Evaluation of position dependency in non-apneic snorers

The outcome of oral appliance therapy on position-dependent obstructive sleep apnea: A multicenter randomized controlled trial

INTRODUCTION

This multicenter trial on patients with obstructive sleep apnea (OSA) treated with an oral appliance aimed to determine the effect of sleeping positions.

METHODS

A cohort of 314 patients with OSA were enrolled and evaluated at 8 weeks and 1 year, focusing on treatment effects. At baseline and the 2 follow-ups, new polygraphic registration comparing the proportion of treatment responders without position-dependent OSA (non-position-dependent OSA [non-POSA]) and with POSA was used.

RESULTS

At the 8-week and 1-year follow-up, 205 and 139 patients were included, respectively. The proportion of responders (apnea-hypopnea index [AHI] <10 and/or ≥50% reduction in AHI) was 56% for the non-POSA group and 69% for the POSA group (not significant [NS]). The responders increased at the 1-year follow-up: 68% and 77% for the non-POSA and POSA groups (NS), respectively. The absolute change in AHI in all sleeping positions at 8 weeks was -12.9 (interquartile range, -25.0 to -0.5) in the non-POSA group and -10.5 (interquartile range, -19.9 to -5.3; NS) in the POSA group. However, the decrease in supine AHI was significantly greater among subjects with POSA. In contrast, the decrease in nonsupine AHI was significantly greater in the non-POSA group, an effect that remained at the 1-year follow-up.

CONCLUSIONS

Our hypothesis that subjects with POSA at baseline would have a higher treatment response rate after oral appliance treatment compared with subjects without POSA was rejected. However, those with POSA had a significantly higher supine AHI decrease, and those without POSA had significantly less nonsupine AHI.

Towards Sleep Study Automation: Detection Evaluation of Respiratory-Related Events

The diagnosis of sleep disordered breathing depends on the detection of several respiratory-related events: apneas, hypopneas, snores, or respiratory event-related arousals from sleep studies. While a number of automatic detection methods have been proposed, reproducibility of these methods has been an issue, in part due to the absence of a generally accepted protocol for evaluating their results. With sleep measurements this is usually treated as a classification problem and the accompanying issue of localization is not treated as similarly critical. To address these problems we present a detection evaluation protocol that is able to qualitatively assess the match between two annotations of respiratory-related events. This protocol relies on measuring the relative temporal overlap between two annotations in order to find an alignment that maximizes their F1-score at the sequence level. This protocol can be used in applications which require a precise estimate of the number of events, total event duration, and a joint estimate of event number and duration. We assess its application using a data set that contains over 10,000 manually annotated snore events from 9 subjects, and show that when using the American Academy of Sleep Medicine Manual standard, two sleep technologists can achieve an F1-score of 0.88 when identifying the presence of snore events. In addition, we drafted rules for marking snore boundaries and showed that one sleep technologist can achieve F1-score of 0.94 at the same tasks. Finally, we compared our protocol against the protocol that is used to evaluate sleep spindle detection and highlighted the differences.

Criteria for oral appliance and/or supine avoidance therapy selection based on outcome optimization and cost-effectiveness

AIM

Produce empirical support for further enhancements to a therapy selection protocol for obstructive sleep apnea (OSA) patients intolerant of positive airway pressure.

METHODS

A retrospective analysis was conducted in 101 men and 69 women patients. Two-night home sleep apnea studies were conducted at baseline and with a trial oral appliance. Twenty-minutes in-position sleep was required to compute supine and non-supine apnea-hypopnea indexes (AHI). Data analyses were applied after stratification by sex and response to oral appliance therapy (OAT), and the results used for to calculate incremental cost-effectiveness ratios (ICER).

RESULTS

Compared with men, women had significantly lower pre-treatment supine and non-supine AHI values (p < .05). OAT non-responders had higher non-supine AHIs, resulting in less positional-OSA and more cases with severe OSA (p < .05). Across the cohort, 21% had positional-OSA with a pre-treatment non-supine AHI < 5 events/h. In those who met this criterion, supine avoidance therapy (SAT) could have reduced the AHI values more than OAT by an average of 33% (p < .0001). The ICER for SAT instead of OAT in this group was negative, a condition that only occurs when one therapy is both less expensive and more effective than the other. A greater proportion of non-responders had post-OAT overall AHI ≥ 10 events/h with residual positional-OSA compared with responders (p < .0001). Combination therapy could reduce the AHI values by an average of 68%, resulting in ICER estimates five-times less than the reimbursement decision-making threshold.

CONCLUSIONS AND LIMITATIONS

Based on pre-treatment non-supine AHI values, SAT would provide a superior first-line treatment outcome as compared to OAT in 21% of patients diagnosed with OSA. SAT would also provide a cost-effective adjuvant to OAT in an additional 15% of cases. The benefit of SAT could not be determined in one-fifth of the cohort who slept exclusively supine.

Accelerometer based Active Snore Detection for Behavioral Modification

Habitual snoring has been known to increase the risk for serious health problems in addition to affecting the quality of others' sleep. Several recent consumer products aim to automatically detect snoring events and wake the snorer to elicit a posture change. In this paper, we present a study comparing two of the methods, electromyography vs. accelerometry, proposed for automated snoring detection and incorporation of these into a wearable system. The study includes (a) the testing of various sensor configurations and placements to obtain optimal electromyography and accelerometry signals, (b) a review of the accuracy of a variety of snore detection algorithms from previously attained biological signals, and (3) design of an embedded device with integrated sensors and haptic feedback capability. Our preliminary results indicate superiority of accelerometry over electromyography. Further research opportunities to prove the concept and improve the design are then detailed for future work.

Subjective effects of the sleep position trainer on snoring outcomes in position-dependent non-apneic snorers

Purpose

To evaluate the effect of a new-generation positional device, the sleep position trainer (SPT), in non-apneic position-dependent snorers.

Methods

Non-apneic position-dependent snorers with an apnea–hypopnea index (AHI) < 5 events/h were included between February 2015 and September 2016. After inclusion, study subjects used the SPT at home for 6 weeks. The Snore Outcome Survey (SOS) was filled out by the subjects at baseline and after 6 weeks, and at the same time, the Spouse/Bed Partner Survey (SBPS) was filled out by their bed partners.

Results

A total of 36 participants were included and 30 completed the study. SOS score improved significantly after 6 weeks from 35.0 ± 13.5 to 55.3 ± 18.6, p < 0.001. SBPS score also improved significantly after 6 weeks from 24.7 ± 16.0 versus 54.5 ± 25.2, p < 0.001. The severity of snoring assessed with a numeric visual analogue scale (VAS) by the bed partner decreased significantly from a median of 8.0 with an interquartile range (IQR) of [7.0–8.5] to 7.0 [3.8–8.0] after 6 weeks (p = 0.004).

Conclusions

Results of this study indicate that positional therapy with the SPT improved several snoring-related outcome measures in non-apneic position-dependent snorers. The results of this non-controlled study demonstrate that this SPT could be considered as an alternative therapeutic option to improve sleep-related health status of snorers and their bed partners.

Efficacy of the New Generation of Devices for Positional Therapy for Patients With Positional Obstructive Sleep Apnea: A Systematic Review of the Literature and Meta-Analysis

STUDY OBJECTIVES

In approximately 56% to 75% of patients with obstructive sleep apnea (OSA), the frequency and duration of apneas are influenced by body position. This is referred to as position-dependent OSA or POSA. Patients with POSA can be treated with a small device attached to either the neck or chest. These devices-a new generation of devices for positional therapy (PT)-provide a subtle vibrating stimulus that prevents patients adopting the supine position. The objectives of this study were to determine whether PT is effective in improving sleep study variables and sleepiness, and to assess compliance.

METHODS

A systematic review and meta-analysis.

RESULTS

Three prospective cohort studies and four randomized controlled trials were included in this review. Combined data for studies reporting on the effect of PT show that there was a mean difference of 11.3 events/h (54% reduction) in apnea-hypopnea index and 33.6% (84% reduction) in percentage total sleeping time in the supine position. The standardized mean difference for both parameters demonstrated a large magnitude of effect (> 0.8 in both cases).

CONCLUSIONS

There is strong evidence that the new generation of devices for PT are effective in reducing the apnea-hypopnea index during short-term follow-up. These devices are simple-to-use for patients and clinicians and are reversible. Under study conditions with short-term follow-up, compliance is high; however, long-term compliance cannot be assessed because of lack of reliable data. Additional long-term, high-quality studies are needed to confirm the role of PT as a single or as a combination treatment modality for OSA patients and to assess long-term compliance.

Positional therapy in patients with residual positional obstructive sleep apnea after upper airway surgery

PURPOSE/BACKGROUND

A considerable portion of patients has residual positional obstructive sleep apnea (POSA) after upper airway surgery. Those patients could benefit from additional treatment with positional therapy (PT). The objective of this prospective study was to assess the additional effect of PT in patients with residual POSA after upper airway surgery for sleep apnea.

METHODS

A polysomnography (PSG) was used to diagnose a patient with residual POSA after surgery. After informed consent, patients were treated with PT for 3 months and underwent a follow-up PSG while using the sleep position trainer (SPT). Changes in apnea-hypopnea index (AHI) and sleep position parameters were analyzed. Compliance rates and mean disease alleviation (MDA) were determined.

RESULTS

Thirty-three patients with a median postoperative AHI of 18.3/h sleep were included. With the SPT median AHI dropped to 12.5/h sleep and the Epworth Sleepiness Scale (ESS) improved from 10.0 to 7.0. After 3 months, 37.5 % patients were considered responders of whom 31.3 % had treatment success. The compliance rate with SPT was 89.0 %. MDA was 44.7 % for SPT alone. With the combination of both surgery and SPT, MDA was 65.6 %.

CONCLUSIONS

The results of this study indicate that additional PT in a complex OSA patient population with residual POSA after surgery can increase overall therapeutic effectiveness by improving the median MDA from 39.5 % (effect of surgery alone) to 65.6 % (effect of combining surgery and PT).

Short-term effects of a vibrotactile neck-based treatment device for positional obstructive sleep apnea: preliminary data on tolerability and efficacy

BACKGROUND

Positional supine obstructive sleep apnea syndrome (OSAS) characterizes a subgroup of patients suffering from OSAS. Several devices designed to limit supine position have been developed, but evidences of their efficacy and safety are lacking. It is unclear whether a neck-worn vibrating device could induce positional change in patients with positional OSAS. We evaluated the efficacy of a neck-worn device to induce supine avoidance positional feedback over a short-term trial in OSAS patients and its impact on sleep quality and polysomnographyc indexes.

METHODS

Twenty patients with positional apneas/hypopneas were prospectively studied. Baseline characteristics of daytime somnolence and risk of sleep apnea were screened and the efficacy of a 3-day trial of supine-avoidance therapy by vibrotactile neck worn device assessed by reporting the self-perceived change in quality of sleep and performing cardio-respiratory polysomnography. Comparison between baseline and treatment results was performed.

RESULTS

The neck device produced a reduction in overall apnea-hypopnea index (AHI) (mean AHI pre =16.8/h and post =4.4/h, P<0.0001), oxygen desaturation (pre =13.7/h and post =3.8/h, P<0.0001) and Respiratory Disturbance Indexes (RDI) (20.0/h vs. 5.2/h; P<0.0001).The time spent in supine position decreased from 62.1% to 33.7% of the total (P<0.001). However, the impact on the perceived quality of sleep was unpredictable.

CONCLUSIONS

The neck position therapy device is effective in restricting supine sleep, improving AHI and related polysomnographic indexes. However, at least in a short-term trial, it seems unable to improve the patient's sleep quality.

Continuous and Loud Snoring Only in the Supine Posture

Snoring and suspected sleep apneas are the most frequent causes for referral for a sleep study. Snoring varies across night and is usually recorded in all body postures. Here we report a unique patient showing continuous and loud snoring only in the supine posture.

Analysis of respiratory events in obstructive sleep apnea syndrome: Inter-relations and association to simple nocturnal features

OBJECTIVE

This study carefully evaluates the association of different respiration-related events to each other and to simple nocturnal features in obstructive sleep apnea-hypopnea syndrome (OSAS). The events include apneas, hypopneas, respiratory event-related arousals and snores.

METHODS

We conducted a statistical study on 158 adults who underwent polysomnography between July 2012 and May 2014. To monitor relevance, along with linear statistical strategies like analysis of variance and bootstrapping a correlation coefficient standard error, the non-linear method of mutual information is also applied to illuminate vague results of linear techniques.

RESULTS

Based on normalized mutual information weights (NMIW), indices of apnea are 1.3 times more relevant to AHI values than those of hypopnea. NMIW for the number of blood oxygen desaturation below 95% is considerable (0.531). The next relevant feature is "respiratory arousals index" with NMIW of 0.501. Snore indices (0.314), and BMI (0.203) take the next place. Based on NMIW values, snoring events are nearly one-third (29.9%) more dependent to hypopneas than RERAs.

CONCLUSION

1. The more sever the OSAS is, the more frequently the apneic events happen. 2. The association of snore with hypopnea/RERA revealed which is routinely ignored in regression-based OSAS modeling. 3. The statistical dependencies of oximetry features potentially can lead to home-based screening of OSAS. 4. Poor ESS-AHI relevance in the database under study indicates its disability for the OSA diagnosis compared to oximetry. 5. Based on poor RERA-snore/ESS relevance, detailed history of the symptoms plus polysomnography is suggested for accurate diagnosis of RERAs.

Assessment of a neck-based treatment and monitoring device for positional obstructive sleep apnea

STUDY OBJECTIVES

A majority of patients diagnosed with obstructive sleep apnea are position dependent whereby they are at least twice as severe when sleeping supine (POSA). This study evaluated the accuracy and efficacy of a neck-worn device designed to limit supine sleep. The study included nightly measurements of snoring, sleep/wake, time supine, and the frequency and duration of feedback to monitor compliance.

METHODS

Thirty patients between ages 18 and 75 years, BMI ≤ 35 with an overall apnea-hypopnea index (AHI) ≥ 5 and an overall AHI ≥ 1.5 times the non-supine AHI, and an Epworth score ≥ 5 were prospectively studied. Subjective reports and polysomnography were used to assess efficacy resulting from 4 weeks of in-home supine-avoidance therapy and to measure device accuracy. From 363 polysomnography reports, 209 provided sufficient positional data to estimate one site's prevalence of positional OSA.

RESULTS

In 83% of participants exhibiting > 50% reduction in overall AHI, the mean and median reductions were 69% and 79%. Significant reductions in the overall and supine AHI, apnea index, percent time SpO2 < 90%, and snoring contributed to significant improvements in stage N1 and N2 sleep, reductions in cortical arousals and awakenings, and improved depression scores. Supine position was under-detected by > 5% in 3% of cases. Sleep efficiency by neck actigraphy was within 10% of polysomnography in 87% of the studies when position feedback was delivered. The prevalence of POSA was consistently > 70% when the overall AHI was < 60.

CONCLUSIONS

The neck position therapy device is accurate and effective in restricting supine sleep, improving AHI, sleep architecture and continuity, and monitoring treatment outcomes.

Capability of a neck worn device to measure sleep/wake, airway position, and differentiate benign snoring from obstructive sleep apnea

To evaluate the accuracy of a neck-worn device in measuring sleep/wake, detecting supine airway position, and using loud snoring to screen for obstructive sleep apnea. Study A included 20 subjects who wore the neck-device during polysomnography (PSG), with 31 records obtained from diagnostic and split-night studies. Study B included 24 community-based snorers studied in-home for up to three-nights with obstructive sleep apnea (OSA) severity measured with a validated Level III recorder. The accuracy of neck actigraphy-based sleep/wake was measured by assessing sleep efficiency (SE). Differences in sleep position measured at the chest and neck during PSG were compared to video-editing. Loud snoring acquired with an acoustic microphone was compared to the apnea-hypopnea index (AHI) by- and acrosspositions. Over-reported SE by neck actigraphy was inversely related to OSA severity. Measurement of neck and chest supine position were highly correlated with video-edits (r = 0.93, 0.78). Chest was bias toward over-estimating supine time while the majority of neck-device supine position errors occurred during CPAP titrations. Snoring was highly correlated with the overall, supine, and non-supine PSG-AHI (r = 0.79, 0.74, 0.83) and was both sensitive and specific in detecting overall, supine, and non-supine PSGAHI >10 (sensitivity = 81, 88, 82 %; specificity = 87, 79, 100 %). At home sleep testing-AHI > 10, the sensitivity and specificity of loud snoring was superior when users were predominantly non-supine as compared to baseline (sensitivity = 100, 92 %; specificity = 88, 77 %). Neck actigraphy appears capable of estimating sleep/wake. The accuracy of supine airway detection with the neck-device warrants further investigation. Measurement of loud snoring appears to provide a screening tool for differentiating positional apneic and benign snorers.