Loss of Rapid Eye Movement Sleep Atonia in Patients with REM Sleep Behavioral Disorder, Narcolepsy, and Isolated Loss of REM Atonia

Abstract

Study Objectives: To compare the amounts of REM sleep without atonia (RSWA) between patients with REM sleep behavior disorder (RBD), "isolated loss of REM atonia," narcolepsy, and control subjects and determine if there were threshold values for the amount of RSWA that differentiate each group from controls. Methods: Retrospective analyses of polysomnography (PSG) records were used employing strict quantitative criteria for the measurement of phasic and tonic EMG activity during REM sleep. The PSG recordings of 47 individuals were analyzed (RBD 16, isolated loss of REM atonia 11, narcolepsy 10, control 10). Results: Patients with the diagnosis of isolated loss of REM atonia had signifi cantly lower levels of EMG activity during REM sleep than those with RBD but higher than control subjects. RSWA was higher in narcolepsy than in loss of REM atonia but lower than for RBD patients. Receiver operating characteristic (ROC) curves provided threshold values with high specifi city and sensitivity in all patient groups with a cutoff value ≥ 1.22% (100% correctly classifi ed) for phasic and ≥ 3.17% for tonic (92% correctly classifi ed) EMG activity in RBD. Conclusion S C I E N T I F I C I N V E S T I G A T I O N SR EM sleep behavior disorder (RBD) is a parasomnia characterized by loss of normal muscle atonia during REM sleep with abnormal motor activity that is proposed to be associated with dream content.1 RBD is associated with neurodegenerative disorders and in particular with synucleinopathies such as Parkinson disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA) (secondary RBD). Long-term follow-up studies have shown that a large proportion (38% to 65%) of patients with presumed idiopathic RBD develop Parkinsonism and/or dementia.2,3 EEG and neuropsychological tests have also revealed early evidence of CNS dysfunction in idiopathic RBD patients.4-7 Furthermore, diffusion tensor imaging has uncovered microstructural abnormalities in the brain areas responsible for REM sleep regulation in idiopathic RBD patients. In addition to neurodegenerative disease, RBD is also associated with other sleep disorders. Periodic limb movements of sleep (PLMS) are highly prevalent (70%) in patients with RBD.5 In addition, RBD is frequently seen in patients with narcolepsy.9,10 REM sleep without atonia (RSWA) in narcolepsy was fi rst described in 1992.10 RBD and/or RSWA are thought to be common in narcolepsy with cataplexy and rare in narcolepsy without cataplexy. 11,12It has been proposed that hypocretin defi ciency plays an essential role for both RBD and cataplexy in narcolepsy. Department of Clinical and Experimental Epilepsy, Institute of Neurology, UCL, London UKIsolated loss of REM atonia or RSWA is a condition usually identifi ed incidentally in patients during polysomnography. The loss of REM atonia is an electrophysiological fi nding without accompanying abnormal motor behavior during REM sleep. Although the condition may represent "subclinical" or "preclinical" RBD in some cases, 14 there are no ...

Sleep-stage transitions during polysomnographic recordings as diagnostic features of type 1 narcolepsy

“…We suggest that when evaluating subjects in a clinic, the features in combination with a nocturnal SOREMP could be used to screen for type 1 narcolepsy based on the results of a nocturnal PSG alone. Combined with other PSG features as well, such as state-space analysis [43] or analysis of REM sleep atonia [44] in narcolepsy, these features could lead to new diagnostic procedures for type 1 narcolepsy.…”

Polysomnographic Assessment of Sleep Comorbidities in Drug-Naïve Narcolepsy-Spectrum Disorders—A Japanese Cross-Sectional Study

“…As for the scoring methods of RWA proposed by the AASM, no optimal cut-off value for diagnosis of RBD had been reported during the study period. Therefore, we adopted the cut-off value for phasic EMG activity in the submentalis muscle referring to a recent report in which phasic EMG activity in the submentalis muscle was scored in a similar way to the AASM scoring methods[ 32 ]. Third is the possible heterogeneity of the patients diagnosed as IHS w/o LST.…”

“…According to the aforementioned scoring rules[ 29 ], board-certified sleep technologists carefully scored RWA on the chin EMG. Referring to the recent study defining cut-off value of RWA to discriminate RBD from controls, subjects having more than 1.22% of a proportion of 3-sec mini epochs with phasic activity to the total duration of REM sleep were defined as those with RWA with allowance of scoring using 3-sec epoch alternative to 2-sec epoch[ 32 ].…”

Advanced Analysis of Pharmaco-Sleep Data in Humans

“…4 for the distribution of delta power in the course of the night). In recent years, studies on REM sleep behavior disorder showed increased evidence that the loss of REM sleep atonia may be an early manifestation of degenerative neurological disease [42,43]. A simple measure to automatically quantify the time in REM sleep without atonia - the atonia index - was developed and validated by Ferri et al [44] in 2010.…”