STATISTICAL METHODS FOR ASSESSING AGREEMENT BETWEEN TWO METHODS OF CLINICAL MEASUREMENT Increased prevalence of sleep-disordered breathing in adults. Home-based diagnosis of obstructive sleep apnea in an urban population. Assessment of sleep-disordered breathing using a non-contact bio-motion sensor. Novel mathematical processing method of nocturnal oximetry for screening patients with suspected sleep apnoea syndrome The accuracy and uncertainty of a sheet-type portable monitor as a screening device to identify obstructive sleep apnea-hypopnea syndrome. Comparison between a single-channel nasal airflow device and oximetry for the diagnosis of obstructive sleep apnea. Diagnosis of obstructive sleep apnea using pulse oximeter derived photoplethysmographic signals. Validation of an automated algorithm for detecting apneas and hypopneas by acoustic analysis of breath sounds.
In clinical measurement comparison of a new measurement technique with an established one is often needed to see whether they agree sufficiently for the new to replace the old . Such investigations are often analysed inappropriately , notably by using correlation coefficients . The use of correlation is misleading . An alternative approach , based on graphical techniques and simple calculations , is described , together with the relation between this analysis and the assessment of repeatability Sleep-disordered breathing is a common disorder with a range of harmful sequelae . Obesity is a strong causal factor for sleep-disordered breathing , and because of the ongoing obesity epidemic , previous estimates of sleep-disordered breathing prevalence require updating . We estimated the prevalence of sleep-disordered breathing in the United States for the periods of 1988 - 1994 and 2007 - 2010 using data from the Wisconsin Sleep Cohort Study , an ongoing community-based study that was established in 1988 with participants r and omly selected from an employed population of Wisconsin adults . A total of 1,520 participants who were 30 - 70 years of age had baseline polysomnography studies to assess the presence of sleep-disordered breathing . Participants were invited for repeat studies at 4-year intervals . The prevalence of sleep-disordered breathing was modeled as a function of age , sex , and body mass index , and estimates were extrapolated to US body mass index distributions estimated using data from the National Health and Nutrition Examination Survey . The current prevalence estimates of moderate to severe sleep-disordered breathing ( apnea-hypopnea index , measured as events/hour , ≥15 ) are 10 % ( 95 % confidence interval ( CI ) : 7 , 12 ) among 30 - 49-year-old men ; 17 % ( 95 % CI : 15 , 21 ) among 50 - 70-year-old men ; 3 % ( 95 % CI : 2 , 4 ) among 30 - 49-year-old women ; and 9 % ( 95 % CI : 7 , 11 ) among 50 - 70 year-old women . These estimated prevalence rates represent substantial increases over the last 2 decades ( relative increases of between 14 % and 55 % depending on the subgroup ) STUDY OBJECTIVES Home-based diagnosis of obstructive sleep apnea ( OSA ) with portable monitoring ( PM ) is increasingly utilized , but remains understudied in underserved and minority population s. We tested the feasibility of home PM in an urban population at risk for OSA compared to in-laboratory polysomnography ( PSG ) and examined patient preference with respect to home PM versus PSG . METHODS R and omized crossover study of home PM ( WatchPAT200 ) and in-laboratory simultaneous PSG and PM in 75 urban African Americans with high pre-test probability of OSA , identified with the Berlin question naire . RESULTS Fifty-seven of 75 participants were women , average age 45 ± 11 years ( mean ± SD ) , 35 % with ≤ high school education , and 76 % with annual household income < $ 50,000 . Technical failure rates were 5.3 % for home vs. 3.1 % for in-laboratory PM . There was good agreement between apnea hypopnea index on PSG ; AHIPSG and AHI on home PM ( mean ± 2 SD of the differences = 0.64 ± 46.5 and intraclass correlation coefficient ; ICC = 0.73 ) . The areas under the curve for the receiver-operator characteristic curves for home PM were 0.90 for AHIPSG ≥ 5 , 0.95 for AHIPSG ≥ 10 , and 0.92 for AHIPSG ≥ 15 . 62/75 ( 82 % ) participants preferred home over in-laboratory testing . CONCLUSIONS Home PM for diagnosis of OSA in a high risk urban population is feasible , accurate , and preferred by patients . As home PM may improve access to care , the cost-effectiveness of this diagnostic strategy for OSA should be examined in underserved urban and rural population s. CLINICAL TRIALS REGISTRATION Clinical Trials.gov , identifier : NCT01997723 Obstructive sleep apnoea is a highly prevalent but under-diagnosed disorder . The gold st and ard for diagnosis of obstructive sleep apnoea is inpatient polysomnography . This is re source intensive and inconvenient for the patient , and the development of ambulatory diagnostic modalities has been identified as a key research priority . SleepMinder ( BiancaMed , NovaUCD , Irel and ) is a novel , non-contact , bedside sensor , which uses radio-waves to measure respiration and movement . Previous studies have shown it to be effective in measuring sleep and respiration . We sought to assess its utility in the diagnosis of obstructive sleep apnoea . SleepMinder and polysomnographic assessment of sleep-disordered breathing  were performed simultaneously on consecutive subjects recruited prospect ively from our sleep clinic . We assessed the diagnostic accuracy of SleepMinder in identifying  obstructive sleep apnoea  , and how SleepMinder assessment of the apnoea-hypopnoea index correlated with polysomnography .  Seventy-four subjects were recruited . The apnoea-hypopnoea index as measured by SleepMinder correlated strongly with polysomnographic measurement ( r = 0.90 ; P ≤ 0.0001 ) . When a diagnostic threshold of moderate-severe ( apnoea-hypopnoea index ≥15 events h(-1 ) ) obstructive sleep apnoea was used , SleepMinder displayed a sensitivity of 90 % , a specificity of 92 % and an accuracy of 91 % in the diagnosis of sleep-disordered breathing . The area under the curve for the receiver operator characteristic was 0.97 . SleepMinder  correctly classified obstructive sleep apnoea severity in the majority of cases , with only one case different from equivalent polysomnography by more than one diagnostic class . We conclude that in an unselected clinical population undergoing investigation for suspected obstructive sleep apnoea , SleepMinder measurement of sleep-disordered breathing correlates significantly with polysomnography Aim Polysomnography ( PSG ) is the current st and ard for diagnosing sleep apnea syndrome ( SAS ) . A reliable test would be useful to reduce the considerable re sources required for PSG . Methods We developed a new mathematical analysis , which quantifies amplitude variations of pulse oximetry ( SpO2 ) and heart rate ( HR ) throughout the night , allowing measurement of the total time in which ΔSpO2 > 4 % and presented as a new oximetric index ventilatory hypoxemic index ( VHI ) . VHI was compared prospect ively with st and ard PSG parameters apnea – hypopnea index ( AHI ) and oxygen desaturation index ( ODI )  in 106 patients ( aged , 57 ± 14 years ; BMI , 29 ± 5 kg/m2 ) suspected of having SAS . The criterion for diagnosis of SAS was AHI > 15/h of sleep during PSG . The relationship between ΔSpO2 and ΔΗR was also investigated . Results We observed a significant correlation between the AHI and VHI ( R = 0.87 , p < 0.0001 ) . Using VHI > 15 as the criterion for SpO2 , oximetry had a sensitivity of 81 % , specificity of 98 % , positive predictive value ( PPV ) of 98 % , and negative predictive value ( NPV ) of 84 % as a screening test for SAS . We also observed a clear linear relationship between ΔSpO2 and ΔΗR , and concomitant use of VHI and the ΔSpO2/ΔHR slope improved the NPV to 90 % . Conclusions The present findings from wavelet-aggregate processing of oximeter data and the relationship between ΔSpO2 and ΔΗR show promise as a useful summary prediction of screening SAS OBJECTIVE Laboratory-based polysomnography ( PSG ) is the gold st and ard for diagnosing obstructive sleep apnea-hypopnea syndrome ( OSAHS ) , but it is expensive and requires overnight hospitalization . Recently , a sheet-shaped breath detection monitor , the SD-101 , has been developed , and several reports have so far demonstrated the screening accuracy of this device . The aim of this study was to assess the accuracy and the uncertainty of this device . METHODS A total of 101 suspected OSAHS patients underwent simultaneous examinations with PSG and the SD-101 . RESULTS There was a statistically significant relationship between the respiratory disturbance index ( RDI ) by the SD-101 and the apnea-hypopnea index ( AHI ) by PSG . At an RDI cutoff of 14 episodes per hour , the sensitivity and specificity to detect an AHI ≥20 episodes per hour were 90.2 % and 90.0 % , respectively . To reduce the influence of sleep efficiency , the time in bed ( TIB ) obtained from PSG , instead of the total seep time ( TST ) , was used to calculate the AHI from the PSG data . There was also a statistically significant relationship between the RDI and AHI for the TIB . Moreover , it was suggested that arousal index and TIB were likely associated with false-negative and /or false-positive results . CONCLUSION Although the present study demonstrated a close relationship between the RDI and the AHI , use of the SD-101 to examine symptomatic OSAHS patients should be performed with a full underst and ing of its incapability to detect the sleep state , including arousal reaction and the existence of false respiratory events caused by body movements RATIONALE The most common single channel devices used for obstructive sleep apnea ( OSA ) screening are nasal airflow and oximetry . No studies have directly compared their role in diagnosing OSA at home . STUDY OBJECTIVES To prospect ively compare the diagnostic utility of home-based nasal airflow and oximetry to attended polysomnography ( PSG ) and to assess the diagnostic value of adding oximetry to nasal airflow for OSA . DESIGN Cross-sectional study . SETTING Laboratory and home . PARTICIPANTS Sleep clinic patients with suspected OSA . INTERVENTIONS All patients had laboratory PSG and 2 sets of 3 consecutive nights on each device ; nasal airflow ( Flow Wizard , DiagnoselT , Australia ) and oximetry ( Radical Set , Masimo , USA ) at home in r and om order . RESULTS Ninety-eight of the 105 patients enrolled completed home monitoring . The accuracy of nasal airflow respiratory disturbance index ( NF RDI ) was not different from oximetry ( ODI 3 % ) for diagnosing OSA ( area under the ROC curve ( AUC ) difference , 0.04 ; 95 % CI of difference -0.05 to 0.12 ; P = 0.43 ) over 3 nights of at-home recording . The accuracy of NF RDI was higher after 3 nights compared to one night ( AUC difference , 0.05 ; 95 % CI of difference , 0.01 to 0.08 ; P = 0.04 ) . Addition of oximetry to nasal airflow did not increase the accuracy for predicting OSA compared to nasal airflow alone ( P > 0.1 ) . CONCLUSIONS Nasal flow and oximetry have equivalent accuracy for diagnosing OSA in the home setting . Choice of device for home screening of sleep apnea may depend on logistical and service delivery issues OBJECTIVES Increasing awareness of the high prevalence of obstructive sleep apnea ( OSA ) and its impact on health in conjunction with high cost , inconvenience , and short supply of in-lab polysomnography ( PSG ) has led to the development of more convenient , affordable , and accessible diagnostic devices . We evaluated the reliability and accuracy of a single-channel ( finger pulse-oximetry ) photoplethysmography (PPG)-based device for detection of OSA ( Morpheus Ox ) . METHODS Among a cohort of 73 patients referred for in-laboratory evaluation of OSA , 65 were simultaneously monitored with the PPG based device while undergoing PSG .  Among these , 19 had significant cardiopulmonary comorbidities . Using the PSG as the " gold st and ard , " the sensitivity , specificity , negative predictive value ( NPV ) , positive predictive value ( PPV ) , as well as the positive likelihood ratio ( + LR ) for an apnea hypopnea index (AHI)PSG > 5/h and AHIPSG > 15/h were calculated for the PPG . RESULTS Valid results were available for 65 subjects . Mean age : 52.1 ± 14.2 , Male : 52 % , and BMI : 36.3 ± 9.7 kg/m(2 ) . Positive correlation was found between PPG-derived and PSG-derived AHI ( r = 0.81 , p < 0.001 ) . For AHIPSG > 5/h , sensitivity was 80 % , specificity 86 % , PPV 93 % , NPV 68 % , and + LR was 5.9 . For AHIPSG > 15/h , sensitivity was 70 % , specificity 91 % , PPV 80 % , NPV 85 % , and + LR was 7.83 . The corresponding areas under the receiver operator curves were 0.91 and 0.9 . CONCLUSIONS PPG-derived data compare well with simultaneous in-lab PSG in the diagnosis of suspected OSA among patients with and without cardiopulmonary comorbidities . CITATION Romem A ; Romem A ; Koldobskiy D ; Scharf SM . Diagnosis of obstructive sleep apnea using pulse oximeter derived photoplethysmographic signals BACKGROUND Sleep-disordered breathing ( SDB ) is common and is associated with increased risk for cardiovascular disease . However , most patients remain undiagnosed due to lack of access to sleep laboratories . We therefore tested the validity of a single-channel monitoring setup that captures and analyzes breath sounds ( BSs ) to detect SDB . METHODS BS were recorded from 50 patients undergoing simultaneous polysomnography ( PSG ) .  Using custom- design ed automatic software , BS were subjected to a set of pattern recognition rules to identify apneas and hypopneas from which the acoustic apnea-hypopnea index ( AHI-a ) was calculated . Apneas and hypopneas from PSG were scored blindly by three technicians according to two criteria ; one relying solely on the drop of the respiratory signal by > 90 % for an apnea and by 50 % to 90 % for a hypopnea ( TV50 criteria ) , and another that also required a desaturation or an arousal for a hypopnea ( American Association of Sleep Medicine [ AASM ] criteria ) . PSG AHI ( AHI-p ) was calculated for each technician according to both criteria . RESULTS There was no significant difference between AHI-p scores according to TV50 and AASM criteria . AHI-a was strongly correlated with AHI-p according to both TV50 ( R=94 % ) and AASM criteria ( R=93 % ) . Bl and -Altman plot analysis revealed that 98 % and 92 % of AHI-a fell within the limits of agreement for AHI-p according to TV50 and AASM criteria , respectively . Based on a diagnostic cutoff of AHI-p≥10 for SDB , overall accuracy of AHI-a reached 88 % and negative predictive value reached 100 % . CONCLUSION Acoustic analysis of BS is a reliable method for quantifying AHI and diagnosing SDB compared to simultaneous PSG
Purpose Obstructive sleep apnea ( OSA ) is the most common sleep-related breathing disorder .
In-laboratory , overnight type I polysomnography ( PSG ) is the current “ gold st and ard ” for diagnosing OSA .
Home sleep apnea testing ( HSAT ) using portable monitors ( PMs ) is an alternative testing method offering better comfort and lower costs .
We aim ed to systematic ally review the evidence on diagnostic ability of type IV PMs compared to PSG in diagnosing OSA .