Energy Expenditure is Affected by Rate of Accumulation of Sleep Deficit in Rats

Study Objectives:

Short sleep is a putative risk factor for obesity. However, prolonged total sleep deprivation (TSD) leads to negative energy balance and weight loss in rodents, whereas sleep-restricted humans tend to gain weight. We hypothesized that energy expenditure (V̇O₂) is influenced by the rate of accumulation of sleep deficit in rats.

Design and Intervention:

Six Sprague-Dawley rats underwent chronic sleep-restriction (CSR, 6-h sleep opportunity at ZT0-6 for 10 days) and stimulus-control protocols (CON, 12-h sleep opportunity for 10 days, matched number of stimuli) in a balanced cross-over design. Four additional rats underwent TSD (4 days). Sleep was manipulated using a motor-driven walking wheel.

Measurements and Results:

Electroencephalography, electromyography, and body temperature were measured by telemetry, and V̇O₂, by respirometry. Total sleep deficits of 55.1 ± 6.4 hours, 31.8 ± 6.8 hours, and 38.2 ± 2.3 hours accumulated over the CSR, CON, and TSD protocols, respectively. Responses to TSD confirmed previous reports of elevated V̇O₂ and body temperature. These responses were attenuated in CSR, despite a greater cumulative sleep deficit. Rate of rise of O₂ was strongly correlated with rate of accumulation of sleep deficit, above a threshold deficit of 3.6 h·day⁻¹.

Conclusion:

The change in V̇O₂ is affected by rate of accumulation of sleep deficit and not the total sleep loss accrued. Negative energy balance, observed during TSD, is strongly attenuated when brief daily sleep opportunities are available to rats (CSR), despite greater accumulated sleep deficit.

Citation:

Caron AM; Stephenson R. Energy expenditure is affected by rate of accumulation of sleep deficit in rats. SLEEP 2010;33(9):1226-1235.     

Upper Airway Sensory Function in Children with Obstructive Sleep Apnea Syndrome

Study Objectives:

Children with the obstructive sleep apnea syndrome (OSAS) have impaired responses to hypercapnia, subatmospheric pressure, and inspiratory resistive loading during sleep. This may be due, in part, to an impairment in the afferent limb of the upper airway sensory pathway. Therefore, we hypothesized that children with OSAS had diminished upper airway sensation compared to controls.

Design:

Case-control

Setting:

Academic hospital

Participants:

Subjects with OSAS aged 6–16 years, and age- and BMI-matched controls.

Interventions:

Two-point discrimination (TPD) was measured during wakefulness with modified calipers in the anterior tongue, right interior cheek, and hard palate.

Results:

Thirteen children with OSAS and 9 controls were tested. The age (mean ± SD) for OSAS and controls was 11 ± 4 vs. 13 ± 2 years (NS); OSAS BMI Z score 2.4 ± 0.5, controls 2.2 ± 0.5 (NS); OSAS apnea hypopnea index 31 ± 48, controls 0.4 ± 0.5 events/hour (P < 0.001). Children with OSAS had impaired TPD in the anterior tongue (median [range]) = 9 [3–14] mm, controls 3 [1–7], P = 0.002) and hard palate (OSAS 6 [3–9] mm, controls 3 [1–4], P < 0.001). TPD in the cheek was similar between the groups (P = 0.12).

Conclusion:

TPD in the anterior tongue and hard palate was impaired in children with OSAS during wakefulness. We speculate that this impairment might be due to a primary sensory function abnormality or secondary to nerve damage and/or hypoxemia caused by OSAS. Further studies after treatment of OSAS are needed.

Citation:

Tapia IE; Bandla P; Traylor J; Karamessinis L; Huang J; Marcus CL. Upper airway sensory function in children with obstructive sleep apnea syndrome. SLEEP 2010;33(7):968–972.     

Differences in Craniofacial Structures and Obesity in Caucasian and Chinese Patients with Obstructive Sleep Apnea

Study Objectives:

To explore differences in craniofacial structures and obesity between Caucasian and Chinese patients with obstructive sleep apnea (OSA).

Design:

Inter-ethnic comparison study.

Setting:

Two sleep disorder clinics in Australia and Hong Kong.

Patients:

150 patients with OSA (74 Caucasian, 76 Chinese).

Interventions:

Anthropometry, cephalometry, and polysomnography were performed and compared. Subgroup analyses after matching for: (1) body mass index (BMI); (2) OSA severity.

Measurements and Results:

The mean age and BMI were similar between the ethnic groups. Chinese patients had more severe OSA (AHI 35.3 vs 25.2 events/h, P = 0.005). They also had more craniofacial bony restriction, including a shorter cranial base (63.6 ± 3.3 vs 77.5 ± 6.7 mm, P < 0.001), maxilla (50.7 ± 3.7 vs 58.8 ± 4.3 mm, P < 0.001) and mandible length (65.4 ± 4.2 vs 77.9 ± 9.4 mm, P < 0.001). These findings remained after correction for differences in body height. Similar results were shown in the BMI-matched analysis (n = 66). When matched for OSA severity (n = 52), Chinese patients had more craniofacial bony restriction, but Caucasian patients were more overweight (BMI 30.7 vs 28.4 kg/m², P = 0.03) and had a larger neck circumference (40.8 vs 39.1 cm, P = 0.004); however, the ratios of BMI to the mandible or maxilla size were similar.

Conclusions:

Craniofacial factors and obesity contribute differentially to OSA in Caucasian and Chinese patients. For the same degree of OSA severity, Caucasians were more overweight, whereas Chinese exhibited more craniofacial bony restriction.

Citation:

Lee RWW; Vasudavan S; Hui DS; Prvan T; Petocz P; Darendeliler MA; Cistulli PA. Differences in craniofacial structures and obesity in Caucasian and Chinese patients with obstructive sleep apnea. SLEEP 2010;33(8):1075-1080.     

Empirical Evidence for “Syndrome Z”: A Hierarchical 5-Factor Model of the Metabolic Syndrome Incorporating Sleep Disturbance Measures

Study Objective:

Sleep disturbances have been associated with individual components of the metabolic syndrome (“syndrome X”), and, although the concept has been proposed, it is not known whether sleep disturbances actually cluster with features of the metabolic syndrome to produce a unifying trait, “syndrome Z”. Therefore, we evaluated a second-order factor model, whereby syndrome Z was described by 5 first-order factors – insulin resistance, obesity, hypertension, dyslipidemia, and sleep disturbance – with the sleep disturbance factor defined using the apnea-hypopnea index, arousal index, percentage of sleep time with oxygen saturation less than 90%, and percentage of slow wave sleep.

Design:

Observational, cross-sectional study.

Setting:

Clinical research center.

Participants:

Five hundred thirty-three adults from the Cleveland Family Sleep Study who underwent polysomnography and were not treated by continuous positive airway pressure.

Measurements and Results:

When modeling syndrome Z as a second-order factor unifying 5 first-order factors, we observed good overall model fit (χ²/df = 3.20; CFI = 0.96; RMSEA = 0.06; SRMR = 0.05) and found that obesity was the most important determining factor (standardized loading = 0.85 ± standard error = 0.02; P < 0.01) followed by sleep disturbance (0.82 ± 0.03; P < 0.01), insulin resistance (0.67 ± 0.03; P < 0.01), hypertension (0.64 ± 0.04; P < 0.01), and dyslipidemia (0.60 ± 0.05; P < 0.01). Simultaneous multiple group analyses revealed that this model was essentially generalizable across age, race, and sex subgroups.

Conclusions:

Our results demonstrate that sleep disturbance co-aggregates with other metabolic features to represent a single unifying trait, syndrome Z. Although our model awaits validation in other populations, it provides a tool for better understanding the synergistic risk of syndrome Z, compared with syndrome X, on type 2 diabetes and cardiovascular disease in future studies.

Citation:

Nock NL; Larkin EK; Patel SR; Redline S. Empirical evidence for “Syndrome Z”: a hierarchical 5-factor model of the metabolic syndrome incorporating sleep disturbance measures. SLEEP 2009;32(5):615-622.     

Idiopathic Hypersomnia with and without Long Sleep Time: A Controlled Series of 75 Patients

Objective:

To characterize the clinical, psychological, and sleep pattern of idiopathic hypersomnia with and without long sleep time, and provide normative values for 24-hour polysomnography.

Setting:

University Hospital

Design:

Controlled, prospective cohort

Participants:

75 consecutive patients (aged 34 ± 12 y) with idiopathic hypersomnia and 30 healthy matched controls.

Intervention:

Patients and controls underwent during 48 hours a face-to face interview, questionnaires, human leukocyte antigen genotype, a night polysomnography and multiple sleep latency test (MSLT), followed by 24-h ad libitum sleep monitoring.

Results:

Hypersomniacs had more fatigue, higher anxiety and depression scores, and more frequent hypnagogic hallucinations (24%), sleep paralysis (28%), sleep drunkenness (36%), and unrefreshing naps (46%) than controls. They were more frequently evening types. DQB1*0602 genotype was similarly found in hypersomniacs (24.2%) and controls (19.2%). Hypersomniacs had more frequent slow wave sleep after 06:00 than controls. During 24-h polysomnography, the 95% confidence interval for total sleep time was 493–558 min in controls, versus 672–718 min in hypersomniacs. There were 40 hypersomniacs with and 35 hypersomniacs without long ( > 600 min) sleep time. The hypersomniacs with long sleep time were younger (29 ± 10 vs 40 ± 13 y, P = 0.0002), slimmer (body mass index: 26 ± 5 vs 23 ± 4 kg/m²; P = 0.005), and had lower Horne-Ostberg scores and higher sleep efficiencies than those without long sleep time. MSLT latencies were normal ( > 8 min) in 71% hypersomniacs with long sleep time.

Conclusions:

Hypersomnia, especially with long sleep time, is frequently associated with evening chronotype and young age. It is inadequately diagnosed using MSLT.

Citation:

Vernet C; Arnulf I. Idiopathic Hypersomnia with and without Long Sleep Time: A Controlled Series of 75 Patients. SLEEP 2009;32(6):753-759.     

A Randomized,Double-Blind,Placebo-Controlled,Crossover Study of XP13512/GSK1838262 in the Treatment of Patients With Primary Restless Legs Syndrome

Study Objective:

To evaluate the efficacy and tolerability of XP13512/GSK1838262, an investigational nondopaminergic agent for the treatment of moderate-to-severe primary restless legs syndrome (RLS).

Design:

Randomized, double-blind, placebo-controlled, crossover trial.

Setting:

Nine US clinical sites.

Patients:

Thirty-eight treatment-naïve subjects with RLS (mean ± SD age 50.1 ± 13.2 years).

Interventions:

XP13512 1800 mg/day followed by placebo or placebo followed by XP13512 1800 mg/day for 14 days, with a 7-day washout between treatment periods.

Measurements and Results:

The primary endpoint was mean change from baseline International RLS Study Group rating scale (IRLS) total score on Day 14, analyzed using analysis of variance with sequence, period, and treatment as fixed effects and subjects within sequence as a random effect. XP13512 significantly reduced IRLS total score on Day 14 compared with placebo (mean ± SD: XP13512 −12.1 ± 6.5, placebo −1.9 ± 6.3; P < 0.0001). Polysomnographic data showed that XP13512 significantly improved sleep architecture on Day 14 compared with placebo (mean ± SD change from baseline sleep time [minutes]: stage 1: XP13512 −9.8 ± 23.9, placebo 0.4 ± 23.2; adjusted P < 0.0054, nominal P < 0.0001; stage 3/4 (slow-wave sleep): XP13512 22.8 ± 40.8, placebo 1.4 ± 34.3; adjusted P = 0.0092, nominal P = 0.0002). The most frequently reported adverse events were somnolence (XP13512 30.6%, placebo 2.8%) and dizziness (XP13512 27.8%, placebo 5.6%).

Conclusions:

XP13512 1800 mg/day significantly reduced RLS symptoms, improved sleep, and was generally well tolerated in subjects with moderate-to-severe primary RLS across 14 days of treatment.

Citation:

Kushida CA; Walters AS; Becker P; Thein SG; Perkins AT; Roth T; Canafax D; Barrett RW. A randomized, double-blind, placebo-controlled, crossover study of XP13512/GSK1838262 in the treatment of patients with primary restless legs syndrome. SLEEP 2009;32(2):159-168.     

Endothelial Function in Normotensive Men with Obstructive Sleep Apnea Before and 6 Months After CPAP Treatment

Study Objectives:

To evaluate endothelium-dependent flow-mediated dilation (FMD) and endothelium–independent nitroglycerin (NTG)-induced dilation of the brachial artery with Doppler ultrasound in patients with obstructive sleep apnea (OSA) and impact of six months of continuous positive airway pressure (CPAP) treatment.

Design:

A prospective, controlled, observational study.

Setting:

Single-site, clinic-based.

Patients:

Twenty-nine normotensive men with OSA (apnea-hypopnea index [AHI], mean ± SD, 60.4 ± 22.1-h), and 17 men without OSA (AHI 2.5 ± 0.6-h).

Interventions:

Six months of CPAP therapy in OSA patients.

Measurements and Results:

FMD was lower in patients with OSA compared with in controls (7.19 ± 1.78 % vs 10.93 ± 2.59 %; P < 0.001) while NTG-induced vasodilation was similar in both groups (13.75 ± 1.01 % vs 14.25 ± 1.83 %; n.s.). An inverse relationship was found between FMD and AHI adjusted for age and body mass index (BMI) (β = − 0.05, P < 0.001). Following 6 months of CPAP treatment in the OSA group, FMD was increased from 7.38 ± 2.06 % to 10.45 ± 1.68; P = 0.001) in 20 patients compliant with the device whereas the corresponding values did not change in the non-user group (7.08 ± 1.50% vs 7.26 ± 1.01%). No significant changes were observed regarding the NTG–induced vasodilation after CPAP compared with the baseline values.

Conclusion:

Our results confirm the previous reports suggesting impaired endothelium-dependent FMD in OSA, and additionally document the sustained improvement in endothelial function after 6 months of CPAP treatment in complaint patients.

Citation:

Bayram NA; Ciftci B; Keles T; Durmaz T; Turhan S; Bozkurt E; Peker Y. Endothelial function in normotensive men with obstructive sleep apnea before and 6 months after CPAP treatment. SLEEP 2009;32(10):1257-1263.     

Nighttime Blood Pressure in Normotensive Subjects With Chronic Insomnia: Implications for Cardiovascular Risk

Objective:

To assess as whether insomniacs have higher nighttime blood pressure (BP) and a blunted day-to-night BP reduction, recognized markers of increased risk of cardiovascular morbidity and mortality.

Design:

Prospective case-control study.

Setting:

University hospital-based sleep research laboratory.

Participants:

Thirteen normotensive subjects with chronic primary insomnia (9 women, 42 ± 7 y) and 13 sex- and age-matched good sleepers.

Measurements and results:

Subjects underwent 2-week sleep diary and 3 sleep studies to provide subjective and objective sleep variables, and 24-h beat-to-beat BP recording to provide daytime, night-time and day-to-night BP changes ([nighttime-daytime]/daytime)*100) (BP dipping). Spectral analysis of the electroencephalogram (EEG) was also performed during sleep of night 3 to assess EEG activity in the β frequency (16-32 Hz), a measure of brain cortical activation. Nighttime SBP was higher (111 ± 15 vs 102 ± 12 mm Hg, P < 0.01) and day-to-night SBP dipping was lower (−8% ± 6% vs −15% ± 5%, P < 0.01) in insomniacs than good sleepers. Insomniacs also had higher activity in EEG β frequency (P < 0.05). Higher nighttime SBP and smaller SBP dipping were independently associated with increased EEG β activity (P < 0.05).

Conclusions:

Higher nighttime SBP and blunted day-to-night SBP dipping are present in normotensive subjects with chronic insomnia and are associated with a hyperactivity of the central nervous system during sleep. An altered BP profile in insomniacs could be one mechanism implicated in the link between insomnia and cardiovascular morbidity and mortality documented in epidemiological studies.

Citation:

Lanfranchi PA; Pennestri MH; Fradette L; Dumont M; Morin CM; Montplaisir J. Nighttime blood pressure in normotensive subjects with chronic insomnia: implications for cardiovascular risk. SLEEP 2009;32(6):760-766.     

The Association of Sleep Duration with Adolescents' Fat and Carbohydrate Consumption

Study Objectives:

To investigate the relation between sleep duration and energy consumption in an adolescent cohort.

Design:

Cross-sectional.

Setting:

Free-living environment.

Participants:

Two hundred forty adolescents (mean age 17.7 ± 0.4 years).

Measurements and Results:

Daily 24-hour food-recall questionnaires and wrist-actigraphy measurements of sleep duration were employed to test the hypothesis that shorter weekday sleep duration (< 8 h) is associated with altered nutrient intake. Nutrition parameters included total calories, calories from meals and snacks, and proportions of caloric intake from fat and carbohydrates. Compared with adolescents sleeping 8 or more hours on average on weekdays, those sleeping less than 8 hours consumed a higher proportion of calories from fats (35.9% ± 6.7% vs 33.2% ± 6.9%; mean ± SD; P = 0.004) and a lower proportion of calories from carbohydrates (49.6% ± 8.2% vs 53.3% ± 8.3%; P = 0.001). After adjusting for potential confounders, shorter sleep duration was significantly associated with an average daily increase of calories consumed from fat of 2.2 percentage points and an average daily decrease in percentage of calories from carbohydrates of 3.0 percentage points. In unadjusted analyses, shorter sleep duration was also associated with a 2.1-fold increased odds (95% confidence interval: 1.03, 4.44) of daily consuming 475 or more kcal from snacks.

Conclusion:

Quantitative measures of macronutrient intake in adolescents were associated with objectively measured sleep duration. Short sleep duration may increase obesity risk by causing small changes in eating patterns that cumulatively alter energy balance.

Citation:

Weiss A; Xu F; Storfer-Isser A; Thomas A; Ievers-Landis CE; Redline S. The association of sleep duration with adolescents'' fat and carbohydrate consumption. SLEEP 2010;33(9):1201-1209.     

Sleep Disruption Aggravates Focal Cerebral Ischemia in the Rat

Study Objectives:

Sleep changes are frequent in stroke patients and predict a poor outcome. It remains unclear how sleep influences stroke evolution and recovery. We assessed effects of sleep disruption on brain damage and on the expression of axon sprouting genes after focal cerebral ischemia in rats.

Design:

12 h after ischemia induced by occlusion of the middle cerebral artery, rats were subjected to sleep disruption including sleep deprivation for 12h (SDpv12h) and sleep disturbances (SDis) by SDpv12h for consecutive 3 days. Control groups included ischemia without SDpv12h or SDis, sham surgery plus SDis and sham surgery without SDis. Sleep changes were evaluated based on EEG and EMG recordings.

Measurements and Results:

SDpv12h increased the infarct volume by 40% (SDpv12h 82.8 ± 10.9 vs. control 59.2 ± 13.9 mm³, P = 0.008) and SDis by 76% (SDis 58.8 ± 20.4 vs. control 33.8 ± 6.3 mm³, P = 0.017). SDpv12h also increased the number of damaged cells, visualized by TUNEL staining, by 137% (SDpv12h 46.8 ± 15 vs. control 19.7 ± 7.7/mm², P < 0.001) and SDis by 219% (SDis 32.9 ± 13.2 vs. control 10.3 ± 2.5/mm², P = 0.002). In addition, SDis significantly elevated the expression of the axonal extension inhibitory molecule neurocan (SDis 14.3 ± 0.4 vs. control 6.2 ± 0.1-fold of change, P < 0.001) in the injured hemisphere.

Conclusions:

These results provide the first direct evidence for a detrimental impact of sleep disruption on stroke evolution and suggest a potential role of sleep modulating treatments on stroke outcomes.

Citation:

Gao B; Cam E; Jaeger H; Zunzunegui C; Sarnthein J; Bassetti CL. Sleep disruption aggravates focal cerebral ischemia in the rat. SLEEP 2010;33(7):879-887.     

Acute Cardiovascular Changes with Obstructive Events in Children with Sleep Disordered Breathing

Study Objectives:

Obstructive apneas in adults are associated with acute changes in blood pressure (BP) and heart rate (HR) that may contribute to poor cardiovascular outcome. Children with sleep disordered breathing (SDB) are similarly at risk for cardiovascular complications. We aimed to test the hypothesis that BP and HR are augmented during obstructive events in children equivalent to levels reported in adults.

Design:

Beat-by-beat mean arterial pressure (MAP) and HR were analyzed over the course of obstructive events (pre, early, late, and post-event) during NREM and REM sleep and compared using 2-way ANOVA with post hoc analyses.

Setting:

Pediatric sleep laboratory.

Patients or Participants:

30 children (15M/15F) aged 7–12 y referred for investigation of SDB

Interventions:

N/A

Measurements and Results:

All children underwent overnight polysomnography with continuous BP recording. MAP and HR increased significantly from late to post event in both sleep states (mean ± SEM, NREM: MAP, 74 ± 3 to 93 ± 3 mm Hg; HR, 76 ± 2 to 97 ± 2 bpm. REM: MAP, 76 ± 3 to 89 ± 3 mm Hg; HR, 76 ± 2 to 91 ± 2 bpm. P < 0.05 for all). NREM sleep state and arousal from sleep were significant independent predictors of the magnitude of cardiovascular change from late to post event (P < 0.05 for all).

Conclusions:

Children with SDB experience significant changes in HR and BP during obstructive events with magnitudes that are similar to levels reported in adults. These changes are more pronounced during NREM sleep and with arousal. These acute cardiovascular changes may have important implications for poor cardiovascular outcome in children with OSA as repetitive cardiovascular perturbations may contribute to the development of hypertension.

Citation:

O''Driscoll DM; Foster AM; Ng ML; Yang JSC; Bashir F; Nixon GM; Davey MJ; Anderson V; Walker AM; Trinder J; Horne RSC. Acute cardiovascular changes with obstructive events in children with sleep disordered breathing. SLEEP 2009;32(10):1265-1271.     

Consequences of Comorbid Sleep Apnea in the Metabolic Syndrome—Implications for Cardiovascular Risk

Study Objectives:

Metabolic syndrome (MetSyn) increases overall cardiovascular risk. MetSyn is also strongly associated with obstructive sleep apnea (OSA), and these 2 conditions share similar comorbidities. Whether OSA increases cardiovascular risk in patients with the MetSyn has not been investigated. We examined how the presence of OSA in patients with MetSyn affected hemodynamic and autonomic variables associated with poor cardiovascular outcome.

Design:

Prospective clinical study.

Participants:

We studied 36 patients with MetSyn (ATP-III) divided into 2 groups matched for age and sex: (1) MetSyn+OSA (n = 18) and (2) MetSyn-OSA (n = 18).

Measurements:

OSA was defined by an apnea-hypopnea index (AHI) > 15 events/hour by polysomnography. We recorded muscle sympathetic nerve activity (MSNA - microneurography), heart rate (HR), and blood pressure (BP - Finapres). Baroreflex sensitivity (BRS) was analyzed by spontaneous BP and HR fluctuations.

Results:

MSNA (34 ± 2 vs 28 ± 1 bursts/min, P = 0.02) and mean BP (111 ± 3 vs. 99 ± 2 mm Hg, P = 0.003) were higher in patients with MetSyn+OSA versus patients with MetSyn-OSA. Patients with MetSyn+OSA had lower spontaneous BRS for increases (7.6 ± 0.6 vs 12.2 ± 1.2 msec/mm Hg, P = 0.003) and decreases (7.2 ± 0.6 vs 11.9 ± 1.6 msec/mm Hg, P = 0.01) in BP. MSNA was correlated with AHI (r = 0.48; P = 0.009) and minimum nocturnal oxygen saturation (r = −0.38, P = 0.04).

Conclusion:

Patients with MetSyn and comorbid OSA have higher BP, higher sympathetic drive, and diminished BRS, compared with patients with MetSyn without OSA. These adverse cardiovascular and autonomic consequences of OSA may be associated with poorer outcomes in these patients. Moreover, increased BP and sympathetic drive in patients with MetSyn+OSA may be linked, in part, to impairment of baroreflex gain.

Citation:

Trombetta IC; Somers VK; Maki-Nunes C; Drager LF; Toschi-Dias E; Alves MJNN; Fraga RF; Rondon MUPB; Bechara MG; Lorenzi-Filho G; Negrão CE. Consequences of comorbid sleep apnea in the metabolic syndrome—implications for cardiovascular risk. SLEEP 2010;33(9):1193-1199.     

Sleep Disturbance,Daytime Sleepiness,and Neurocognitive Performance in Children with Juvenile Idiopathic Arthritis

Study Objectives:

To compare daytime sleepiness and neurobehavioral performance in children with active and inactive juvenile idiopathic arthritis (JIA), and explore relations among measures of sleep disturbance, daytime sleepiness, and neurobehavioral performance.

Design:

Cross-sectional, comparison.

Setting:

A university-based research sleep laboratory.

Participants:

Seventy (70) children 6-11 years of age with active or inactive JIA.

Measurements and Results:

Self-reported daytime sleepiness, multiple sleep latency tests (MSLTs), and computerized neurobehavioral performance test scores were obtained after 2 nights of polysomnography. Children with active disease (mean physician global rating score = 2.9 ± 1.9 SD) showed shorter mean MSLT latency (15 ± 6.0 min) than those with inactive disease (16.5 ± 5.5 min, P < 0.03). Scores on neurobehavioral performance tests showed no group differences. However, number of wake bouts predicted sustained visual attention (rapid visual processing, P < 0.05) and apnea hypopnea index (AHI) predicted reaction time (P < 0.0001), after controlling for age, IQ, medication, and disease status.

Conclusion:

Indices of sleep disturbance were associated with validated tests of neurobehavioral performance in JIA, regardless of disease activity. Additional research is needed about the extent of sleep disturbances in relation to neurocognitive performance in JIA and compared to healthy children.

Citation:

Ward TM; Archbold K; Lentz M; Ringold S; Wallace CA; Landis CA. Sleep disturbance, daytime sleepiness, and neurocognitive performance in children with juvenile idiopathic arthritis. SLEEP 2010;33(2):252-259.     

Assessment of Sleep in Ventilator-Supported Critically Ill Patients

Objectives:

In critically ill patients, sleep derangements are reported to be severe using Rechtschaffen and Kales (R&K) methodology; however, whether such methodology can reliably assess sleep during critical illness is unknown. We set out to determine the reproducibility of 4 different sleep-assessment methods (3 manual and 1 computer-based) for ventilator-supported critically ill patients and also to quantify the extent to which the reproducibility of the manual methods for measuring sleep differed between critically ill and ambulatory (control) patients.

Design:

Observational methodologic study.

Setting:

Academic center.

Patients:

Critically ill patients receiving mechanical ventilation and age-matched controls underwent polysomnography.

Interventions:

None.

Measurements and Results:

Reproducibility for the computer-based method (spectral analysis of electroencephalography [EEG]) was better than that for the manual methods: R&K methodology and sleep-wakefulness organization pattern (P = 0.03). In critically ill patients, the proportion of misclassifications for measurements using spectral analysis, sleep-wakefulness organization pattern, and R&K methodology were 0%, 36%, and 53%, respectively (P < 0.0001). The EEG pattern of burst suppression was not observed. Interobserver and intraobserver reliability of the manual sleep-assessment methods for critically ill patients (κ = 0.52 ± 0.23) was worse than that for control patients (κ = 0.89 ± 0.13; P = 0.03). In critically ill patients, the overall reliability of the R&K methodology was relatively low for assessing sleep (κ = 0.19), but detection of rapid eye movement sleep revealed good agreement (κ = 0.70).

Conclusions:

Reproducibility for spectral analysis of EEG was better than that for the manual methods: R&K methodology and sleep-wakefulness organization pattern. For assessment of sleep in critically ill patients, the use of spectral analysis, sleep-wakefulness organization state, or rapid eye movement sleep alone may be preferred over the R&K methodology.

Citation:

Ambrogio C; Koebnick J; Quan SF; Ranieri VM; Parthasarathy S. Assessment of sleep in ventilator-supported critically ill patients. SLEEP 2008;31(11):1559–1568.     

Validation of the Fatigue Severity Scale in a Swiss Cohort

Background:

Fatigue is highly prevalent and has a negative impact on quality of life and performance in a variety of disorders. The 9-item Fatigue Severity Scale (FSS) is one of the most commonly used self-report questionnaires to measure fatigue, but has only been validated in small sample-sized studies and in single disorders.

Objective:

To validate the FSS in healthy subjects and different disorders known to be commonly associated with fatigue.

Material and Methods:

The FSS was administered to 454 healthy subjects, 188 patients with multiple sclerosis (MS), 235 patients with recent ischemic stroke, and 429 patients with sleep-wake disorders including narcolepsy with cataplexy (n = 22), restless legs syndrome (RLS) (n = 79), sleep apnea (n = 108), insomnia (n = 62), parasomnia (n = 25), excessive daytime sleepiness/hypersomnia of other origin (n = 84), and other sleep-wake disorders (n = 49).

Results:

FSS scores were 4.66 ± 1.64 (mean ± SD) in patients with MS, 3.90 ± 1.85 in patients after ischemic stroke, and 4.34 ± 1.64 in patients with sleep-wake disorders. Compared to patients, values were significantly lower in healthy subjects (3.00 ± 1.08, P < 0.01). Scores did not correlate with gender, age, or education. Item analysis showed an excellent internal consistency and reliability (Cronbach α = 0.93). Test-retest variability was assessed in 104 healthy subjects, showing stable values over time (2.94 ± 0.90 vs. 2.90 ± 0.74; P = 0.27).

Conclusions:

This first validation of a fatigue scale in a large sample size demonstrates that the FSS is a simple and reliable instrument to assess and quantify fatigue for clinical and research purposes.

Citation:

Valko PO; Bassetti CL; Bloch KE; Held U; Baumann CR. Validation of the fatigue severity scale in a swiss cohort. SLEEP 2008;31(11):1601–1607.     

Changes in Serum TSH and Free T4 during Human Sleep Restriction

Study Objectives:

To examine whether recurrent sleep restriction is accompanied by changes in measures of thyroid function.

Design:

Two-period crossover intervention study.

Setting:

University clinical research center and sleep laboratory.

Participants:

11 healthy volunteers (5F/6M) with a mean (± SD) age of 39 ± 5 y and BMI 26.5 ± 1.5 kg/m².

Intervention:

Randomized exposure to 14 days of sedentary living with ad libitum food intake and 5.5- vs. 8.5-h overnight sleep opportunity.

Measurements and Results:

Serum thyroid-stimulating hormone (TSH) and free thyroxine (T4) were measured at the end of each intervention. Partial sleep restriction was accompanied by a modest but statistically significant reduction in TSH and free T4, seen mainly in the female participants of the study.

Conclusions:

Compared to the well-known rise in TSH and thyroid hormone concentrations during acute sleep loss, tests obtained after 14 days of partial sleep restriction did not show a similar activation of the human thyroid axis.

Citation:

Kessler L; Nedeltcheva A; Imperial J; Penev PD. Changes in serum TSH and free T4 during human sleep restriction. SLEEP 2010;33(8):1115-1118.     

Diclofenac Potassium Restores Objective and Subjective Measures of Sleep Quality in Women with Primary Dysmenorrhea

Study Objectives:

Primary dysmenorrhea is a common gynecological disorder that disrupts daytime functioning and nighttime sleep quality. We determined the effectiveness of diclofenac potassium, compared to placebo, in alleviating nighttime pain and restoring sleep architecture in women with primary dysmenorrhea.

Design:

Randomized, double-blind, crossover study

Setting:

Sleep laboratory

Participants:

Ten healthy women (21 ± 1 years) with a history of primary dysmenorrhea.

Interventions:

Placebo or diclofenac potassium (150 mg per day) for menstrual pain.

Measurements and results:

We assessed objective measures of sleep (polysomnography) and subjective measures of sleep quality, mood, and intensity of menstrual pain. Compared to a pain-free phase of the menstrual cycle (mid-follicular), women receiving placebo for their menstrual pain had a poorer mood (P < 0.01), decreased sleep efficiency (P < 0.05), less REM sleep (P < 0.05), more stage 1 sleep (P < 0.01), and more sleep stage changes per hour of sleep during the night. Administration of diclofenac potassium compared to placebo not only attenuated the women''s menstrual pain (P < 0.05), but also increased sleep efficiency (P < 0.05) and percentage of REM sleep (P < 0.01), decreased percentage of stage 1 sleep (P < 0.05) and number of sleep stage changes per hour of sleep (P < 0.05), and improved subjective ratings of sleep quality and morning vigilance (P < 0.05).

Conclusion:

Diclofenac potassium effectively attenuates nighttime dysmenorrheic pain and restores subjective and objective measures of sleep quality to values recorded in a pain-free phase of the menstrual cycle.

Citation:

Iacovides S; Avidon I; Bentley A; Baker FC. Diclofenac potassium restores objective and subjective measures of sleep quality in women with primary dysmenorrhea. SLEEP 2009;32(8):1019-1026.     

Changes in Cardiac Variability after REM Sleep Deprivation in Recurrent Nightmares

Study Objectives:

To assess whether dysfunctional autonomic regulation during REM sleep as indexed by heart rate variability (HRV) is a pathophysiological factor in frequent nightmares (NMs).

Design:

Monitoring with polysomnography (PSG) and electrocardiography (ECG) for 3 consecutive nights: Night 1 (N1), adaptation night; N2, administration of partial REM sleep deprivation; N3, recovery night. Differences between NM and control (CTL) groups assessed for ECG measures drawn from wakefulness, REM sleep, and Stage 2 sleep on both N1 and N3.

Setting:

Hospital-based sleep laboratory

Participants:

Sixteen subjects with frequent NMs ( ≥ 1 NM/week; mean age = 26.1 ± 8.7 years) but no other medical or psychiatric disorders and 11 healthy comparison subjects ( < 1 NM/month; mean age = 27.1±5.6 years).

Results:

NM and CTL groups differed on 2 REM sleep measures only on N1; the NM group had longer REM latencies and REM/NREM cycle durations than did the CTL group. No differences were found on time domain and absolute frequency domain ECG measures for either N1 or N3. However, altered HRV for the NM group was suggested by significantly higher LFnu, lower HFnu, and higher LF/HF ratio than for the CTL group.

Conclusions:

Results are consistent with a higher than normal sympathetic drive among NM subjects which is unmasked by high REM sleep propensity. Results also support a growing literature linking anxiety disorders of several types (panic disorder, posttraumatic stress disorder (PTSD), generalized anxiety disorder) to altered HR variability.

Citation:

Nielsen T; Paquette T; Solomonova E; Lara-Carrasco J; Colombo R; Lanfranchi P. Changes in cardiac variability after rem sleep deprivation in recurrent nightmares. SLEEP 2010;33(1):113-122.