Validation of a sleep staging classification model for healthy adults based on two combinations of a single-channel EEG headband and wrist actigraphy.

STUDY OBJECTIVES: The aim of this study was to develop a sleep staging classification model capable of accurately performing on different wearable devices. METHODS: Twenty-three healthy participants underwent a full-night type I polysomnography and used two device combinations: (A) flexible single-channel electroencephalogram (EEG) headband + actigraphy (n = 12) and (B) rigid single-channel EEG headband + actigraphy (n = 11). The signals were segmented into 30-second epochs according to polysomnographic stages (scored by a board-certified sleep technologist; model ground truth) and 18 frequency and time features were extracted. The model consisted of an ensemble of bagged decision trees. Bagging refers to bootstrap aggregation to reduce overfitting and improve generalization. To evaluate the model, a training dataset under 5-fold cross-validation and an 80-20% dataset split was used. The headbands were also evaluated without the actigraphy feature. Participants also completed a usability evaluation (comfort, pain while sleeping, and sleep disturbance). RESULTS: Combination A had an F1-score of 98.4% and the flexible headband alone of 97.7% (error rate for N1: combination A = 9.8%; flexible headband alone = 15.7%). Combination B had an F1-score of 96.9% and the rigid headband alone of 95.3% (error rate for N1: combination B = 17.0%; rigid headband alone = 27.7%); in both, N1 was more confounded with N2. CONCLUSIONS: We developed an accurate sleep classification model based on a single-channel EEG device, and actigraphy was not an important feature of the model. Both headbands were found to be useful, with the rigid one being more disruptive to sleep. Future research can improve our results by applying the developed model in a population with sleep disorders. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Name: Actigraphy, Wearable EEG Band and Smartphone for Sleep Staging; URL: https://clinicaltrials.gov/study/NCT04943562; Identifier: NCT04943562. CITATION: Melo MC, Vallim JRS, Garbuio S, et al. Validation of a sleep staging classification model for healthy adults based on 2 combinations of a single-channel EEG headband and wrist actigraphy. J Clin Sleep Med. 2024;20(6):983-990.

Feasibility of Single Channel Oximetry for Mass Screening of Obstructive Sleep Apnea.

BACKGROUND: The growing awareness for the high prevalence of obstructive sleep apnea (OSA) coupled with the dramatic proportion of undiagnosed individuals motivates the elaboration of a simple but accurate screening test. This study assesses, for the first time, the performance of oximetry combined with demographic information as a screening tool for identifying OSA in a representative (i.e. non-referred) population sample. METHODS: A polysomnography (PSG) clinical database of 887 individuals from a representative population sample of São Paulo's city (Brazil) was used. Using features derived from the oxygen saturation signal during sleep periods and demographic information, a logistic regression model (termed OxyDOSA) was trained to distinguish between non-OSA and OSA individuals (mild, moderate, and severe). The OxyDOSA model performance was assessed against the PSG-based diagnosis of OSA (AASM 2017) and compared to the NoSAS and STOP-BANG questionnaires. FINDINGS: The OxyDOSA model had mean AUROC = 0.94 ±â€¯0.02, Se = 0.87 ±â€¯0.04 and Sp = 0.85 ±â€¯0.03. In particular, it did not miss any of the 75 severe OSA individuals. In comparison, the NoSAS questionnaire had AUROC = 0.83 ±â€¯0.03, and missed 23/75 severe OSA individuals. The STOP-BANG had AUROC = 0.77 ±â€¯0.04 and missed 14/75 severe OSA individuals. INTERPRETATION: We provide strong evidence on a representative population sample that oximetry biomarkers combined with few demographic information, the OxyDOSA model, is an effective screening tool for OSA. Our results suggest that sleep questionnaires should be used with caution for OSA screening as they fail to identify many moderate and even some severe cases. The OxyDOSA model will need to be further validated on data recorded using overnight portable oximetry.

Robust evaluation of time since awakening using force platform posturography

INTRODUCTION: Sleepiness is responsible for a considerable proportion of traffic accidents. It is thus an important traffic safety issue to find a robust, objective and practical way to estimate the amount of time a person has been awake. To attempt to meet this goal, we investigated the relationship between sleepiness and posture control. METHODS: Subjects were kept awake for 36 hours and posturographic data during quiet standing were collected every two hours by means of a force platform. The standing surface (rigid surface or foam surface) and visual (eyes open or eyes closed) conditions were manipulated. RESULTS: In the more challenging conditions (with foam surface and/or eyes closed), the body sway variables derived from the center of the pressure measurement increased significantly when time since awakening became greater than 21 h in almost all subjects. CONCLUSION: Based on this result, we propose a practical protocol that could robustly assess whether time since awakening was greater than 21 h.

Mandibular advancement device and CPAP upon cardiovascular parameters in OSA.

PURPOSE: This study aims to compare the effects of a mandibular advancement device (MAD) with continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea (OSA) on blood pressure (BP), oxidative stress, and heart rate variability (HRV) in a randomized, crossed-over, single-blind, and controlled trial. METHODS: Twenty-nine moderate-to-severe adult OSA patients underwent MAD, CPAP, and placebo oral appliance treatment. Polysomnography, Epworth sleepiness scale, 24-h ambulatory BP monitoring, oxidative stress parameters (malondialdehyde, catalase, superoxide dismutase, vitamins C, E, B6, B12, folate, homocysteine, uric acid), and HRV were assessed at baseline and after 1 month of each treatment. Diaries were used to evaluate compliance for devices and a pressure-time meter for CPAP. RESULTS: Both active treatments resulted in decreases in apnea and hypopnea index and Epworth sleepiness scale; CPAP showed a greater effect. Frequency of diastolic BP dipping was higher in the MAD group compared with the CPAP group. A significant drop from baseline levels for catalase activity was observed after MAD. For HRV, there was a significant decrease in total power at night with CPAP and MAD compared with POA, and a decrease in index of sleep autonomic variation with MAD compared with baseline levels. Compliance rates were higher with MAD rather than CPAP. CONCLUSIONS: Even though CPAP proved to be more effective at attenuating OSA, better compliance with MAD favored the reduction of one of the enzymes which participates in oxidative stress and better autonomic modulation during sleep.

Sleep complaints in the Brazilian population: Impact of socioeconomic factors.

National surveys are relevant for the study of sleep epidemiology since they can provide specific data about sleep in large dimension with important implications for the health system. Thus, the aim of this study was to investigate the prevalence of sleep complaints among the Brazilian population using a randomized cluster sample according to region and socioeconomic class. For this, a 3-stage sampling technique was used to randomly select Brazilian subjects of both genders older than 16 years. A total of 2017 subjects, from 132 different cities, were selected to estimate prevalence in the Brazilian population with a sampling error of ±2%. Questions about sleep complaints were administered face-to-face by Instituto Datafolha interviewers on April 10 and 16, 2012. Data were expanded using a weighted variable. The results showed that 76% of the study population suffers from at least 1 sleep complaint, indicating that approximately 108 million Brazilians may be affected by sleep disorders. On average, each subject had 1.9 sleep problems with the most common complaints being light and insufficient sleep, snoring, moving a lot during sleep, and insomnia, which usually occurred more than 3 times per week. Low income was associated with higher number of sleep complaints only in Northeast and Southeast regions. In conclusion, this study showed a high prevalence of sleep complaints in a sample of the Brazilian population, suggesting that sleep disorders may be markedly frequent in the Brazilian population with a possible correlation with the socioeconomic situation of the interviewed subjects.

The use of portable monitoring for sleep apnea diagnosis in adults.

Due to increasing demand for sleep services, there has been growing interest in ambulatory models of care for patients with obstructive sleep apnea (OSA). The implementation of alternative approaches to the current management by full polysomnography (PSG) in the sleep laboratory is necessary for diagnosing this syndrome due to the high cost of full-night PSG. A good alternative option for OSA diagnosis is portable monitoring (PM), which is known for its accuracy, ease of management and lower cost when compared with full PSG. PM has not been well validated for OSA diagnosis in patients with medical comorbidities or in elderly individuals and children. PM may be recommended as an alternative method to PSG for patients with high clinical risk for OSA. In the present review, we describe the use of PM for OSA diagnosis and evaluate the current progress, costs, limitations and applications of these devices in various groups of patients, particularly for patients with comorbid diseases.

Whole blood hypoxia-related gene expression reveals novel pathways to obstructive sleep apnea in humans.

In this study, our goal was to identify the key genes that are associated with obstructive sleep apnea (OSA). Thirty-five volunteers underwent full in-lab polysomnography and, according to the sleep apnea hypopnea index (AHI), were classified into control, mild-to-moderate OSA and severe OSA groups. Severe OSA patients were assigned to participate in a continuous positive airway pressure (CPAP) protocol for 6 months. Blood was collected and the expression of 84 genes analyzed using the RT(2) Profiler™ PCR array. Mild-to-moderate OSA patients demonstrated down-regulation of 2 genes associated with induction of apoptosis, while a total of 13 genes were identified in severe OSA patients. After controlling for body mass index, PRPF40A and PLOD3 gene expressions were strongly and independently associated with AHI scores. This research protocol highlights a number of molecular targets that might help the development of novel therapeutic strategies.

Síndrome da apneia obstrutiva do sono: conceitos básicos / Obstructive sleep apnea syndrome: basic concepts

A síndrome da apneia obstrutiva do sono é o distúrbio respiratório do sono mais comum na população geral. Faremos breve revisão de sua definição, prevalência, fisiopatologia, consequências e quadro clínico. O diagnóstico deve ser suspeitado sempre que houver história de ronco alto, relato de paradas respiratórias observadas e sonolência excessiva diurna. No exame físico chama a atenção a presença de obesidade e/ou de garganta estreita (com dificuldade de visualizar o cavum). A polissonografia completa de noite inteira sob supervisão é o padrão de referência para o diagnóstico, mas em pacientes cuja suspeita clínica é alta os registros simplificados domiciliares podem ser uma alternativa. O tratamento da síndrome da apneia obstrutiva do sono vai depender da gravidade (determinada na polissonografia) dos sintomas clínicos e das comorbidades presentes. O tratamento inclui medidas gerais, como evitar álcool e benzodiazepínicos, dormir em decúbito lateral, número adequado de horas de sono, perda de peso e uso de aparelhos intraorais e de pressão positiva contínua em vias aéreas através de máscara (CPAP). Os procedimentos cirúrgicos têm indicação restrita em adultos. O CPAP é o tratamento de escolha para síndrome da apneia obstrutiva do sono moderada e grave.

Effect of acute physical exercise on patients with chronic primary insomnia.

STUDY OBJECTIVES: The aim was to assess and to compare the acute effects of three different modalities of physical exercise on sleep pattern of patients with chronic primary insomnia. METHODS: Forty-eight insomnia patients, 38 female (mean age 44.4 +/- 8 y) were randomly assigned to 4 groups: control (CTR, n=12), moderate-intensity aerobic exercise (MAE, n=12), high-intensity aerobic exercise (HAE, n=12), and moderate-intensity resistance exercise (MRE, n=12). The patients were assessed on sleep pattern (by polysomnogram and daily sleep log) and anxiety (STAI) before and after the acute exercise. RESULTS: The polysomnogram data showed reduction in the sleep onset latency (SOL) (55%) and in the total wake time (TWT) (30%); increase in total sleep time (TST) (18%), and in the sleep efficiency (SE) (13%) in the MAE group. The daily sleep log data showed increase in the TST (26%) and reduction in the SOL (39%). In addition, reduction (15%) in anxiety was also observed after moderate-intensity aerobic exercise. CONCLUSIONS: Acute moderate-intensity aerobic exercise appears to reduce pre-sleep anxiety and improve sleep in patients with chronic primary insomnia.

Placebo and modafinil effect on sleepiness in obstructive sleep apnea.

INTRODUCTION: Previous studies have evaluated the effect of modafinil on residual excessive daytime sleepiness (EDS) in patients with obstructive sleep apnea syndrome (OSAS) under effective CPAP treatment. Even though those trials also used placebo groups, we suppose that the placebo effect might influence the patients' response to modafinil. METHODS: Twenty sleepy patients with OSAS under CPAP treatment were selected. All of them had Epworth Sleepiness Scale (ESS) >10. Following baseline evaluation (T1), all subjects were instructed to take placebo for 7 days. After this single-blind placebo phase and second evaluation (T2), patients were randomly allocated to placebo or modafinil treatment for 21 days in a double-blind protocol. Patients underwent a final evaluation (T3) on the last day of drug intake. The evaluations at T1, T2 and T3 consisted of: medical and laboratory examinations, nocturnal polysomnography, ESS, maintenance of wakefulness test (MWT) and complex reaction time (CRT-NY). In addition, in T2 and T3 the change of illness severity scale (CGI-C) and the evaluation of quality of life (SF-36) were applied. RESULTS: The comparison between the two groups during the three periods studied, showed the following results: in the modafinil group, ESS score did not change during the initial placebo period, but there was a significant reduction during the modafinil treatment period (p=0.0006); in the placebo group a significant reduction occurred during the initial placebo period (p=0.05), and no further change was observed in the treatment (placebo) period. A significant difference was found between the two groups after the placebo period (T2) (p=0.02). Three patients (33%) of the modafinil group and 9 patients (81%) of the placebo group were classified as placebo-responsive (X2: p=0.039). In the treatment period, reaction time was significantly reduced in the modafinil group compared to the placebo group (p<0.02). There was a trend toward improvement in overall clinical condition and also in some domains of SF-36 in the modafinil group. CONCLUSION: In summary, our study confirms that modafinil used adjunctively with CPAP therapy improves subjective daytime sleepiness in patients with OSAS who were regular users of CPAP therapy but still experienced sleepiness. Moreover, it could help in the improvement of objective measures of behavioral alertness and reduce functional impairments. The usefulness of a blinded placebo period for systematic investigation of placebo role in studies based on subjective response is a point that should be considered in this type of drug trial.

Effects of anabolic androgenic steroids on sleep patterns of individuals practicing resistance exercise.

Anabolic androgenic steroid (AAS) abuse has become a public health problem in many countries, and is associated with many psychiatric disorders. Epidemiological studies have also found increasing numbers of sleep disorders reported by individuals using AASs. The purpose of this study was to evaluate sleep patterns and disorders in anabolic androgenic users who practice resistance exercise. The sample comprised 58 males divided into three groups: (1) 20 current AAS users aged 26 +/- 1.2, (2) 21 controls with no history of AAS use, aged 26 +/- 1 and (3) 17 sedentary men with no sleep disorders aged 27.2 +/- 0.34. The volunteers spent a night in the sleep laboratory for polysomnography. Comparing the three groups, the user group showed reduced sleep efficiency and more wakings after sleep onset than the sedentary group (P = 0.001). The sedentary group showed a higher percentage of stage 4 than the non-users group. We suggest that using of anabolic steroids reduced sleep efficiency and alters sleep architecture.