Striatal Dopaminergic Deficit and Sleep in Idiopathic Rapid Eye Movement Behaviour Disorder: An Explorative Study

Abstract

Introduction: Idiopathic rapid eye movement (REM) sleep behavior disorder (iRBD) is increasingly recognised as an important precursor disease state of alpha-synucleinopathies. This parasomnia is characterized by a history of recurrent nocturnal dream enactment behaviour, loss of skeletal muscle atonia, and increased phasic muscle activity during REM sleep. Neuroimaging studies of striatal dopamine transporter uptake tracer signaling suggest increasing dopaminergic deficit across the continuum of the alpha-synucleinopathies, with early sleep dysfunction suggestive of early caudate dysfunction. Henceforth, we set out to investigate the relationship between early sleep changes and the striatal dopaminergic availability in iRBD. Methods: Twelve patients with iRBD, who had undergone a video polysomnography and a neuroimaging assessment of striatal dopamine transporter (DaT) uptake tracer signaling, and 22 matched controls who had similarly undergone a video polysomnography were retrospectively identified. Data were statistically analyzed to identify altered sleep parameters and correlate them with striatal dopamine transporter uptake tracer signaling. Results: The iRBD patients exhibited an increased number of periodic limb movements during sleep (P=0.001), compared to 22 age-matched healthy subjects. In addition, several significant links were found between regional DaT-uptakes and sleep architecture. Correlational analyses suggested a strong positive association between sleep fragmentation and dopamine deficiency in left caudate (r=−0.630, P=0.028), whilst an increased uptake in the whole striatum was strongly linked to the sleep efficiency, and to a lesser degree to the length of sleep duration. Discussion: To the best of our knowledge, this is the first demonstration of a close relationship between dopaminergic availability in striatum and the quality of sleep in iRBD. Taken together, our exploratory findings suggest that subtle but functionally significant striatal changes in early stages of iRBD may contribute to the further shaping of sleep architecture.

Restricted truncal sagittal movements of rapid eye movement behaviour disorder

“…We are yet to understand if identical neural egocentric (e.g., striatal system) and allocentric (e.g., hippocampal/primary somatosensory 17 , 18 ) architecture is utilised during spatial exploration of the ambulatory dreamscapes. However, based on our 19 and others 20 , 21 recent work suggestive of early caudate/striatal 21 and phasic REM changes in RBD patients, we speculate that limited ambulation in RBD reflects an aberrant contribution of the egocentric neural architecture during dream mentation. For example, parkinsonisms are known to disappear during RBD‐associated complex movements, suggesting that the upper motor stream bypasses the basal ganglia during REM sleep 22 .…”

“…Scoring sleep stages was done according to standard criteria of the AASM Scoring Manual ( Version 2.4, 2017 ), and as previously reported 19 . The selected PSG videos and reports were carefully analysed by two investigators for the purpose of this study.…”

“…Our group recently argued that early synucleinopathy process may lead to changes in the egocentric neural architecture (e.g., caudate) 19 , 21 , 32 , and consequently, to decreased suppression of frontal beta rhythms during phasic REM 20 . Consecutively, this may also lead to heightened cortical arousal in the primary sensorymotor cortex 20 .…”

Periodic limb movements during sleep: a narrative review

“…PLMS commonly start during the non-rapid eye movement (NREM) stage N1, are predominant in N2, and less frequent in N3. PLMS are generally absent during REM, with exception of patients with REM behavior disorder, where PLMS are commonly recorded during REM (61,62). Historically, the association of PLMS to stages N1 and N2 has been argued to be due to the significant link (up to 92% of the PLMS) with the cyclic alternating pattern (CAP), especially with its fast activity subtypes (A2 and A3) (63).…”

Predictors of dream enactment behavior among medical students: The case of the University of Gondar, Ethiopia

“…Contrary to this, there are studies illustrating DEB is not a bad phenomenon [10]. Dream enactment behavior could be due to partly by striatal changes in the dopaminergic pathways [11]. The knowledge of DEB is helpful to design intervention and prevention strategies for neurological disorders [12].…”