Overnight Distribution of REM Sleep Features in People with Parkinson's Disease (PD) and Non-PD Controls.

BACKGROUND: Rapid eye movement (REM) sleep behavior disorder (RBD) is a leading predictor of Parkinson's disease (PD). Diagnosis is performed in the sleep laboratory by detecting pathological REM sleep without atonia (RSWA). The evidence on the overnight distribution of RSWA% is conflicting. OBJECTIVE: To investigate the temporal distribution of the number of ocular movements per REM sleep minute (REM density), and RSWA% in people with PD and non-PD controls. METHODS: All participants underwent a single overnight evaluation in a sleep laboratory. Clinical evaluation was performed on a separate day. REM density and RSWA% were compared between PD and controls both across four sleep periods and individual REM cycles. RESULTS: A total of 51 participants with recorded RSWA in polysomnography laboratory were included, 28 with PD aged 64±9 years with a disease duration of 3.3±2.9 years, and 23 controls aged 55±8 years. People with PD had lower REM density and higher RSWA% compared to controls. As expected, REM density was higher towards the morning. In contrast, RSWA% was equally distributed across the night, for both PD and controls. CONCLUSIONS: PD pathology affects REM sleep features, but not the overnight distribution of those features. While REM density increased towards the end of the night, RSWA% was equally distributed across the night for both PD and controls. Our findings have clinical implications for diagnosing RBD, as quantification of RSWA% in any sleep cycle is sufficient for reliably evaluating total RSWA% and reduced REM density may be a marker of PD.

Monitoring sleep stages with a soft electrode array: Comparison against vPSG and home-based detection of REM sleep without atonia.

Sleep disorders are symptomatic hallmarks of a variety of medical conditions. Accurately identifying the specific stage in which these disorders occur is particularly important for the correct diagnosis of non-rapid eye movement and rapid eye movement parasomnias. In-lab polysomnography suffers from limited availability and does not reflect habitual sleep conditions, which is especially important in older adults and those with neurodegenerative diseases. We aimed to explore the feasibility and validity of a new wearable system for accurately measuring sleep at home. The system core technology is soft, printed dry electrode arrays and a miniature data acquisition unit with a cloud-based data storage for offline analysis. The positions of the electrodes allow manual scoring following the American Association of Sleep Medicine guidelines. Fifty participants (21 healthy subjects, mean age 56.6 ± 8.4 years; and 29 patients with Parkinson's disease, 65.4 ± 7.6 years) underwent a polysomnography evaluation with parallel recording with the wearable system. Total agreement between the two systems reached Cohen's kappa (k) of 0.688 with agreement in each stage of: wake k = 0.701; N1 = 0.224; N2 = 0.584; N3 = 0.410; and rapid eye movement = 0.723. Moreover, the system reliably detected rapid eye movement sleep without atonia with a sensitivity of 85.7%. Additionally, a comparison between sleep as measured in the sleep lab with data collected from a night at home showed significantly lower wake after sleep onset at home. The results demonstrate that the system is valid, accurate and allows for the exploration of sleep at home. This new system offers an opportunity to help detect sleep disorders on a larger scale than possible today, fostering better care.

Home monitoring of sleep with a temporary-tattoo EEG, EOG and EMG electrode array: a feasibility study.

OBJECTIVE: Circadian and sleep dysfunction have long been symptomatic hallmarks of a variety of devastating neurodegenerative conditions. The gold standard for sleep monitoring is overnight sleep in a polysomnography (PSG) laboratory. However, this method has several limitations such as availability, cost and being labour-intensive. In recent years there has been a heightened interest in home-based sleep monitoring via wearable sensors. Our objective was to demonstrate the use of printed electrode technology as a novel platform for sleep monitoring. APPROACH: Printed electrode arrays offer exciting opportunities in the realm of wearable electrophysiology. In particular, soft electrodes can conform neatly to the wearer's skin, allowing user convenience and stable recordings. As such, soft skin-adhesive non-gel-based electrodes offer a unique opportunity to combine electroencephalography (EEG), electromyography (EMG), electrooculography (EOG) and facial EMG capabilities to capture neural and motor functions in comfortable non-laboratory settings. In this investigation temporary-tattoo dry electrode system for sleep staging analysis was designed, implemented and tested. MAIN RESULTS: EMG, EOG and EEG were successfully recorded using a wireless system. Stable recordings were achieved both at a hospital environment and a home setting. Sleep monitoring during a 6 h session shows clear differentiation of sleep stages. SIGNIFICANCE: The new system has great potential in monitoring sleep disorders in the home environment. Specifically, it may allow the identification of disorders associated with neurological disorders such as rapid eye movement (REM) sleep behavior disorder.

Near-total absence of REM sleep co-occurring with normal cognition: an update of the 1984 paper.

BACKGROUND: REM sleep (REMS) is considered vital for supporting well-being and normal cognition. However, it remains unclear if and how decreases in REMS impair cognitive abilities. Rare case studies of patients with REMS abolishment due to pontine lesions remain sporadic, and formal evaluation of cognitive status is lacking. In 1984, Lavie and colleagues described the case of Y.C. - a man with a pontine lesion and near-total absence of REMS who led a normal life. Here, we set out to re-evaluate this individual's REMS status 30 years after the original report, and formally assess his cognitive abilities. METHODS: Four whole-night polysomnographic sleep recordings were conducted to evaluate sleep architecture. Sleep scoring was performed according to the American Academy of Sleep Medicine (AASM) guidelines. Cranial Computed Tomography (CT) imaging was performed, as well as formal neuropsychological testing to evaluate cognitive functions. RESULTS: Y.C. averaged 4.5% of sleep time in REMS, corresponding to the 0.055 percentile of normal values for his age. Furthermore, residual REMS episodes were short and only occurred towards the end of the night. CT imaging revealed damage and metallic fragments in pons, cerebellum, and thalamus. Neuropsychological evaluation demonstrated average to high-average cognitive skills, normal memory, and motor difficulties including speech and left hand dyspraxia. CONCLUSIONS: To our knowledge, this is the only case where REMS loss resulting from pontine lesion was re-evaluated after many years. We find a near-total absence of REMS with no signs of significant compensation throughout adult life, along with normal cognitive status. The results provide a unique perspective on the ongoing debate regarding the functional role of REMS in supporting cognition.