reports novel prevalence estimates and risk factors for probable REM sleep behavior disorder in essential tremor patients.

## Key findings

- pRBD was identified in 11.6% of ET patients in the study cohort.
- ET-pRBD patients had higher frequencies of midline and rest tremor and elevated NMSS scores.
- Lower educational attainment and higher NMSS scores were independent risk factors for pRBD in ET patients.

## Abstract

To investigate the prevalence of probable REM sleep behavior disorder (pRBD) in essential tremor (ET), identify associated risk factors, and evaluate its effects on motor and non‐motor symptoms.

Clinical data were collected from 1297 ET patients across multicenter. pRBD was assessed using the RBD Questionnaire‐Hong Kong (RBDQ‐HK). Risk factors associated with pRBD were identified through multivariable logistic regression. Furthermore, a meta‐analysis was conducted to synthesize existing estimates of pRBD/RBD prevalence in ET.

In this study, pRBD was identified in 11.6% of ET patients. Meta‐analysis yielded pooled prevalence estimates of 16% for pRBD (ES = 0.16, 95% CI [0.10–0.21]) and 14% for RBD (ES = 0.14, 95% CI [0.07–0.21]). ET patients with pRBD were older (59.89 ± 13.99 vs. 54.63 ± 16.59 years, p < 0.001) and had a later tremor onset (47.55 ± 15.98 vs. 43.15 ± 17.62 years, p = 0.007) compared with those without pRBD. ET‐pRBD patients also exhibited a higher frequency of midline tremor (54.67% vs. 43.93%, p = 0.003), rest tremor (27.33% vs. 16.04%, p = 0.001), and elevated Non‐Motor Symptom Scale (NMSS) scores (20.30 ± 18.50 vs. 10.43 ± 12.42, p < 0.001). Multivariable logistic regression identified lower educational attainment (OR = 0.93, p = 0.002) and higher NMSS scores (OR = 1.03, p < 0.001) as independent risk factors.

pRBD is prevalent in ET and independently associated with lower education and increased non‐motor symptom burden. Recognition of pRBD may help identify an ET subgroup with distinctive clinical features.

In our cohort, probable REM sleep behavior disorder (pRBD) was identified in 11.6% of essential tremor (ET) patients, while a meta‐analysis yielded pooled prevalence estimates of 16% for pRBD and 14% for RBD. Compared to ET patients without pRBD, those patients with pRBD exhibited a higher frequency of midline tremor, rest tremor, and a significantly elevated Non‐Motor Symptoms Scale (NMSS) total score. Multivariable logistic regression identified lower educational attainment and higher NMSS total score as independent risk factors for ET‐pRBD.