Effects of Weight Loss on Obstructive Sleep Apnea Severity. Ten-Year Results of the Sleep AHEAD Study.

Rationale: Weight loss is recommended to treat obstructive sleep apnea (OSA).Objectives: To determine whether the initial benefit of intensive lifestyle intervention (ILI) for weight loss on OSA severity is maintained at 10 years.Methods: Ten-year follow-up polysomnograms of 134 of 264 adults in Sleep AHEAD (Action for Health in Diabetes) with overweight/obesity, type 2 diabetes mellitus, and OSA were randomized to ILI for weight loss or diabetes support and education (DSE).Measurements and Main Results: Change in apnea-hypopnea index (AHI) was measured. Mean ± SE weight losses of ILI participants of 10.7 ± 0.7, 7.4 ± 0.7, 5.1 ± 0.7, and 7.1 ± 0.8 kg at 1, 2, 4, and 10 years, respectively, were significantly greater than the 1-kg weight loss at 1, 2, and 4 years and 3.5 ± 0.8 kg weight loss at 10 years for the DSE group (P values ≤ 0.0001). AHI was lower with ILI than DSE by 9.7, 8.0, and 7.9 events/h at 1, 2, and 4 years, respectively (P values ≤ 0.0004), and 4.0 events/h at 10 years (P = 0.109). Change in AHI over time was related to amount of weight loss, baseline AHI, visit year (P values < 0.0001), and intervention independent of weight change (P = 0.01). OSA remission at 10 years was more common with ILI (34.4%) than DSE (22.2%).Conclusions: Participants with OSA and type 2 diabetes mellitus receiving ILI for weight loss had reduced OSA severity at 10 years. No difference in OSA severity was present between ILI and DSE groups at 10 years. Improvement in OSA severity over the 10-year period with ILI was related to change in body weight, baseline AHI, and intervention independent of weight change.

Effects of a lifestyle intervention on REM sleep-related OSA severity in obese individuals with type 2 diabetes.

The aim of this study was to determine if an intensive lifestyle intervention (ILI) reduces the severity of obstructive sleep apnea (OSA) in rapid-eye movement (REM) sleep, and to determine if longitudinal changes in glycaemic control are related to changes in OSA severity during REM sleep over a 4-year follow-up. This was a randomized controlled trial including 264 overweight/obese adults with type 2 diabetes (T2D) and OSA. Participants were randomized to an ILI targeted to weight loss or a diabetes support and education (DSE) control group. Measures included anthropometry, apnea-hypopnea index (AHI) during REM sleep (REM-AHI) and non-REM sleep (NREM-AHI) and glycated haemoglobin (HbA1c) at baseline and year 1, year 2 and year 4 follow-ups. Mean baseline values of REM-AHI were significantly higher than NREM-AHI in both groups. Both REM-AHI and NREM-AHI were reduced significantly more in ILI versus DSE, but these differences were attenuated slightly after adjustment for weight changes. Repeated-measure mixed-model analyses including data to year 4 demonstrated that changes in HbA1c were related significantly to changes in weight, but not to changes in REM-AHI and NREM-AHI. Compared to control, the ILI reduced REM-AHI and NREM-AHI during the 4-year follow-up. Weight, as opposed to REM-AHI and NREM-AHI, was related to changes in HbA1c. The findings imply that weight loss from a lifestyle intervention is more important than reductions in AHI for improving glycaemic control in T2D patients with OSA.

Subjective sleepiness and daytime functioning in bariatric patients with obstructive sleep apnea.

PURPOSE: The purpose of this study was to evaluate associations between obstructive sleep apnea (OSA) severity and self-reported sleepiness and daytime functioning in patients considering bariatric surgery for treatment of obesity. METHODS: Using a retrospective cohort design, we identified 342 patients who had sleep evaluations prior to bariatric surgery. Our final sample included 269 patients (78.6 % of the original cohort, 239 females; mean age = 42.0 ± 9.5 years; body mass index = 50.2 ± 7.7 kg/m(2)) who had overnight polysomnography and completed the Epworth Sleepiness Scale (ESS) and the Functional Outcomes of Sleep Questionnaire (FOSQ). Patients' OSA was classified as none/mild (apnea-hypopnea index (AHI) < 15, n = 112), moderate (15 ≤ AHI < 30, n = 77), or severe (AHI ≥ 30, n = 80). We calculated the proportion of unique variance (PUV) for the five FOSQ subscales. ANOVA was used to determine if ESS and FOSQ were associated with OSA severity. Unpaired t tests compared ESS and FOSQ scores in our sample with published data. RESULTS: The average AHI was 29.5 ± 31.5 events per hour (range = 0-175.8). The mean ESS score was 6.3 ± 4.8, and the mean global FOSQ score was 100.3 ± 18.2. PUVs for FOSQ subscales showed moderate-to-high unique contributions to FOSQ variance. ESS and global FOSQ score did not differ by AHI group. Only the FOSQ vigilance subscale differed by OSA severity with the severe group reporting more impairment than the moderate and none/mild groups. Our sample reported less sleepiness and daytime impairment than previously reported means in patients and controls. CONCLUSIONS: Subjective sleepiness and functional impairment were not associated significantly with OSA severity in our sample of patients considering surgery for obesity. Further research is needed to understand individual differences in sleepiness in patients with OSA. If bariatric patients underreport symptoms, self-report measures are not an adequate substitute for objective assessment and clinical judgment when evaluating bariatric patients for OSA. Patients with severe obesity need evaluation for OSA even in the absence of subjective complaints.

Treatment of severe morning sleep inertia with bedtime long-acting bupropion and/or long-acting methylphenidate in a series of 4 patients.

STUDY OBJECTIVES: To assess the benefit of bedtime long-acting bupropion and/or long-acting methylphenidate in the therapy of severe morning sleep inertia (SI), a chronic condition that has major adverse consequences on level of functioning and quality of life, and for which there is no recognized therapy. METHODS: Patients underwent clinical interviews and examinations and completed comprehensive questionnaires. They underwent overnight video-polysomnography and next-day multiple sleep latency testing (apart from 1 case with obstructive sleep apnea). Treatments are described in the case reports. RESULTS: Case 1, a 16-year-old girl who was very late to school every day from severe morning SI despite obstructive sleep apnea being fully controlled with continuous positive airway pressure therapy, responded to bedtime bupropion-extended release (xl) 150 mg, together with methylphenidate-sr (sustained release), 36 mg (along with 20 mg methylphenidate taken 1 hour before the alarm would go off). She woke up in a timely fashion and has started her classes on time, with benefit maintained at 6-month follow-up. Case 2, a 29-year-old female with idiopathic hypersomnia and major depression and associated severe morning SI while maintained on 20 mg twice-daily generic Adderall, responded immediately (first night) to bedtime bupropion-xl, 150 mg, with benefit maintained at the 4-month follow-up. Case 3, a 74-year-old man with idiopathic hypersomnia and major depression maintained on daily methylphenidate-sr and direct-release methylphenidate, along with 300 mg bupropion-xl, developed progressively severe morning SI that immediately responded to changing his bupropion-xl regimen to 150 mg nightly and 150 mg every morning, with benefit maintained at the 3-year follow-up. Case 4, a 60-year-old female with idiopathic hypersomnia and severe morning SI, was immediately intolerant to bedtime bupropion-xl, which was discontinued. CONCLUSIONS: Bedtime use of long-acting bupropion and/or long-acting methylphenidate can be effective in the therapy for severe morning SI and warrants further clinical use along with systematic research.

Treatment effects on brain activity during a working memory task in obstructive sleep apnea.

Positive airway pressure (PAP) is the most common form of treatment for obstructive sleep apnea (OSA). Treatment adherence is notoriously low, and holidays from treatment are common. To date, there is no literature on the effects of acute withdrawal from PAP treatment on the brain activity of individuals with OSA. Nine participants with OSA performed a 2-Back verbal working memory paradigm during repeated functional magnetic resonance imaging (FMRI). Counterbalanced FMRI sessions were under conditions of PAP treatment (at least one consecutive week) or non-treatment (for two consecutive nights). Treatment effects on 2-Back-related brain activity were significant, with greater deactivation in the right posterior insula and overactivation in the right inferior parietal lobule. The observed responses to PAP treatment withdrawal were more extreme in all regions of interest, such that 2-Back-related activity increased and 2-Back-related deactivation decreased further relative to the 0-Back control task. The withdrawal of PAP treatment in effectively treated individuals with OSA might result in the need to reallocate resources in order to perform at the same cognitive level.

Home polysomnography in methadone maintenance patients with subjective sleep complaints.

OBJECTIVE: Most patients in methadone maintenance treatment (MMT) complain of poor sleep. Few studies have examined MMT patients' sleep using polysomnography (PSG), and none to our knowledge have employed home PSG. Standard sleep laboratory research protocols often require two consecutive PSG nights because of inter-night variability in sleep attributed to first-night adaptation to a novel sleep environment and recording procedures. The purpose of this study was to assess the stability of sleep measures across two consecutive nights of home PSG in opioid-dependent MMT patients. METHODS: Home PSG was performed in 50 MMT patients with subjective sleep complaints. Participants were 54% female and 82% white with mean age = 36.8 years, median methadone dose = 100 mg/day, and median MMT duration = 286 days. RESULTS: Thirty-six participants completed two consecutive nights of at-home PSG and 14 completed one. For the former group, no differences in sleep measures were found across recordings. The one-night group had significantly less total sleep time, Stage 2 sleep, REM sleep, and shorter REM latency than the two-night group. CONCLUSIONS: Home PSG is a viable method for recording sleep in opioid-dependent MMT patients, and was stable across consecutive nights of study. Two nights of home PSG for MMT patients, therefore, are not necessarily required and confidence in the reliability of data from one night of recording can be assumed. Excluding MMT research participants with one PSG may exclude patients with the worst sleep--precisely the group that most warrants investigation.

Pulse transit time in pregnancy: a new way to diagnose and classify sleep disordered breathing?

STUDY OBJECTIVES: There are significant discrepancies between the prevalence of snoring and that of objectively defined sleep disordered breathing among pregnant women, suggesting subtle airflow limitations that may not be captured by conventional scoring. This study examined the performance of pulse transit time, an indirect measure of arterial stiffness and sympathetic activation, in pregnancy. METHODS: Pregnant women with obesity and snoring and a group of controls without symptoms of sleep disordered breathing were recruited in the first trimester. Women underwent a level III in-laboratory sleep monitoring study including an electrocardiogram and pulse oximetry, and pulse transit time was measured. Sleep disordered breathing was defined as an apnea-hypopnea index at least five events per hour of sleep. Statistical analysis was performed using Spearman correlation, Fisher's exact t-test, and univariate analysis. RESULTS: Of the 222 women, 38 met criteria for sleep disordered breathing. Pulse transit time drops were very prevalent (95% of participants with snoring had > 5 drops per hour). Median apnea-hypopnea index was 0.7 (interquartile range [IQR]: 2.6) events per hour whereas median pulse transit time drop index was 20.70 (IQR: 35.90) events per hour. Pulse transit time index was significantly higher in snorers with apnea-hypopnea index less than five events per hours and participants with apnea-hypopnea index greater than five events per hour compared to controls. Examination of random epochs with pulse transit time drops showed that 95% of pulse transit time drops were associated with airflow limitation. CONCLUSIONS: Pulse transit time ascertains frequent events of sympathetic activation in at-risk women with and without sleep disordered breathing beyond conventional apneas and hypopneas. Pulse transit time may be an important addition to the identification of clinically significant sleep disordered breathing in pregnant women, and may identify more sleep disordered breathing than apnea-hypopnea index.

Trazodone for sleep disturbance after alcohol detoxification: a double-blind, placebo-controlled trial.

BACKGROUND: Trazodone is a commonly prescribed off-label for sleep disturbance in alcohol-dependent patients, but its safety and efficacy for this indication is unknown. METHODS: We conducted a randomized, double-blind, placebo-control trial of low-dose trazodone (50 to 150 mg at bedtime) for 12 weeks among 173 alcohol detoxification patients who reported current sleep disturbance on a validated measure of sleep quality or during prior periods of abstinence. Primary outcomes were the proportion of days abstinent and drinks per drinking day over 6-months; sleep quality was also assessed. RESULTS: Urn randomization balanced baseline features among the 88 subjects who received trazodone and 85 who received placebo. The trazodone group experienced less improvement in the proportion of days abstinent during administration of study medication (mean change between baseline and 3 months: -0.12; 95% CI: -0.15 to -0.09), and an increase in the number of drinks per drinking day on cessation of the study medication (mean change between baseline and 6 months, 4.6; 95% CI: 2.1 to 7.1). Trazodone was associated with improved sleep quality during its administration (mean change on the Pittsburgh Sleep Quality Index between baseline and 3 months: -3.02; 95% CI: -3.38 to -2.67), but after it was stopped sleep quality equalized with placebo. CONCLUSIONS: Trazodone, despite a short-term benefit on sleep quality, might impede improvements in alcohol consumption in the postdetoxification period and lead to increased drinking when stopped. Until further studies have established benefits and safety, routine initiation of trazodone for sleep disturbance cannot be recommended with confidence during the period after detoxification from alcoholism.

Time series analysis of treatment adherence patterns in individuals with obstructive sleep apnea.

BACKGROUND: Adherence to medical recommendations is often suboptimal, making examination of adherence data an important scientific concern. Studies that attempt to predict or modify adherence often face the problem that adherence as a dependent variable is complex and non-normally distributed. Traditional statistical approaches to adherence data may mask individual variability that may guide clinician and researcher's development of adherence interventions. In this study, we employ time series analysis to examine adherence patterns objectively in patients with obstructive sleep apnea (OSA). Although treatment adherence is poor in OSA, state-of-the-art adherence monitoring allows a comprehensive examination of objective data. PURPOSE: The purpose of the study is to determine the number and types of adherence patterns seen in a sample of patients with OSA receiving positive airway pressure (PAP). METHODS: Seventy-one moderate to severe OSA participants with 365 days of treatment data were studied. RESULTS: Adherence patterns could be classified into seven categories: (1) Good Users (24%), (2) Slow Improvers (13%), (3) Slow Decliners (14%), (4) Variable Users (17%), (5) Occasional Attempters (8%), (6) Early Drop-outs (13%), and (7) Non-Users (11%). CONCLUSIONS: Time series analysis provides a useful method for examining adherence while maintaining a focus on individual differences. Implications for future research are discussed.

Sleep disturbances and Parkinson's disease.

Although Parkinson's disease is defined by its motor symptoms, the symptoms that are most devastating to patients and caregivers are dementia and psychosis. In addition, sleep has a tremendous impact on patient well being and quality of life. Eighty percent to 90% of Parkinson's disease patients have a sleep disorder affecting their ability to fall asleep, ability to stay asleep, dreams, motor activity during sleep, post-sleep behavior, or daytime somnolence. Treatment plans for patients with Parkinson's disease who experience sleep disorders aim to improve nighttime sleep or daytime wakefulness, and treatment options vary by sleep disorder.

The impact of cardiac resynchronization therapy on obstructive sleep apnea in heart failure patients: a pilot study.

BACKGROUND: Cardiac resynchronization therapy (CRT) has been shown to improve cardiac function and reduce Cheyne-Stokes respiration but has not been evaluated in patients with obstructive sleep apnea (OSA). In this pilot study, we investigated the impact of both CRT and CRT plus increased rate pacing in heart failure (ie, congestive heart failure [CHF]) patients with OSA. We hypothesized that through increased cardiac output CRT/pacing would reduce obstructive events and daytime symptoms of sleepiness. METHODS: Full polysomnograms were performed on CHF patients who were scheduled for CRT, and those patients with an apnea-hypopnea index (AHI) of > 5 events per hour were approached about study enrollment. Patients had a pre-CRT implant baseline echocardiogram and an echocardiogram a mean (+/- SEM) duration of 6.6 +/- 1.4 months post-CRT implant; polysomnography; and responded to the Minnesota Living with Heart Failure questionnaire, the Epworth sleepiness scale, and the Functional Outcomes of Sleep Questionnaire. An additional third polysomnography was performed combining CRT with a pacing rate of 15 beats/min above the baseline sleeping heart rate within 1 week of the second polysomnography. Assessments for the change in cardiac output during the polysomnography were performed using circulation time to pulse oximeter as a surrogate. RESULTS: Twenty-four patients were screened, and 13 patients (mean age, 68.6 years; body mass index, 28.7 kg/m(2)) had evidence of OSA. The mean AHI decreased from 40.9 +/- 6.4 to 29.5 +/- 5.9 events per hour with CRT (p = 0.04). The mean baseline ejection fraction was 22 +/- 1.7% and increased post-CRT to 33.6 +/- 2.0% (p < 0.05). The reduction in AHI with CRT closely correlated with a decrease in circulation time (r = 0.89; p < 0.001) with CRT. Increased rate pacing made no additional impact on the AHI or circulation time. CRT had a limited impact on sleep architecture or daytime symptom scores. CONCLUSIONS: CRT improved cardiac function and reduced the AHI. Reduced circulatory delay likely stabilized ventilatory control systems and may represent a new therapeutic target in OSA.

Normalization of memory performance and positive airway pressure adherence in memory-impaired patients with obstructive sleep apnea.

BACKGROUND: Although the treatment of obstructive sleep apnea (OSA) with positive airway pressure (PAP) has been shown to be effective, nightly adherence to treatment remains poor. The objective of this study was to examine the degree to which various levels of PAP therapy adherence normalized verbal memory function after 3 months of therapy in patients with OSA who were memory-impaired prior to the initiation of PAP therapy. METHODS: Participants were administered neuropsychological testing prior to the initiation of PAP treatment and at a 3-month follow-up visit. Fifty-eight memory-impaired participants were categorized into the following three groups based on 3 months of adherence to PAP therapy: (1) poor users (n = 14), participants who averaged < 2 h of PAP use per night; (2) moderate users (n = 25), participants who averaged 2 to 6 h of PAP use per night; and (3) optimal users (n = 19), participants who averaged > 6 h of PAP use per night. RESULTS: Logistic regression analyses revealed that the odds of optimal users exhibiting normalization of memory function following 3 months of PAP therapy were 7.9 times (p = 0.01) the odds of poor users exhibiting normalization of memory abilities. Overall, 21% of poor users, 44% of moderate users, and 68% of optimal users exhibited memory performance in the clinically normal range following 3 months of PAP use (chi(2) = 7.27; p = 0.03). CONCLUSIONS: These preliminary findings indicate that impaired verbal memory performance in patients with OSA may be reversible with optimal levels of PAP treatment. OSA patients exhibiting verbal memory impairments may experience a clinically meaningful benefit in their memory abilities when they use PAP for at least 6 h per night.

The Effect of Changes in Cardiorespiratory Fitness and Weight on Obstructive Sleep Apnea Severity in Overweight Adults with Type 2 Diabetes.

STUDY OBJECTIVES: To examine the effect of changes in cardiorespiratory fitness on obstructive sleep apnea (OSA) severity prior to and following adjustment for changes in weight over the course of a 4-y weight loss intervention. METHODS: As secondary analyses of a randomized controlled trial, 263 overweight/obese adults with type 2 diabetes and OSA participated in an intensive lifestyle intervention or education control condition. Measures of OSA severity, cardiorespiratory fitness, and body weight were obtained at baseline, year 1, and year 4. Change in the apnea-hypopnea index (AHI) served as the primary outcome. The percentage change in fitness (submaximal metabolic equivalents [METs]) and change in weight (kg) were the primary independent variables. Primary analyses collapsed intervention conditions with statistical adjustment for treatment group and baseline METs, weight, and AHI among other relevant covariates. RESULTS: At baseline, greater METs were associated with lower AHI (B [SE] = -1.48 [0.71], P = 0.038), but this relationship no longer existed (B [SE] = -0.24 [0.73], P = 0.75) after adjustment for weight (B [SE] = 0.31 [0.07], P < 0.0001). Fitness significantly increased at year 1 (+16.53 ± 28.71% relative to baseline), but returned to near-baseline levels by year 4 (+1.81 ± 24.48%). In mixed-model analyses of AHI change over time without consideration of weight change, increased fitness at year 1 (B [SE] = -0.15 [0.04], P < 0.0001), but not at year 4 (B [SE] = 0.04 [0.05], P = 0.48), was associated with AHI reduction. However, with weight change in the model, greater weight loss was associated with AHI reduction at years 1 and 4 (B [SE] = 0.81 [0.16] and 0.60 [0.16], both P < 0.0001), rendering the association between fitness and AHI change at year 1 nonsignificant (B [SE] = -0.04 [0.04], P = 0.31). CONCLUSIONS: Among overweight/obese adults with type 2 diabetes, fitness change did not influence OSA severity change when weight change was taken into account. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identification number NCT00194259.

Treatment adherence and outcomes in flexible vs standard continuous positive airway pressure therapy.

STUDY OBJECTIVES: To compare adherence and clinical outcomes between flexible positive airway pressure (PAP) [C-Flex; Respironics; Murraysville, PA] and standard PAP therapy (ie, continuous positive airway pressure [CPAP]). DESIGN AND SETTING: A controlled clinical trial of CPAP therapy vs therapy using the C-Flex device in participants with moderate-to-severe obstructive sleep apnea. Participants were recruited from and followed up through an academic sleep disorders center. PARTICIPANTS: Eighty-nine participants were recruited into the study after they had undergone complete in-laboratory polysomnography and before initiating therapy. Participants received either therapy with CPAP (n = 41) or with the C-Flex device (n = 48), depending on the available treatment at the time of recruitment, with those recruited earlier receiving CPAP therapy and those recruited later receiving therapy with the C-Flex device. Follow-up assessments were conducted at 3 months. MEASUREMENTS AND RESULTS: The groups were similar demographically. The mean (+/- SD) treatment adherence over the 3-month follow-up period was higher in the C-Flex group compared to the CPAP group (weeks 2 to 4, 4.2 +/- 2.4 vs 3.5 +/- 2.8, respectively; weeks 9 to 12, 4.8 +/- 2.4 vs 3.1 +/- 2.8, respectively). Clinical outcomes and attitudes toward treatment (self-efficacy) were also measured. Change in subjective sleepiness and functional outcomes associated with sleep did not improve more in one group over the other. Self-efficacy showed a trend toward being higher at the follow-up in those patients who had been treated with the C-Flex device compared to CPAP treatment. CONCLUSIONS: Therapy with the C-Flex device may improve overall adherence over 3 months compared to standard therapy with CPAP. Clinical outcomes do not improve consistently, but C-Flex users may be more confident about their ability to adhere to treatment. Randomized clinical trials are needed to replicate these findings.

Examining the construct of depression in obstructive sleep apnea syndrome.

BACKGROUND AND PURPOSE: Depression is commonly reported by patients suffering from Obstructive Sleep Apnea Hypopnea Syndrome (OSAS). We used the factor structure of the Beck Depression Inventory-2nd edition (BDI-II) to examine the unique contributions of OSAS severity and obesity to depressive symptoms in OSAS. We predicted that the Somatic and Cognitive dimensions of the BDI-II would be more strongly associated with apnea severity and obesity, respectively. PATIENTS AND METHODS: Ninety-three moderate to severe OSAS patients (61 men, 32 women) were seen for psychological testing prior to initiating CPAP treatment. They completed the BDI-II and Epworth Sleepiness Scale (ESS). Measures of apnea severity (RDI, percent of sleep time below 90% oxygen saturation) and BMI were also collected. RESULTS: RDI was significantly related to BMI and BDI-II total score, but not to ESS score. BMI was related to BDI-II total score and ESS score. Partial correlations indicated that RDI was independently related to the Somatic dimension on the BDI-II. By contrast, BMI was uniquely associated with the Cognitive dimension. Although there was no difference in depression scores between men and women, the relationship between the Somatic factor and apnea severity was significant in men, whereas obesity and the Cognitive factor were significantly associated in women. CONCLUSIONS: OSAS severity and obesity contribute differentially to symptoms of depression in OSAS. In addition, symptoms of depression in OSAS manifest differently in men than in women.

The influence of white noise on sleep in subjects exposed to ICU noise.

BACKGROUND AND PURPOSE: There is disagreement in the literature about the importance of sleep disruption from intensive care unit (ICU) environmental noise. Previous reports have assumed that sleep disruption is produced by high-peak noise. This study aimed to determine whether peak noise or the change in noise level from baseline is more important in inducing sleep disruption. We hypothesized that white noise added to the environment would reduce arousals by reducing the magnitude of changing noise levels. PATIENTS AND METHODS: Four subjects underwent polysomnography under three conditions: (1) baseline, (2) exposure to recorded ICU noise and (3) exposure to ICU noise and mixed-frequency white noise, while one additional subject completed the first two conditions. Baseline and peak noise levels were recorded for each arousal from sleep. RESULTS: A total of 1178 arousals were recorded during these studies. Compared to the baseline night (13.3+/-1.8 arousals/h) the arousal index increased during the noise (48.4+/-7.6) but not the white noise/ICU noise night (15.7+/-4.5) (P<0.004). The change in sound from baseline to peak, rather than the peak sound level, determined whether an arousal occurred and was the same for the ICU noise and white noise/ICU noise condition (17.7+/-0.4 versus 17.5+/-0.3 DB, P=0.65). CONCLUSIONS: Peak noise was not the main determinant of sleep disruption from ICU noise. Mixed frequency white noise increases arousal thresholds in normal individuals exposed to recorded ICU noise by reducing the difference between background noise and peak noise.

Evaluation of the accuracy of SNAP technology sleep sonography in detecting obstructive sleep apnea in adults compared to standard polysomnography.

OBJECTIVE: To determine the accuracy of snoring and apnea analysis by SNAP (SNAP Laboratories; Glenview, IL), a technology that uses snoring recorded by a home microphone system and nasal airflow, to diagnose obstructive sleep apnea (OSA) as well as determine its severity. METHODS: For all patients who had undergone a prior SNAP study and were referred to the Sleep Disorders Center of Lifespan Hospitals for polysomnography testing from January 2000 through December 2001, we compared the results of the SNAP study to standard polysomnography (polysomnography). The severity of each apnea-hypopnea index (AHI) [mild, moderate, or severe, as defined by the AHI Severity Task Force of the American Academy of Sleep Medicine] recorded by SNAP was compared to that of the polysomnography result. All polysomnography tests were scored independently and without the prior knowledge of any SNAP results. RESULTS: For the 31 patients on whom data were available, the mean age, body mass index, and Epworth sleepiness scale scores were 50.3 years (range, 29 to 77 years), 31.6 kg/m(2) (range, 24 to 44 kg/m(2)), and 11.3 (range, 1 to 20), respectively. The mean follow-up time between the two studies was 5 months. The severity criteria indicated by the SNAP study accurately assessed the true severity confirmed by polysomnography in only 11 of 31 patients (35.5%). When the AHI severity score from the SNAP study was compared to polysomnography using a kappa statistic measure of agreement, there was overall agreement with a kappa value of 0.23 (p = 0.008), but the agreement was only fair. SNAP study severity scores were overestimated in 13 of 31 patients (41.9%) compared to the polysomnography results. In the majority of these subjects (8 of the 13 "overestimated" patients or 8 of 31 total patients [25.8%]), the SNAP study diagnosed OSA when the patient had a normal polysomnography finding. CONCLUSION: Although there may be some night-to-night variability in polysomnography testing, these results suggest that SNAP studies do not appear to accurately assess the severity of OSA.

Validation of the Apnea Risk Evaluation System (ARES) device against laboratory polysomnography in pregnant women at risk for obstructive sleep apnea syndrome.

STUDY OBJECTIVE: To assess the validity of using the Apnea Risk Evaluation System (ARES) Unicorder for detecting obstructive sleep apnea (OSA) in pregnant women. METHODS: Sixteen pregnant women, mean age (SD) = 29.8 (5.4) years, average gestational age (SD) = 28.6 (6.3) weeks, mean body mass index (SD) = 44.7 (6.9) kg/m(2) with signs and symptoms of OSA wore the ARES Unicorder during one night of laboratory polysomnography (PSG). PSG was scored according to AASM 2007 criteria, and PSG AHI and RDI were compared to the ARES 1%, 3%, and 4% AHIs calculated with the ARES propriety software. RESULTS: Median PSG AHI and PSG RDI were 3.1 and 10.3 events/h of sleep, respectively. Six women had a PSG AHI ≥ 5 events/h of sleep and 11 had a PSG RDI ≥ 5 events/h of sleep. PSG AHI and RDI were strongly correlated with the ARES AHI measures. When compared with polysomnographic diagnosis of OSA, the ARES 3% algorithm provided the best balance between sensitivity (1.0 for PSG AHI, 0.91 for PSG RDI) and specificity (0.5 for PSG AHI, 0.8 for PSG RDI) for detecting sleep disordered breathing in our sample. CONCLUSIONS: The ARES Unicorder demonstrated reasonable consistency with PSG for diagnosing OSA in this small, heterogeneous sample of obese pregnant women.

Airflow limitations in pregnant women suspected of sleep-disordered breathing.

BACKGROUND AND AIM: Pregnancy physiology may predispose women to the development of airflow limitations during sleep. The goal of this study was to evaluate whether pregnant women suspected of sleep-disordered breathing (SDB) are more likely to have airflow limitations compared to non-pregnant controls. METHODS: We recruited pregnant women referred for polysomnography for a diagnosis of SDB. Non-pregnant female controls matched for age, body mass index (BMI), and apnoea-hypopnoea index (AHI) were identified from a database. We examined airflow tracings for changes in amplitude and shape. We classified airflow limitation by (a) amplitude criteria defined as decreased airflow of > or =10 s without desaturation or arousal (FL 10), or decreased airflow of any duration combined with either 1-2% desaturation or arousal, (FL 1-2%); and (b) shape criteria defined as the presence of flattening or oscillations of the inspiratory flow curve. RESULTS: We identified 25 case-control pairs. Mean BMI was 44.0±6.9 in cases and 44.1±7.3 in controls. Using shape criteria, pregnant women had significantly more flow-limited breaths throughout total sleep time (32.4±35.8 vs. 9.4±17.9, p<0.0001) and in each stage of sleep (p<0.0001) than non-pregnant controls. In a subgroup analysis, pregnant women without a diagnosis of obstructive sleep apnoea (OSA) who had an AHI <5 had similar findings (p<0.0001). There was no difference in airflow limitation by amplitude criteria between pregnant women and controls (p=0.22). CONCLUSIONS: Pregnant women suspected of OSA have more frequent shape-defined airflow limitations than non-pregnant controls, even when they do not meet polysomnographic OSA criteria.