Validation a portable monitoring device for sleep apnea diagnosis in a population based cohort using synchronized home polysomnography

SUBJECT OBJECTIVE: To assess the accuracy of a portable monitoring device based on peripheral arterial tonometry to diagnose obstructive sleep apnea (OSA). To propose a new standard for limited-channel device validation using synchronized polysomnography (PSG) home recordings and a population-based cohort. DESIGN: Single-night, unattended PSG and Watch_PAT 100 (WP_100). SETTING: Home environment. PARTICIPANTS: Ninety-eight subjects (55 men; age, 60 +/- 7 year; body mass index, 28 +/- 4 kg/m2) consecutively recruited from the Skaraborg Hypertension and Diabetes Project. MEASUREMENTS AND RESULTS: The WP_100 records peripheral arterial tone, heart rate, oxygen saturation and actigraphy for automatic analysis of respiratory disturbance index (RDI), apnea-hypopnea index (AHI), oxygen desaturation index (ODI), and sleep-wake state. The accuracy of WP_100 in RDI, AHI, ODI, and sleep-wake detection was assessed by comparison with data from simultaneous PSG recordings. The mean PSG-AHI in this population was 25.5 +/- 22.9 events per hour. The WP_100 RDI, AHI, and ODI correlated closely (0.88, 0.90, and 0.92; p < .0001, respectively) with the corresponding indexes obtained by PSG. The areas under the curve for the receiver-operator characteristic curves for WP_100 AHI and RDI were 0.93 and 0.90 for the PSG-AHI and RDI thresholds 10 and 20 (p < .0001, respectively). The agreement of the sleep-wake assessment based on 30-second bins between the 2 systems was 82 +/- 7%. CONCLUSIONS: The WP_100 was reasonably accurate for unattended home diagnosis of OSA in a population sample not preselected for OSA symptoms. The current design, including simultaneous home PSG recordings in population-based cohorts, is proposed as a reasonable validation standard for assessment of simplified recording tools for OSA diagnosis.     

Short-term variability of respiration and sleep during unattended nonlaboratory polysomnography--the Sleep Heart Health Study. [corrected

STUDY OBJECTIVES: To determine the short-term variability of indices of disturbed respiration and sleep during 2 nights of unattended nonlaboratory polysomnography conducted several months apart. DESIGN: Participants were randomly selected using a block design with stratification on preliminary estimates of 2 criteria: respiratory disturbance index [RDI3% (apnea or hypopnea events associated with > or = 3% O2 desaturation): < 15/hour total sleep time, > or = 15/hour total sleep time] and sleep efficiency (SEff: < 85% and > or = 85%). The RDI and sleep data from initial and repeated polysomnography were compared. SETTING: NA. PARTICIPANTS: A subset of 99 participants in the Sleep Heart Health Study who agreed to have a repeat polysomnogram within 4 months of their original study. INTERVENTIONS: NA. MEASUREMENTS AND RESULTS: Acceptable repeat polysomnograms were obtained in 91 subjects (mean study interval: 77 +/- 18 [sd] days; range: 31-112 days). There was no significant bias in RDI between study nights using several different RDI definitions including RDI3% and RDI4% (apnea or hypopnea events associated with > or = 4% O2 desaturation). Variability between studies estimated using intraclass correlations (ICC) ranged from 0.77 to 0.81. For subjects with a RDI3% < 15, variability increased as a function of increasing RDI, but for those with a RDI3% > or = 15, variability was constant. Body mass index, SEff, gender, or age did not directly predict RDI variability. Using RDI4% cutpoints of < or = 5, < or = 10 and < or = 15 events per hour of sleep demonstrated that 79.1%, 85.7%, and 87.9% of subjects, respectively, had the same classification of SDB status on both nights of study. There also was no significant bias in sleep staging, sleep efficiency, or arousal index between studies. However, variability was greater with ICC values ranging from 0.37 (% time in REM) to 0.76 (arousal index). CONCLUSION: In the Sleep Heart Health Study, accurate estimates of the severity of sleep-disordered breathing and the quality of sleep were obtained from a single night of unattended nonlaboratory polysomnography. These findings may be applicable to other large epidemiologic studies provided that similar recording techniques and quality-assurance procedures are followed.     

Reliability of scoring respiratory disturbance indices and sleep staging

STUDY OBJECTIVES: Unattended, home-based polysomnography (PSG) is increasingly used in both research and clinical settings as an alternative to traditional laboratory-based studies, although the reliability of the scoring of these studies has not been described. The purpose of this study is to describe the reliability of the PSG scoring in the Sleep Heart Health Study (SHHS), a multicenter study of the relation between sleep-disordered breathing measured by unattended, in-home PSG using a portable sleep monitor, and cardiovascular outcomes. DESIGN: The reliability of SHHS scorers was evaluated based on 20 randomly selected studies per scorer, assessing both interscorer and intrascorer reliability. RESULTS: Both inter- and intrascorer comparisons on epoch-by-epoch sleep staging showed excellent reliability (kappa statistics >0.80), with stage 1 having the greatest discrepancies in scoring and stage 3/4 being the most reliably discriminated. The arousal index (number of arousals per hour of sleep) was moderately reliable, with an intraclass correlation (ICC) of 0.54. The scorers were highly reliable on various respiratory disturbance indices (RDIs), which incorporate an associated oxygen desaturation in the definition of respiratory events (2% to 5%) with or without the additional use of associated EEG arousal in the definition of respiratory events (ICC>0.90). When RDI was defined without considering oxygen desaturation or arousals to define respiratory events, the RDI was moderately reliable (ICC=0.74). The additional use of associated EEG arousals, but not oxygen desaturation, in defining respiratory events did little to increase the reliability of the RDI measure (ICC=0.77). CONCLUSIONS: The SHHS achieved a high degree of intrascorer and interscorer reliability for the scoring of sleep stage and RDI in unattended in-home PSG studies.     

Polysomnography performed in the unattended home versus the attended laboratory setting--Sleep Heart Health Study methodology

STUDY OBJECTIVE: To compare polysomnographic recordings obtained in the home and laboratory setting. DESIGN AND SETTING: Multicenter study comparing unsupervised polysomnography performed in the participant's home with polysomnography supervised at an academic sleep disorders center, using a randomized sequence of study setting. Sleep Heart Health Study (SHHS) standardized polysomnographic recording and scoring techniques were used for both settings. PARTICIPANTS: 64 of 76 non-SHHS participants recruited from 7 SHHS field sites who had both a laboratory and home polysomnogram meeting acceptable quality criteria. MEASUREMENTS AND RESULTS: Median sleep duration was greater in the home than in the laboratory (375 vs 318 minutes, respectively, P < .0001) as was sleep efficiency (86% vs 82%, respectively, P < .0024). Very small, but significant increases in percentage of rapid eye movement sleep and decreases in stage 1 sleep were noted in the laboratory. Employing multiple definitions of respiratory disturbance index (RDI), median RDI was similar in both settings (for example, RDI with 3% desaturation: home 12.4, range 0.6-67; laboratory 9.5, range 0.1-93.4, P = .41). Quartile analysis of laboratory RDI showed moderate agreement with home RDI measurements. Based on the mean of laboratory and home RDI and using a cutpoint of 20, there was a biphasic distribution, with the RDI 3% above 20 being more common in the recordings performed in the laboratory than in the home and below 20 being more common in the recordings performed in the home than in the laboratory. These differences could not be attributed to quality of recording, age, sex, or body mass index. CONCLUSIONS: Using SHHS methodology, median RDI was similar in the unattended home and attended laboratory setting with differences of small magnitude in some sleep parameters. Differences in RDI between settings resulted in a rate of disease misclassification that is similar to repeated studies in the same setting.     

The Utility of Single-Channel Nasal Airflow Pressure Transducer in the Diagnosis Of OSA at Home

Rationale:

Given the high prevalence of obstructive sleep apnea (OSA) and the demand on polysomnography (PSG), there is a need for low cost accurate simple diagnostic modalities that can be easily deployed in primary care to improve access to diagnosis.

Study Objectives:

The aim was to examine the utility of single-channel nasal airflow monitoring using a pressure transducer at home in patients with suspected OSA.

Design:

Cross-sectional study

Setting:

Laboratory and home

Participants:

The study was conducted in two populations. Consecutive patients with suspected OSA were recruited from the sleep disorders clinic at a tertiary referral center and from 6 local metropolitan primary care centers.

Interventions:

All patients answered questionnaires and had laboratory PSG. Nasal airflow was monitored for 3 consecutive nights at home in random order either before or after PSG.

Results:

A total of 193 patients participated (105 sleep clinic patients and 88 from primary care). The mean bias PSG apnea hypopnea index (AHI) minus nasal flow respiratory disturbance index (NF RDI) was –4.9 events per hour with limits of agreement (2 SD) of 27.8. NF RDI monitored over 3 nights had high accuracy for diagnosing both severe OSA (defined as PSG AHI > 30 events per hour) with area under the receiver operating characteristic curve (AUC) 0.92 (95% confidence interval (CI) 0.88-0.96) and any OSA (PSG AHI >5), AUC 0.87 (95% CI 0.80-0.94).

Conclusions:

Single-channel nasal airflow can be implemented as an accurate diagnostic tool for OSA at home in both primary care and sleep clinic populations.

Citation:

Makarie Rofail L; Wong KKH; Unger G; Marks GB; Grunstein RR. The utility of single-channel nasal airflow pressure transducer in the diagnosis of OSA at home. SLEEP 2010;33(8):1097-1105.     

Accuracy of oximetry with thermistor (OxiFlow) for diagnosis of obstructive sleep apnea and hypopnea

OBJECTIVES: To evaluate the diagnostic accuracy for obstructive sleep apnea and hypopnea (OSAH) of the OxiFlow (OF) device which combines oximetry with recording of thermistor airflow. DESIGN & SETTING: Patients scheduled for overnight diagnostic polysomnography (PSG) were studied with OF either simultaneously during laboratory PSG (L-OF, n=86), at home on a separate night (H-OF, n=66), or both (n=55). PATIENTS: 97 patients with suspected OSAH, of whom 40 had OSAH defined as an apnea-hypopnea index (AHI) of more than 15 events per hour of sleep on PSG. INTERVENTIONS: NA. MEASUREMENTS & RESULTS: The automated respiratory disturbance index (RDI) generated by the OF software considerably underestimated the AHI by PSG for both L-OF and H-OF. Altering the parameters for hypopnea identification by the software did not improve this. Visual inspection of the computerized OF tracings added considerable diagnostic information, but a manual count of RDI during visual review overestimated AHI. For the identification of cases vs. non-cases of OSAH, receiver operating characteristic area-under-the-curve statistics ranged from 0.77-0.90 for L-OF and from 0.71-0.77 for H-OF. Combining automated analysis with subsequent visual inspection of OF tracings yielded an overall sensitivity of 86% and specificity of 74% for the diagnosis of OSAH during H-OF recordings. Analysis of potential technician time saved indicated a benefit from the use of OF. CONCLUSIONS: OF has diagnostic utility for the identification of OSAH. However, because of hardware and software limitations, it is unclear whether this device is superior to oximetry alone.     

Comparison between a Single-Channel Nasal Airflow Device and Oximetry for the Diagnosis of Obstructive Sleep Apnea

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 prospectively 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, DiagnoseIT, Australia) and oximetry (Radical Set, Masimo, USA) at home in random 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.

Citation:

Makarie Rofail L; Wong KKH; Unger G; Marks GB; Grunstein RR. Comparison between a single-channel nasal airflow device and oximetry for the diagnosis of obstructive sleep apnea. SLEEP 2010;33(8):1106-1114.     

Measures of cognitive function in persons with varying degrees of sleep-disordered breathing: the Sleep Heart Health Study

Epidemiologic literature suggests that persons with clinically diagnosed sleep apnoea frequently have impaired cognitive function, but whether milder degrees of sleep-disordered breathing (SDB) are associated with cognitive dysfunction in the general population is largely unknown. Approximately 1700 subjects free of clinically diagnosed SDB underwent at-home polysomnography (PSG) as part of the Sleep Heart Health Study (SHHS) and completed three cognitive function tests within 1-2 years of their PSG: the Delayed Word Recall Test (DWR), the WAIS-R Digit Symbol Subtest (DSS), and the Word Fluency test (WF). A respiratory disturbance index (RDI) was calculated as the number of apnoeas and hypopnoeas per hour of sleep. After adjustment for age, education, occupation, field centre, diabetes, hypertension, body-mass index, use of CNS medications, and alcohol drinking status, there was no consistent association between the RDI and any of the three cognitive function measures. There was no evidence of a dose-response relation between the RDI and cognitive function scores and the adjusted mean scores by quartiles of RDI never differed from one another by more than 5% for any of the tests. In this sample of free-living individuals with mostly mild to moderate levels of SDB, the degree of SDB appeared to be unrelated to three measures of cognitive performance.     

Comparison of portable apnea monitors in the detection of apnea episode during daytime rest

Although polysomnography (PSG) is the golden standard for the diagnosis of sleep apnea syndrome (SAS), access to this procedure is limited because it requires special institution and trained technicians. Therefore, many portable recording devices have been developed for detection of SAS including home monitoring. The present study evaluated the usefulness of four portable devices in detecting apneic events. The four devices are, (1) FM-500 thermister sensor type III device, (2) LS-300 pressure sensor type III device, (3) Morpheus pressure sensor type III device, and (4) SD-101, a sheet-type type IV device that detects chest wall movement. This study included 1,114 patients who underwent a daytime rest session during a routine clinic visit. The subjects were asked to remain quiet and in a supine position in a dark room. We compared the respiratory disturbance index (RDI) and number of oxygen desaturation events (OD) measured by the four portable devices in each patient. The RDI and number of OD measured by the device using the thermister sensor were significantly lower than those measured by the three other devices. These findings suggest that when using a portable recording device to screen for SAS, the characteristics of the device should be taken into account.     

穿戴式呼吸感应体积描记用于睡眠呼吸事件检测

可穿戴式呼吸感应体积描记(背心式RIP)系统是我们根据呼吸感应体积描记技术的基本原理研发的一种可穿戴、低负荷的呼吸监测系统.在实现通气量无创测量的基础上,我们将该系统用于睡眠期呼吸事件检测,将该系统与多导睡眠图仪(PSG)对9例疑似睡眠呼吸暂停低通气综合症(SAHS)病人和7名健康男性志愿者进行同步对照检测与分析.通过对比实验,根据背心式RIP系统发生呼吸事件的特征性变化,提出了背心式RIP系统判别呼吸事件的规则.依据该规则,所有经背心式RIP系统诊断为SAHS患者的结果与PSG的诊断结果完全一致,背心式RIP系统检测呼吸事件的敏感性为97.8%,特异性为95.8%,实验结果表明背心式RIP系统能够可靠地检测出睡眠呼吸事件.由于其低生理、心理负荷特性,不需要佩带口鼻气流传感器,可用于家庭环境下、自然睡眠过程的睡眠呼吸紊乱性疾病的诊断.     

Polysomnographic respiratory abnormalities in asymptomatic individuals

STUDY OBJECTIVES: Polysomnographic respiratory abnormalities have been extensively studied in the general population, but studies have not targeted completely healthy individuals. We aimed to (1) define the frequency of respiratory disturbances (RDI: events per hour of sleep) during sleep in healthy individuals using current techniques and criteria and (2) determine how these abnormalities change with age and sex. DESIGN AND SETTING: Cross-sectional analyses of RDI in healthy volunteers. PARTICIPANTS: One hundred sixty-three individuals (106 men) were screened for chronic medical illness, as confirmed by extensive questionnaires, physical examination, electrocardiography, and laboratory analysis. Obese subjects (body mass index > 30 kg/m2) and subjects taking medications were excluded. INTERVENTIONS, MEASUREMENTS AND RESULTS: Subjects underwent full polysomnography using current standard recording and scoring techniques. There was a remarkable increase in RDI with age, particularly over 50 years. Ninety-five percent of currently healthy subjects under 50 years of age had an RDI <15, whereas 50% of subjects older than 65 years had an RDI <15. Men had a higher RDI (median 10) than women (median 5). The effect of age on RDI was similar in men and women. CONCLUSIONS: RDI increases with age even in healthy individuals without symptoms or signs of obstructive sleep apnea syndrome. We do not know whether these individuals will develop pathophysiologic consequences over time or whether this increase with age reflects a normal aging process. If the former, treatment should be considered regardless of symptoms. If the latter, the criteria for treatment should be adjusted by age.     

Autonomic arousal index: an automated detection based on peripheral arterial tonometry

Arousals from sleep are associated with increased sympathetic activation and are therefore associated with peripheral vasoconstriction. We hypothesized that digital vasoconstrictions as measured by peripheral arterial tonometery (PAT), combined with an increase in pulse rate, would accurately reflect arousals from sleep, and can provide an autonomic arousal index (AAI). Based on a previously studied group of 40 sleep apnea patients simultaneously recorded by both polysomnography (PSG) and PAT systems, an automated algorithm using the PAT signal (and pulse rate derived from it) was developed for detection of arousals from sleep. This was further validated in a separate group of 96 subjects (85 patients referred with suspected obstructive sleep apnea and 11 healthy volunteers mean age 46.2+/-14.4 years, BMI 28.5+/-5.4 kg/m2). All underwent a whole night PSG with simultaneous PAT recording. The PSG recordings were blindly manually analyzed for arousals based on American Academy of Sleep Medicine (AASM) criteria, while PAT was scored automatically. There was a significant correlation between PSG and PAT arousals (R=0.82, p<0.0001) with a good agreement across a wide range of values, with a ROC curve having an area under the curve (AUC) of 0.88. We conclude that automated analysis of the peripheral arterial tonometry signal can detect EEG arousals from sleep, in a relatively quick and reproducible fashion.     

Peripheral arterial tonometry events and electroencephalographic arousals in children

STUDY OBJECTIVES: Peripheral arterial tonometry (PAT) is a sensitive measure of moment-to-moment changes in sympathetic activity and reliably identifies arousals in adult subjects. We investigated whether PAT events during sleep are associated with visually recognizable electroencephalographic arousals in healthy children and in children with sleep-disordered breathing. DESIGN: Prospective cohort. SETTING: Pediatric Sleep Research Laboratory. PARTICIPANTS: Twenty children with obstructive sleep apnea syndrome, 20 children with mild sleep-disordered breathing, and 20 control children with a mean age of 7.6 +/- 2.6 years (range: 5.7-16.5 years); 53% of children were boys. INTERVENTIONS AND MEASUREMENTS: Polysomnographic evaluation in the sleep laboratory with concomitant recording of PAT. PAT events were defined as attenuations from immediately preceding baseline of 20% to 50% (PAT20) and > 50% (PAT50) for at least 5 seconds and the indexes calculated per hour of sleep time that included good-quality PAT signals. Total PAT index (the sum of PAT20 index and PAT50 index) was also calculated. RESULTS: Total PAT index correlated with total arousal index and spontaneous arousal index (r = 0.55, P < .0001, r = 0.64, P < .001, respectively), especially in the group with obstructive sleep apnea syndrome (r = 0.71, P < .0001). The sensitivity and specificity of PAT for identifying electroencephalographic arousals were 95% and 35%, respectively. The PAT device identified pathologic arousals indexes (> or = 16 per hour) (area under the curve 0.79, P = .002). Thirty-five percent of respiratory events (eg, obstructive apnea or hypopnea) were associated with a visual electroencephalographic arousal, compared to 92% being associated with PAT attenuation events. CONCLUSIONS: Arousals in sleeping children are associated with increased sympathetic discharge, as evidenced by attenuations in PAT signal. However, a significant proportion of PAT attenuations were not accompanied by visual electroencephalographic arousals. Thus, the importance of these autonomic arousals has yet to be explored in association with morbidities related to sleep-disordered breathing and, therefore, PAT technology cannot be recommended as an alternative tool for measuring arousals in children. Nevertheless, these data further support the contention that adult criteria for the measurement for arousals may not be adequate in children.     

Effect of sleep disordered breathing on the sleep of bed partners in the Sleep Heart Health Study

OBJECTIVE: To study the sleep quality of bed partners of persons with sleep disordered breathing in a non-clinical population based sample in a home environment. DESIGN: Cross-sectional study in a community sample. METHODS: 110 pairs of subjects living in the same household from the Tucson, Minnesota, and Pittsburgh sites of the Sleep Heart Health Study (SHHS) were included if both partners had an in-home, unattended polysomnogram (PSG) performed as a part of SHHS exam cycle 2. Sleep disordered breathing (SDB) was considered present if the respiratory disturbance index (RDI) was > or =10 events/h and no SDB if RDI was <5 events/h. Pairs were classified according to their SDB status and assigned to one of 3 groups: 1) NoSDB-NoSDB (n = 46), 2) NoSDB-SDB (n = 42), and 3) SDB-SDB (n = 22). RESULTS: There were no differences between the NoSDB-NoSDB and the SDB-SDB partners in their demographic, PSG, or quality of life variables. However, within the NoSDB-SDB group, NoSDB in comparison to their SDB partners weighed less (mean BMI: 26 vs. 29 kg/m2, P < 0.0003), had decreased stage 2% (55 vs. 64, P < 0.0001), increased stage 3 and 4% (21 vs. 11, P <0.0005) and a lower arousal index (13.8 vs. 20 events/h, P < 0.0001). When comparing the NoSDB subjects from the NoSDB-SDB group to subjects in the NoSDB-NoSDB group and to subjects in the SDB-SDB group, significant differences were seen for RDI and BMI but not for any other parameter. CONCLUSION: In a non-clinical population based sample, the sleep quality of bed partners of SDB subjects without SDB is better than their SDB bed partner. However, their sleep quality was not different in comparison to the sleep of those without SDB who also had a bed partner without SDB.     

A multicentric validation study of a novel home sleep apnea test based on peripheral arterial tonometry

Study ObjectivesThis paper reports on the multicentric validation of a novel FDA-cleared home sleep apnea test based on peripheral arterial tonometry (PAT HSAT).MethodsOne hundred sixty-seven participants suspected of having obstructive sleep apnea (OSA) were included in a multicentric cohort. All patients underwent simultaneous polysomnography (PSG) and PAT HSAT, and all PSG data were independently double scored using both the recommended 1A rule for hypopnea, requiring a 3% desaturation or arousal (3% Rule), and the acceptable 1B rule for hypopnea, requiring a 4% desaturation (4% Rule). The double-scoring of PSG enabled a comparison of the agreement between PAT HSAT and PSG to the inter-rater agreement of PSG. Clinical endpoint parameters were selected to evaluate the device’s ability to determine the OSA severity category. Finally, a correction for near-boundary apnea–hypopnea index values was proposed to adequately handle the inter-rater variability of the PSG benchmark.ResultsFor both the 3% and the 4% Rules, most endpoint parameters showed a close agreement with PSG. The 4-way OSA severity categorization accuracy of PAT HSAT was strong, but nevertheless lower than the inter-rater agreement of PSG (70% vs 77% for the 3% Rule and 78% vs 81% for the 4% Rule).ConclusionsThis paper reported on a multitude of robust endpoint parameters, in particular OSA severity categorization accuracies, while also benchmarking clinical performances against double-scored PSG. This study demonstrated strong agreement of PAT HSAT with PSG. The results of this study also suggest that different brands of PAT HSAT may have distinct clinical performance characteristics.     

Relation between ambulatory actigraphy and laboratory polysomnography in insomnia practice and research

Actigraphy is increasingly used in practice and research studies because of its relative low cost and decreased subject burden. How multiple nights of at‐home actigraphy compare to one independent night of in‐laboratory polysomnography (PSG) has not been examined in people with insomnia. Using event markers (MARK) to set time in bed (TIB) compared to automatic program analysis (AUTO) has not been systematically evaluated. Subjects (n = 30) meeting DSM‐5 criteria for insomnia and in‐laboratory PSG sleep efficiency (SE) of <85% were studied. Subjects were free of psychiatric, sleep or circadian disorders, other chronic conditions and medications that effect sleep. Subjects had an in‐laboratory PSG, then were sent home for 7 nights with Philips Actiwatch Spectrum Plus. Data were analysed using Philips Actiware version 6. Using the mean of seven nights, TIB, total sleep time (TST), SE, sleep‐onset latency (SOL) and wake after sleep onset (WASO) were examined. Compared to PSG, AUTO showed longer TIB and TST and less WASO. MARK only differed from PSG with decreased WASO. Differences between the PSG night and the following night at home were found, with better sleep on the first night home. Actigraphy in people with insomnia over seven nights is a valid indicator of sleep compared to an independent in‐laboratory PSG. Event markers increased the validity of actigraphy, showing no difference in TIB, TST, SE and SOL. AUTO was representative of SE and SOL. Increased SE and TST without increased TIB suggests possible compensatory sleep the first at night home after in‐laboratory PSG.     

Comparison of limited monitoring using a nasal-cannula flow signal to full polysomnography in sleep-disordered breathing

STUDY OBJECTIVES: Evaluate the utility of overnight monitoring limited to nasal cannula airflow and oximetry in the diagnosis of obstructive sleep apnea-hypopnea syndrome (OSAHS). DESIGN: Prospective randomized study, blinded analysis. SETTING: Sleep disorder center, academic institution. PARTICIPANTS: 56 patients with suspected OSAHS, 10 normal volunteers. MEASUREMENTS AND RESULTS: In-laboratory full nocturnal polysomnography (NPSG) and unattended ambulatory study with monitoring of only airflow and oximetry performed in randomized order. Obstructive respiratory events were scored on the full NPSG while visualizing all signals and then rescored on the full NPSG and on the ambulatory study while visualizing only airflow and oximetry signals. Respiratory disturbance indexes (RDI) for the limited studies (RDIFlowNPSG and RDIFlowAmbulatory) were calculated as the sum of the apneas and hypopneas (defined using airflow amplitude and O2 desaturation) divided by the valid flow-signal time. The reference RDIFullNPSG was calculated from the sum of the apneas and hypopneas (defined using flow amplitude, O2 desaturation and electroencephalographic arousal) identified on the full NPSG divided by the total sleep time. RDIFullNPSG was greater than RDIFlowNPSG (bias = 5.6 events per hour) and RDIFlowAmbulatory (bias = 10.9 events per hour), but the differences were mainly in subjects with an RDI > 40 events per hour. The diagnostic sensitivity and specificity for the diagnosis of OSAHS using a cutoff of 18 events per hour were 96% and 93% using the flow signal from the NPSG and 88% and 92% using the flow signal from the ambulatory study performed on a separate night. CONCLUSIONS: In subjects with OSAHS, analysis of the flow signal from a nasal cannula can provide an RDI similar to that obtained in a full NPSG.     

The effect of in-laboratory polysomnography on sleep and objective daytime sleepiness

MSLT guidelines recommend performing MSLTs following polysomnography (PSG) to document the preceding night's sleep. We tested the hypothesis that patients are objectively sleepier after in-laboratory full diagnostic PSG than after a sleep recording at home. Sixteen patients with the sleep apnea/hypopnea syndrome (SAHS; AHI 35+/-SD 28 per hour slept) were recruited into a randomized crossover study. To monitor sleep with minimal disruption at home, only sleep was recorded on 2 consecutive nights, the first for acclimatization. The laboratory limb followed standard PSG. Both study nights were followed next day by MSLT and MWT. There were no differences in MSLT (12.0 SD 5.1 home, 11.6+/-4.7 min laboratory; p=0.7), MWT (32.7+/-8.7, 31.6+/-9.3 min; p=0.6) or total sleep time (362+/-53, 343+/-51 min; p=0.15) between home and laboratory limbs. However, on the home night, fewer microarousals (31+/-14, 54+/-25/hr slept; p<0.0001) and less % wake (15+/-10, 24+/-11; p=0.006) were found. On the home study night, patients had greater % REM sleep, slow-wave sleep and sleep efficiency (all p<0.009). This study does not support the hypothesis that patients are sleepier after laboratory PSG compared to home study night. However, the improved sleep at home raises the question whether laboratory-based polysomnography is always required prior to MSLT/MWT testing or whether less obtrusive monitoring of sleep duration at home would sometimes suffice.     

Rates of sensor loss in unattended home polysomnography: the influence of age, gender, obesity, and sleep-disordered breathing

OBJECTIVES: To evaluate study failure and sensor loss in unattended home polysomnography and their relationship to age, gender, obesity, and severity of sleep-disordered breathing (SDB). DESIGN: A cross-sectional analysis of data gathered prospectively for the Sleep Heart Health Study (SHHS). SETTING: Unattended polysomnography was performed in participants' homes by the staff of the sites that are involved in SHHS. PARTICIPANTS: 6,802 individuals who met the inclusion criteria (age >40 years, no history of treatment of sleep apnea, no tracheostomy, no current home oxygen therapy) for SHHS. RESULTS: A total of 6802 participants had 7151 studies performed. 6161 of 6802 initial studies (90.6%) were acceptable. Obesity was associated with a decreased likelihood of a successful initial study. After one or more attempts, 6440 participants (94.7%) had studies that were judged as acceptable. The mean duration of scorable signals for specific channels ranged from 5.7 to 6.8 hours. The magnitudes of the effects of age, gender, BMI, and RDI on specific signal durations were not clinically significant. CONCLUSION: Unattended home PSG as performed for SHHS was usually successful. Participant characteristics had very weak associations with duration of scorable signal. This study suggests that unattended home PSG, when performed with proper protocols and quality controls, has reasonable success rates and signal quality for the evaluation of SDB in clinical and research settings.     

A novel adaptive wrist actigraphy algorithm for sleep-wake assessment in sleep apnea patients

STUDY OBJECTIVES: Current actigraphic algorithms are relatively less accurate in detecting sleep and wake in sleep apnea patients than in people without sleep apnea. In the current study, we attempted to validate a novel automatic algorithm, which was developed for actigraphic studies in normal subjects and patients with obstructive sleep apnea by comparing it on an epoch-by-epoch basis to standard polysomnography. DESIGN: Prospective cohort study. SETTING: Multicenter, university hospital, sleep laboratories. PARTICIPANTS: A total of 228 subjects from 3 different sleep centers (Skara, Boston, Haifa) participated. INTERVENTION AND MEASUREMENTS: Simultaneous recording of polysomnography and Watch_PAT100, an ambulatory device that contains a built-in actigraph. The automatic sleep/wake algorithm is based on both the quantification of motion (magnitude and duration) and the various periodic movement patterns, such as those occurring in patients with moderate to severe obstructive sleep apnea. RESULTS: The overall sensitivity and specificity to identify sleep was 89% and 69%, respectively. The agreement ranged from 86% in the normal subjects to 86%, 84%, and 80% in the patients with mild, moderate, and severe obstructive sleep apnea, respectively. There was a tight agreement between actigraphy and polysomnography in determining sleep efficiency (78.4 +/- 9.9 vs 78.8 +/- 13.4%), total sleep time (690 +/- 152 vs 690 +/- 154 epochs), and sleep latency (56.8 +/- 31.4 vs 43.3 +/- 45.4 epochs). While for most individuals the difference between the polysomnography and actigraphy was relatively small, for some there was a substantial disagreement. CONCLUSIONS: We conclude that this actigraphy algorithm provides a reasonably accurate estimation of sleep and wakefulness in normal subjects and patients with obstructive sleep apnea on an epoch-by-epoch basis. This simple method for assessment of total sleep time may provide a useful tool for the accurate quantification of obstructive sleep apnea in the home environment.