Real world challenges and barriers for positive airway therapy use in acute ischemic stroke patients.

PURPOSE: Untreated obstructive sleep apnea (OSA) in patients with acute ischemic stroke (AIS) is associated with increased morbidity and mortality. However, diagnosing and treating OSA in AIS is challenging. We aimed to determine the feasibility of portable monitoring (PM) for diagnosis and positive airway pressure therapy for treatment of OSA in an inpatient stroke population. METHODS: We recruited inpatients with AIS from Cleveland Clinic. Those who consented underwent PM; participants with a respiratory event index (REI) ≥ 10 were offered auto-titrating positive airway pressure therapy (APAP). Ease-of-use questionnaires were completed. We summarized categorical variables using n(%) and continuous variables using mean ± SD or median [IQR]. RESULTS: 27 participants (age 59.8 ± 11.8, 51.9% female, 51.9% Black, BMI 33.4 ± 8.5) enrolled. The study ended early due to Medicare contracting that forced most patients to complete stroke rehabilitation outside the Cleveland Clinic health system. 59.3% had large vessel occlusions and 53.8% had moderate/severe disability (Modified Rankin score ≥ 2). PM was attempted in 21 participants, successful in 18. Nurses and patients rated the PM device as highly easy to use. 13 of 18 (72%) patients who had an REI ≥ 10 consented to APAP titration, but only eight (61.5%) of those 13 used APAP for more than one night, and only five (27.8%) used APAP up to 90 days with data captured for only one participant. Five required troubleshooting at titration, and only one had adherent APAP usage by objective assessment after discharge. CONCLUSIONS: This study demonstrates the real-world challenges of assessing and treating OSA in an AIS population, highlighting the necessity for further research into timely and feasible screening and treatment.

Assessment of the exposure to PM2.5 in different Lebanese microenvironments at different temporal scales.

The weak potential of using the sole outdoor concentrations to represent personal exposure to PM2.5 is confirmed by the literature; therefore, it is important to account for a person's movements over time when estimating the short-term personal air pollution exposure within different microenvironments (MEs). This study is an example of applying an assessment method of the exposure to PM2.5 in different microenvironments at different temporal scales. A low-cost particle counter (the Dylos 1700) was used; its performance was validated in comparison with equivalent instruments such the SidePak AM520 Personal Aerosol Monitor (R2 = 0.89). This validation also provided a function to convert measured particle number concentrations (PNCs) into calculated particle mass concentrations. The 150 profiles that was collected on a minute-by-minute basis regarding PM2.5 concentration from December 2018 to May 2021 highlight the influence of individual activities and contextual factors on the air quality, so that Lebanon's annual PM2.5 mean (24.2 µg/m3) is 142% higher than the World Health Organization (WHO) annual mean guideline (10 µg/m3). Winter is the most polluted period due to the increased application of space heating devices. Additionally, the occurrence of dusty winds during the spring period leads to the elevated levels of dispersed PM2.5. Simultaneously, the rural zones are more polluted than urban ones due to the usage of more traditional heating equipment, in addition to the usage of chemical products like pesticides and fertilizers in agricultural activities in such areas. Furthermore, the (outdoor-indoor-transport) MEs indicate that the transport and indoor MEs have similar levels of suspended fine particulates, while outdoor MEs are less polluted. Studies based on the personal exposure to PM2.5 were generally applied on specific and limited places such as schools, workplaces, or residences. The study aims to shed light on the modern method in an attempt to estimate the personal exposure to PM2.5 and to inspire similar studies to achieve the maximum efficiency.

Sleep apnea diagnosis in children using software-generated apnea-hypopnea index (AHI) derived from data recorded with a single photoplethysmogram sensor (PPG) : Results from the Childhood Adenotonsillectomy Study (CHAT) based on cardiopulmonary coupling analysis.

OBJECTIVE: Sleep quality is vital for healthy development in children. Sleep disorders are prevalent and negatively affect sleep quality. Early identification and appropriate intervention can improve children's health and quality of life. The current reference standard, polysomnography (PSG) has limitations regarding availability, cost, and access and may not replicate normal sleep patterns in the home. Simple, accurate sleep tests, available for repeated testing should be beneficial in management of sleep disorders. METHOD: Secondary analysis of PSG data from the prospective multicenter Childhood Adenotonsillectomy Trial (CHAT) to evaluate FDA-cleared cloud-based software (Software-as-a-Medical-Device), which is based on analysis of photoplethysmogram data (PPG; plethysmogram-signal (PLETH) and oxygen saturation data (SpO2)), to automatically generate a novel apnea-hypopnea index (sAHI). sAHI is compared to manually scored AHI from PSG. RESULTS: Significant correlation is observed comparing the software-generated sAHI and manually derived AHI from the in-laboratory PSG-studies (Pearson correlation = 0.954, p < 0.0001) and receiver operating characteristics (ROC) demonstrate strong agreement in all OSA categories (mild, moderate, severe) 91.4%[CI95%89.5, 93.4]; 96.7%[CI95%95.4, 97.9]; 98.6%[CI95%97.8, 99.4], sensitivities 95.4%[CI95%93.2, 97.0]; 86.5%[CI95%80.3, 91.3]; 88.4%[CI95%78.4, 94.9] and specificities 84.4%[CI95%79.7, 88.4]; 99.2%[CI95%98.2, 99.7]; 99.6%[CI95%98.8, 99.9], respectively. CONCLUSION: sAHI is comparable to manual scoring of AHI from in-laboratory PSG studies and effective to rule-in and rule-out obstructive sleep apnea (OSA) in all disease categories, providing safe and convenient approach for diagnosis and management of OSA in children. The data is recorded with a single-sensor, making the method suitable for multi-night testing in the child's home at considerably lower cost. This technology provides a simple tool to adhere to guidelines for diagnosis and management of OSA in children. CLINICAL TRIAL REGISTRATION NAME AND NUMBER: Childhood Adenotonsillectomy Study for Children with OSA (CHAT) https://clinicaltrials.gov/ct2/show/NCT00560859.

Electrocardiogram-based sleep analysis for sleep apnea screening and diagnosis.

PURPOSE: Despite the increasing number of research studies of cardiopulmonary coupling (CPC) analysis, an electrocardiogram-based technique, the use of CPC in underserved population remains underexplored. This study aimed to first evaluate the reliability of CPC analysis for the detection of obstructive sleep apnea (OSA) by comparing with polysomnography (PSG)-derived sleep outcomes. METHODS: Two hundred five PSG data (149 males, age 46.8 ± 12.8 years) were used for the evaluation of CPC regarding the detection of OSA. Automated CPC analyses were based on ECG signals only. Respiratory event index (REI) derived from CPC and apnea-hypopnea index (AHI) derived from PSG were compared for agreement tests. RESULTS: CPC-REI positively correlated with PSG-AHI (r = 0.851, p < 0.001). After adjusting for age and gender, CPC-REI and PSG-AHI were still significantly correlated (r = 0.840, p < 0.001). The overall results of sensitivity and specificity of CPC-REI were good. CONCLUSION: Compared with the gold standard PSG, CPC approach yielded acceptable results among OSA patients. ECG recording can be used for the screening or diagnosis of OSA in the general population.

Reliability of autonomic activations as surrogates of cortical arousals in ventilated patients affected by amyotrophic lateral sclerosis.

PURPOSE: The study aims to evaluate the performance of autonomic activations as a tool to assess sleep fragmentation and to recognize hypopneas in patients with amyotrophic lateral sclerosis (ALS) under non-invasive mechanical ventilation and secondarily, to evaluate, in patients with the same disease, the relationship between disruption of autonomic nervous system (ANS) activity and the usefulness of the autonomic activations as surrogates of cortical arousals. METHODS: Sixteen ALS patients underwent simultaneous polysomnography and portable cardiorespiratory monitoring (PM). On the polysomnography, standard rules were used for scoring arousals and respiratory events. On the PM, autonomic arousals were scored as ≥ 15% heart rate (HR) increase with a ≥ 35% pulse wave amplitude (PWA) reduction, HR increase ≥ 20%, or PWA decrease ≥ 40%. Nocturnal HR variability was analyzed in the ALS patients and in 11 control subjects as an index of ANS activity. RESULTS: Synchronized epoch by epoch analysis of the polysomnography and PM recordings showed that only 31.0 (22.5-58.7)% cortical and 36.1 (20.5-47.2)% autonomic arousals were associated with one another. Among hypopneas scored at polysomnography, 71.7% were associated with a cortical arousal but not with a desaturation. On average, HR variability in ALS showed signs of depressed ANS activity that was particularly evident in the patients where the cortical arousals exceeded the autonomic ones. CONCLUSIONS: In ventilated ALS patients, autonomic activations may hardly have a role as surrogates of cortical arousals for assessment of sleep fragmentation and for respiratory scoring. Depression of ANS activity may be related to their poor performance.

Arousal responses to respiratory events during sleep: the role of pulse wave amplitude.

The study aims at assessing the changes in electroencephalography (as measured by the A-phases of cyclic alternating pattern) and autonomic activity (based on pulse wave amplitude) at the recovery of airway patency in patients with obstructive sleep apnea syndrome. Analysis of polysomnographic recordings from 20 male individuals with obstructive sleep apnea syndrome was carried out in total sleep time, non-rapid eye movement and rapid eye movement sleep. Scoring quantified the combined occurrence (time range of 4 s before and 4 s after respiratory recovery) or separate occurrence of A-phases (cortical activation), and pulse wave amplitude drops (below 30%) to apneas, hypopneas or flow limitation events. A dual response (A-phase associated with a pulse wave amplitude drop) was the most frequent response (71.8% in total sleep time) for all types of respiratory events, with a progressive reduction from apneas to hypopneas and flow limitation events. The highly significant correlation in total sleep time (r = 0.9351; P < 0.0001) between respiratory events combined with A-phases and respiratory events combined with pulse wave amplitude drops was confirmed both in non-rapid eye movement (r = 0.9622; P < 0.0001) and rapid eye movement sleep (r = 0.7162; P < 0.0006). In conclusion, a dual cortical and autonomic activation is the most common manifestation at the recovery of airway patency. The significant correlation between A-phases and relevant pulse wave amplitude drops suggests a possible role of pulse wave amplitude as a marker of cerebral response to respiratory events.

Screen-printed ambulatory electrode set enables accurate diagnostics of sleep bruxism.

Currently, definite diagnosis of sleep bruxism requires polysomnography. However, it is restrictedly available, and too cumbersome and expensive for the purpose. The aim of this study was to introduce an ambulatory electrode set and evaluate its feasibility for more cost-effective diagnostics of sleep bruxism. Six self-assessed bruxers (one male, five females; aged 21-58 years) and six healthy controls (four males, two females, aged 21-25 years) underwent a standard polysomnographic study and a concurrent study with the ambulatory electrode set. Bruxism events, cortical arousals and sleep stages were scored for the two montages separately in a random order, and obtained sleep parameters were compared. In addition, the significance of video recording and sleep stage scoring for the diagnostic accuracy of ambulatory electrode set was determined. Ambulatory electrode set yielded similar diagnoses as standard polysomnography in all subjects. However, compared with standard polysomnography the median (interquartile range) tonic bruxism event index was significantly higher in the control group [+0.38 (+0.08 to +0.56) events per hour, P = 0.046], and the phasic bruxism event index was significantly lower in the bruxer group [-0.44 (-1.30 to +0.07) events per hour, P = 0.046]. Exclusion of video recording and both video recording and sleep stage scoring from analysis increased overestimation of the tonic bruxism event index in the control group +0.86 (+0.42 to +1.03) and +1.19 (+0.55 to +1.39) events per hour, P = 0.046 and P = 0.028, respectively], resulting in one misdiagnosed control subject. To conclude, ambulatory electrode set is a sensitive method for ambulatory diagnostics of sleep bruxism, and video recording and sleep stage scoring help reaching the highest specificity of sleep bruxism diagnostics.

Addition of frontal EEG to adult home sleep apnea testing: does a more accurate determination of sleep time make a difference?

RATIONALE: Home sleep apnea testing (HSAT) typically does not include electroencephalogram (EEG) monitoring for sleep assessment. In patients with insomnia and low sleep efficiency, overestimation of the sleep period can result from absence of EEG, which will reduce sleep disordered breathing (SDB) indices and may lead to a false-negative result. OBJECTIVE: To validate a single channel frontal EEG for scoring sleep versus wake against full EEG during polysomnography, and then to examine the utility of adding this single channel EEG to standard HSAT to prevent false-negative results. METHODS: Epoch-by-epoch validation for sleep scoring of single channel EEG versus full PSG was first performed in 21 subjects. This was followed by a separate retrospective analysis of 207 consecutive HSATs in adults performed in a university-affiliated sleep center using the Somte (Compumedics) HSAT with one frontal EEG as well as chin EMG, nasal airflow, oxyhemoglobin saturation, respiratory effort, pulse rate, and body position. Each study was scored twice, with (HSATEEG) and without the EEG signal visible (HSATPolygraphy), to calculate AHI4 and RDI and the effect on OSA diagnosis and severity. Analyses were repeated in 69 patients with poor sleep suggesting insomnia plus Epworth Sleepiness Scale < 7 as well as in 38 patients ultimately shown to have sleep efficiency < 70% on HSAT with EEG. MEASUREMENTS AND MAIN RESULTS: Single channel and full EEG during polysomnography agreed on sleep versus wake in 92-95% of all epochs. HSAT without EEG overestimated the sleep period by 20% (VST = 440 ± 76 min vs TST = 356 ± 82 min), had a false-negative rate of 8% by AHI4 criteria, and underestimated disease severity in 11% of all patients. Sub-group analysis of patients with subjective poor sleep suggesting insomnia did not change the results. Patients later shown to have low sleep efficiency had lower SDB indices and a 20.8% false negative rate of sleep apnea diagnosis. CONCLUSIONS: Although overall false negative rates using HSATPolygraphy were moderate, suggesting utility for ruling out OSA, there was a specific subgroup in whom there were significant missed diagnoses. However, we were unable to identify this subgroup a priori.

Comparison of two home sleep testing devices with different strategies for diagnosis of OSA.

PURPOSE: Home sleep testing devices are being widely used in diagnosis/screening for obstructive sleep apnea (OSA). We examined differences in OSA metrics obtained from two devices with divergent home monitoring strategies, the Apnea Risk Evaluation System (ARES™, multiple signals plus forehead reflectance oximetry) and the Nonin WristOx2™ (single channel finger transmission pulse oximeter), compared to differences from night-night variability of OSA. METHODS: One hundred fifty-two male/26 female subjects (BMI = 30.3 ± 5.6 kg/m2, age = 52.5 ± 8.9 years) were recruited without regard to OSA symptoms and simultaneously wore both ARES™ and Nonin WristOx2™ for two nights (n = 351 nights). Automated analysis of the WristOx2 yielded oxygen desaturation index (ODIOx2, ≥4% O2 dips/h), and automated analysis with manual editing of ARES™ yielded AHI4ARES (apneas + hypopneas with ≥4% O2 dips/h) and RDIARES (apneas + hypopneas with ≥4% O2 dips/h or arousal surrogates). Baseline awake oxygen saturation, percent time < 90% O2 saturation (%time < 90%O2Sat), and O2 signal loss were compared between the two methods. RESULTS: Correlation between AHI4ARES and ODIOx2 was high (ICC = 0.9, 95% CI = 0.87-0.92, p < 0.001, bias ± SD = 0.7 ± 6.1 events/h). Agreement values for OSA diagnosis (77-85%) between devices were similar to those seen from night-to-night variability of OSA using a single device. Awake baseline O2 saturation was significantly higher in the ARES™ (96.2 ± 1.6%) than WristOx2™ (92.2 ± 2.1%, p < 0.01). There was a significantly lower %time < 90%O2Sat reported by the ARES™ compared to WristOx2 (median (IQR) 0.5 (0.0, 2.6) vs. 2.1 (0.3, 9.7), p < 0.001), and the correlation was low (ICC = 0.2). CONCLUSIONS: OSA severity metrics predominantly dependent on change in oxygen saturation and metrics used in diagnosis of OSA (AHI4 and ODI) correlated well across devices tested. However, differences in cumulative oxygen desaturation measures (i.e., %time < 90%O2Sat) between the devices suggest that caution is needed when interpreting this metric particularly in populations likely to have significant hypoxia.

The role of compact polysomnography/polygraphy in sleep breathing disorder patients' management.

While managing obstructive sleep apnea (OSA) or suspicious OSA patients, the otorhinolaryngologist frequently has to deal with patients undergoing repeated polysomnography (PSG) or portable monitoring (PM) and, on the other hand, should be confident about the quality and consistency of the polysomnographic diagnosis. The main polysomnographic traces compressed in a unique epoch, defined as compact PSG/PM (CP), which should be reported in all PSG/PM report, could represent an efficient tool to confirm the quality of PSG/PM diagnosis and to recognize the sleep breathing disorders (SBD): OSA, no-OSA SBD and overlap of OSA with no-OSA SBD. In this study, a synthetic and clear guided iconography and an easy decision-making algorithm based on desaturation patterns (phasic, prolonged and overlap desaturation patterns) identifiable on the CP are suggested for a quick check of the quality of PSG/PM diagnosis and to achieve an improvement in the patient's clinical management.

The interpretation of compact polysomnography/polygraphy in sleep breathing disorders patients: a validation's study.

The Otorhinolaryngologist (ENT) frequently has to deal with OSA or suspicious OSA patients and undergone polysomnography (PSG) or portable monitoring (PM) and should be confident about the quality and consistency of the polysomnographic diagnosis. The main polysomnographic traces compressed in a unique epoch, defined as compact PSG/PM (CP), could represent an efficient tool to confirm the quality of PSG/PM Sleep Breathing Disorders diagnosis. This is a validation's study of a CP interpretation's method, analyzing the learning curve, the level of diagnostic accuracy, and the inter-operator agreement in interpreting the CP pattern between a group of ENT specialists not skilled in PSG/PM scoring, but managing SBD patients during daily practice. Seven ENT specialists have been enrolled in the study. 50 CP traces (ranging from normal to all main SBD patterns) have been showed to each participant for the interpretation and scoring process, before and after a 2-h theoretical-practical interactive lesson, focusing on the recognition of the four main oximetric patterns on CP traces (normal, phasic, prolonged, and overlap patterns). RESULTS: before and after the theoretical-practical interactive lesson, the whole diagnostic accuracy in interpreting the 50 CP has been reported improved from 0.12 to 0.80 (median 0.52) to 0.82-0.96 (median 0.92) (p = 0.006) and the inter-scorers' agreement showed a kappa value increased from of 0.18 to 0.75 (p < 0.0001). A complete clinical diagnostic evaluation is essential in OSA patients and the ENT specialist should be concerned to verify if the patient, suitable for surgical therapy, is affected really by an isolated form of OSA. The CP interpretation allows a checking of the proper nosographic SBD framework and could be significantly important for all ENT specialists not skilled in PSG/PM scoring, but managing SBD patients during daily practice. The data reported in our validation's study showed that the CP interpretation's method is easy to apply, with a rapid learning curve. The level of diagnostic accuracy is high with a high inter-scorer agreement in interpreting the CP patterns.

Assessment of the suitability of using a forehead EEG electrode set and chin EMG electrodes for sleep staging in polysomnography.

Recently, a number of portable devices designed for full polysomnography at home have appeared. However, current scalp electrodes used for electroencephalograms are not practical for patient self-application. The aim of this study was to evaluate the suitability of recently introduced forehead electroencephalogram electrode set and supplementary chin electromyogram electrodes for sleep staging. From 31 subjects (10 male, 21 female; age 31.3 ± 11.8 years), sleep was recorded simultaneously with a forehead electroencephalogram electrode set and with a standard polysomnography setup consisting of six recommended electroencephalogram channels, two electrooculogram channels and chin electromyogram. Thereafter, two experienced specialists scored each recording twice, based on either standard polysomnography or forehead recordings. Sleep variables recorded with the forehead electroencephalogram electrode set and separate chin electromyogram electrodes were highly consistent with those obtained with the standard polysomnography. There were no statistically significant differences in total sleep time, sleep efficiency or sleep latencies. However, compared with the standard polysomnography, there was a significant increase in the amount of stage N1 and N2, and a significant reduction in stage N3 and rapid eye movement sleep. Overall, epoch-by-epoch agreement between the methods was 79.5%. Inter-scorer agreement for the forehead electroencephalogram was only slightly lower than that for standard polysomnography (76.1% versus 83.2%). Forehead electroencephalogram electrode set as supplemented with chin electromyogram electrodes may serve as a reliable and simple solution for recording total sleep time, and may be adequate for measuring sleep architecture. Because this electrode concept is well suited for patient's self-application, it may offer a significant advancement in home polysomnography.

Diagnosis of obstructive sleep apnea using a bio-radar contact-free system compared with an established HST device in older adults.

GOAL AND AIMS: To compare a bio-radar contact-free monitoring device in diagnosing obstructive sleep apnea (OSA) in older people with an established home sleep apnea testing system (HST). FOCUS METHOD/TECHNOLOGY: A bio-radar contact-free monitoring device (OrbSense+). REFERENCE METHOD/TECHNOLOGY: An established HST, Alice NightOne. SAMPLE: Fifty-three out of 63 recruited subjects were included in the final analysis. Seventy-two percent were male (age 72 ± 9 years; body mass index 31.05 ± 5.56 kg/m2). DESIGN: An observational, prospective study. CORE ANALYTICS: Intraclass correlation coefficient (ICC), Bland-Altman analysis, and receiver operating characteristic analysis. ADDITIONAL ANALYTICS AND EXPLORATORY ANALYSES: None. CORE OUTCOMES: Both 45 (84.91%) were diagnosed with OSA by Alice NightOne (average respiratory event index = 21.23 events/h) and by OrbSense+ (average respiratory event index = 25.98 events/h). Respiratory event index and oxygen desaturation index obtained by Alice NightOne and OrbSense+ were highly correlated, with ICC of 0.93 and 0.88, respectively. The Bland-Altman plot comparing the means showed good agreement between the 2 diagnostic techniques. With more than 5 respiratory events per hour as the standard for OSA diagnosis, OrbSense+ had a sensitivity of 100% and a specificity of 100% in diagnosis of OSA (P < .0001). With more than 15 respiratory events per hour as the standard for OSA diagnosis, OrbSense+ was found to have a sensitivity of 100% and a specificity of 86.96% in diagnosis of OSA (P < .0001). IMPORTANT ADDITIONAL OUTCOMES: None. CORE CONCLUSION: The bio-radar sleep monitoring device is a reasonably accurate home sleep apnea test for use in older patients.

Personal Heart Health Monitoring Based on 1D Convolutional Neural Network.

The automated detection of suspicious anomalies in electrocardiogram (ECG) recordings allows frequent personal heart health monitoring and can drastically reduce the number of ECGs that need to be manually examined by the cardiologists, excluding those classified as normal, facilitating healthcare decision-making and reducing a considerable amount of time and money. In this paper, we present a system able to automatically detect the suspect of cardiac pathologies in ECG signals from personal monitoring devices, with the aim to alert the patient to send the ECG to the medical specialist for a correct diagnosis and a proper therapy. The main contributes of this work are: (a) the implementation of a binary classifier based on a 1D-CNN architecture for detecting the suspect of anomalies in ECGs, regardless of the kind of cardiac pathology; (b) the analysis was carried out on 21 classes of different cardiac pathologies classified as anomalous; and (c) the possibility to classify anomalies even in ECG segments containing, at the same time, more than one class of cardiac pathologies. Moreover, 1D-CNN based architectures can allow an implementation of the system on cheap smart devices with low computational complexity. The system was tested on the ECG signals from the MIT-BIH ECG Arrhythmia Database for the MLII derivation. Two different experiments were carried out, showing remarkable performance compared to other similar systems. The best result showed high accuracy and recall, computed in terms of ECG segments and even higher accuracy and recall in terms of patients alerted, therefore considering the detection of anomalies with respect to entire ECG recordings.

A portable air quality monitoring unit and a modular, flexible tool for on-field evaluation and calibration of low-cost gas sensors.

In recent years, several research projects have investigated the use of low-cost devices for air pollution monitoring. As a result of these activities, various air quality monitoring systems have been developed following diverse approaches and methods. However, in most cases, these monitoring systems lack flexibility, extendibility, and openness. The device presented in this article provides a cost-effective, expandable, flexible, open-source solution. SentinAir has been designed to act as a portable air quality monitoring unit and also for facilitating the on-field evaluation and calibration of air quality sensors. The high grade of flexibility featuring this tool enables the data acquisition from heterogeneous kinds of devices deployed far from the laboratory facilities, even in areas featured by a weak or unstable Internet connection. Moreover, the system proposed in this article provides a reasonably easy way to integrate a wide range of sensors or devices produced by diverse manufacturers, offering a tool that is not bound to the use of a limited and fixed set of sensors or devices. The modularity approach followed in SentinAir design constitutes another key factor to consider: it allows each user to easily adapt this device to his requirements. This system is therefore capable of providing a robust framework for environmental monitoring activities to researchers or low-skilled end-users.

Variability and Misclassification of Sleep Apnea Severity Based on Multi-Night Testing.

BACKGROUND: Portable monitoring is a convenient means for diagnosing sleep apnea. However, data on whether one night of monitoring is sufficiently precise for the diagnosis of sleep apnea are limited. RESEARCH QUESTION: The current study sought to determine the variability and misclassification in disease severity over three consecutive nights in a large sample of patients referred for sleep apnea. METHODS: A sample of 10,340 adults referred for sleep apnea testing was assessed. A self-applied type III monitor was used for three consecutive nights. The apnea-hypopnea index (AHI) was determined for each night, and a reference AHI was computed by using data from all 3 nights. Pairwise correlations and the proportion misclassified regarding disease severity were computed for each of the three AHI values against the reference AHI. RESULTS: Strong correlations were observed between the AHI from each of the 3 nights (r = 0.87-0.89). However, substantial within-patient variability in the AHI and significant misclassification in sleep apnea severity were observed based on any 1 night of monitoring. Approximately 93% of the patients with a normal study on the first night and 87% of those with severe sleep apnea on the first night were correctly classified compared with the reference derived from all three nights. However, approximately 20% of the patients with mild and moderate sleep apnea on the first night were misdiagnosed either as not having sleep apnea or as having mild disease, respectively. CONCLUSIONS: In patients with mild to moderate sleep apnea, one night of portable testing can lead to misclassification of disease severity given the substantial night-to-night variability in the AHI.

Night-to-night variability in respiratory parameters in children and adolescents examined for obstructive sleep apnea.

INTRODUCTION: The diagnosis of obstructive sleep apnea (OSA) is routinely based on just a single night's sleep examination. The night-to-night variability in children and adolescents has previously been investigated using type 4 sleep monitors or PSG. However, there is a lack of studies investigating the night-to-night variability when using type 3 sleep monitors. Therefore, the main purpose was to investigate the night-to-night variability in respiratory parameters in children and adolescents using a portable type 3 monitor. Furthermore, the purpose was to investigate the clinical relevance of night-to-night variability. METHODS: The study population was recruited from an ongoing research project concerning the effect of weight loss in children and adolescents with OSA and overweight/obesity. The inclusion criterion was the successful recording of two consecutive nights of sleep. Sleep examinations were recorded at home using the Nox T3 device and then blindly scored by the same registered polysomnographic technologist. To compare the respiratory parameters measured each night, a paired t-test or a Wilcoxon signed-rank test was used. The apnea-hypopnea index (AHI) was further described graphically with a scatter plot and a Bland-Altman plot. The presence and severity of OSA were described in tables. RESULTS: A total of 30 children and adolescents with a median age of 14.8 years were included. When comparing respiratory parameters between nights, all p-values derived from paired t-tests and Wilcoxon signed-rank tests were >0.05. When considering the graphical depictions of AHI, it was evident that for some participants AHI measurements varied widely from night to night. Regarding the presence of OSA, 27% of participants changed diagnostic category between nights and 40% of those with a normal AHI on the first night had OSA on the second night. Regarding OSA severity, 50% of participants changed severity category between nights. CONCLUSIONS: AHI measurements varied widely between nights in some children and adolescents leading to frequent changes in both diagnosis and severity of OSA from night to night. We therefore suggest the presence of a clinically relevant night-to-night variability which should be taken into account when diagnosing pediatric OSA.

Validation of the MediByte Portable Monitor for the Diagnosis of Sleep Apnea in Pediatric Patients.

STUDY OBJECTIVES: Polysomnography (PSG) is considered the gold standard in the diagnosis of sleep apnea. In pediatric patients, because of limited availability and access to laboratory-based PSG, there can be significant delays in the diagnosis and management of sleep apnea that can result in progressive associated comorbidities. The main objective of the current study was to test the diagnostic value of a portable sleep monitor (PM), the MediByte, in comparison with laboratory PSG in pediatric patients wearing both setups simultaneously. METHODS: A consecutive series of pediatric patients referred to the University of Illinois Sleep Science Center wore the MediByte during simultaneous PSG. The apnea-hypopnea index (AHI) was calculated for PSG and both manual and autoscoring functions of the PM. Pearson correlation and Bland-Altman plots were assessed. RESULTS: A total of 70 patients successfully completed simultaneous PSG and PM studies (median age 10.8 years). The AHI obtained both manually and automatically scored PM studies strongly correlated with the AHI obtained from the PSG (r ≥ .932, P < .001). The oxygen saturation obtained by the PM showed significant correlation with that obtained by PSG among children aged 12 to 17 years (P < .001), but not among children aged 7 to 11 years (P ≥ .24). The sensitivity and specificity for detection of severe sleep apnea diagnosed by PSG (AHI ≥ 10 events/h) using both PM scoring methods was very high (> 93% for both). CONCLUSIONS: Although PSG is still recommended for the diagnosis of sleep apnea, PMs can play a valuable role in diagnosing moderate and severe sleep apnea, especially in older pediatric patients. COMMENTARY: A commentary on this article appears in this issue on page 685.

Agreement between manual and automatic analyses of home sleep examinations in pediatric obstructive sleep apnea.

Aim: Home sleep testing is becoming more common in the diagnostics of pediatric obstructive sleep apnea. The aim was to examine the agreement between manual and automatic analyses of home sleep examinations in children and adolescents. Materials & methods: Sleep examinations recorded with a type 3 sleep monitor (Nox T3) were analyzed manually by a registered polysomnographic technologist and automatically with Noxturnal version 5.1. Results: 51sleep examinations on children and adolescents with a median age of 13.6 years were included. The median manual apnea-hypopnea index (AHI) was 2.7 (range 0.2 to 28.2), while the median automatic AHI was 11.9 (range 4.2 to 45.6; p < 0.001). Conclusion: The agreement between manual and automatic analyses was poor. The AHI was consistently overestimated by automatic analysis.

Autonomic Arousals as Surrogates for Cortical Arousals Caused by Respiratory Events: A Methodological Optimization Study in the Diagnosis of Sleep Breathing Disorders.

INTRODUCTION: Portable monitoring (PM) is an alternative to laboratory polysomnography (PSG) for diagnosing obstructive sleep apnea (OSA). However, PM tends to underestimate the apnea-hypopnea index (AHI), as it does not identify non-desaturating events associated with electroencephalographic (EEG) arousal. The objectives were to explore heart rate acceleration (HRa) and decrease in pulse transit time (PTT) as surrogates to EEG arousal for non-desaturating hypopnea and respiratory effort-related arousal (RERA), and to estimate cut-off values for their use with both total sleep time (TST), the standard method for PSG, and total recording time (TRT), the usual method for PM. METHODS: Twenty-four consecutive individuals with suspected OSA were studied with PSG. Calculated outcomes were: AHI, respiratory disturbance index with EEG arousal (RDIe) and autonomic arousal by HRa (RDI-HRa) and PTT decreases (RDI-PTT) at different time cut-offs. Using RDIe as reference, Bland Altman and intraclass coefficient of correlation (ICC) were used to calculate agreement between indexes, and receiver operating curves (ROC) for sensitivity/specificity of the different cut-offs. RESULTS: Autonomic arousals, limited to respiratory events, were present in 36% of non-desaturating hypopneas and 29% of RERAs. Using TST, RDI-HRa of 10 bpm (ICC= 0.89) and RDI-PTT with a decrease of -15 msec (ICC=0.90) agreed better with RDIe. With TRT, the RDI-HRa of 5 bpm agreed better with the RDIe (ICC=0.89). Bland-Altman plots showed mean differences of 1.53 between RDI-HRa10-TST and RDIe and 0.89 between RDI-HRa5-TRT and RDIe. CONCLUSION: Autonomic arousals (HRa and PTT) may be a suitable proxy of EEG arousals associated with respiratory events, using both TST and TRT. Therefore, they could potentially help to capture borderline symptomatic patients and to monitor treatment outcomes.