Alteration of circadian sleep-wake rhythm and salivary melatonin secretion in idiopathic/isolated REM sleep behavior disorder: Preliminary evidence

Matteo Carpi; Mariana Fernandes; Irene Risino; Riccardo Benedetti; Greta Testone; Flavia Cirillo; Marzia Nuccetelli; Sergio Bernardini; Nicola Biagio Mercuri; Claudio Liguori

doi:10.1016/j.sleep.2024.04.020

Alteration of circadian sleep-wake rhythm and salivary melatonin secretion in idiopathic/isolated REM sleep behavior disorder: Preliminary evidence

Sleep Med. 2024 Apr 16:119:135-138. doi: 10.1016/j.sleep.2024.04.020. Online ahead of print.

Affiliations

¹ Sleep and Epilepsy Centre, Neurology Unit, University Hospital Tor Vergata, Rome, Italy; Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy.
² Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy.
³ Department of Experimental Medicine, University of Rome Tor Vergata, Rome, Italy.
⁴ Sleep and Epilepsy Centre, Neurology Unit, University Hospital Tor Vergata, Rome, Italy; Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy.
⁵ Sleep and Epilepsy Centre, Neurology Unit, University Hospital Tor Vergata, Rome, Italy; Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy. Electronic address: dott.claudioliguori@yahoo.it.

PMID: 38678756
DOI: 10.1016/j.sleep.2024.04.020

Abstract

Objective/background: Idiopathic/isolated REM sleep behavior disorder (iRBD) is widely regarded as an early sign of neurodegeneration leading to synucleinopathies. While circadian rhythm alterations in iRBD have been preliminarily demonstrated, evidence on melatonin secretion patterns in this clinical condition is limited. To address this knowledge gap, this exploratory study aimed to integrate salivary melatonin measurement with actigraphic monitoring in individuals with iRBD and age-matched healthy controls (HC) under real-life conditions.

Methods: Participants diagnosed with iRBD and HC underwent clinical evaluation and wore an actigraph for seven days and nights. Salivary melatonin concentrations were measured at five time points during the last night of recording. Comparative analyses were conducted on clinical data, actigraphic parameters, and melatonin levels between the two groups.

Results: iRBD participants (n = 18) showed greater motor (p < 0.01) and non-motor symptoms (p < 0.001), alongside disruptions in circadian sleep-wake rhythm compared to HC (n = 10). Specifically, actigraphy revealed a delayed central phase measurement (p < 0.05), reduced activity during the most active hours (p < 0.001), and decreased relative amplitude (p < 0.05). Total salivary melatonin concentration was significantly lower in iRBD (p < 0.05), with a slight but non-significant phase delay in dim light melatonin onset.

Conclusions: This exploratory study highlights a dysregulation of circadian sleep-wake rhythm coupled with reduced melatonin secretion in iRBD. Future research could add to these preliminary findings to evaluate novel treatment approaches to regulate the sleep-wake cycle and elucidate the implications of circadian dysregulation in the conversion from iRBD to neurodegeneration.

Keywords: Actigraphy; DLMO; Melatonin; RBD; Salivary; Sleep-wake rhythm.