Systematic video-analysis of motor events during REM sleep in idiopathic REM sleep behavior disorder, follow-up and DAT-SPECT

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 .…”

“…Movements associated with respiratory events or EEG arousals were disregarded. The categorisation of RBD motor events was undertaken, as previously published and further adapted 21 , 34 . The type of movement, anatomic distribution, synchrony, symmetry, onset, offset, vocalisation, were further evaluated and classified according to the predefined classification (Supplementary Table 2 ) 34 – 36 .…”

“…To date, only a handful of RBD semiology studies are published, and there is a dearth of VPSG-based RBD-related data 21 , 25 – 27 . The additional explicit relevance of our VPSG study is that here, for the first time, primary focus is on categorisation and demonstration of the paradoxically restricted semiology of truncal/thoraco-lumbar movements during RBD events, which persists even during complex dream re-enactments 23 .…”

“…Arguably, these global phasic events may also lead to transitions between discrete epochs of visual-like processing during REM sleep 29 . Early striatal dopaminergic/cholinergic imbalance in RBD patients may also account for specific dream mentation commonly consisting of threatening events 1 , 21 (see Fig. 1b ).…”

“…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 .…”