Agreement of different methods for assessing sleep characteristics: a comparison of two actigraphs,wrist and hip placement,and self-report with polysomnography

ObjectiveTo assess the agreement of sleep parameters measured by two actigraphs (SOMNOwatch plus^®, ActiGraph GT3X+^®) at two different placements (wrist, hip) and of self-reported sleep with polysomnography (PSG).MethodsWe estimated agreement with PSG for total sleep time (TST), sleep onset latency (SOL), wake after sleep onset (WASO), number of awakenings after sleep onset (NASO), and sleep efficiency (SE%) for 100 participants of the general population, aged 18–75 years by judging mean differences to PSG and intervals of agreement using Bland–Altman plots.ResultsMean difference to PSG for TST was 8.3 min (95% confidence intervals [CI] −7.4; 24.1) for SOMNOwatch plus^® (wrist), 39.8 min (95% CI 24.3; 55.3) for self-report, −79.0 min (95% CI −89.0; −68.9) for SOMNOwatch plus^® (hip), and −81.1 min (95% CI −91.9; −70.4) for GT3X+^® (hip), respectively. The width of intervals of agreement differed with the placement of the devices. Mean differences to PSG were higher for hip-based measurements compared with wrist placement for most parameters.ConclusionsAgreement of sleep parameters assessed by actigraphy with PSG differs with the placement of the device and is limited for hip-based measurements. Agreement of self-report with PSG is comparable to that of actigraphy for some parameters.     

Actigraphy scoring for sleep outcome measures in chronic obstructive pulmonary disease

BackgroundActigraphy is commonly used to measure sleep outcomes so that sleep can be measured conveniently at home over multiple nights. Actigraphy has been validated in people with sleep disturbances; however, the validity of scoring settings in people with chronic medical illnesses such as chronic obstructive pulmonary disease remains unclear. The purpose of this secondary analysis was to compare actigraphy-customized scoring settings with polysomnography (PSG) for the measurement of sleep outcomes in people with chronic obstructive pulmonary disease who have insomnia.MethodsParticipants underwent overnight sleep assessment simultaneously by PSG and actigraphy at the University of Illinois of Chicago Sleep Science Center. Fifty participants (35 men and 15 women) with mild-to-severe chronic obstructive pulmonary disease and co-existing insomnia were included in the analysis. Sleep onset latency, total sleep time (TST), wake after sleep onset (WASO), and sleep efficiency (SE) were calculated independently from data derived from PSG and actigraphy. Actigraphy sleep outcome scores obtained at the default setting and several customized actigraphy settings were compared to the scored PSG results.ResultsAlthough no single setting was optimal for all sleep outcomes, the combination of 10 consecutive immobile minutes for sleep onset or end and an activity threshold of 10 worked well. Actigraphy overestimated TST and SE and underestimated WASO, but there was no difference in variance between PSG and actigraphy in TST and SE when the 10 × 10 combination was used. As the average TST and SE increased, the agreement between PSG and actigraphy appeared to increase, and as the average WASO decreased, the agreement between PSG and actigraphy appeared to increase.ConclusionResults support the conclusion that the default actigraphy settings may not be optimal for people with chronic obstructive pulmonary disease and co-existing insomnia.     

A novel approach using actigraphy to quantify the level of disruption of sleep by in-home polysomnography: the MrOS Sleep Study: Sleep disruption by polysomnography

BackgroundThe “first-night effect” of polysomnography (PSG) has been previously studied; however, the ability to quantify the sleep disruption level has been confounded with the use of PSG on all nights. We used actigraphy to quantify disruption level and examined characteristics associated with disruption.MethodsTotally, 778 older men (76.2 ± 5.4 years) from a population-based study at six US centers underwent one night of in-home PSG. Actigraphy was performed on the PSG night and three subsequent nights. Actigraphically measured total sleep time (TST), sleep efficiency (SE), wake after sleep onset (WASO), and sleep onset latency (SOL) from the PSG night and subsequent nights were compared. Linear regression models were used to examine the association of characteristics and sleep disruption.ResultsOn average, sleep on the PSG night was worse than the following night (p < 0.05, TST 21 ± 85 min less, SE 2.3 ± 11.3% less, WASO 4.9 ± 51.8 min more, SOL 6.6 ± 56.2 min more). Sleep on the PSG night was significantly worse than that two and three nights later. Characteristics associated with greater sleep disruption on the PSG night included older age, higher apnea–hypopnea index, worse neuromuscular function, and more depressive symptoms. Minorities and men with excessive daytime sleepiness slept somewhat better on the PSG night.ConclusionsAmong older men, there was sleep disruption on the PSG night, which may lead to sleep time underestimation. The increase of sleep on the night after the PSG suggests that data from the second monitoring may overestimate sleep.     

Validation of a multi-sensor activity monitor for assessing sleep in children and adolescents

ObjectiveTo assess the validity of a multi-sensor activity monitor in estimating sleep and wake compared to polysomnography in children and adolescents.MethodsA total of 43 children and adolescents (29 boys, 14 girls), aged 7–17 years (mean age [SD] = 11.0 [2.4] years) participated in the study. Participants wore the SenseWear Pro₃ Armband™ (SWA) body monitor (BodyMedia Inc) during an overnight polysomnographic assessment in a paediatric sleep laboratory. Sleep measures included sleep onset latency (SOL), wake after sleep onset (WASO), total sleep time (TST) and sleep efficiency (SE).ResultsNo systematic bias of the SWA was noted for any of the sleep measures assessed, but limits of agreement were wide and amounted to −76 to +58 min for SOL, −75 to 102 min for WASO, −109 to +99 min for TST and −22 to +20% for SE. In addition, no effect of gender, age group (children versus adolescents) or overweight on the accuracy of the SWA was found.ConclusionsThe SenseWear Armband™ showed good agreement with polysomnography at the group level, while at the individual level rather, poor agreement between the two methods was observed. Consequently, at this point the use of the SWA in the clinical evaluation of sleep cannot be advocated.     

Digital phenotyping of sleep patterns among heterogenous samples of Latinx adults using unsupervised learning

ObjectiveThis study aimed to identify sleep disturbance subtypes (“phenotypes”) among Latinx adults based on objective sleep data using a flexible unsupervised machine learning technique.MethodsThis study was an analysis of sleep data from three cross-sectional studies of the Precision in Symptom Self-Management Center at Columbia University. All studies focused on sleep health in Latinx adults at increased risk for sleep disturbance. Data on total sleep time (TST), time in bed (TIB), wake after sleep onset (WASO), sleep efficiency (SE), number of awakenings (NOA) and the mean length of nightly awakenings were collected using wrist-mounted accelerometers. Cluster analysis of the sleep data was conducted using an unsupervised machine learning approach that relies on mixtures of multivariate generalized linear mixed models.ResultsThe analytic sample included 494 days of data from 118 adults (Ages 19–77). A 3-cluster model provided the best fit based on deviance indices (ie, DΔ∼ −75 and −17 from 1- and 2- to 3-cluster models, respectively) and likelihood ratio (P_diff ∼ 0.93). Phenotype 1 (n = 64) was associated with greater likelihood of overall adequate SE and less variability in SE and WASO. Phenotype 2 (n = 11) was characterized by higher NOAs, and greater WASO and TIB than the other phenotypes. Phenotype 3 (n = 43) was characterized by greater variability in SE, bed times and awakening times.ConclusionRobust digital data-driven modeling approaches can be useful for detecting sleep phenotypes from heterogenous patient populations, and have implications for designing precision sleep health strategies for management and early detection of sleep problems.     

Efficacy of brief behavioral treatment for insomnia in older adults: examination of sleep,mood, and cognitive outcomes

ObjectiveThe aim of the present study was to examine the effects of a brief behavioral intervention for insomnia (BBTi) on sleep parameters, mood, and cognitive functioning in older adults.MethodsOlder adults (aged 65 years or more) underwent four weekly sessions of BBTi or self-monitoring control (SMC). Participants completed 14 days of sleep diaries and actigraphy measuring sleep onset latency (SOL), wake after sleep onset (WASO), total sleep time (TST), sleep efficiency (SE), and sleep quality ratings at baseline, post-treatment, and three month follow-up. Participants also completed mood scales (Geriatric Depression Scale [GDS]; Beck Depression Inventory-II; and State Trait Anxiety Inventory) and neuropsychological testing (measuring global cognition, language, memory, attention and processing speed, and executive function) at the three timepoints.ResultsSignificant condition (BBTi vs. SMC) x time (baseline vs. post-treatment vs. follow-up) interactions revealed that BBTi improved relative to baseline in sleep diary-reported SOL, WASO, SE, and sleep quality, and these improvements were maintained at follow-up. SMC showed no change in these measures. A main effect of time showed that actigraphy-measured WASO improved from baseline for both BBTi and SMC at post-treatment. A main effect of time revealed that both BBTi and SMC patients endorsed fewer GDS symptoms relative to baseline at post-treatment and follow-up. We observed no change in performance on neuropsychological measures.ConclusionsA four-week BBTi is an efficacious intervention for reducing insomnia symptoms in older adults. BBTi does not selectively improve mood or cognitive functioning. Future work should examine effects of BBTi on physiological measures of sleep architecture and day-to-day cognition.Clinical Trial IdentiferNCT02967185.     

Application of deep learning to improve sleep scoring of wrist actigraphy

BackgroundEstimation of sleep parameters by wrist actigraphy is highly dependent on performance of the interpretative algorithm (IA) that converts movement data into sleep/wake scores.Research questions(1) Does the actigraphy mode of operation -Proportional Integrating Measure (PIM) or Zero Crossing Mode (ZCM), responsive respectively to intensity and frequency of movements- impact sleep scoring; and (2) Can a better performing sleep scoring IA be developed by a deep learning approach combining PIM/ZCM data.Study design and MethodsZCM and PIM plus electroencephalographic (EEG) data of 40 healthy adults (17 female, mean age: 26.7 years) were obtained from a single in-home nighttime sleep study. Effect of mode of operation was first evaluated by applying several classic deep learning models to PIM only, ZCM only, and combined ZCM/PIM data. After, a novel deep learning model was developed incorporating combined ZCM/PIM data, and its performance was compared with existing Cole-Kripke, rescored Cole-Kripke, Sadeh, and UCSD IAs.ResultsRelative to the EEG reference, ZCM/PIM combined mode produced higher agreement of scoring sleep/wake epochs than only ZCM or PIM modes. The proposed novel deep learning model showed 87.7% accuracy (0.2–1% higher than the other IAs), 94.1% sensitivity (0.7–4.3% lower than the other IAs), 64.0% specificity (9.9–21.5% higher than the other IAs), and 59.9% Kappa agreement (∼6.9–11.6% higher than other IAs) in detecting sleep epochs. The proposed deep learning model did not differ significantly from the reference EEG in estimating sleep onset latency (SOL), wake after sleep onset (WASO), total sleep time (TST), and sleep efficiency (SE). Amount of bias and minimum detectable change in estimating SOL, WASO, TST and SE by the deep learning model was smaller than other four IAs.InterpretationThe proposed novel deep learning algorithm simultaneously incorporating ZCM/PIM mode data performs significantly better in assessing sleep than existing conventional IAs.     

Agreement between sleep diary and actigraphy in a highly educated Brazilian population

ObjectiveThis study evaluated the agreement between a sleep diary and actigraphy on the assessment of sleep parameters among school teachers from Brazil.MethodsA total of 163 teachers (66.3% women; aged 45 ± 9 years) filled out a sleep diary and wore a wrist actigraph device for seven consecutive days. Data were collected from August 2014 to March 2015 in Londrina, a large city in southern Brazil. Intraclass correlation coefficients (ICC) and Pearson correlation coefficients (r) were used to compare self-reported and actigraphic data.ResultsSelf-reported total sleep time (TST), sleep onset latency (SOL), and sleep efficiency were higher than measured by actigraphy (mean difference: 22.6 ± 46.9 min, 2.6 ± 13.3 min, and 7.3± 5.7%, respectively). Subjective total time in bed (TIB) and wake-up time were lower than measured by actigraphy (mean difference: −10.7 ± 37.6 and −19.7 ± 29.6, respectively). Moderate or good agreement and correlation were found between the sleep diary and the actigraphic data for TST (ICC = 0.70; r = 0.60), TIB (ICC = 0.83; r = 0.73), bedtime (ICC = 0.95; r = 0.91), sleep start time (ICC = 0.94; r = 0.88), and wake-up time (ICC = 0.87; r = 0.78). However, SOL (ICC = 0.49; r = 0.38) and sleep efficiency (ICC = 0.16; r = 0.22) showed only fair or poor agreement and correlation.ConclusionIn this highly educated population, the sleep diary and the actigraphy showed moderate or good agreement to assess several sleep parameters. However, these methods seemed to measure different dimensions of sleep regarding sleep onset latency and efficiency. These findings moderately varied according to the individual's subjective sleep quality.     

Invalidity of one actigraphy brand for identifying sleep and wake among infants

Study objectivesFew commercially available brands of actigraphs (ACT) have been subjected to rigorous validation with infant participants. The purpose of this study was to examine the agreement between concurrent polysomnography (PSG) and one brand of ACT (AW-64, Mitter Co. Inc.) using appropriate statistical techniques among a sample of healthy infants.MethodsTwenty-two healthy infants (14.1 ± 0.6 months) had one night of ankle ACT recording during research PSG at Kosair Children’s Hospital Sleep Research Center in Louisville, Kentucky. Macroanalyses were conducted using the Bland–Altman concordance technique to assess agreement between total sleep time (TST) and wake after sleep onset (WASO) simultaneously measured by PSG and ACT, using two ACT algorithm settings. Microanalyses were also calculated to examine sensitivity, specificity, and accuracy of ACT within each PSG-identified sleep state. Correlations were calculated between PSG-identified arousals and the discrepancies between ACT and PSG.ResultsThe Bland–Altman concordance technique revealed that ACT underestimated TST by 72.25 (SD = 61.48) minutes and by ?60 min among 54.55% of infants. Furthermore, ACT overestimated WASO by 13.85 (SD = 30.94) minutes and by ?30 min among 40.91% of infants. Sensitivity, specificity, and accuracy analyses revealed that ACT adequately identified sleep, but poorly identified wake. PSG and ACT discrepancies were positively associated with PSG-identified arousals (r = .45).ConclusionsImproved device and/or software development is needed before the AW-64 can be considered a valid method for identifying infant sleep and wake.     

Sleep in adults with Autism Spectrum Disorder: a systematic review and meta-analysis of subjective and objective studies

Background/ObjectiveSleep problems are commonly reported by individuals with Autism Spectrum Disorder (ASD). However, to date, no quantitative evidence synthesis of available studies has been performed to quantify sleep alterations in adults with ASD. We performed a systematic review and meta-analysis of objective (ie, based on actigraphy or polysomnography [PSG]) and subjective (ie, based on sleep diaries/questionnaires) studies comparing sleep parameters in adults with ASD and in a typically developing (TD) control group.MethodsPubMed, OVID databases and Web of Knowledge were systematically searched up to February 2019 with no language restrictions. Original studies including adults with a diagnosis of ASD according to DSM, ICD, or based on standard diagnostic tools (eg, ADOS), and a TD control group were included. Random-effects models were used. Study quality was evaluated with the Newcastle Ottawa Scale (NOS). Analyses were conducted using Comprehensive Meta-Analysis.ResultsFrom initial pool of 1948 references, 14 publications including 8 datasets, (194 ASD and 277 controls) met the inclusion criteria. Compared to controls, individuals with ASD were significantly more impaired in six out of 11 subjective parameters, including lower sleep efficiency (SE, SMD = −0.87, CI = −1.14 – 0.60) and in 10 out of 17 objective outcomes, including longer sleep onset latency (PSG) (SMD = 0.86, CI = 0.29–1.07) and wake after sleep onset (WASO, actigraphy) (SMD = 0.57, CI = 0.28–0.87). The mean NOS score was 4.88/6.ConclusionsIndividuals with ASD demonstrated impaired sleep compared to controls in most subjective and objective measures.     

Effect of maternal sleep in late pregnancy on leptin and lipid levels in umbilical cord blood

ObjectivesTo study the impact of maternal sleep in late pregnancy on birth weight (BW) and leptin and lipid levels in umbilical cord blood.Study designA total of 277 healthy and singleton pregnancy women were recruited for participation in the Shanghai Sleep Birth Cohort Study (SSBC) during their 36–38 weeks of pregnancy, from May 2012 to July 2013. Maternal night sleep time (NST), sleep efficiency (SE), sleep onset latency (SOL) and the percentage of wake after sleep onset (WASO) in NST and midpoint of sleep (MSF) were measured by actigraphy for seven consecutive days. The leptin and lipid levels were determined in cord blood samples collected from the umbilical vein immediately after delivery. Birth information (birth weight, gender, delivery type, etc.) was extracted from medical records. A multivariable linear regression model was applied to examine the effect of maternal sleep in late pregnancy on newborn leptin and lipid levels in umbilical cord blood.ResultsA total of 177 women and their infants were included in the analysis. Maternal mean NST was 7.03 ± 1.10 h in late pregnancy, and 48% had a shorter sleep time (NST < 7 h). The average maternal SE was 72.54% ± 9.66%. The mean percentage WASO/NST was 21.62% ± 9.98%; the average MSF was about 3:34 (0:53); and the SOL was 46.78 ± 36.00 min. After adjustment for confounders, both maternal NST and SE were found to be significantly associated with triglyceride levels (β = −0.219, p = 0.006; β = −0.224, p = 0.006) in umbilical cord blood; and maternal NST was also observed to have positive association with newborn leptin levels (β = 0.146, p = 0.047). However, we did not find significant association between other maternal sleep parameters in late pregnancy and leptin and lipid levels and birth weight.ConclusionsShort sleep duration and poor sleep quality during late pregnancy were associated with newborn leptin and lipid levels, and efforts on improving maternal sleep during late pregnancy should be advocated for children's health.     

The role of actigraphy in the assessment of primary insomnia: a retrospective study

ObjectiveThe aim of our study was to evaluate quantitative actigraphic criteria obtained using the Actiwatch device (AW64; Cambridge Neurotechnology Ltd., Cambridge, UK) to differentiate participants with insomnia from normal sleepers.MethodsIn our retrospective study, we recovered 493 actigraphic records from two sleep measure databases of patients with insomnia (n = 151) and one of normal sleepers (n = 342). We considered the following actigraphic sleep parameters: time in bed (TIB), sleep-onset latency (SOL), total sleep time (TST), wake after sleep onset (WASO), sleep efficiency (SE), number of awakenings (NWAK), terminal wakefulness (TWAK), fragmentation index (FI), and mean motor activity (MA). We also considered two actigraphic circadian indexes: interdaily stability and intradaily variability. Using the Youden index, we calculated the quantitative actigraphic criteria that performed best for each actigraphic sleep parameter. Finally, we created receiver operating characteristic curves to test the accuracy of each criterion identified.ResultsAll sleep parameters except TST and TWAK differentiated the two groups of participants, allowing calculation of quantitative actigraphic criteria. There were no differences in the circadian indices.ConclusionsThe quantitative actigraphic criteria obtained in our study were not the same as those obtained previously with a different device, suggesting the need to adopt shared technical solutions for actigraphy.     

Sleep disturbance and cardiometabolic risk factors in early pregnancy: a preliminary study

BackgroundCardiometabolic (CM) risk factors are linked to increased morbidity. Disturbed sleep is associated with CM risk factors in late pregnancy, but little is known about sleep in early pregnancy and CM risk factors.MethodsDiary and actigraphy-assessed sleep information, as well as CM outcomes (blood pressure (BP) and body mass index (BMI)), were collected thrice from pregnant women (N = 161) in early pregnancy: T1 (10–12 weeks), T2 (14–16 weeks) and T3 (18–20 weeks). The sleep variables evaluated included sleep onset latency (SOL), wake after sleep onset (WASO) and total sleep time (TST). Sleep variables were dichotomised using established clinical cut-offs.ResultsBMI and BP significantly changed across time. Women with persistent SOL ⩾ 20 min had greater BMI than women without persistent SOL ⩾ 20 min prior to covariate adjustment at T1 and T2, but at T3 the BMI values converged. Similar results were observed for persistent WASO ⩾ 30 min. Persistently long WASO, as measured by actigraphy, was associated with elevated SBP, after controlling for covariates.ConclusionsConsistent with anecdotal evidence, it appears as if a subset of women report substantial difficulty initiating and maintaining sleep during early pregnancy and this may augment the risk of higher BP and BMI. Understanding these relationships is important as CM risk factors are linked to maternal and infant morbidity. Assessing sleep in early pregnancy may bestow time necessary for appropriate intervention.     

Nocturnal sleep architecture in idiopathic hypersomnia: a systematic review and meta-analysis

BackgroundCurrent sleep medicine nosology places increased importance on nocturnal polysomnographic sleep recordings in the diagnosis of central nervous system disorders of hypersomnolence, particularly idiopathic hypersomnia (IH).ObjectiveDetermine what differences in sleep staging and architecture exist between IH and healthy controls using meta-analysis.MethodsSystematic review identified relevant studies that included nocturnal polysomnography data for IH and healthy control groups. Meta-analysis compared standardized mean differences (Hedge's g) for total sleep time (TST), sleep onset latency (SOL), sleep efficiency (SE), rapid eye movement (REM) sleep percentage, slow wave sleep (SWS) percentage, and REM latency (REML). Moderator analyses were also conducted for variables with significant heterogeneity among studies.ResultsThe meta-analysis included 10 studies. Relative to controls, IH demonstrated increased TST (pooled g = 0.92; 95% CI: 0.46 to 1.38, p < 0.0001) and REM percentage (pooled g = 0.36, 95% CI: 0.09 to 0.64, p = 0.01), decreased SOL (pooled g = −0.46; 95% CI: −0.81 to −0.12, p = 0.009) and SWS percentage (pooled g = −0.28, 95% CI: −0.50 to −0.07, p = 0.01), without significant differences in SE (pooled g = 0.03; 95% CI: −0.32 to 0.38, p = 0.86) or REML (pooled g = 0.14, 95% CI: −0.21 to 0.49, p = 0.42). Moderator analysis demonstrated a significant effect of sex on SE, with a higher proportion of women to men significantly predicting lower SE between in IH and controls (p < 0.0001).ConclusionsIH is associated with several changes in sleep staging and architecture relative to healthy persons, including alterations in REM and SWS not currently delineated in nosological constructs. Further research is indicated to clarify how these findings are related the pathophysiology of IH and related disorders.     

Night-to-night sleep variability in older adults with and without chronic insomnia

Objectives(1) To quantify night-to-night variability in sleep behaviors and sleep measures among older chronic insomnia (CI) subjects and non-insomnia (NI) controls; (2) to investigate systematic temporal patterns of sleep behaviors and sleep measures across nights; and (3) to examine clinical correlates of sleep variability.MethodsSixty-one older adults with CI (71.4 years old, 67% F) and 31 older adults with NI (70.7 years old, 65% F) completed questionnaires, kept sleep diaries and wore wrist actigraphs for 2 weeks. Mixed models were used to estimate within-subject mean and standard deviation values; these were then compared across groups. Mixed models were also used to determine associations across nights of sleep measures.ResultsCI and NI differed on mean values for clinical ratings and sleep diary measures, but not for actigraphy measures. CI also showed significantly greater variability than NI on most sleep diary measures and on actigraphically measured wakefulness after sleep onset (WASO) and sleep efficiency. Among CI, neither diary nor actigraphy measures from one night correlated with values from the previous night. Diary WASO, sleep time, actigraphy sleep latency and sleep time, however, positively correlated with values from the previous two nights. Variability measures were not correlated with other global clinical measures among CI.ConclusionsCompared to NI, older adults with CI report worse sleep and greater night-to-night variability, which was confirmed with actigraphy. There was little evidence for positive or negative correlation of sleep measures across nights. Variability of sleep may be an important target for insomnia treatments.     

The influence of placebo administration on the first- night effect in patients with insomnia disorder

ObjectiveWe aimed to investigate the effects of placebo on the first-night effect (FNE) in insomniacs.MethodsIn sum, 36 patients with insomnia disorder who met the DSM-5 criteria were enrolled in this study. Sixteen patients with insomnia disorder were given two days of placebo intervention (placebo-administration group, PL). Twenty patients with insomnia disorder (drug-free group, DF) were not given any interventions. All participants underwent two consecutive nights of polysomnographic (PSG) testing in the sleep laboratory. Sleep diaries were recorded during one week at home before the PSG nights and on two subsequent nights.ResultsThe results demonstrated that compared with the DF group, sleep onset latency (SOL), time in bed (TIB) and wake after sleep onset (WASO) significantly increased and sleep efficiency (SE) significantly decreased in the first sleep lab night in the PL group (all p < 0.05). Moreover, compared with the second night, significant differences were observed in lower self-reported total sleep time (TST) and more subjective WASO during the first night in the PL group (all p < 0.05). However, no significant difference was found in the duration and percentage of N1, N2, N3 and REM between the two groups.ConclusionIn patients with insomnia disorder, placebo administration may increase the occurrence of worse sleep without causing a change in the duration and percentage of N1, N2, N3 and REM on the first sleep lab night. In some cases, a placebo may not serve as treatment but may result in a nocebo effect.     

Comparison of actigraphy and polysomnography to assess effects of zolpidem in a clinical research unit

ObjectiveThis study sought to compare devices that use actigraphy for measuring sleep endpoints in the clinical research unit (CRU) and home environment. The abilities of polysomnography (PSG) and actigraphy monitors to detect drug effects in a CRU were also investigated.MethodsEleven healthy subjects were recruited and monitored with PSG for four consecutive nights in a CRU after receiving no treatment (night 1, N1), and then placebo or 5 mg day^?1 or 10 mg day^?1 zolpidem in a randomised, cross-over design. Subjects wore two devices that use actigraphy (a Respironics® Actiwatch® on the wrist and a BodyMedia® Sensewear® Armband on the upper-arm) on the non-dominant arm for five nights at home and four nights in the CRU during PSG.ResultsWake after sleep onset (WASO) and total sleep time (TST) measured by PSG and estimates of WASO by the Actiwatch decreased significantly with 5 mg but not 10 mg of zolpidem versus placebo. Direct activity (counts/min) with the Actiwatch decreased in response to zolpidem (both 5 and 10 mg day^?1) versus placebo. Armband recordings of direct activity were similar to the Actiwatch but not significantly different versus placebo. Both actigraphy device estimates of TST were approximately 1 h longer in CRU versus home. Agreement between actigraphy estimates of TST and WASO and PSG values of TST and WASO were closer during nights with zolpidem treatment.ConclusionsPSG can detect the effects of zolpidem on sleep in a CRU setting. Actigraphy can provide useful assessment of sleep, but direct activity endpoints may be more effective than estimates of TST and WASO.     

Intraindividual sleep variability and its association with insomnia identity and poor sleep

ObjectiveInsomnia identity refers to the conviction that one has insomnia, which can occur independently of poor sleep. Night-to-night variability in sleep (termed intraindividual variability [IIV]) may contribute to insomnia identity yet remain undetected via conventional mean analyses. This study compared sleep IIV across four subgroups: noncomplaining good sleepers (NG), complaining poor sleepers (CP), complaining good sleepers (CG), and noncomplaining poor sleepers (NP).MethodsThis study analyzed 14 days of sleep diary data from 723 adults. Participants were classified according to presence/absence of a sleep complaint and presence/absence of poor sleep. A 2 × 2 multivariate analysis of covariance (MANCOVA) was performed to explore differences on five measures of sleep IIV: intraindividual standard deviation in total sleep time (iSD TST), sleep onset latency (iSD SOL), wake after sleep onset (iSD WASO), number of nightly awakenings (iSD NWAK), and sleep efficiency (iSD SE).ResultsMANCOVA revealed significant main effects of poor sleep, sleep complaint, and their interaction on sleep IIV. Poor sleepers exhibited greater IIV across all sleep parameters compared to good sleepers. Similarly, individuals with a sleep complaint exhibited greater IIV compared to individuals with no complaint. The interaction revealed that iSD SOL was significantly greater among CP than NP, and iSD NWAK was significantly greater among CG than NG.ConclusionsGreater night-to-night variability in specific sleep parameters was present among complaining versus noncomplaining sleepers in good and poor sleep subgroups. These findings suggest certain aspects of sleep consistency may be salient for treatment-seeking individuals based on their quantitative sleep status.     

Associations of self-reported and actigraphy-assessed sleep characteristics with body mass index and waist circumference in adults: moderation by gender

ObjectivesSelf-reported sleep duration has been linked to body mass index (BMI) and waist circumference in previous work; however, data regarding if these associations are stronger in men or women have been mixed, and few studies have objectively measured sleep. We investigated self-reported and actigraphy-assessed sleep characteristics in relation to BMI and waist circumference and examined the extent to which these associations differ by gender.DesignArchived cross-sectional data collected from 2004 to 2006 from the National Survey of Midlife Development in the United States (MIDUS) Biomarkers Study were used. Participants included 1248 adults (43% men) who reported their habitual sleep duration, and a subset of participants (N = 441; 40% men) who underwent seven nights of wrist actigraphy.ResultsSelf-reported total sleep time (TST), actigraphy-assessed TST, and actigraphy-assessed sleep efficiency (SE) were inversely associated with BMI in the full sample of both men and women. Gender moderated associations between actigraphy assessments of sleep and anthropometric variables; however, TST and SE were related to BMI and waist circumference in women only. Associations between sleep and waist circumference were independent of BMI.ConclusionsSleep duration and sleep continuity are associated with body weight and distribution of body fat, but these associations were stronger or were only present in women.     

Quantitative association between nocturnal voiding frequency and objective sleep quality in the general elderly population: the HEIJO-KYO cohort

ObjectiveA significant association between nocturia and subjective sleep quality has previously been reported; however, the association between nocturia and objective sleep quality remains unclear. The purpose of this study was to evaluate the quantitative association between nocturnal voiding (NV) frequency and objective sleep quality in a large, general, elderly population.MethodsNocturnal voiding frequency, objective sleep quality, and subjective sleep quality were measured among 1086 community-based elderly individuals using actigraphy and the Pittsburgh Sleep Quality Index (PSQI) questionnaire.ResultsIn multivariate analyses adjusted for potential confounding factors (such as age, gender, body mass index, medication use, renal function, bedtime, rising time, daytime physical activity, endogenous melatonin levels, and bedroom light levels), increased NV frequency, ranging from zero, one, two, three or more voids, was significantly associated with poorer objective sleep quality, including lower sleep efficiency (SE) and longer wake after sleep onset (WASO) (mean SE, 86.3, 84.8, 83.6, and 81.2%, respectively; p for trend <0.001; mean WASO: 42.6, 49.0, 53.6, and 66.1 min, respectively; p for trend <0.001), but shorter sleep onset latency (SOL) (mean SOL, 3.0, 3.0, 2.8, and 2.8 log min, respectively; p for trend = 0.018). In addition, an increased NV frequency was significantly associated with poorer subjective sleep quality in a multivariate model (mean PSQI global score, 4.60, 4.86, 5.22, and 5.48, respectively; p for trend 0.012).ConclusionThe present study revealed a quantitative association between NV frequency and objective sleep quality in the general elderly population.