A comparison of polysomnography and a portable home sleep study in the diagnosis of obstructive sleep apnea syndrome

A Feature Fusion Model Based on Temporal Convolutional Network for Automatic Sleep Staging Using Single-Channel EEG

Sleep staging is a crucial task in sleep monitoring and diagnosis, but clinical sleep staging is both time-consuming and subjective. In this study, we proposed a novel deep learning algorithm named feature fusion temporal convolutional network (FFTCN) for automatic sleep staging using single-channel EEG data. This algorithm employed a one-dimensional convolutional neural network (1D-CNN) to extract temporal features from raw EEG, and a two-dimensional CNN (2D-CNN) to extract time-frequency features from spectrograms generated through continuous wavelet transform (CWT) at the epoch level. These features were subsequently fused and further fed into a temporal convolutional network (TCN) to classify sleep stages at the sequence level. Moreover, a two-step training strategy was used to enhance the model's performance on an imbalanced dataset. Our proposed method exhibits superior performance in the 5-class classification task for healthy subjects, as evaluated on the SHHS-1, Sleep-EDF-153, and ISRUC-S1 datasets. This work provided a straightforward and promising method for improving the accuracy of automatic sleep staging using only single-channel EEG, and the proposed method exhibited great potential for future applications in professional sleep monitoring, which could effectively alleviate the workload of sleep technicians.

A multi-branch convolutional neural network for snoring detection based on audio

Obstructive sleep apnea (OSA) is associated with various health complications, and snoring is a prominent characteristic of this disorder. Therefore, the exploration of a concise and effective method for detecting snoring has consistently been a crucial aspect of sleep medicine. As the easily accessible data, the identification of snoring through sound analysis offers a more convenient and straightforward method. The objective of this study was to develop a convolutional neural network (CNN) for classifying snoring and non-snoring events based on audio. This study utilized Mel-frequency cepstral coefficients (MFCCs) as a method for extracting features during the preprocessing of raw data. In order to extract multi-scale features from the frequency domain of sound sources, this study proposes the utilization of a multi-branch convolutional neural network (MBCNN) for the purpose of classification. The network utilized asymmetric convolutional kernels to acquire additional information, while the adoption of one-hot encoding labels aimed to mitigate the impact of labels. The experiment tested the network's performance by utilizing a publicly available dataset consisting of 1,000 sound samples. The test results indicate that the MBCNN achieved a snoring detection accuracy of 99.5%. The integration of multi-scale features and the implementation of MBCNN, based on audio data, have demonstrated a substantial improvement in the performance of snoring classification.

Mood Disorders are Correlated with Autonomic Nervous Function in Chronic Insomnia Patients with OSA

Purpose

To evaluate the correlation between sleep microstructure, autonomic nervous system activity, and neuropsychological characteristics in chronic insomnia (CI) patients with obstructive sleep apnea (OSA).

Patients and Methods

Forty-five CI-OSA patients, forty-six CI patients and twenty-two matched healthy control subjects (HCs) were enrolled. CI-OSA patients were then divided into two groups: mild OSA and moderate-to-severe OSA. All participants completed neuropsychological tests, which included the Hamilton Depression and Anxiety Scales (HAMD and HAMA), the Pittsburgh Sleep Quality Index (PSQI), the Insomnia Severity Index (ISI), the Epworth Sleepiness Scale (ESS), and the Mini-mental State Examination (MMSE). The autonomic nervous system activity and sleep microstructure were examined by the PSM-100A.

Results

The CI-OSA patients exhibited higher scores on the PSQI, ESS, ISI, HAMA, and HAMD than HCs and CI patients (all p < 0.01). The CI-OSA patients had a lower proportion of stable sleep, REM sleep and a higher proportion of unstable sleep ratio (all p < 0.01) than HCs and CI patients (all p < 0.01). The CI-OSA patients had higher ratios of LF and LF/HF, and lower ratios of HF and Pnn50% (all p < 0.01) than HCs and CI patients (all p < 0.01). Compared to CI-mild OSA patients, the CI-moderate-to-severe OSA patients presented with a higher ESS scores, higher ratios of LF and LF/HF, and lower ratios of HF (all p < 0.05). In CI-OSA patients, higher HAMD scores were correlated with decreased MMSE scores (r=-0.678, p < 0.01). A higher LF ratio was correlated with higher HAMD and HAMA scores (r=0.321, p=0.031, r =0.449, p =0.002), and a higher HF ratio was correlated with lower HAMD and HAMA scores (r=-0.321, P =0.031, r =-0.449, p =0.002).

Conclusion

OSA exacerbates the abnormalities of sleep microstructure and the autonomic nervous dysfunction in CI patients. Dysfunction of the autonomic nervous system could contribute to mood deterioration in CI with OSA patients.

Validity of non-contact methods for diagnosis of Obstructive Sleep Apnea: a systematic review and meta-analysis

STUDY OBJECTIVE

Obstructive Sleep Apnea (OSA) is associated with increased perioperative cardiac, respiratory and neurological complications. Pre-operative OSA risk assessment is currently done through screening questionnaires with high sensitivity but poor specificity. The objective of this study was to evaluate the validity and diagnostic accuracy of portable, non-contact devices in the diagnosis of OSA as compared with polysomnography.

DESIGN

This study is a systematic review of English observational cohort studies with meta-analysis and risk of bias assessment.

SETTING

Pre-operative, including in the hospital and clinic setting.

PATIENTS

Adult patients undergoing sleep apnea assessment using polysomnography and an experimental non-contact tool.

INTERVENTIONS

A novel non-contact device, which does not utilize any monitor that makes direct contact with the patient's body, in conjunction with polysomnography.

MEASUREMENTS

Primary outcomes included pooled sensitivity and specificity of the experimental device in the diagnosis of obstructive sleep apnea, in comparison to gold-standard polysomnography.

RESULTS

Twenty-eight of 4929 screened studies were included in the meta-analysis. A total of 2653 patients were included with the majority being patients referred to a sleep clinic (88.8%). Average age was 49.7(SD±6.1) years, female sex (31%), average body mass index of 29.5(SD±3.2) kg/m², average apnea-hypopnea index (AHI) of 24.7(SD±5.6) events/h, and pooled OSA prevalence of 72%. Non-contact technology used was mainly video, sound, or bio-motion analysis. Pooled sensitivity and specificity of non-contact methods in moderate to severe OSA diagnosis (AHI > 15) was 0.871 (95% CI 0.841,0.896, I² 0%) and 0.8 (95% CI 0.719,0.862), respectively (AUC 0.902). Risk of bias assessment showed an overall low risk of bias across all domains except for applicability concerns (none were conducted in the perioperative setting).

CONCLUSION

Available data indicate contactless methods have high pooled sensitivity and specificity for OSA diagnosis with moderate to high level of evidence. Future research is needed to evaluate these tools in the perioperative setting.

Portable evaluation of obstructive sleep apnea in adults: A systematic review

Obstructive sleep apnea (OSA) is a significant healthcare burden affecting approximately one billion people worldwide. The prevalence of OSA is rising with the ongoing obesity epidemic, a key risk factor for its development. While in-laboratory polysomnography (PSG) is the gold standard for diagnosing OSA, it has significant drawbacks that prevent widespread use. Portable devices with different levels of monitoring are available to allow remote assessment for OSA. To better inform clinical practice and research, this comprehensive systematic review evaluated diagnostic performances, study cost and patients' experience of different levels of portable sleep studies (type 2, 3, and 4), as well as wearable devices and non-contact systems, in adults. Despite varying study designs and devices used, portable diagnostic tests are found to be sufficient for initial screening of patients at risk of OSA. Future studies are needed to evaluate cost effectiveness with the incorporation of portable diagnostic tests into the diagnostic pathway for OSA, as well as their application in patients with chronic respiratory diseases and other comorbidities that may affect test performance.

Automated Scoring of Respiratory Events in Sleep With a Single Effort Belt and Deep Neural Networks

OBJECTIVE

Automatic detection and analysis of respiratory events in sleep using a single respiratoryeffort belt and deep learning.

METHODS

Using 9,656 polysomnography recordings from the Massachusetts General Hospital (MGH), we trained a neural network (WaveNet) to detect obstructive apnea, central apnea, hypopnea and respiratory-effort related arousals. Performance evaluation included event-based analysis and apnea-hypopnea index (AHI) stratification. The model was further evaluated on a public dataset, the Sleep-Heart-Health-Study-1, containing 8,455 polysomnographic recordings.

RESULTS

For binary apnea event detection in the MGH dataset, the neural network obtained a sensitivity of 68%, a specificity of 98%, a precision of 65%, a F1-score of 67%, and an area under the curve for the receiver operating characteristics curve and precision-recall curve of 0.93 and 0.71, respectively. AHI prediction resulted in a mean difference of 0.41 ± 7.8 and a r2 of 0.90. For the multiclass task, we obtained varying performances: 84% of all labeled central apneas were correctly classified, whereas this metric was 51% for obstructive apneas, 40% for respiratory effort related arousals and 23% for hypopneas.

CONCLUSION

Our fully automated method can detect respiratory events and assess the AHI accurately. Differentiation of event types is more difficult and may reflect in part the complexity of human respiratory output and some degree of arbitrariness in the criteria used during manual annotation.

SIGNIFICANCE

The current gold standard of diagnosing sleep-disordered breathing, using polysomnography and manual analysis, is time-consuming, expensive, and only applicable in dedicated clinical environments. Automated analysis using a single effort belt signal overcomes these limitations.

The Utility of Recording Submental Electrical Activity in Polysomnography

Background

Polysomnography is widely utilized as a diagnostic tool in sleep medicine. It is used to diagnose a variety of sleep disorders, including obstructive and central sleep apnea, periodic limb movements, parasomnia, and other sleep disorders. The objective of this study is to discuss the utility of recording submental electrical activity as a tool that provides the additional information needed in producing accurate results of a polysomnogram and emphasize the importance of including this recording in home sleep apnea tests.

Methods

A total of 1472 consecutive polysomnograms were used to assess the usefulness of submental activity in contributing to the accurate reporting of polysomnographic findings. These records were gathered over a one-year period at a major academic sleep center.

Results

Some of the observed electrical activities in the submental area are rare, although they may be important in confirming the findings of the polysomnogram or provide additional information. Adding an electroencephalographic channel and submental electromyographic recording is likely to increase the accuracy of home sleep apnea tests.

Conclusions

Recording of submental electrical activity is an integral part of polysomnography and provides more information than just recording the muscle tone of the submental area and is important in increasing the accuracy of home sleep apnea tests. 

Diagnostic accuracy and feasibility of portable sleep monitoring in patients with obstructive sleep apnea: Re-exploring the utility in the current COVID-19 pandemic

Portable sleep monitoring (PSM) is a promising alternative diagnostic tool for Obstructive Sleep Apnea (OSA) especially in high burden resource limited settings. We aimed to determine the diagnostic accuracy and feasibility of PSM device-based studies in patients presenting for evaluation of OSA at a tertiary care hospital in North-India. PSM studies (using a Type-III PSM device) were compared for technical reliability and diagnostic accuracy with the standard laboratory-based Type-I polysomnography (PSG). Patients were also interviewed about their experience on undergoing an unsupervised PSM studies. Fifty patients (68% males) were enrolled in the study, of which only 30% patients expressed their concerns about undergoing unsupervised PSM studies which included safety issues, ease of use, diagnostic accuracy, etc. Technical acceptability criteria were easily met by the PSM studies with signal loss in 12% studies (complete data loss and inaccessible data in 6% studies), warranting repetition sleep studies in four patients. The overall sensitivity of PSM device (AHI ≥5) was 93.5% (area under curve; AUC: 0.87). The diagnostic accuracy was 68.5%, 80%, and 91.4% for mild, moderate, and severe cases of OSA, respectively. An overall strong correlation was observed between PSM-AHI (apnoea-hypopnoea index) and PSG (r>0.85, p≤0.001), especially in severe OSA. The observed sensitivity was >90% for AHI>20 (clinically significant OSA), with high specificity of 91% for severe OSA (AUC: 0.94, 0.97 for AHI>20, AHI>30 respectively). The overall Bland-Altman concordance analysis also demonstrated only a small dispersion for PSM studies with a Cronbach's coefficient of 0.95. Therefore, there is good diagnostic accuracy as well as feasibility of home-based portable sleep studies in Indian patients. It can be promoted for widespread use in high burden countries like India for diagnosing and managing appropriately selected stable patients with high clinical probability of OSA, especially during the ongoing crises of COVID-19 pandemic.

Toward standardizing the clinical testing protocols of point-of-care devices for obstructive sleep apnea diagnosis

PURPOSE

In recent years, point-of-care (POC) devices, especially smart wearables, have been introduced to provide a cost-effective, comfortable, and accessible alternative to polysomnography (PSG)-the current gold standard-for the monitoring, screening, and diagnosis of obstructive sleep apnea (OSA). Thorough validation and human subject testing are essential steps in the translation of these device technologies to the market. However, every device development group tests their device in their own way. No standard guidelines exist for assessing the performance of these POC devices. The purpose of this paper is to critically distill the key aspects of the various protocols reported in the literature and present a protocol that unifies the best practices for testing wearable and other POC devices for OSA.

METHODS

A limited review and graphical descriptive analytics of literature-including journal articles, web sources, and clinical manuscripts by authoritative agencies in sleep medicine-are performed to glean the testing and validation methods employed for POC devices, specifically for OSA.

RESULTS

The analysis suggests that the extent of heterogeneity of the demographics, the performance metrics, subject survey, hypotheses, and statistical analyses need to be carefully considered in a systematic protocol for testing POC devices for OSA.

CONCLUSION

We provide a systematic method and list specific recommendations to extensively assess various performance criteria for human subject testing of POC devices. A rating scale of 1-3 is provided to encourage studies to put a focus on addressing the key elements of a testing protocol.

Validity of the STOP-Bang Questionnaire in Identifying OSA in a Dental Patient Cohort

Background and objectives: Obstructive Sleep Apnea represents a widespread problem in the population, but it is often not diagnosed and not considered a true pathology. Different diagnostic tools are available for the diagnosis of sleep apnea. This study aims to demonstrate the ability of the STOP-Bang (Snoring, Tiredness, Observed apnea, high blood Pressure, Body mass index, Age, Neck circumference, and Gender) questionnaire in identifying subjects with Obstructive Sleep Apnea (OSA) Syndrome, highlighting the role of dentists as epidemiological sentinels. Materials and methods: the STOP-Bang questionnaire was administered to a cohort of 1000 patients, assessing three private dental clinics in Italy. Excessive daytime sleepiness was measured using Epworth Sleepiness Scale (ESS) and defined as ≥ 10. Subjects were considered at risk of OSA if they had three or more positive items at STOP-Bang and were invited to undergo further examination with a type 3 polygraph. Presence of OSA was measured with the apnea-hypopnea index (AHI) and defined as AHI ≥ 5. Results: 482/1000 subjects (48.2%) had three or more positive items in the STOP-Bang questionnaire and were considered at risk for Obstructive Sleep Apnea Syndrome (OSAS). Excessive daytime sleepiness (EDS ≥ 10) was more frequent among subjects at risk for OSAS (73/482, 15.1%) vs. those not at risk for OSAS (30/518, 5.8%) (p < 0.0001). Moreover, 153/482 subjects at risk for OSAS (31.7%) accepted further examination with a type 3 polygraph. Presence of OSAS (AHI ≥ 5) was suggested in 121/153 subjects (79.1%, 95% CI 71.6% to 85.1%), with 76/121 subjects (62.8%) needing treatment (AHI ≥ 15). Conclusion: the high prevalence of OSAS highlights the role of dentists as “epidemiological sentinels”. The STOP-Bang questionnaire is a simple and efficacious instrument for screening sleep apnea patients.

The effect of in-lab polysomnography and home sleep polygraphy on sleep position

PURPOSE

Little is known regarding the influence of in-laboratory polysomnography (PSG) equipment on sleep position, especially on the prevalence of supine positioning, which in many cases may lead to a more severe sleep apnea diagnosis. The aim of this study was to assess the percentage of supine sleep during an in-laboratory PSG compared to that seen during a home sleep apnea test (HSAT).

METHODS

This was a retrospective cohort study comparing in-laboratory PSG and HSAT using a peripheral arterial tone (PAT) technology device.

RESULTS

Of 445 PSG and 416 HSAT studies analyzed, there was no significant difference in the proportion of supine sleep time between PSG (44%) and HSAT (45%, p = 0.53). Analysis of the differences in sleep position (supine versus non-supine), analyzed by sex, BMI (≥ 30 kg/m2 versus < 30 kg/m2), and age (≥ 60 years versus < 60 years), was significant only for women, who had more supine sleep during HSAT at 61 ± 24% than during PSG at 45 ± 26% (p < 0.001).

CONCLUSION

Overall there was no difference in the percentage of supine sleep when comparing in-laboratory PSG to HSAT. However, women had more supine sleep with HSAT than with PSG.

Night-to-night fluctuations in sleep apnea severity: diagnostic and treatment implications

STUDY OBJECTIVES

Sleep apnea is a common disorder with serious consequences; however, effective treatments are available. Successful implementation of treatment strategies relies on accurate diagnosis, which may be hampered by the presence of substantial nightly fluctuation in sleep apnea severity. We examined the amount of nightly fluctuation in the severity of sleep apnea around commonly used diagnostic and treatment cut points in individuals who underwent two nights of home sleep apnea testing (HSAT).

METHODS

A nationwide retrospective cohort study of adults thought to have sleep apnea underwent two nights of HSAT between 2005 and 2017.

RESULTS

The study included 47,423 adults (mean age, 55.2 [14.6] years; 53.7% male). The average apnea-hypopnea index (AHI) for the sample was 26.9. The average amount of nightly fluctuation in AHI was 5.5. More than a third of the sample, 16,115 individuals, had fluctuations between diagnostic cut points across the two nights of HSAT. The negative predictive value of the HSAT in the first night was 47.42%, 73.57%, and 88.65% for detecting an AHI ≥ 5, AHI ≥ 15, and AHI ≥ 30, respectively.

CONCLUSIONS

The addition of a second night of HSAT has the potential to reduce the likelihood of missed diagnoses that could result from nightly fluctuation in the severity of sleep apnea.

A new office-based procedure for treatment of snoring: The S.I.Le.N.C.E. study

OBJECTIVE

Demonstrate the safety and effectiveness of palatal foreshortening and stiffening in reducing snoring severity in nonobstructive sleep apnea (non-OSA) patients complaining of chronic disruptive snoring.

METHODS

In a US-based 8-center, open-label, prospective, single-arm cohort study, 52 consenting adults with chronic disruptive snoring (snoring impacting a patient's life and causing patient or bed partner to seek medical intervention) were treated via office-based placement of resorbable, bidirectional, barbed suture implants into the soft palate under local anesthesia. Prior to intervention, home sleep tests (HSTs) were performed to rule out OSA and to document snoring noise level. Both subject and their bed/sleep partners (also consented) completed questionnaires including: bed/sleep partner's scored visual analog scale (VAS) for subjects' snoring severity, and subject scoring for Epworth Sleepiness Scale (ESS) and Pittsburgh Sleep Quality Index (PSQI). Following intervention, HSTs, VAS, ESS and PSQI were repeated at 30, 90 and 180 days.

RESULTS

Mean baseline bed/sleep partner VAS was 7.81 ± 1.59. Mean postimplant VAS scores decreased significantly at each measured interval; to 5.77±2.35 (P < .001) at 30 days, 4.48 ± 1.81 (P < .001) at 90 days, and 5.40 ± 2.28 (P < .001) at 180 days. Post treatment improvements in daytime sleepiness and QOL were also observed. Two partial extrusions were reported. No further adverse events were identified.

CONCLUSION

The current study demonstrates the safety and efficacy of the Elevoplasty procedure in reducing snoring severity over a follow-up period of 6 months.

LEVEL OF EVIDENCE

2b.

Devices for home detection of obstructive sleep apnea: A review

One of the most common sleep-related disorders is obstructive sleep apnea, characterized by a reduction of airflow while breathing during sleep and cause significant health problems. This disorder is mainly diagnosed in sleep labs with polysomnography, involving high costs and stress for the patient. To address this situation multiple systems have been proposed to conduct the examination and analysis in the patient's home, using sensors to detect physiological signals that are examined by algorithms. The objective of this research is to review publications that show the performance of different devices for ambulatory diagnosis of sleep apnea. Commercial systems that were examined by an independent research group and validated research projects were selected. In total 117 articles were analysed, including a total of 50 commercial devices. Each article was evaluated according to diagnostic elements, level of automatisation implemented and the deducted level of evidence and quality rating. Each device was categorized using the SCOPER categorization system, including an additional proposed category, and a final comparison was performed to determine the sensors that provided the best results.

Methodological strategies in using home sleep apnea testing in research and practice

PURPOSE

Home sleep apnea testing (HSAT) has increased due to improvements in technology, accessibility, and changes in third party reimbursement requirements. Research studies using HSAT have not consistently reported procedures and methodological challenges. This paper had two objectives: (1) summarize the literature on use of HSAT in research of adults and (2) identify methodological strategies to use in research and practice to standardize HSAT procedures and information.

METHODS

Search strategy included studies of participants undergoing sleep testing for OSA using HSAT. MEDLINE via PubMed, CINAHL, and Embase with the following search terms: "polysomnography," "home," "level III," "obstructive sleep apnea," and "out of center testing."

RESULTS

Research articles that met inclusion criteria (n = 34) inconsistently reported methods and methodological challenges in terms of: (a) participant sampling; (b) instrumentation issues; (c) clinical variables; (d) data processing; and (e) patient acceptability. Ten methodological strategies were identified for adoption when using HSAT in research and practice.

CONCLUSIONS

Future studies need to address the methodological challenges summarized in this paper as well as identify and report consistent HSAT procedures and information.

Validations of a Portable Home Sleep Study with Twelve-Lead Polysomnography: Comparisons and Insights into a Variable Gold Standard

Objectives:

Accurate and timely diagnosis for patients with obstructive sleep apnea (OSA) is imperative. Unfortunately, growing interest in this diagnosis has resulted in increased requests and waiting times for polysomnography (PSG), as well as a potential delay in diagnosis and treatment. This study evaluated the accuracy and viability of utilizing SNAP (SNAP Laboratories, LLC, Wheeling, Illinois), a portable home sleep test, as an alternative to traditional PSG in diagnosing OSA.

Methods:

This prospective clinical trial included 59 patients evaluated at our institution's sleep laboratory. Concurrent PSG and SNAP testing was performed for 1 night on each patient. Independent, blinded readers at our institution and at an outside-accredited institution read the PSG data, and 2 independent, blinded readers interpreted the SNAP data at SNAP laboratories. The apnea-hypopnea index (AHI) was used to compare the 2 testing modalities. The correlation coefficient, receiver operating characteristic curve analysis, and the Bland-Altman curves, as well as sensitivity, specificity, inter-reader variability, positive predictive value, and negative predictive value, were used to compare SNAP and PSG.

Results:

There is a definitive, statistically sound correlation between the AHIs determined from both PSG and SNAP. This relationship holds true for all measures of comparison, while displaying a concerning, weaker correlation between the different PSG interpretations.

Conclusions:

There is a convincing correlation between the study-determined AHIs of both PSG and SNAP. This finding supports SNAP as a suitable alternative to PSG in identifying OSA, while accentuating the inherent variation present in a PSG-derived AHI. This test expands the diagnostic and therapeutic prowess of the practicing otolaryngologist by offering an alternative OSA testing modality that is associated with not only less expense, decreased waiting time, and increased convenience, but also statistically proven accuracy.

Utility of portable monitoring in the diagnosis of obstructive sleep apnea

Obstructive sleep apnea (OSA) is a common but underdiagnosed sleep disorder, which is associated with systemic consequences such as hypertension, stroke, metabolic syndrome, and ischemic heart disease. Nocturnal laboratory-based polysomnography (PSG) is the gold standard test for diagnosis of OSA. PSG consists of a simultaneous recording of multiple physiologic parameters related to sleep and wakefulness including electroencephalography (EEG), electrooculography (EOG), surface electromyography (EMG), airflow measurement using thermistor and nasal pressure transducer, pulse oximetry and respiratory effort (thoracic and abdominal). Multiple alternative and simpler methods that record respiratory parameters alone for diagnosing OSA have been developed in the past two decades. These devices are called portable monitors (PMs) and enable performing sleep studies at a lower cost with shorter waiting times. It has been observed and reported that comprehensive sleep evaluation coupled with the use of PMs can fulfill the unmet need for diagnostic testing in various out-of-hospital settings in patients with suspected OSA. This article reviews the available medical literature on PMs in order to justify the utility of PMs in the diagnosis of OSA, especially in resource-poor, high-disease burden settings. The published practice parameters for the use of these devices have also been reviewed with respect to their relevance in the Indian setting.

An Economic Evaluation of Home Versus Laboratory-Based Diagnosis of Obstructive Sleep Apnea

STUDY OBJECTIVES

We conducted an economic analysis of the HomePAP study, a multicenter randomized clinical trial that compared home-based versus laboratory-based testing for the diagnosis and management of obstructive sleep apnea (OSA).

DESIGN

A cost-minimization analysis from the payer and provider perspectives was performed, given that 3-mo clinical outcomes were equivalent.

SETTING

Seven academic sleep centers.

PARTICIPANTS

There were 373 subjects at high risk for moderate to severe OSA.

INTERVENTIONS

Subjects were randomized to either home-based limited channel portable monitoring followed by unattended autotitration with continuous positive airway pressure (CPAP), versus a traditional pathway of in-laboratory sleep study and CPAP titration.

MEASUREMENTS AND RESULTS

From the payer perspective, per subject costs for the laboratory-based pathway were $1,840 (95% confidence interval [CI] $1,660, $2,015) compared to $1,575 (95% CI $1,439, $1,716) for the home-based pathway under the base case. Costs were $264 (95% CI $39, $496, P = 0.02) in favor of the home arm. From the provider perspective, per subject costs for the laboratory arm were $1,697 (95% CI $1,566, $1,826) compared to $1,736 (95% CI $1,621, $1,857) in the home arm, for a difference of $40 (95% CI -$213, $142, P = 0.66) in favor of the laboratory arm under the base case. The provider operating margin was $142 (95% CI $85, $202,P < 0.01) in the laboratory arm, compared to a loss of -$161 (95% CI -$202, -$120, P < 0.01) in the home arm.

CONCLUSIONS

For payers, a home-based diagnostic pathway for obstructive sleep apnea with robust patient support incurs fewer costs than a laboratory-based pathway. For providers, costs are comparable if not higher, resulting in a negative operating margin.

CLINICALTRIALSGOV IDENTIFIER

NCT00642486.

An anatomically based analysis of objectively measured pediatric snoring: a pilot study

OBJECTIVE

To assess pediatric habitual snoring (PS) using home sleep test (HST) technology and attempt to correlate the objective components of PS to specific upper airway anatomy. In addition, the effects of adenotonsillectomy (±turbinoplasty) on objective measures of PS were evaluated.

STUDY DESIGN

Prospective cohort study.

SETTING

Tertiary medical center.

SUBJECTS AND METHODS

Pediatric patients with a chief complaint of snoring and probable obstructive sleep apnea underwent an HST (SNAP Diagnostics, Wheeling, Illinois) with a detailed acoustical snoring analysis prior to adenotonsillectomy (±turbinoplasty). During surgery, detailed anatomical measurements were performed and correlated to snoring analysis results. After surgery, patients were offered another HST with snoring analysis. Data analysis was performed using descriptive statistics and statistical correlation with attention to the multiple-comparisons paradox.

RESULTS

Twenty-two patients (45% male; mean age, 5.4 years [range, 2.4-8.4 years]) completed the preoperative HST and operative measurements. Unlike typical adult snoring, only a minority of PS was from palatal flutter (mean palatal component, 24%; median, 10%). The resistance occurrence percentage (ROP, percentage of breathing events with snoring noise) was associated with body mass index (BMI; Spearman ρ=0.55; P=.017), subjective turbinate size (0.54; P=.032), palatal obstruction (0.63; P=.008), and mean oxygen saturation (-0.729; P=.0003) but not adenotonsillar hypertrophy. Twelve patients (54%) completed a postoperative HST. The ROP was significantly reduced (median, 20.5% vs 6.5%; P=.006, sign rank test) postoperatively. The magnitude of the ROP reduction was proportional to the volume of the removed tonsils (0.74; P=.022).

CONCLUSION

Pediatric snoring has different acoustical characteristics than adult snoring. Objective PS is associated with BMI, turbinate size, and palatal obstruction. Adenotonsillectomy (±turbinoplasty) may significantly reduce objective PS.

Diagnostic accuracy of level 3 portable sleep tests versus level 1 polysomnography for sleep-disordered breathing: a systematic review and meta-analysis

BACKGROUND

Greater awareness of sleep-disordered breathing and rising obesity rates have fueled demand for sleep studies. Sleep testing using level 3 portable devices may expedite diagnosis and reduce the costs associated with level 1 in-laboratory polysomnography. We sought to assess the diagnostic accuracy of level 3 testing compared with level 1 testing and to identify the appropriate patient population for each test.

METHODS

We conducted a systematic review and meta-analysis of comparative studies of level 3 versus level 1 sleep tests in adults with suspected sleep-disordered breathing. We searched 3 research databases and grey literature sources for studies that reported on diagnostic accuracy parameters or disease management after diagnosis. Two reviewers screened the search results, selected potentially relevant studies and extracted data. We used a bivariate mixed-effects binary regression model to estimate summary diagnostic accuracy parameters.

RESULTS

We included 59 studies involving a total of 5026 evaluable patients (mostly patients suspected of having obstructive sleep apnea). Of these, 19 studies were included in the meta-analysis. The estimated area under the receiver operating characteristics curve was high, ranging between 0.85 and 0.99 across different levels of disease severity. Summary sensitivity ranged between 0.79 and 0.97, and summary specificity ranged between 0.60 and 0.93 across different apnea-hypopnea cut-offs. We saw no significant difference in the clinical management parameters between patients who underwent either test to receive their diagnosis.

INTERPRETATION

Level 3 portable devices showed good diagnostic performance compared with level 1 sleep tests in adult patients with a high pretest probability of moderate to severe obstructive sleep apnea and no unstable comorbidities. For patients suspected of having other types of sleep-disordered breathing or sleep disorders not related to breathing, level 1 testing remains the reference standard.

A review of signals used in sleep analysis

This article presents a review of signals used for measuring physiology and activity during sleep and techniques for extracting information from these signals. We examine both clinical needs and biomedical signal processing approaches across a range of sensor types. Issues with recording and analysing the signals are discussed, together with their applicability to various clinical disorders. Both univariate and data fusion (exploiting the diverse characteristics of the primary recorded signals) approaches are discussed, together with a comparison of automated methods for analysing sleep.

Screening for obstructive sleep apnoea in obesity and diabetes--potential for future approaches

BACKGROUND

It is recognised that sleep-disordered breathing (SDB), in particular, obstructive sleep apnoea (OSA) is associated with obesity and diabetes. The complications of OSA include dysregulation of metabolic and cardiovascular homeostasis. With the growing population of diabetes and obesity globally, it is becoming apparent that identifying and screening patients who are at risk is becoming increasingly crucial. Many patients may remain unaware of the potential diagnosis and continue to be undiagnosed. The high prevalence of OSA poses a demanding challenge to healthcare providers in order to provide sufficient resources and facilities for patient diagnosis and treatment.

DESIGN

In this article, we review the evidence in favour of screening populations deemed to be at increased risk of OSA, with particular reference to patients with obesity and diabetes. We consider the recent advances in potential screening methods that may allow new prognostic and predictive tools to be developed. A detailed search of Medline and Web of Science electronic databases for relevant articles in English was performed.

RESULTS

Apart from the use of screening tools such as questionnaires and clinical decision models, there is increasing evidence to suggest that there are differences in biological parameters in patients with OSA. Although further studies are required, there may be potential for such biomarkers to contribute to and augment the screening process. However, the significance of such biological tools remains to be elucidated.

CONCLUSIONS

A fundamental role for improved screening in patients with conditions such as obesity and diabetes can enable early interventions that may improve health outcomes relating to the adverse consequences of OSA. The future will see further research being carried out in the development of potential screening methods with emphasis on the selection of patients at risk of sleep disorders, thereby allowing more detailed physiological studies to be carried out where needed.

Home sleep study characteristics in patients with mucopolysaccharidosis

BACKGROUND

Mucopolysaccharidoses (MPS) are a group of inherited lysosomal storage disorders caused by the deficiency of hydrolases involved in the degradative pathway of glycosaminoglycans. In MPS, upper airway obstruction may result from multiple causative factors which may impact severely upon morbidity and mortality.

METHODS

We evaluated upper airway obstructive disease and related clinical findings through home sleep study in 19 patients (11 with MPS VI, 4 with MPS I, 4 with MPS II) with MPS followed at Gazi University Pediatric Metabolic Unit. Patients underwent home-based sleep measurements, and sleep respiratory problems were asked in a detailed clinical history. Measurements of apnea, apnea-hypopnea index (AHI), hypopnea index, oxygen desaturation index, and minimal oxygen saturation were obtained through home sleep study.

RESULTS

For 19 children, the disorder was normal in 1, mild (AHI=1.5-5/h) in 5, moderate (AHI=5-10/h) in 2, and severe (AHI>10/h) in 11. The prevalence of OSA was 94.7 % (18/19) in patients with MPS. Snoring, witnessed apnea, pectus carinatum, and macroglossia were the main clinical findings. Echocardiograms showed evidence of pulmonary hypertension in 13 patients.

CONCLUSION

Home sleep study is a quick and accessible screening test to determine the abnormalities of breathing during sleep and enables clinicians to take necessary action for patients with severe manifestations.

All-Cause Mortality and Obstructive Sleep Apnea Severity Revisited

Objective

Obstructive sleep apnea syndrome (OSAS) is a pervasive problem that affects millions worldwide. It is strongly linked to hypertension, coronary artery disease, and stroke. However, its association with mortality is not clearly quantified. A large database of patients who underwent sleep testing was explored for associations with all-cause mortality.

Study Design

Database study.

Setting

Community-based use of a portable sleep study device.

Subjects and Methods

More than 77,000 patients who underwent a validated, portable sleep study were matched to the Social Security Death File to establish mortality. Measures of OSAS severity and other confounding factors were correlated to all-cause mortality using survival analysis with multivariate Cox proportional hazards regression.

Results

As expected, increasing age (adjusted hazard ratio [HR], 1.080; 95% confidence interval [CI], 1.074-1.086; P < .0001), body mass index (HR, 1.042; 95% CI, 1.033-1.051; P < .0001), and male sex (HR, 1.378; 95% CI, 1.190-1.595; P < .001) were associated with increased all-cause mortality. Epworth sleepiness score was also associated with mortality (HR, 1.015; 95% CI, 1.005-1.025; P = .002). Apnea-hypopnea index (AHI) was not associated with mortality after adjustment for age (HR, 1.001; 95% CI, 0.998-1.004; P = .416). However, within 10-year age subgroups, desaturation index (ages 41-50 years; adjusted HR, 1.217; 95% CI, 1.014-1.461; P = .035), apnea index (ages 21-30 years; HR, 1.632; 95% CI, 1.053-2.532; P = .028), and AHI (ages 31-40 years; HR, 1.222; 95% CI, 1.010-1.478; P = .039) were significantly associated with all-cause mortality in younger patients. In patients older than 50 years, age, sex, and body mass index were dominantly associated with mortality.

Conclusion

Increasing OSAS severity, measured by a validated home sleep test and quantified by AHI, the apnea index, and the desaturation index, is independently associated with modestly increased all-cause mortality in patients younger than 50 years after adjustment for major confounding factors.

Obstructive sleep apnea devices for out-of-center (OOC) testing: technology evaluation

Guidance is needed to help clinicians decide which out-of-center (OOC) testing devices are appropriate for diagnosing obstructive sleep apnea (OSA). A new classification system that details the type of signals measured by these devices is presented. This proposed system categorizes OOC devices based on measurements of Sleep, Cardiovascular, Oximetry, Position, Effort, and Respiratory (SCOPER) parameters.Criteria for evaluating the devices are also presented, which were generated from chosen pre-test and post-test probabilities. These criteria state that in patients with a high pretest probability of having OSA, the OOC testing device has a positive likelihood ratio (LR+) of 5 or greater coinciding with an in-lab-polysomnography (PSG)-generated apnea hypopnea index (AHI) ≥ 5, and an adequate sensitivity (at least 0.825).Since oximetry is a mandatory signal for scoring AHI using PSG, devices that do not incorporate oximetry were excluded. English peer-reviewed literature on FDA-approved devices utilizing more than 1 signal was reviewed according to the above criteria for 6 questions. These questions specifically addressed the adequacy of different respiratory and effort sensors and combinations thereof to diagnose OSA. In summary, the literature is currently inadequate to state with confidence that a thermistor alone without any effort sensor is adequate to diagnose OSA; if a thermal sensing device is used as the only measure of respiration, 2 effort belts are required as part of the montage and piezoelectric belts are acceptable in this context; nasal pressure can be an adequate measurement of respiration with no effort measure with the caveat that this may be device specific; nasal pressure may be used in combination with either 2 piezoelectric or respiratory inductance plethysmographic (RIP) belts (but not 1 piezoelectric belt); and there is insufficient evidence to state that both nasal pressure and thermistor are required to adequately diagnose OSA. With respect to alternative devices for diagnosing OSA, the data indicate that peripheral arterial tonometry (PAT) devices are adequate for the proposed use; the device based on cardiac signals shows promise, but more study is required as it has not been tested in the home setting; for the device based on end-tidal CO(2) (ETCO(2)), it appears to be adequate for a hospital population; and for devices utilizing acoustic signals, the data are insufficient to determine whether the use of acoustic signals with other signals as a substitute for airflow is adequate to diagnose OSA.Standardized research is needed on OOC devices that report LR+ at the appropriate AHI (≥ 5) and scored according to the recommended definitions, while using appropriate research reporting and methodology to minimize bias.

Sources of variability in epidemiological studies of sleep using repeated nights of in-home polysomnography: SWAN Sleep Study

STUDY OBJECTIVE

To quantify sources of night-to-night variability.

METHODS

This project was conducted in 285 middle-aged African American, Caucasian, and Chinese women from the Study of Women's Health Across the Nation (SWAN) Sleep Study living in Chicago, the Detroit area, Oakland, and Pittsburgh. The study used 3 repeated nights of in-home polysomnography (PSG) measures. Night 1 data included assessment of sleep staging, sleep apnea, and periodic limb movements, while Nights 2 and 3 focused on sleep staging.

RESULTS

Mean total sleep time (TST) increased substantially from 365 minutes on Night 1 to 391 minutes and 380 minutes, respectively, on Nights 2 and 3. Mean percent sleep efficiency (SE%) for the 3 nights were 83%, 85%, and 85%, respectively. Night 1 sleep values were significantly different than Nights 2 and 3 measures except for S2 (%), S1 (min), and Delta (S3+4)%. Nights 2 and 3 differences in variability were negligible. Obesity, past smoking, and financial strain measures were associated with greater Night 1 vs. Night 2 or Night 3 differences. We concluded that there was significant Night 1 vs. Nights 2 and 3 variability and, though relatively modest, it was sufficient to bias estimates of association. Additionally, personal characteristics including smoking, obesity, and financial strain increased night-to-night variability.

CONCLUSIONS

This reports adds new information about between and within person sources of variation with in-home PSG and identifies elements that are essential in the design and planning of future sleep studies of multi-ethnic groups in social and physiological transition states such as the menopause.

An epidemiologic study of snoring and all-cause mortality

OBJECTIVE

Snoring is a common problem that is often associated with obstructive sleep apnea syndrome (OSAS). However, it is suggested that snoring may itself be harmful. Patients with objectively measured snoring were matched against a mortality database and associations were explored.

STUDY DESIGN

Database study.

SETTING

Community-based use of a portable sleep study device.

SUBJECTS AND METHODS

More than 77,000 patients who underwent a portable sleep study (SNAP Test, SNAP Labs Inc, Wheeling, Illinois) with a detailed, acoustical snoring analysis were matched to the Social Security Death Master File to establish mortality (1653 deaths matched). Snoring indices to include amount (snoring events per hour), volume (dB), and palatal versus nonpalatal snoring were correlated to mortality using stepwise multivariate logistic regression and survival analysis.

RESULTS

As expected, increasing age (odds ratio [OR] = 1.84; 95% confidence interval [CI], 1.76-1.93; P < .001), body mass index (BMI) (OR = 1.23; 95% CI, 1.18-1.28; P < .001), and male sex (OR = 1.38; 95% CI, 1.2-1.56; P < .001) were associated with increased all-cause mortality. The presence of increasing OSAS confounded the relationship between snoring and mortality. For patients without OSAS (apnea–hypopnea index [AHI] < 5) and with a BMI < 30 (n = 5955), increasing snoring was associated with an age- and sex-adjusted increase in mortality (OR = 1.16; 95% CI, 1.01-1.32; P = .034). For all patients, increasing nonpalatal snoring was associated with an increase in mortality (OR = 1.21; 95% CI, 1.09-1.35; P < .001) after adjustment for age, sex, BMI, and AHI. Survival analysis produced identical results to logistic regression.

CONCLUSION

In patients without OSAS and with a BMI less than 30, increasing snoring was associated with a significant increase in all-cause mortality. Nonpalatal snoring is associated with an increase in observed all-cause mortality controlling for age, sex, BMI, and AHI.

Therapeutic decision-making for sleep apnea and hypopnea syndrome using home respiratory polygraphy: a large multicentric study

RATIONALE

Home respiratory polygraphy (HRP) is an alternative to polysomnography (PSG) for sleep apnea-hypopnea syndrome (SAHS) diagnosis. However, therapeutic decision-making is a different process than diagnosis.

OBJECTIVES

This study aimed to determine the agreement between HRP and in-hospital PSG for therapeutic decision-making in a large sample.

METHODS

Patients with an intermediate or high SAHS suspicion were included in a multicenter study (eight sleep centers) and assigned to home and hospital protocols in a random order. Therapeutic decisions (continuous positive airway pressure, no continuous positive airway pressure, or impossible decision) were made by an investigator in each center, based on using either HRP or PSG and a single set of auxiliary clinical variables. Patients and diagnostic methods (HRP and PSG) were assessed in random order using an electronic database. After a month the same therapeutic decision-making procedure was repeated with the same method.

MEASUREMENTS AND MAIN RESULTS

Of 366 randomized patients, 348 completed the protocol. The "impossible decision" case was not observed with either PSG or HRP. Therapeutic decisions using HRP had a sensitivity of 73%, a specificity of 77%, and an agreement level (sum of true positives and negatives) of 76%. Patients with higher HRP apnea-hypopnea index (AHI) scores (≥ 30; 41% of the total sample) had a sensitivity of 94%, a specificity of 44%, and the agreement level was 91%.

CONCLUSIONS

The HRP-based therapeutic decision was adequate when AHI was high, but deficient in the large population of patients with mild to moderate AHI. Therefore, both selecting patients with a high suspicion and severity of SAHS and future prospective cost-effectiveness studies are necessary.

Effects of mandibular retropositioning, with or without maxillary advancement, on the oro-naso-pharyngeal airway and development of sleep-related breathing disorders

PURPOSE

Literature suggests that patients without pre-existing sleep-related breathing disorders who undergo orthognathic surgery for treatment of facial asymmetry may experience changes in their oropharyngeal airway. Mandibular retropositioning can compromise the posterior airway space, alter the physiologic airflow through the upper airway, and predispose patients to development of obstructive sleep apnea syndrome (OSAS).

PATIENTS AND METHODS

This study was a retrospective cohort analysis of 26 patients who underwent mandibular retropositioning with or without maxillary advancement within the past 5 years at Tufts University School of Dental Medicine. Pre- and postoperative lateral cephalometric radiographs were analyzed with digital DOLPHIN software (Dolphin Imaging, Chatsworth, CA) for evidence of changes to the posterior airway dimension. In addition, patients were evaluated postoperatively with SNAP polysomnography (model 4/6; SNAP Laboratories, Wheeling, IL) for evidence of OSAS.

RESULTS

Results indicated that mandibular retropositioning greater than or equal to 5 mm decreased the posterior airway space below 11 mm (30.75%, P = .03) and showed evidence of soft palate elongation greater than 32 mm (15.39%, P = .037) in a significant number of patients. However, as determined by cephalometric analysis, mandibular retropositioning greater than or equal to 5 mm in combination with maxillary advancement had no significant effect on the posterior airway space or soft palate.

CONCLUSION

Postoperative SNAP polysomnography showed higher incidence of mild to moderate OSAS in patients who underwent mandibular retropositioning greater than or equal to 5 mm (69.25%) compared with patients who underwent mandibular retropositioning in combination with maxillary advancement (38.46%, P = .039).

Cheyne-Stokes respiration in heart failure: cycle length is dependent on left ventricular ejection fraction

BACKGROUND

Cheyne-Stokes respiration (CSR) is common in patients with congestive heart failure (CHF) and is associated with poor prognosis. The aim of this study was to analyse the characteristics of CSR in patients with varying degrees of impaired left ventricular ejection fraction (LVEF).

METHODS

A total of 104 patients with CSR (apnea-hypopnea index [AHI]15/h) and exertional dyspnea were divided into FIVE groups according to their LVEF (<20% upto 50%). A subgroup of 22 patients was studied twice: 15 in whom LVEF improved between studies and 7 in whom LVEF deteriorated. Using cardiorespiratory polygraphy recordings, cycle length (CL), apnea length (AL), ventilation length (VL), time to peak ventilation (TTPV), circulatory delay (CD) and VL:AL ratio were determined.

RESULTS

There was no relationship between AHI and impairment of LVEF, but the characteristics of CSR were related to LV function. Comparing the groups with the best LVEF (>50%) and the worst LVEF (<20%), there were significant increases in CL (49+/-17-86+/-23s), AL (21+/-9-31+/-10s), VL (28+/-10-55+/-17s), TTPV (19+/-5-32+/-11s), VL:AL ratio (1.5+/-0.4-1.9+/-0.7s) and CD (29+/-8-49+/-16s). In the subgroup of patients who were studied twice, improvement in EF was associated with a decrease in these parameters.

CONCLUSION

The current classification of CSR in CHF patients using AHI may be overly simplistic. Parameters such as CL, VL, TTPV and CD are related to cardiac function and could potentially be used for disease monitoring.

A disquisition on sleep-disordered breathing in children

Sleep-disordered breathing (SDB) is a continuum of breathing abnormalities that affects children and adults. This disorder has been continuously evolving, particularly in children, with new insights in its pathogenesis, clinical manifestations, diagnosis, treatments, and outcomes. The purpose of this review is to provide a current framework for pediatric anesthesiologists to address the perioperative needs of these children to ensure their safe conduct through anesthesia.

Low night-to-night variability of sleep disordered breathing in patients with stable congestive heart failure

Sleep disordered breathing (SDB) has a high prevalence and prognostic impact in patients with chronic heart failure (CHF). Aim of this study was to investigate variability of SDB parameters in patients with stable CHF. Cardiorespiratory polygraphy was used to determine SDB in two consecutive nights in 50 CHF patients (NYHA class > or = II, LV-EF < or = 40%). The apnea-hypopnea-index (AHI) and apnoea-index (AI) were used to quantify SDB severity. Central, obstructive or mixed SDB were classified according to the majority of events. There was an excellent correlation in AHI (r = 0.948, P < 0.001) and AI (r = 0.842, P < 0.001) results of both nights. The overall number of detected apnea and hypopnea during the first night as compared to the maximum of both nights was 85% for the AHI and 77% for the AI. The reproducibility was dependent on SDB severity: AHI 15-29/h = 87%, AHI > or = 30/h = 92% and AI > or = 10/h = 83%. Classification was identical in 17 out of 19 patients with AI > or = 10/h. In patients with stable CHF a single night of cardiorespiratory monitoring leads to representative results on severity and type of SDB. This may enhance the applicability and dissemination of cardiorespiratory polygraphy in clinical practice.

Home Sleep Testing in the Diagnosis and Treatment of Sleep Disordered Breathing

Sleep-disordered breathing is a growing public health concern and an integral part of head and neck surgery. Multichannel home sleep testing is a cost-effective, patient-friendly, scientifically valid technique of evaluating patients who present with symptoms of sleep-disordered breathing, typically snoring or daytime sleepiness. Home sleep tests can be dispensed from the physician's office. They have a 95% successful recording rate. Scoring can be autoscore or manual score. There are several protocols that can be followed based on diagnostic outcomes.

Does an oral appliance reduce palatal flutter and tongue base snoring?

OBJECTIVES

Oral appliances are designed to treat snoring and sleep apnea by advancing the mandible and tongue. We test the hypothesis that an oral appliance affects palatal snoring as well as tongue base obstruction.

METHODS

Prospective observational cohort study. Sixty patients with a chief complaint of snoring with or without apnea were enrolled. Each patient underwent a home sleep test followed by 3 weeks sleeping with an oral appliance. Each patient then underwent a repeat home sleep test while using the device.

RESULTS

There was a statistically significant improvement in the snores per hour (P = 0.0005), the maximum snoring loudness (P = 0.0001), average snoring loudness (P = 0.00001), and the percentage of palatal snoring (P = 0.0007). There was also a significant decrease in oxygen desaturation events (P = 0.003).

CONCLUSIONS

This study suggests oral appliances may be effective treatment for both palatal and tongue base snoring.

Acoustical analysis of pediatric snoring: what can we learn?

OBJECTIVE

Evaluate a database of pediatric patients who underwent snoring acoustical analysis for associations between snoring measurements, demographics, and obstructive sleep apnea/hypopnea syndrome (OSAHS) severity.

STUDY DESIGN AND SETTING

A database of pediatric patients who underwent home testing with a polysomnogram device (SNAP Test, Glenview, IL) that includes acoustical snoring analysis was reviewed.

RESULTS

Four hundred fifty-six patients were included (mean age, 6.87 years). Four hundred twenty-nine (94.1%) patients had measurable snoring. Snoring index (events/hr) (r = 0.2073; P < 0.0001) and maximal loudness (dB) (r = 0.2218; P < 0.0001) were directly proportional to the apnea/hypopnea index. Among patients without OSAHS (apnea index <1), increasing snoring index (r = -0.2102; P < 0.0001) and volume (P < 0.005 ANOVA) were associated with increasing oximetry desaturation events.

CONCLUSION

The majority of children evaluated had objective snoring. Increasing snoring index and loudness are associated with increased severity of OSAHS. In the absence of OSAHS, increasing snoring is associated with oxygen desaturations.

SIGNIFICANCE

Pediatric snoring is objectively related to OSAHS severity.

Respiratory polygraphy with actigraphy in the diagnosis of sleep apnea-hypopnea syndrome

OBJECTIVE

To determine the utility and reliability of a respiratory polygraphy (RP) device with actigraphy (Apnoescreen II; Erich Jaeger GMBH & CoKg; Wuerzburg, Germany) in the diagnosis of sleep apnea-hypopnea syndrome (SAHS).

DESIGN

A prospective randomized study with blinded analysis.

PATIENTS

Sixty-two patients with suspected SAHS.

MEASUREMENTS

the following two RP studies were performed: one in the sleep laboratory (sleep laboratory RP [LRP]), simultaneously with polysomnography; and the other at home (home RP [HRP]). To study the interobserver reliability of RP, two manual analyses were carried out by two different researchers.

RESULTS

In LRP, when the respiratory disturbance index was calculated using the total sleep time estimated by actigraphy (RDI) as a denominator, the sensitivity ranged between 94.6% and 100%, and the specificity between 88% and 96.7% for the different cutoff points of the apnea-hypopnea indexes studied. When the respiratory disturbance index was calculated according to the total recording time (RDITRT), the sensitivity was slightly lower (91.6 to 96.9%) and the specificity was similar (92 to 96.7%). In HRP, the sensitivity of the RDI ranged between 83.8% and 95.8%, and the specificity between 92% and 100%, whereas, when the RDITRT was used, the sensitivity was between 83.8% and 87.5%, and the specificity was between 94.7% and 100%. With regard to interobserver reliability, the intraclass correlation coefficient for the RDI of the two analyses of the RP was 0.99 for both LPR and HPR.

CONCLUSION

HPR is an effective and reliable technique for the diagnosis of SAHS, although it is less sensitive than LRP. Wrist actigraphy improves the results of HRP only slightly.

Laboratory versus portable sleep studies: a meta-analysis

OBJECTIVE

The objective of this meta-analysis study was to compare the accuracy of home sleep studies with laboratory polysomnography in the diagnosis of obstructive sleep apnea (OSA).

METHODS

Eligible studies included prospective cohort studies of portable and in-laboratory sleep studies performed on the same groups of patients. A comparison of respiratory disturbance index (RDI), mean low oxygen saturation levels, sleep time, rate of inadequate studies, and average cost per examination was made between portable and in-laboratory sleep studies. A total of 18 papers were identified in two independent Medline searches.

RESULTS

RDI values on portable sleep studies were 10% lower on average compared with laboratory studies (odds ratio [OR], 0.90; 95% confidence interval [CI], 0.87-0.92). There was no significant difference in the mean low oxygen saturation on portable versus laboratory studies (OR, 1.0; 95% CI, 0.94-1.10). Recorded sleep time was significantly higher by 13% for laboratory compared with portable studies (OR, 0.87; 95% CI, 0.86-0.89), and portable studies were significantly more likely to give a poor recording when compared with laboratory examinations (P = .0001). The cost of home studies ranged from 35% to 88% lower than laboratory studies across a number of countries.

CONCLUSION

Home sleep studies provide similar diagnostic information to laboratory polysomnograms in the evaluation of sleep-disordered breathing but may underestimate sleep apnea severity. The lower cost of home sleep studies makes it a viable screening tool for patients with suspected OSA; however, these lower costs are partially offset by the higher rate of inadequate examinations.

Screening for obstructive sleep apnea: an evidence-based analysis

Sleep disordered breathing is a spectrum of diseases that includes snoring, upper airway resistance syndrome, and obstructive sleep apnea (OSA). Obstructive sleep apnea is a common sleep disorder and is estimated to have an incidence of 24% in men and 9% in women. However, many authors believe that up to 93% of women and 82% of men with moderate to severe OSA remain undiagnosed. There is a strong link between sleep disordered breathing and hypertension, believed to be due to sleep fragmentation, intermittent hypoxemia, and increased sympathetic tone, which results in a higher mortality and morbidity rate among these patients. It is therefore desirable to attempt to diagnose all patients with OSA, to institute early treatment intervention, and to prevent development of cardiovascular complications. The gold standard for diagnosing OSA remains the attended overnight level I polysomnogram. However, in view of the limited resources, including limited number of recording beds, high cost, long waiting lists, and labor requirements, many authors have explored the use of clinical predictors or questionnaires that may help to identify higher-risk patients. Screening devices in the form of single or multiple channel monitoring systems have also been introduced and may represent an alternative method to diagnose OSA. The ideal screening device should be cheap, readily accessible, easily used with minimal instructions, have no risk or side effects to the patient, and be safe and accurate. We review a variety of clinical predictive formulae and several screening devices available for the diagnosis of OSA.