Measured Sleep Parameters Research Articles

Estimating sleep from multisensory armband measurements: validity and reliability in teens.

Given the recognition that sleep may influence obesity risk, there is increasing interest in measuring sleep parameters within obesity studies. The goal of the current analyses was to determine whether the SenseWear(®) Pro3 Armband (armband), typically used to assess physical activity, is reliable at assessing sleep parameters. The armband was compared with the AMI Motionlogger(®) (actigraph), a validated activity monitor for sleep assessment, and with polysomnography, the gold standard for assessing sleep. Participants were 20 adolescents (mean age = 15.5 years) with a mean body mass index percentile of 63.7. All participants wore the armband and actigraph on their non-dominant arm while in-lab during a nocturnal polysomnographic recording (600 min). Epoch-by-epoch sleep/wake data and concordance of sleep parameters were examined. No significant sleep parameter differences were found between the armband and polysomnography; the actigraph tended to overestimate sleep and underestimate wake compared with polysomnography. Both devices showed high sleep sensitivity, but lower wake detection rates. Bland-Altman plots showed large individual differences in armband sleep parameter concordance rates. The armband did well estimating sleep overall, with group results more similar to polysomnography than the actigraph; however, the armband was less accurate at an individual level than the actigraph.

Sleep matters: Associations between cognition and objectively measured sleep parameters in older adults with or without mild cognitive impairment

Sleep matters: Associations between cognition and objectively measured sleep parameters in older adults with or without mild cognitive impairment

Effects of Aquatic Exercise on Sleep in Older Adults with Mild Sleep Impairment: a Randomized Controlled Trial.

Exercise has been found to be associated with improved sleep quality. However, most of the evidence is based on resistance exercise, walking, or gym-based aerobic activity. This study aimed to examine the effects of an 8-week aquatic exercise program on objectively measured sleep parameters among older adults with mild sleep impairment. A total of 67 eligible older adults with sleep impairment were selected and randomized to exercise and control groups, and 63 participants completed the study. The program involved 2 × 60-min sessions of aquatic exercise for 8weeks. Participants wore wrist actigraphs to assess seven parameters of sleep for 1week before and after the intervention. Mixed-design analysis of variance (ANOVA) was used to assess the differences between groups in each of the sleep parameters. No significant group differences on demographic variables, life satisfaction, percentage of body fat, fitness, seated blood pressure, and any parameter of sleep were found at baseline. Significant group × time interaction effects were found in sleep onset latency, F(1,58) = 6.921, p = .011, partial eta squared = .011, and in sleep efficiency, F(1, 61) = 16.909, p < 0.001, partial eta squared = .217. The exercise group reported significantly less time on sleep onset latency (mean difference = 7.9min) and greater sleep efficiency (mean difference = 5.9%) than the control group at posttest. There was no significant difference between groups in change of total sleep time, wake after sleep onset, activity counts, or number and length of awakenings. An 8-week aquatic exercise has significant benefits on some sleep parameters, including less time for sleep onset latency and better sleep efficiency in older adults with mild sleep impairment.

Health and well-being related to wind turbine noise exposure: Summary of results

This paper summarizes the results of the Health Canada Wind Turbine Noise and Health Study. One participant between the ages of 18–79 years was randomly selected from each household. The final sample included 1238 participates (606 males) living between 0.25 and 11.22 km from wind turbines. The response rate was 78.9% and did not significantly vary across sampling strata or between provinces. Wind turbine noise (WTN) exposure was not found to be related to hair cortisol concentrations, resting blood pressure, resting heart rate, or any of the measured sleep parameters. Self-reported results obtained through an in-person questionnaire do not provide support for an association between increasing WTN levels and self-reported sleep disturbance, use of sleep medication, or diagnosed sleep disorders. Similarly, no significant association was found between WTN levels and self-reported migraines, tinnitus, dizziness, diabetes, asthma, hypertension, perceived stress, or any measure of quality of life. Statistically significant exposure-response relationships were observed between increasing WTN levels and an increase in the prevalence of long term high annoyance towards several wind turbine features, including: noise, shadow-flicker, visual impacts, and vibrations. The influence of background noise on annoyance and the association between WTN annoyance and other reported and measured outcomes is presented.

Validation study on sleep parameters by actigraphy for normal subjects

Dear Editor: O’Hare et al. reported the performance of three sleep monitoring devices for measuring sleep parameters in 20 normal subjects against sleep polysomnography (PSG) [1]. The authors used two non-contact radio-frequency biomot ion sensors , named SleepMinder® and S leepDes ign® , and an acce l e rome te r , named Actiwatch®. Compared with sleep PSG, all three devices overestimated total sleep time and underestimated wake after sleep onset and sleep onset latency. I appreciate that the authors checked the validity of three sleep monitoring devices, including Actiwatch®, against sleep PSG. Although the agreement of sleep/wake judgment by sleep monitoring devices is satisfactory for normal subjects, the authors recognized the limitation when these devices were applied for patients with insomnia. I have a query on their study with special emphasis on Actiwatch®. O’Hare et al. quoted a paper on selecting appropriate cutoff point for sleep-wake judgment [2], but there is no definite way to determine the best sensitivity of sleepwake judgment for every subject. Kushida et al. found the best overall accuracy and ability to detect wakefulness using Actiwatch® and PSG, when the “high-sensitivity” setting (20 counts per minute) was used [3]. Peterson et al. adopted the default sensitivity setting (40 counts per minute), and they described the overestimation of total sleep time and underestimation of wake after sleep onset by Actiwatch® [4], which was the same study outcome by O’Hare et al. There is a difference between brain activity and physical movement during sleep, and the discrepancy of sleep parameters between sleep PSG and sleep monitoring devices would be obvious for insomniacs [5]. Validation study of sleep parameters by SleepMinder®, SleepDesign®, and Actiwatch® as a tool for sleep/wake judgment should also be conducted in patients with sleep apnea syndrome and other sleep disorders.

A comparison of radio-frequency biomotion sensors and actigraphy versus polysomnography for the assessment of sleep in normal subjects

This paper aims to compare the absolute performance of three noncontact sleep measurement devices for measuring sleep parameters in normal subjects against polysomnography and to assess their relative performance. The devices investigated were two noncontact radio-frequency biomotion sensors (SleepMinder (SM) and SleepDesign (HSL-101)) and an actigraphy-based system (Actiwatch). Overnight polysomnography measurements were carried out in 20 normal subjects, with simultaneous assessment of sleep parameters using the three devices. The parameters measured included total sleep time (TST), sleep efficiency (SE), sleep-onset latency (SOL), and wake-after-sleep onset (WASO). The per-epoch agreement level for sleep/wake distinction was evaluated. The TSTs reported by the three devices were 426 ± 34, 434 ± 22, and 441 ± 16min, for the SM, HSL-101, and Actiwatch, respectively, against polysomnogram (PSG)-reported TST of 391 ± 49min. The SOLs were 10 ± 10, 5 ± 6, and 3 ± 2min for the SM, HSL-101 and Actiwatch, respectively against PSG SOL of 19 ± 13min. The WASO times were 46 ± 33, 43 ± 22, and 38 ± 17min, as against PSG-reported 69 ± 46min. All three devices had a statistically significant bias to overestimate sleep time and underestimate WASO and SOL compared with PSG. The performance of the three devices was basically equivalent, with only minor interdevice differences. The overall per-epoch agreement levels were 86% for the SM, 86% for the HSL-101, and 85% for the Actiwatch. Noncontact biomotion approaches to sleep measurement provided reasonable estimates of TST, but with a bias to over-estimation of sleep. The radio-frequency biomotion sensors provided similar accuracies for sleep/wake determination in normal subjects as the actigraph used in this study and slightly improved estimates of TST, SOL, and WASO.

A Pilot Study Investigating Differences in Sleep and Life Preoccupations in Chronic and Acute Insomnia

Background and Objective - Theory suggests that during the transition from acute to chronic insomnia a shift in attention, from life events to sleep difficulties, occurs. The aim of this study was to examine whether this shift indeed exists, by measuring the frequency and type of preoccupations in acute and chronic insomnia. Methods - Using a cross-sectional design, two groups [people with acute insomnia (n = 11) and chronic insomnia (n = 20)] completed a series of standardized and semi-idiosyncratic measures daily, over the period of one week. They also wore actigraphs to provide objective measures of sleep parameters. Results - Findings suggest no differences in preoccupation between the two groups but show the acute insomnia group report significantly higher levels of perceived stress. Exploratory analysis suggests a reduction in scores on standardized measures across all participants between time 1 and time 2, and no differences on objectively measured sleep parameters. Conclusions - Results indicate there is no difference between people with acute and chronic insomnia in level, and type, of reported preoccupation and that people with acute insomnia are as preoccupied during the day by both sleep and life events, as people with chronic insomnia. Limitations are discussed and future research questions are considered.

Insomnia symptoms, objectively measured sleep, and disease severity in chronic obstructive pulmonary disease outpatients

BackgroundSleep disturbances are known to have a negative impact on a range of clinical outcomes in chronic obstructive pulmonary disease (COPD). We examined the associations of insomnia symptoms and objectively measured sleep parameters to a composite score for body mass index, airflow obstruction, dyspnea, and exercise capacity (BODE) index (a multidimensional index of COPD severity), arterial blood gases, nocturnal respiratory disturbances, periodic limb movements (PLM), psychologic distress, pain, age, and sex. MethodsThe sample comprised 73 COPD outpatients (mean age, 63.6years; standard deviation {SD}, 7.5; range 47–85years; 41.1% women). Insomnia symptoms were measured with the Bergen Insomnia Scale (BIS) and sleep efficiency (SE), slow-wave sleep (SWS), and total sleep time (TST) were assessed with clinical polysomnography (PSG). ResultsBODE index was positively associated with composite BIS score (P=.040). Patients with more severe COPD presented more complaints of nonrestorative sleep compared to patients with less severe COPD (P=.010). In multivariate analysis, the composite BIS score was independently associated with PLM (P<.001), nocturnal respiratory disturbances (P=.001), pain (P=.031), and psychologic distress (P=.044) but not with the BODE index. Objectively measured sleep variables were not associated with any of the health-related variables. ConclusionInsomnia symptoms in COPD patients result from a wide range of health-related factors. More severe COPD may be associated with a subjective experience of nonrestorative sleep but not with objectively measured sleep variables.

Repetitive Thought Impairs Sleep Quality: An Experience Sampling Study

Although previous research has suggested that presleep negative cognitive activities are associated with poor sleep quality, there is little evidence regarding the association between negative thoughts and sleep in real-life settings. The present study used experience sampling and long-term sleep monitoring with actigraphy to investigate the relationships among negative repetitive thought, mood, and sleep problems. During a 1-week sampling period, 43 undergraduate students recorded their thought content and mood eight times a day at semirandom intervals. In addition to these subjective reports, participants wore actigraphs on their wrists in order to measure sleep parameters. Analyses using multilevel modeling showed that repetitive thought in the evening was significantly associated with longer sleep-onset latency, decreased sleep efficiency, and reduced total sleep time. Furthermore, impaired sleep quality was significantly associated with reduced positive affect the next morning, and decreased positive affect was indirectly associated with increased repetitive thought in the evening. These findings suggest the existence of a self-reinforcing cycle involving repetitive thought, mood, and impaired sleep quality, highlighting the importance of cognitive and emotional factors in enhancement and maintenance of good-quality sleep.

FRI0452 Determinants factors of sleep disturbances in spondylarthritis

BackgroundLiterature data suggest that sleep disturbances are prevalent among patients with Spondylarthritis (Spa) and have a close correlation with pain and psychological status.Objectivesour study was designed first to evaluate sleep...

Using Actigraphy to Measure Sleep Patterns in Rheumatoid Arthritis: A Pilot Study in Patients Taking Night‐Time Prednisone

ObjectivePoor sleep quality is a commonly reported but under-investigated consequence of rheumatoid arthritis (RA). Actigraphy is a non-invasive way of measuring sleep, estimated from the frequency and intensity of physical movement at the wrist. We used actigraphy to measure sleep parameters compared with sleep questionnaire data, and assessed the practicality of actigraph use in patients with RA.MethodsIn a pilot study of actigraphy conducted within an investigation of night-time prednisone treatment and circadian interleukin-6 concentrations in ten patients with active RA, we compared actigraphy with the St Mary’s Hospital Sleep Questionnaire and assessed whether night-time administration of prednisone resulted in increased sleep disturbance.ResultsThe actigraph watch was well tolerated by our patients, producing adequate data for analysis for 128 out of 133 test days (96.2%). The results indicated reasonable concordance between actigraph and sleep questionnaire data in the present sample. Patient satisfaction with sleep (question 11) strongly correlated with sleep efficiency measured by the actigraph (r = 0.71, p = 0.22) and showed a trend for inverse correlation with the fragmentation index (r = −0.60, p = 0.067). Quality of sleep (question 9) correlated non-significantly with the fragmentation index (r = −0.59, p = 0.072). We were unable to identify any significant correlations between clinical measures of disease and sleep parameters in this sample. There were no apparent detrimental consequences of the night-time dose of prednisone on the measures of sleep quality and quantity.ConclusionIn spite of the physical disability imposed by RA, the actigraph was well tolerated and gave a useful measure of sleep in patients with active disease. It has the potential for use in larger controlled trials.

Subjectively and objectively measured sleep with and without posttraumatic stress disorder and trauma exposure.

Although reports of sleep disturbances are common among individuals with posttraumatic stress disorder (PTSD), results of polysomnographic (PSG) studies have inconsistently documented abnormalities and have therefore suggested "sleep state misperception." The authors' study objectives were to compare sleep parameters measured objectively and subjectively in the laboratory and at home in civilians with and without trauma exposure and PTSD. Cross-sectional study. PSG recordings in a sleep laboratory and actigraphic recordings in participants' homes. One hundred three urban-residing African Americans with and without trauma exposure and PTSD who participated in a larger study. N/A. Sleep parameters (total sleep time [TST], sleep onset latency [SOL], and wake after sleep onset [WASO]) were assessed using laboratory PSG and home actigraphy. A sleep diary was completed in the morning after PSG and actigraphy recordings. Habitual TST, SOL, and WASO were assessed using a sleep questionnaire. The Clinician Administered PTSD Scale was administered to assess participants' trauma exposure and PTSD diagnostic status. Participants, regardless of their trauma exposure/PTSD status, underestimated WASO in the diary and questionnaire relative to actigraphy and overestimated SOL in the diary relative to PSG. Among participants with current PTSD, TST diary estimates did not differ from the actigraphy measure in contrast with those without current PTSD who overestimated TST. No other significant group differences in discrepancies between subjective and objective sleep measures were found. Discrepancies between subjectively and objectively measured sleep parameters were not associated with trauma exposure or PTSD. This challenges prior assertions that individuals with PTSD overreport their sleep disturbances.

Effects of methamphetamine self‐administration and withdrawal on sleep in rhesus monkeys

Published studies indicate that methamphetamine (METH) abuse may lead to impaired sleep and a higher risk of developing sleep disorders which could contribute to continued drug use. To understand the effects of METH abuse on sleep, we determined how METH self‐administration (SA) in rhesus macaques alters sleep parameters. The subjects were trained to self‐administer METH under a fixed‐ratio schedule of reinforcement in 60‐minute sessions conducted 5 days per week. We measured sleep parameters such as the latency to fall asleep, the duration of sleep, and sleep fragmentation using actigraphy‐based monitors. We also determined the effects of METH SA on sleep by examining several weeks of baseline sleep measures prior to each bout of METH SA, sleep parameters during 5‐week bouts of METH SA, and several weeks of sleep parameters following each bout of METH SA. METH SA elicited modest sleep fragmentation, but did not alter sleep latency or duration when the unit dose available for SA was 0.01 mg/kg and the maximum dose available per day was 0.6 mg/kg. METH induced sleep fragmentation during the active bout of METH SA, but sleep returned to baseline levels within the first week after METH SA. Different effects were apparent when the unit dose available for SA was 0.03 mg/kg. We will further elucidate the effects of METH on sleep and we will determine whether sleep‐promoting drugs reverse these effects.

Early-life trauma is associated with rapid eye movement sleep fragmentation among military veterans

The role of sleep in the relations between early-life trauma and the development of adverse psychological trajectories is relatively unknown and was the primary aim of the present study. Military veterans were evaluated for posttraumatic stress disorder, combat exposure, trauma history, sleep quality, disruptive nocturnal behaviors, and a subsample completed overnight polysomnography that yielded objectively measured sleep parameters. When relevant variables were controlled, increased earlier-life traumatic event exposure was associated with increased rapid-eye-movement sleep (REMs) fragmentation, and increased REMs fragmentation was associated with increased later-life disruptive nocturnal behaviors. REMs fragmentation carried an indirect relation between earlier-life trauma and later-life disruptive nocturnal behaviors. Objectively measured sleep parameters were used to describe REMs fragmentation physiology. The current findings elucidate the important role that earlier-life trauma exposure may have in the development of REM sleep physiology, and how this altered sleep physiology may have dynamic influences on subsequent posttraumatic stress symptoms in adulthood.

Depression is associated with worse objectively and subjectively measured sleep, but not more frequent awakenings, in women with vasomotor symptoms

Depression occurs more commonly during the menopausal transition in women with vasomotor symptoms (VMS) than in those without, but most women with VMS do not develop depression. It has been hypothesized that VMS are associated with depression because VMS lead to repeated awakenings, which impair daytime well-being. We aimed to determine if objectively measured sleep and perceived sleep quality are worse in depressed women with VMS than in nondepressed women with VMS. Objectively and subjectively measured sleep parameters were compared between 52 depressed women with VMS and 51 nondepressed controls with VMS. Actigraphic measures of objective sleep conducted in the home environment and subjective measures of sleep quality (Pittsburgh Sleep Questionnaire Index) were compared using linear regression models. On objective assessments, depressed women with VMS spent less time in bed (by 64.8 min; P < 0.001) and had shorter total sleep time (by 47.7 min; P = 0.008), longer sleep-onset latency (by 13.8 min; P = 0.03), and lower sleep efficiency (by 3.2 percentage points; P = 0.09), but did not awaken more or spend more time awake after sleep onset than nondepressed controls with VMS. Depressed women also reported worse sleep quality (mean Pittsburgh Sleep Questionnaire Index 12.0 vs 8.3; P < 0.001). Adjustment for VMS frequency and important demographic characteristics did not alter these associations. Sleep quality and selected parameters of objectively measured sleep, but not sleep interruption, are worse in depressed than in nondepressed women with VMS. The type of sleep disturbance seen in depressed participants was not consistent with the etiology of depression secondary to VMS-associated awakenings.

Assessment of actigraphy as a method to assess sleep quality following inpatient tonsillectomy in children

Introduction: The aetiology of sleep disturbance in children following surgery is unclear, despite a reported incidence of 47% [1]. The Actiwatch, a small ‘wristwatch’ device, uses actigraphy, a technology based on the principle of movement detection, to assess sleep quality. It can be attached to a child and set to record details of movement at regular intervals. We sought to determine whether the Actiwatch is able to produce useful data for the assessment of sleep in inpatient children following tonsillectomy. Methods: Prior local ethics committee approval and informed parental consent were obtained. Fifteen ASA 1–2 children, aged 2–12 undergoing inpatient tonsillectomy were recruited. The Actiwatch monitor, programmed to record movement at 25 s intervals, was attached to each child after surgery and then retrieved the following morning. Additional data concerning operative details, drugs administered and adverse events were recorded and a sleep diary was provided for nursing staff and parents to record periods of sleep and wake overnight. Actigraph summary data was retrieved from each wristwatch the following day and details of asleep and awake periods recorded in the sleep diary were compared with actigraph data. Results: All parents approached agreed to take part, however one child refused to wear the ‘watch’ and was not included in the study. One further dataset was not collected due to a watch malfunction, leaving data from 13 children (five male, eight female) remaining. A total of 86 sleep assessments were made in the sleep diaries which, when compared with the actigraph data, gave a sensitivity and specificity of 82% and 90% respectively. The mean, range and standard deviation for overnight sleep parameters for all children were as follows: Total sleep time: 8 h 24 min (range 7:04–10:30 h), sd 70.7 min. Total awake time: 1 h 20 min (range 22 min–2:48 h), sd 41 min. Number of sleep bouts: 59.7 (range 33–109) sd 19.5. Sleep efficiency (% of total time spent asleep): 78.8% (range 69–95.8%), sd 8.8%. Discussion: Risk factors previously identified for poor postoperative sleep in the day case setting include pain, preoperative sleep patterns, parental anxiety and aggressive child behaviour [3]. However, there has been little work published using actigraphy in the inpatient setting to determine which factors are associated with poor sleep, such as the ward environment and perioperative medication. The actigraph is a small robust device that appears to be well tolerated by inpatient children, with only one refusal and one malfunction. We have illustrated a good correlation between observed and recorded sleep, indicating that the actigraph is indeed a useful tool for the assessment of postoperative sleep dysfunction in children. This correlates well with other authors [2] who have found a concordance rate of 85.3% compared with polysomnography in children. We have illustrated a large variation in the recorded sleep patterns between children in the inpatient setting. Both the range and standard deviations of the recorded parameters are large, implying that a direct comparative study of perioperative techniques, for example, would require large sample sizes to ensure adequate power. It is possible that more robust data may be obtained by recording control actigraphy data on a child preoperatively, such that a paired comparison can then be made. This approach will, however, be logistically more challenging as it will require multiple preoperative contacts with the child. Conclusions: We conclude that actigraphy is a practical and reasonably reliable tool for the assessment of sleep in children following tonsillectomy although we have also illustrated a large inter-patient variation of all measured sleep parameters.

S298 – Difference of P/Ex and Severity of OSA According to Age

Objectives It has been proved by many researchers that there are different dominant narrowing site of upper airway according to age and many sleep parameters change with age. We evaluate the difference of physical examination and severity of obstructive sleep apnea according to age. Methods 255 male patients were subjected to this study. All of them were diagnosed OSAS by polysomnography and examined preoperative work-up including BMI, cephalometry parameter(PAS, PNS-P, MPH), nasopharyngoscopy with Muller maneuver before surgical treatment. We measured sleep parameters (lowest oxygen saturation, Apnea-hypopnea index) by polysomnography and studied the difference of physical exam and sleep parameter among the 4 groups (-29,30–39, 40-,50-) according to age. Results Among the estimated parameters of 4 groups which were divided according to age, there were significant difference in BMI, neck circumference, chest circumference, abdominal circumference in physical exam and PNS-P, MPH in radiologic finding. (p&lt;0.05) AHI that reflects OSA severity was significantly different among 4 groups. Patient distribution of over 15 AHI score were 36% in the under 29 group, 72% in 30–39 group, 59% in 40–49 group and 55% in the over 50-years-old group. Conclusions According to the ages, we found that physical exam, and radiologic finding were different significantly among age groups. AHI were significantly different among 4 groups and OSA severity was increased significantly after 30 years old, but there was no difference significantly in the over-30 groups.

Indiplon in the treatment of sleep disorders.

Indiplon is a novel sedative-hypnotic recently approved for the treatment of insomnia. Like other non-benzodiazepine hypnotics, its mechanism of action is to modulate subunits, especially the alpha-1 subunit, of the GABA receptor complex in order to induce sedation. Indiplon was developed in two different formulations to address two different types of insomnia complaint: indiplon-IR (immediate release) was designed for sleep onset difficulties, while indiplon-MR (modified release) was developed for sleep maintenance insomnia. While there are currently few peer reviewed articles about indiplon clinical trial results, the early information that is available seems to indicate that both formulations have been well tolerated and have proven effective at improving both patient reported and objectively measured sleep parameters in both adult and elderly insomnia patients. In May 2006, the FDA indicated that indiplon-IR was approvable and plans are to resubmit the application in 2007. Indiplon-MR was unapprovable and may require further evaluation.

Adherence, Reports of Benefits, and Depression Among Patients Treated With Continuous Positive Airway Pressure

To examine if reported obstructive sleep apnea (OSA) symptom improvement, baseline depressive symptoms, or polysomnographically measured sleep parameters are associated with adherence to continuous positive airway pressure (CPAP). CPAP is a highly effective treatment for OSA. Low adherence to CPAP therapy is common and poorly understood. Depression and lack of perceived benefits from CPAP are possible reasons for low adherence. Seventy-eight patients evaluated for OSA at a sleep medicine center agreed to participate in the study; 54 patients completed all study assessments. The Beck Depression Inventory (BDI) and the functional outcomes of sleep questionnaire (FOSQ) were administered before polysomnographic evaluation. A card embedded in the CPAP device electronically recorded adherence. The BDI and FOSQ were administered 1 to 2 months after the baseline measurements were obtained. Baseline depressive symptoms were not correlated with mean duration of CPAP use per night. Reported improvements in OSA symptoms were correlated positively with CPAP adherence. There were significant positive correlations between improvement in depressive symptoms and OSA symptoms after initiation of CPAP therapy. The polysomnographic variables measured did not predict improvement in daytime OSA symptoms or CPAP adherence. Post hoc analyses suggested that those individuals with baseline Apnea Hypopnea Index (AHI) between 40 and 80 experienced more symptom improvement than those with AHI <40 or >80. Patients with the greatest level of CPAP adherence also reported the greatest improvement in OSA symptoms. Patients who continued to experience OSA symptoms after CPAP treatment also tended to have more depressive symptoms after CPAP treatment.

The Efficacy and Safety of the Melatonin Agonist beta-Methyl-6-Chloromelatonin in Primary Insomnia

While melatonin agonists are known to regulate circadian sleep rhythms, it is not clear whether melatonin agonists have a direct soporific effect. It has been suggested that melatonin's soporific effect is secondary to its ability to induce hypothermia. beta-Methyl-6-chloromelatonin is a high-affinity melatonin receptor agonist that is not associated with hypothermia. The purpose of the present study was to determine if the melatonin agonist beta-methyl-6-chloromelatonin has a direct soporific effect in subjects with primary insomnia. A double-blind, placebo-controlled, crossover safety and efficacy study of 20 mg, 50 mg, and 100 mg of beta-methyl-6-chloromelatonin and placebo was conducted in subjects with DSM-IV-TR primary insomnia. Of 84 subjects screened, 40 progressed to randomly receive each of 3 beta-methyl-6-chloromelatonin doses or placebo on each of 2 consecutive nights with 5-day washout periods between treatments. The effect of treatment on both polysomnographic and subjectively measured sleep parameters, next-morning psychomotor performance, and safety measures was determined. The primary outcome measure was latency to persistent sleep measured by polysomnography. A significant effect of beta-methyl-6-chloromelatonin on the primary efficacy variable, latency to persistent sleep, was observed (p = .0003). The 20-mg dose resulted in a significant 31% improvement in sleep latency compared with placebo, while significant 32% and 41% improvements were observed at the 50-mg and 100-mg doses, respectively (20 mg, p = .0082; 50 mg, p = .0062; 100 mg, p < .0001). Similarly, a significant effect of beta-methyl-6-chloromelatonin on subjective measures of time to fall asleep occurred (p = .0050), with significant improvement observed at both the 50-mg and 100-mg doses (p = .0350 and .0198, respectively) and a trend toward improvement observed at the 20-mg dose (p = .0582). Adverse events were mild to moderate in severity and did not differ in frequency between beta-methyl-6-chloromelatonin and placebo treatments. beta-Methyl-6-chloromelatonin significantly decreases both objective and subjective measures of sleep latency in subjects with primary insomnia. Thus, these data suggest that mel-atonin agonists may exert a direct soporific effect, as previous research indicates that beta-methyl-6-chloromelatonin is not associated with changes in body temperature, heart rate, or blood pressure.