Sleep Fragmentation Index Research Articles

Sleep Patterns and Hypertension Using Actigraphy in the Hispanic Community Health Study/Study of Latinos

The aim of this study was to evaluate the association between actigraphy-based measures of sleep and prevalent hypertension in a sample of US Latinos. We analyzed data from 2,148 participants of the Sueño Sleep Ancillary Study of the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), who underwent 1week of wrist actigraphy to characterize sleep duration, sleep efficiency, sleep fragmentation index, and daytime naps. Insomnia was defined as an Insomnia Severity Index≥ 15. Hypertension was defined based on self-reported physician diagnosis. Survey linear regression was used to evaluate the association of sleep measures with hypertension prevalence. Sensitivity analyses excluded participants with an apnea-hypopnea index (AHI)≥ 15 events/h. The mean age was 46.3 ± 11.6 years, and 65%of the sample consisted of women. The mean sleep duration was 6.7 ± 1.1 hours. Thirty-two percent of the sample had hypertension. After adjusting for age, sex, ethnic background, site, and AHI, each 10%reduction in sleep efficiency was associated with a 7.5%(95%CI, -12.9 to -2.2; P=.0061) greater hypertension prevalence, each 10%increase in sleep fragmentation index was associated with a 5.2%(95%CI, 1.4-8.9; P= .0071) greater hypertension prevalence, and frequent napping was associated with a 11.6%greater hypertension prevalence (95%CI, 5.5-17.7; P= .0002). In contrast, actigraphy-defined sleep duration (P= .20) and insomnia (P=.17) were not associated with hypertension. These findings persisted after excluding participants with an AHI≥ 15 events/h. Independent of sleep-disordered breathing, we observed associations between reduced sleep continuity and daytime napping, but not short sleep duration, and prevalent hypertension.

Objectively measured short sleep duration and later sleep midpoint in pregnancy are associated with a higher risk of gestational diabetes

Experimental and epidemiologic data suggest that among nonpregnant adults, sleep duration may be an important risk factor for chronic disease. Although pregnant women commonly report poor sleep, few studies objectively evaluated the quality of sleep in pregnancy or explored the relationship between sleep disturbances and maternal and perinatal outcomes. Our objective was to examine the relationship between objectively assessed sleep duration, timing, and continuity (measured via wrist actigraphy) and maternal cardiovascular and metabolic morbidity specific to pregnancy. This was a prospective cohort study of nulliparous women. Women were recruited between 16 0/7 and 21 6/7 weeks' gestation. They were asked to wear a wrist actigraphy monitor and complete a daily sleep log for a period of 7 consecutive days. The primary sleep exposure variables were the averages of the following over the total valid nights (minimum 5, maximum 7 nights): short sleep duration during the primary sleep period (<7 h/night), late sleep midpoint (midpoint between sleep onset and sleep offset >5 am), and top quartile of minutes of wake time after sleep onset and sleep fragmentation index. The primary outcomes of interest were a composite of hypertensive disorders of pregnancy (mild, severe, or superimposed preeclampsia; eclampsia; or antepartum gestational hypertension) and gestational diabetes mellitus. We used χ2 tests to assess associations between sleep variables and categorical baseline characteristics. Crude odds ratios and 95% confidence intervals were estimated from univariate logistic regression models to characterize the magnitude of the relationship between sleep characteristics and hypertensive disorders of pregnancy and gestational diabetes. For associations significant in univariate analysis, multiple logistic regression was used to explore further the association of sleep characteristics with pregnancy outcomes. In all, 901 eligible women consented to participate; 782 submitted valid actigraphy studies. Short sleep duration and a later sleep midpoint were associated with an increased risk of gestational diabetes (odds ratio, 2.24; 95% confidence interval, 1.11-4.53; and odds ratio, 2.58; 95% confidence interval, 1.24-5.36, respectively) but not of hypertensive disorders. A model with both sleep duration and sleep midpoint as well as their interaction term revealed that while there was no significant interaction between these exposures, the main effects of both short sleep duration and later sleep midpoint with gestational diabetes remained significant (adjusted odds ratio, 2.06; 95% confidence interval, 1.01-4.19; and adjusted odds ratio, 2.37; 95% confidence interval, 1.13-4.97, respectively). Additionally, after adjusting separately for age, body mass index, and race/ethnicity, both short sleep duration and later sleep midpoint remained associated with gestational diabetes. No associations were demonstrated between the sleep quality measures (wake after sleep onset, sleep fragmentation) and hypertensive disorders or gestational diabetes. Our results demonstrate a relationship between short sleep duration and later sleep midpoint with gestational diabetes. Our data suggest independent contributions of these 2 sleep characteristics to the risk for gestational diabetes in nulliparous women.

Nonpharmacological Interventions for Sleep Promotion in the Intensive Care Unit.

Nonpharmacological Interventions for Sleep Promotion in the Intensive Care Unit.

Quantifying the dynamic of OSA brain using multifractal formalism: A novel measure for sleep fragmentation.

It is thought that the critical brain dynamics in sleep is modulated during frequent periods of wakefulness. This paper utilizes the capacity of EEG based scaling analysis to quantify sleep fragmentation in patients with obstructive sleep apnea. The scale-free (fractal) behavior refers to a state where no characteristic scale dominates the dynamics of the underlying process which is evident as long range correlations in a time series. Here, Multiscaling (multifractal) spectrum is utilized to quantify the disturbed dynamic of an OSA brain with fragmented sleep. The whole night multichannel sleep EEG recordings of 18 subjects were employed to compute and quantify variable power-law long-range correlations and singularity spectra. Based on this characteristic, a new marker for sleep fragmentation named ``scaling based sleep fragmentation'' was introduced. This measure takes into account the sleep run length and stage transition quality within a fuzzy inference system to improve decisions made on sleep fragmentation. The proposed index was implemented, validated with sleepiness parameters and compared to some common indexes including sleep fragmentation index, arousal index, sleep diversity index, and sleep efficiency index. Correlations were almost significant suggesting that the sleep characterizing measure, based on singularity spectra range, could properly detect fragmentations and quantify their rate. This method can be an alternative for quantifying the sleep fragmentation in clinical practice after being approved experimentally. Control of sleep fragmentation and, subsequently, suppression of excessive daytime sleepiness will be a promising outlook of this kind of researches.

Actigraphic Sleep Patterns of U.S. Hispanics: The Hispanic Community Health Study/Study of Latinos.

To assess the extent to which objective sleep patterns vary among U.S. Hispanics/Latinos. We assessed objective sleep patterns in 2087 participants of the Hispanic Community Health Study/Study of Latinos from 6 Hispanic/Latino subgroups aged 18-64 years who underwent 7 days of wrist actigraphy. The age- and sex-standardized mean (SE) sleep duration was 6.82 (0.05), 6.72 (0.07), 6.61 (0.07), 6.59 (0.06), 6.57 (0.10), and 6.44 (0.09) hr among individuals of Mexican, Cuban, Dominican, Central American, Puerto Rican, and South American heritage, respectively. Sleep maintenance efficiency ranged from 89.2 (0.2)% in Mexicans to 86.5 (0.4)% in Puerto Ricans, while the sleep fragmentation index ranged from 19.7 (0.3)% in Mexicans to 24.2 (0.7)% in Puerto Ricans. In multivariable models adjusted for age, sex, season, socioeconomic status, lifestyle habits, and comorbidities, these differences persisted. There are important differences in actigraphically measured sleep across U.S. Hispanic/Latino heritages. Individuals of Mexican heritage have longer and more consolidated sleep, while those of Puerto Rican heritage have shorter and more fragmented sleep. These differences may have clinically important effects on health outcomes.

Effect of different types of exercise on sleep quality of elderly subjects

Objective/BackgroundThere are still many gaps in research concerning the effect of different physical training modalities on sleep quality in the elderly population. Thus, the objective of the present study was to compare the quality of sleep of hypertensive elderly subjects submitted to two types of training (ie, aerobic exercise alone or combined aerobic and resistance training). Patients/MethodsParticipants aged 60–75 years were randomized to three groups: aerobic group (AG), combined aerobic and resistance group (ARG), and control untrained group (CG). Training lasted ten consecutive weeks with 30 uninterrupted sessions. The actigraph (Actiwatch Minimitter Company, INC – Sunriver, OR, USA) was placed on the non-dominant wrist and activities were monitored continuously while being recorded at one minute intervals. The participants kept the device for a period of 96 hours before the first and last training sessions. ResultsThere was a reduction in sleep fragmentation index of 18.9 for AG and 13 for ARG (p < 0.01) and the sleep efficacy was improved in the exercise groups, with a 5.6% increase for AG (p = 0.02) and a 6.1% increase for ARG (p = 0.01). After training, percentage of minutes motionless was increased by 8.2% for AG and by 6.9% for ARG (p < 0.01), indicating improved sleep quality. A reduction in total activity score during sleep was observed for AG and ARG (p < 0.01). ConclusionsThe two types of exercise performed for ten weeks similarly improved sleep quality, thus reducing the fragmentation index, the percentage of minutes in motion and total activity score, and increasing sleep efficacy.

Impact of sleep behavior on glycemic control in type 1 diabetes: the role of social jetlag.

Sleep behavior is changing toward shorter sleep duration and a later chronotype. It results in a sleep debt that is acquitted on work-free days, inducing a small but recurrent sleep misalignment each week, referred to as "social jetlag". These sleep habits could affect health through misalignment with circadian rhythms. The primary objective is to address the impact of sleep behavior on glycemic control, assessed by HbA1c, in patients with type 1 diabetes, independently of other lifestyle or sleep-related factors. The secondary objective is to address whether circadian phase affects glycemic control. In total, 80 adult patients with type 1 diabetes (46% female) were included in a clinical cohort study. Sleep behavior was addressed objectively by a 7-day actimetry, lifestyle by questionnaires, sleep breathing disorders by nocturnal oximetry and circadian phase by dim light melatonin onset (DLMO). Univariate analyses showed that chronotype (r = 0.23, P = 0.042) and social jetlag (r = 0.30, P = 0.008) were significantly associated with HbA1c. In multivariable analysis, social jetlag was the only sleep habit independently associated with HbA1c (β = 0.012 (0.006; 0.017), P < 0.001). HbA1c was lower in patients with a social jetlag below versus above the median (7.7% (7.1-8.7) and 8.7% (7.6-9.8), P = 0.011). DLMO was not associated with HbA1c. However, the later the DLMO, the worse the sleep efficiency (r = -0.41, P < 0.001) and fragmentation index (r = 0.35, P = 0.005). Social jetlag, a small but recurrent circadian misalignment, is associated with worse glycemic control in type 1 diabetes, whereas circadian phase is not. Further intervention studies should address the potential improvement of glycemic control by correcting social jetlag.

24-h activity rhythm and sleep in depressed outpatients

Disturbances in sleep and circadian rest-activity rhythms are key features of depression. Actigraphy, a non-invasive method for monitoring motor activity, can be used to objectively assess circadian rest-activity rhythms and sleep patterns. While recent studies have measured sleep and daytime activity of depressed patients using wrist-worn actigraphy, the actigraphic 24-h rest-activity rhythm in depression has not been well documented. We aimed to examine actigraphically measured sleep and circadian rest-activity rhythms in depressed outpatients. Twenty patients with DSM-IV major depressive episode and 20 age- and sex-matched healthy controls participated in this study. Participants completed 7 consecutive days of all-day actigraphic activity monitoring while engaging in usual activities. For sleep parameters, total sleep time, wake after sleep onset, and sleep fragmentation index were determined. Circadian rhythms were estimated by fitting individual actigraphy data to a cosine curve of a 24-h activity rhythm using the cosinor method, which generated three circadian activity rhythm parameters, i.e., MESOR (rhythm-adjusted mean), amplitude, and acrophase. Subjective sleep was also assessed using a sleep diary and the Pittsburgh Sleep Quality Index. Patients showed significantly lower MESOR and more dampened amplitude along with significant sleep disturbances. Logistic regression analysis revealed that lower MESOR and more fragmented sleep emerged as the significant predictors of depression. Correlations between subjectively and actigraphically measured parameters demonstrated the validity of actigraphic measurements. These results indicate marked disturbances in sleep and circadian rest-activity rhythms of depression. By simultaneously measuring sleep and rest-activity rhythm parameters, actigraphy might serve as an objective diagnostic aid for depression.

Actigraphic sleep fragmentation, efficiency and duration associate with dietary intake in the Rotterdam Study.

Short self-reported sleep duration is associated with dietary intake and this association may partly mediate the link between short sleep and metabolic abnormalities. Subjective sleep measures, however, may be inaccurate and biased. The objective of this study was to evaluate the associations between actigraphic measures of sleep fragmentation, efficiency and duration and energy and macronutrient intakes. We used data from a subgroup of 439 participants of the population-based cohort, Rotterdam Study. Sleep was assessed using 7-day actigraphy and sleep diaries, and dietary data with a validated food frequency questionnaire. We assessed the associations of actigraphic sleep parameters with dietary intake using multivariable linear regression models. Higher sleep fragmentation was associated with 4.19g lower carbohydrate intake per standard deviation of fragmentation {β [95% confidence interval (CI)=-4.19 (-8.0, -0.3)]; P=0.03}. Each additional percentage increase in sleep efficiency was associated with 11.1kcal lower energy intake [β (95% CI)=-11.1 (-20.6, -1.7); P=0.02]. Furthermore, very short sleep duration (<5.5h) was associated with 218.1kcal higher energy intake [β (95% CI=218.06 (33.3, 402.8), P=0.02], relative to the reference group (≥6.5 to <7.5h). We observed associations between higher sleep fragmentation with lower carbohydrate intake, and both lower sleep efficiency and very short sleep duration (<5h) with higher energy intake. The association between sleep and higher energy intake could mediate, in part, the link between short sleep or sleep fragmentation index and metabolic abnormalities.

Intermittent hypoxemia and sleep fragmentation: associations with daytime alertness in obese sleep apnea patients living at moderate altitude

BackgroundAlthough obstructive sleep apnea (OSA) has long been associated with daytime sleepiness, far less is known about its association with the ability to remain awake. The aim of this study was to examine the relative importance of inter-correlated measures of OSA severity (eg, various indices of oxygen saturation and sleep fragmentation) in the ability to stay alert as measured objectively by the Maintenance of Wakefulness Test (MWT), defined by a mean sleep latency of ≥12 min. MethodsSeventy-eight obese women and men of similar age and body mass index living at altitude (Mexico City) underwent standard polysomnography, MWT, and completed validated sleep-related questionnaires. ResultsMen had more severe sleep apnea than women (p = 0.002) and were also less alert on MWT (p = 0.022). Logistic regression models indicated that measures of desaturation consistently predicted MWT-defined alertness, whereas varied measures of sleep fragmentation did not. Nearly a third of the variance (r2 = 0.304) in MWT-defined alertness was accounted for by the number of desaturations per hour of sleep (p = 0.003), which is considerably higher than other studies have reported in different populations. ConclusionThe ability to remain awake in obese patients is best accounted for by hypoxemia rather than sleep fragmentation. Whether the size of this effect reflects differences in the population under study (eg, extent of obesity, racial background, residence at moderate altitude) and/or is a function of the measurement of alertness with the MWT remains uncertain.

An intensive longitudinal examination of daily physical activity and sleep in midlife women

ObjectivesPrevious research examining physical activity (PA) and sleep link has largely ignored the day-to-day variability that is present in these 2 health behaviors, and few studies have addressed this relation using objective assessments of PA and sleep. Through an intensive longitudinal design, the present study aimed: (1) to elucidate the reciprocal associations between PA and sleep; and (2) to better understand the role of body mass index (BMI) in these 2 health behaviors. MethodsCommunity-dwelling midlife women (N = 103; M = 53, age range= 40-60 years) wore an accelerometer for the objective assessment of PA and sleep for 21 days. A series of multilevel models were estimated to test concurrent and lagged associations between PA (activity counts, moderate-to-vigorous PA) and sleep (total sleep time [TST], sleep efficiency, sleep fragmentation indices). Results and conclusionsIn concurrent, same-day analyses, a positive association emerged between PA and sleep such that as activity counts increased during the day, TST at night also increased (P < .05). In lagged analyses examining next-day effect of sleep on PA, a negative association was found such that greater TST on a given night was associated with less moderate-to-vigorous PA the subsequent day (P < .05). A moderation effect by BMI was also observed such that women with a high BMI engaging in overall lower levels of PA demonstrated poorer-quality sleep. The data suggest that leading a physically active lifestyle may have protective effects on sleep, particularly for overweight and obese women.

Effects of Dexmedetomidine on Sleep Quality in Critically Ill Patients

BACKGROUND Dexmedetomidine, a potent α-2-adrenergic agonist, is widely used as sedative in critically ill patients. This pilot study was designed to assess the effect of dexmedetomidine administration on sleep quality in critically ill patients. METHODS Polysomnography was performed on hemodynamically stable critically ill patients for 57 consecutive hours, divided into three night-time (9:00 PM to 6:00 AM) and two daytime (6:00 AM to 9:00 PM) periods. On the second night, dexmedetomidine was given by a continuous infusion targeting a sedation level -1 to -2 on the Richmond Agitation Sedation Scale. Other sedatives were not permitted. RESULTS Thirteen patients were studied. Dexmedetomidine was given in a dose of 0.6 μg kg(-1) h(-1) (0.4 to 0.7) (median [interquartile range]). Compared to first and third nights (without dexmedetomidine), sleep efficiency was significantly higher during the second night (first: 9.7% [1.6 to 45.1], second: 64.8% [51.4 to 79.9], third: 6.9% [0.0 to 17.1], P < 0.002). Without dexmedetomidine, night-time sleep fragmentation index (7.6 events per hour [4.8 to 14.2]) and stage 1 of sleep (48.0% [30.1 to 66.4]) were significantly higher (P = 0.023 and P = 0.006, respectively), and stage 2 (47.0% [27.5 to 61.2]) showed values lower (P = 0.006) than the corresponding values (2.7 events per hour [1.6 to 4.9], 13.1% [6.2 to 23.6], 80.2% [68.9 to 92.8]) observed with dexmedetomidine. Without sedation, sleep was equally distributed between day and night, a pattern that was modified significantly (P = 0.032) by night-time dexmedetomidine infusion, with more than three quarters of sleep occurring during the night (79% [66 to 87]). CONCLUSION In highly selected critically ill patients, dexmedetomidine infusion during the night to achieve light sedation improves sleep by increasing sleep efficiency and stage 2 and modifies the 24-h sleep pattern by shifting sleep mainly to the night.

Reproducibility of a Standardized Actigraphy Scoring Algorithm for Sleep in a US Hispanic/Latino Population.

While actigraphy is considered objective, the process of setting rest intervals to calculate sleep variables is subjective. We sought to evaluate the reproducibility of actigraphy-derived measures of sleep using a standardized algorithm for setting rest intervals. Observational study. Community-based. A random sample of 50 adults aged 18-64 years free of severe sleep apnea participating in the Sueño sleep ancillary study to the Hispanic Community Health Study/Study of Latinos. N/A. Participants underwent 7 days of continuous wrist actigraphy and completed daily sleep diaries. Studies were scored twice by each of two scorers. Rest intervals were set using a standardized hierarchical approach based on event marker, diary, light, and activity data. Sleep/wake status was then determined for each 30-sec epoch using a validated algorithm, and this was used to generate 11 variables: mean nightly sleep duration, nap duration, 24-h sleep duration, sleep latency, sleep maintenance efficiency, sleep fragmentation index, sleep onset time, sleep offset time, sleep midpoint time, standard deviation of sleep duration, and standard deviation of sleep midpoint. Intra-scorer intraclass correlation coefficients (ICCs) were high, ranging from 0.911 to 0.995 across all 11 variables. Similarly, inter-scorer ICCs were high, also ranging from 0.911 to 0.995, and mean inter-scorer differences were small. Bland-Altman plots did not reveal any systematic disagreement in scoring. With use of a standardized algorithm to set rest intervals, scoring of actigraphy for the purpose of generating a wide array of sleep variables is highly reproducible.

Sleep deprivation impairs inhibitory control during wakefulness in adult sleepwalkers.

Sleepwalkers often complain of excessive daytime somnolence. Although excessive daytime somnolence has been associated with cognitive impairment in several sleep disorders, very few data exist concerning sleepwalking. This study aimed to investigate daytime cognitive functioning in adults diagnosed with idiopathic sleepwalking. Fifteen sleepwalkers and 15 matched controls were administered the Continuous Performance Test and Stroop Colour-Word Test in the morning after an overnight polysomnographic assessment. Participants were tested a week later on the same neuropsychological battery, but after 25 h of sleep deprivation, a procedure known to precipitate sleepwalking episodes during subsequent recovery sleep. There were no significant differences between sleepwalkers and controls on any of the cognitive tests administered under normal waking conditions. Testing following sleep deprivation revealed significant impairment in sleepwalkers' executive functions related to inhibitory control, as they made more errors than controls on the Stroop Colour-Word Test and more commission errors on the Continuous Performance Test. Sleepwalkers' scores on measures of executive functions were not associated with self-reported sleepiness or indices of sleep fragmentation from baseline polysomnographic recordings. The results support the idea that sleepwalking involves daytime consequences and suggest that these may also include cognitive impairments in the form of disrupted inhibitory control following sleep deprivation. These disruptions may represent a daytime expression of sleepwalking's pathophysiological mechanisms.

The Associations Of Objectively-determined Sleep, Sedentary Behavior, And Physical Activity In Older Women

PURPOSE: Older women are at high risk for both inactivity and sleep difficulties. The purpose of this analysis was to examine differences in sedentary time and physical activity by categories of sleep duration and quality in older women. METHODS: Data for this cross-sectional analyses are from the Healthy Women Study 2010–11 follow-up visit and included 145 women (aged 73.3±1.7 years, white=91.5%, BMI=27.6±5.1 kg/m2). Participants wore an ActiGraph GT1M accelerometer (hip) and an Actiwatch-2 (wrist) for 7 consecutive days, to objectively monitor physical activity and sleep, respectively. Average accelerometer count estimates were computed and time spent per day in various intensities levels were determined using Matthews cut-points. Sleep estimates included, total sleep time, sleep efficiency (total sleep time / time in bed × 100), sleep onset latency (SOL; time in bed to sleep onset), and fragmentation index (sleep restlessness). Physical activity and sleep estimates were averaged across valid wear days (≥4 days of ≥10 hours). Sleep estimates were categorized into two groups based on clinical guidelines (i.e., sleep time, sleep efficiency) or sample-determined median (i.e., SOL, sleep fragmentation index). Wilcoxon rank sum tests were used to compare sedentary and physical activity by categories of sleep duration and quality. RESULTS: Participants with ≥ 7 hours of sleep per night had less time spent per day in light-, moderate-, and moderate- to vigorous- intensity physical activity (MVPA) compared to those with < 7 hours of sleep time (all p<0.05). Participants with higher sleep efficiency (i.e., ≥85%) had higher average accelerometer counts and less sedentary time than those with a lower sleep efficiency (both p<0.05). Participants with higher sleep fragmentation (≥27.3) had higher sedentary time than those with lower sleep fragmentation (p<0.001). Differences in physical activity estimates by SOL group (≥ or 0.05). CONCLUSION: These findings do not support other studies demonstrating a beneficial association between higher physical activity levels and sleep duration. However, findings suggest that lower levels of sedentary time was related to higher sleep efficiency and lower sleep fragmentation in older women. Supported by: R01 HL-028226 (PIs: Kuller & Matthews)

Prevalence and determinants of subjective sleepiness in healthy elderly with unrecognized obstructive sleep apnea

ObjectiveObstructive sleep apnea (OSA) is associated with behavioral consequences such as excessive daytime sleepiness (EDS). The aim of this study was to establish the presence of sleepiness in elderly with unrecognized OSA and the factors explaining its occurrence. MethodologyA total of 825 healthy elderly (aged ≥65 years) undergoing clinical, respiratory polygraphy, and heart-rate variability analysis were studied. According to the apnea–hypopnea index (AHI), the subjects were stratified in four categories: no-OSA (AHI <5), mild (5 > AHI <15), moderate (15 ≥ AHI <30), and severe OSA (AHI ≥30). Participants with EDS were defined on the basis of the Epworth Sleepiness Scale (ESS) score ≥10. ResultsOverall, the mean ESS score was 5.7 ± 5.6, 14.9% showing EDS with an increasing trend according to OSA severity (p < 0.001). Sleepy subjects were more frequently men, having a greater body mass index (BMI), alcohol intake, depression score, and indices of OSA severity (23% of severe OSA cases being sleepy). No differences were present between sleepy and non-sleepy subjects in regard to other clinical, metabolic, and autonomic nervous system measurements. Regression analyses adjusted for age, gender, BMI, hypertension, depression score, autonomic sleep fragmentation, and AHI and/or oxygen desaturation index revealed that gender (p < 0.0001), depression score (p < 0.0001), and BMI (p = 0.01) were the only significant factors affecting the presence of sleepiness in this population. ConclusionsIn healthy elderly with OSA, the prevalence of EDS was low, and it affected only severe cases. Despite a weak association between the ESS score and the AHI index, male gender and depression score were the most significant predictors for the occurrence of sleepiness.

Sleep, anxiety and electronic device use by athletes in the training and competition environments

This study subjectively assessed sleep quality and quantity, state anxiety and electronic device use during a 7-day training week (TRAIN) and a 7-day competitive tournament (COMP). Eight state-level netball players used wrist-watch actigraphy to provide indirect sleep measures of bedtime, wake time, sleep duration, sleep onset latency, sleep efficiency, wake after sleep onset and fragmentation index. State anxiety was reported using the anxiety sub-scale in the Profile of Mood States-Adolescents. Before bed duration of electronic device use and the estimated time to sleep after finishing electronic device use was also recorded. Significant main effects showed that sleep efficiency (p = 0.03) was greater in COMP as compared to TRAIN. Furthermore, the bedtime and wake time were earlier (p = 0.01) during COMP. No further differences existed between conditions (p > 0.05). However, strong negative associations were seen between state anxiety and the sleep quality rating. Here, sleep efficiency was likely greater in COMP due to the homeostatic need for recovery sleep, resulting from the change in environment from training to competition. Furthermore, an increased anxiety before bed seems to influence sleep quality and should be considered in athletes portraying poor sleep habits.

Movement distribution: a new measure of sleep fragmentation in children with upper airway obstruction.

To develop a measure of sleep fragmentation in children with upper airway obstruction based on survival curve analysis of sleep continuity. Prospective repeated measures. Hospital sleep laboratory. 92 children aged 3.0 to 12.9 years undergoing 2 overnight polysomnographic (PSG) sleep studies, 6 months apart. Subjects were divided into 3 groups based on their obstructive apnea and hypopnea index (OAHI) and other upper airway obstruction (UAO) symptoms: primary snorers (PS; n = 24, OAHI <1), those with obstructive sleep apnea syndrome (OSAS; n = 20, OAHI ≥1) and non-snoring controls (C; n = 48, OAHI <1). Subjects in the PS and OSAS groups underwent tonsillectomy and adenoidectomy between PSG assessments. Post hoc measures of movement and contiguous sleep epochs were exported and analyzed using Kaplan-Meier estimates of survival to generate survival curves for the 3 groups. Statistically significant differences were found between these group curves for sleep continuity (P < 0.05) when using movement events as the sleep fragmenting event, but not if stage 1 NREM sleep or awakenings were used. Using conventional indices of sleep fragmentation in survival curve analysis of sleep continuity does not provide a useful measure of sleep fragmentation in children with upper airway obstruction. However, when sleep continuity is defined as the time between gross body movements, a potentially useful clinical measure is produced.

Effects of dexmedetomidine on sleep quality in critically ill patients: a pilot study.

Dexmedetomidine, a potent α-2-adrenergic agonist, is widely used as sedative in critically ill patients. This pilot study was designed to assess the effect of dexmedetomidine administration on sleep quality in critically ill patients. Polysomnography was performed on hemodynamically stable critically ill patients for 57 consecutive hours, divided into three night-time (9:00 PM to 6:00 AM) and two daytime (6:00 AM to 9:00 PM) periods. On the second night, dexmedetomidine was given by a continuous infusion targeting a sedation level -1 to -2 on the Richmond Agitation Sedation Scale. Other sedatives were not permitted. Thirteen patients were studied. Dexmedetomidine was given in a dose of 0.6 μg kg(-1) h(-1) (0.4 to 0.7) (median [interquartile range]). Compared to first and third nights (without dexmedetomidine), sleep efficiency was significantly higher during the second night (first: 9.7% [1.6 to 45.1], second: 64.8% [51.4 to 79.9], third: 6.9% [0.0 to 17.1], P < 0.002). Without dexmedetomidine, night-time sleep fragmentation index (7.6 events per hour [4.8 to 14.2]) and stage 1 of sleep (48.0% [30.1 to 66.4]) were significantly higher (P = 0.023 and P = 0.006, respectively), and stage 2 (47.0% [27.5 to 61.2]) showed values lower (P = 0.006) than the corresponding values (2.7 events per hour [1.6 to 4.9], 13.1% [6.2 to 23.6], 80.2% [68.9 to 92.8]) observed with dexmedetomidine. Without sedation, sleep was equally distributed between day and night, a pattern that was modified significantly (P = 0.032) by night-time dexmedetomidine infusion, with more than three quarters of sleep occurring during the night (79% [66 to 87]). In highly selected critically ill patients, dexmedetomidine infusion during the night to achieve light sedation improves sleep by increasing sleep efficiency and stage 2 and modifies the 24-h sleep pattern by shifting sleep mainly to the night.

Sleep and cognitive problems in patients with&amp;nbsp;attention-deficit hyperactivity disorder

ObjectivesAttention-deficit hyperactivity disorder (ADHD) is characterized by inattentive and impulsive behavior. Many ADHD patients reportedly have cognitive dysfunction and sleep problems, including longer sleep latency, lower sleep efficiency, and shorter total sleep time. The purpose of this study was to examine neurocognitive functions and nocturnal sleep parameters in patients with ADHD, using a cognitive function test and actigraphy.MethodsSubjects included 37 male patients with ADHD and 32 controls (7–12 years of age). For each participant, we determined intelligence quotient (IQ) and administered the Matching Familiar Figures Test (MFFT) and 72-hour actigraphy. The relationships between sleep parameters and cognitive functions were assessed.ResultsADHD patients significantly differed from controls in several cognitive functions and sleep variables. In the MFFT, response error rate (P<0.001) and error counts (P=0.003) were significantly increased in ADHD patients compared with control children. MFFT response latency was significantly shorter in ADHD patients than in controls (P<0.001). In addition, sleep latency (P=0.01), wake after sleep onset (WASO) (P<0.001), and fragmentation index (P<0.001) were evaluated by actigraphy and found to be significantly increased in patients with ADHD compared with controls. However, no significant differences in total sleep time or sleep efficiency were observed. WASO and response error rates were positively correlated in patients with ADHD (rho =0.52, P=0.012). Furthermore, fragmentation index sleep variables were significantly positively correlated with response error (rho =0.44, P=0.008) and response latency rates (rho =0.4, P=0.018) in the MFFT. Reaction error rate was significantly associated with the fragmentation index (beta =0.94, P=0.024).ConclusionPatients with ADHD had more sleep problems, including significantly increased sleep latency, WASO, and fragmentation index, and poorer cognitive function, compared with controls. Some of these sleep problems, including WASO and the fragmentation index, were positively correlated with impulsivity, illustrated by the cognitive function tests in patients with ADHD. However, further studies with large sample sizes and the addition of polysomnography and determination of ADHD subtypes should be performed to confirm our results regarding sleep and cognitive problems in patients with ADHD.