Age-Related Reduction in Daytime Sleep Propensity and Nocturnal Slow Wave Sleep

Objective:

To investigate whether age-related and experimental reductions in SWS and sleep continuity are associated with increased daytime sleep propensity.

Methods:

Assessment of daytime sleep propensity under baseline conditions and following experimental disruption of SWS. Healthy young (20-30 y, n = 44), middle-aged (40-55 y, n = 35) and older (66-83 y, n = 31) men and women, completed a 2-way parallel group study. After an 8-h baseline sleep episode, subjects were randomized to 2 nights with selective SWS disruption by acoustic stimuli, or without disruption, followed by 1 recovery night. Objective and subjective sleep propensity were assessed using the Multiple Sleep Latency Test (MSLT) and the Karolinska Sleepiness Scale (KSS).

Findings:

During baseline sleep, SWS decreased (P < 0.001) and the number of awakenings increased (P < 0.001) across the 3 age groups. During the baseline day, MSLT values increased across the three age groups (P < 0.0001) with mean values of 8.7min (SD: 4.5), 11.7 (5.1) and 14.2 (4.1) in the young, middle-aged, and older adults, respectively. KSS values were 3.7 (1.0), 3.2 (0.9), and 3.4 (0.6) (age-group: P = 0.031). Two nights of SWS disruption led to a reduction in MSLT and increase in KSS in all 3 age groups (SWS disruption vs. control: P < 0.05 in all cases).

Conclusions:

Healthy aging is associated with a reduction in daytime sleep propensity, sleep continuity, and SWS. In contrast, experimental disruption of SWS leads to an increase in daytime sleep propensity. The age-related decline in SWS and reduction in daytime sleep propensity may reflect a lessening in homeostatic sleep requirement. Healthy older adults without sleep disorders can expect to be less sleepy during the daytime than young adults.

Citation:

Dijk DJ; Groeger JA; Stanley N; Deacon S. Age-related reduction in daytime sleep propensity and nocturnal slow wave sleep. SLEEP 2010;33(2):211-223.     

Neurobehavioral Dynamics Following Chronic Sleep Restriction: Dose-Response Effects of One Night for Recovery

Objective:

Establish the dose-response relationship between increasing sleep durations in a single night and recovery of neurobehavioral functions following chronic sleep restriction.

Design:

Intent-to-treat design in which subjects were randomized to 1 of 6 recovery sleep doses (0, 2, 4, 6, 8, or 10 h TIB) for 1 night following 5 nights of sleep restriction to 4 h TIB.

Setting:

Twelve consecutive days in a controlled laboratory environment.

Participants:

N = 159 healthy adults (aged 22-45 y), median = 29 y).

Interventions:

Following a week of home monitoring with actigraphy and 2 baseline nights of 10 h TIB, subjects were randomized to either sleep restriction to 4 h TIB per night for 5 nights followed by randomization to 1 of 6 nocturnal acute recovery sleep conditions (N = 142), or to a control condition involving 10 h TIB on all nights (N = 17).

Measurements and Results:

Primary neurobehavioral outcomes included lapses on the Psychomotor Vigilance Test (PVT), subjective sleepiness from the Karolinska Sleepiness Scale (KSS), and physiological sleepiness from a modified Maintenance of Wakefulness Test (MWT). Secondary outcomes included psychomotor and cognitive speed as measured by PVT fastest RTs and number correct on the Digit Symbol Substitution Task (DSST), respectively, and subjective fatigue from the Profile of Mood States (POMS). The dynamics of neurobehavioral outcomes following acute recovery sleep were statistically modeled across the 0 h-10 h recovery sleep doses. While TST, stage 2, REM sleep and NREM slow wave energy (SWE) increased linearly across recovery sleep doses, best-fitting neurobehavioral recovery functions were exponential across recovery sleep doses for PVT and KSS outcomes, and linear for the MWT. Analyses based on return to baseline and on estimated intersection with control condition means revealed recovery was incomplete at the 10 h TIB (8.96 h TST) for PVT performance, KSS sleepiness, and POMS fatigue. Both TST and SWE were elevated above baseline at the maximum recovery dose of 10 h TIB.

Conclusions:

Neurobehavioral deficits induced by 5 nights of sleep restricted to 4 h improved monotonically as acute recovery sleep dose increased, but some deficits remained after 10 h TIB for recovery. Complete recovery from such sleep restriction may require a longer sleep period during 1 night, and/or multiple nights of recovery sleep. It appears that acute recovery from chronic sleep restriction occurs as a result of elevated sleep pressure evident in both increased SWE and TST.

Citation:

Banks S; Van Dongen HPA; Maislin G; Dinges DF. Neurobehavioral dynamics following chronic sleep restriction: dose-response effects of one night for recovery. SLEEP 2010;33(8):1013–1026.     

Slow Wave Sleep and REM Sleep Awakenings Do Not Affect Sleep Dependent Memory Consolidation

Study Objectives:

The effects of REM sleep and slow wave sleep (SWS) deprivation on sleep-dependent motor and declarative memory consolidation.

Design:

Randomized, within-subject, cross-over study

Setting:

Weekly (women: monthly) sleep laboratory visits, with retest 60 hours later

Participants:

Twelve healthy subjects (6 men) aged between 20 and 30 years

Interventions:

REM sleep deprivation, SWS deprivation, or undisturbed sleep

Measurements and Results:

We deprived subjects once each of REM sleep and SWS, and once let them sleep undisturbed through the night. After each night, we tested declarative and procedural memory consolidation. We tested memory performance by a verbal paired associate task and a sequential finger-tapping task at 21:00 on the study night and again 60 hours later. Although REM sleep and SWS awakenings led to a significant reduction of the respective sleep stages, memory consolidation remained unaffected. We also found a significant correlation between the declarative task and sleep spindles in the undisturbed condition, especially the sleep spindles in the first third of the night.

Conclusion:

We suggest that word-pair learning relies on stage 2 sleep spindles and requires little SWS. Their sleep dependent consolidation is not affected by SWS deprivation. Simple motor tasks may either be consolidated in stage 2 sleep or depend on only small amounts of REM sleep. Their sleep dependent consolidation is not influenced by REM sleep deprivation.

Citation:

Genzel L; Dresler M; Wehrle R; Grözinger M; Steiger A. Slow wave sleep and REM sleep awakenings do not affect sleep dependent memory consolidation. SLEEP 2009;32(3):302–310.     

Daytime Sleepiness and Driving Performance in Patients with Obstructive Sleep Apnea: Comparison of the MSLT,the MWT,and a Simulated Driving Task

Study Objectives:

To test the reliability of a driving-simulation test for the objective measurement of daytime alertness compared with the Multiple Sleep Latency Test (MSLT) and with the Maintenance of Wakefulness Test (MWT), and to test the ability to drive safely, in comparison with on-road history, in the clinical setting of untreated severe obstructive sleep apnea.

Design:

N/A.

Setting:

Sleep laboratory.

Patients or Participants:

Twenty-four patients with severe obstructive sleep apnea and reported daytime sleepiness varying in severity (as measured by the Epworth Sleepiness Scale).

Interventions:

N/A.

Measurements and Results:

Patients underwent MSLT and MWT coupled with 4 sessions of driving-simulation test on 2 different days randomly distributed 1 week apart. Simulated-driving performance (in terms of lane-position variability and crash occurrence) was correlated with sleep latency on the MSLT and more significantly on the MWT, showing a predictive validity toward the detection of sleepy versus alert patients with obstructive sleep apnea. In addition, patients reporting excessive daytime sleepiness or a history of car crashes showed poorer performances on the driving simulator.

Conclusions:

A simulated driving test is a suitable tool for objective measurement of daytime alertness in patients with obstructive sleep apnea. Further studies are needed to clarify the association between simulated-driving performance and on-road crash risk of patients with sleep disordered breathing.

Citation:

Pizza F; Contardi S; Mondini S; Trentin L; Cirignotta F. Daytime sleepiness and driving performance in patients with obstructive sleep apnea: comparison of the MSLT, the MWT, and a simulated driving task. SLEEP 2009;32(3):382-391.     

Banking Sleep: Realization of Benefits During Subsequent Sleep Restriction and Recovery

Objective:

Determine whether sleep extension (a) improves alertness and performance during subsequent sleep restriction and (b) impacts the rate at which alertness and performance are restored by post-restriction recovery sleep.

Design:

Participants were randomly assigned to an Extended (10 h time in bed [TIB]) or Habitual TIB [mean (SD) hours = 7.09 (0.7)] sleep group for one week, followed by 1 Baseline (10 hours or habitual TIB), 7 Sleep Restriction (3 h TIB), and 5 Recovery Sleep nights (8 h TIB). Performance and alertness tests were administered hourly between 08:00–18:00 during all in-laboratory phases of the study.

Setting:

Residential sleep/performance testing facility.

Participants:

Twenty-four healthy adults (ages 18–39) participated in the study.

Interventions:

Extended vs. habitual sleep durations prior to sleep restriction.

Results:

Psychomotor vigilance task (PVT) lapses were more frequent and modified maintenance of wakefulness (MWT) sleep latency was shorter in the Habitual group than in the Extended group across the sleep restriction phase. During the Recovery phase, PVT speed rebounded faster (and PVT lapsing recovered significantly after the first night of recovery sleep) in the Extended group. No group differences in subjective sleepiness were evident during any phase of the study.

Conclusion:

The extent to which sleep restriction impairs objectively measured alertness and performance, and the rate at which these impairments are subsequently reversed by recovery sleep, varies as a function of the amount of nightly sleep obtained prior to the sleep restriction period. This suggests that the physiological mechanism(s) underlying chronic sleep debt undergo long-term (days/weeks) accommodative/adaptive changes.

Citation:

Rupp TL; Wesensten NJ; Bliese PD; Balkin TJ. Banking sleep: realization of benefits during subsequent sleep restriction and recovery. SLEEP 2009;32(3):311–321.     

Effects of Acute 3, 4-Methylenedioxymethamphetamine on Sleep and Daytime Sleepiness in MDMA Users: A Preliminary Study

Study Objective:

3, 4-Methylenedioxymethamphetamine (MDMA) affects monoamine neurotransmitters that play a critical role in sleep and daytime alertness. However, the acute effects of MDMA on sleep and daytime sleepiness have not been studied under placebo-controlled conditions. This study was designed to establish the effects of acute MDMA or placebo administration and sleep restriction on sleep and daytime sleepiness.

Design:

Participants with a history of MDMA use were studied on 3 sessions of 3 nights (baseline, treatment, and recovery) and 2 days (following night 2 and 3) per session. On treatment nights (night 2), participants received placebo or 2 mg/kg of MDMA or underwent a restricted bed schedule with placebo. Sleep restriction was a positive control to compare sleep loss and consequent sleepiness associated with MDMA use. The scheduled sleep period was 8 hours long on nonrestricted nights, and standard sleep recordings and daytime sleepiness tests were conducted. Age-matched controls received 1 night and day of standard sleep and daytime sleepiness testing.

Setting:

Sleep laboratory

Participants:

Seven recreational MDMA-users and 13 matched control subjects.

Measurements and Results:

Acute MDMA shortened sleep primarily by increasing sleep latency, and it reduced stage 3/4 sleep and suppressed rapid eye movement (REM) sleep. The MDMA-reduced sleep time was not associated with increased daytime sleepiness the following day, as was seen in the sleep-restriction condition. Compared with control subjects, the MDMA users on the first night in the laboratory had shorter total sleep times and less stage 3/4 sleep. Average daily sleep latency on daytime sleepiness tests the day after nighttime placebo administration was increased in MDMA users compared with the control subjects, and MDMA users had an elevated number of sleep-onset REM periods on these tests, compared with control subjects.

Conclusions:

Acute MDMA administration disrupts sleep and REM sleep, specifically, without producing daytime sleepiness such as sleep restriction does. Compared with control subjects, recreational MDMA users showed evidence of hyperarousal and impaired REM function. The mechanism behind these effects is likely due to the deleterious effects of MDMA on catecholamines.^1–3

Citation:

Randall S; Johanson CE; Tancer M; Roehrs T. Effects of acute 3, 4-methylenedioxymethamphetamine on sleep and daytime sleepiness in MDMA users: a preliminary study. SLEEP 2009;32(11):1513-1519.     

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.     

Upper Airway Collapsibility During REM Sleep in Children with the Obstructive Sleep Apnea Syndrome

Study Objectives:

In children, most obstructive events occur during rapid eye movement (REM) sleep. We hypothesized that children with the obstructive sleep apnea syndrome (OSAS), in contrast to age-matched control subjects, would not maintain airflow in the face of an upper airway inspiratory pressure drop during REM sleep.

Design:

During slow wave sleep (SWS) and REM sleep, we measured airflow, inspiratory time, inspiratory time/total respiratory cycle time, respiratory rate, tidal volume, and minute ventilation at a holding pressure at which flow limitation occurred and at 5 cm H₂O below the holding pressure in children with OSAS and in control subjects.

Setting:

Sleep laboratory.

Participants:

Fourteen children with OSAS and 23 normal control subjects.

Results:

In both sleep states, control subjects were able to maintain airflow, whereas subjects with OSAS preserved airflow in SWS but had a significant decrease in airflow during REM sleep (change in airflow of 18.58 ± 12.41 mL/s for control subjects vs −44.33 ± 14.09 mL/s for children with OSAS, P = 0.002). Although tidal volume decreased, patients with OSAS were able to maintain minute ventilation by increasing the respiratory rate and also had an increase in inspiratory time and inspiratory time per total respiratory cycle time

Conclusion:

Children with OSAS do not maintain airflow in the face of upper-airway inspiratory-pressure drops during REM sleep, indicating a more collapsible upper airway, compared with that of control subjects during REM sleep. However, compensatory mechanisms exist to maintain minute ventilation. Local reflexes, central control mechanisms, or both reflexes and control mechanisms need to be further explored to better understand the pathophysiology of this abnormality and the compensation mechanism.

Citation:

Huang J; Karamessinis LR; Pepe ME; Glinka SM; Samuel JM; Gallagher PR; Marcus CL. Upper airway collapsibility during REM sleep in children with the obstructive sleep apnea syndrome. SLEEP 2009;32(9):1173-1181.     

Determining Sleep Quality in Children with Sleep Disordered Breathing: EEG Spectral Analysis Compared with Conventional Polysomnography

Study Objectives:

To identify the extent of sleep disruption in children with various severities of sleep disordered breathing (SDB) using both conventional visually scored assessment of sleep stages and arousal indices together with EEG power spectral analysis.

Design:

Sleep stages and power spectral analysis of the sleep EEG in children with varying severities of SDB with matched control subjects with no history of snoring were compared across the whole night, across sequential hours from sleep onset, and across sleep stages.

Measurements:

Overnight polysomnography was performed on 90 children (49M/41F) aged 7-12 y with SDB and 30 age-matched healthy controls (13M/17F). Sleep stages were visually scored and the EEG spectra were analyzed in 5-s epochs.

Results:

Conventional visual scoring indicated that, although sleep duration was reduced in severely affected children, sleep quality during the essential stages of SWS and REM was preserved, as evidenced by the lack of any significant decrease in their duration in SDB severity groups. This finding was supported by the lack of substantial differences in EEG spectral power between the groups over the whole night, within specific hours, and in individual sleep stages.

Conclusions:

Both conventional scoring and EEG spectral analysis indicated only minor disruptions to sleep quality in children with SDB when assessed across the night, in any specific hour of the night, or in any specific sleep stage. These results suggest that reduced daytime functioning previously reported in children with SDB may not be due to sleep disruption. We speculate that in children, in contrast to adults, a stronger sleep drive may preserve sleep quality even in severe SDB.

Citation:

Yang JSC; Nicholas CL; Nixon GM; Davey MJ; Anderson V; Walker AM; Trinder JA; Horne RSC. Determining sleep quality in children with sleep disordered breathing: EEG spectral analysis compared with conventional polysomnography. SLEEP 2010;33(9):1165-1172.     

Effects of the Melatonin MT-1/MT-2 Agonist Ramelteon on Daytime Body Temperature and Sleep

Study Objectives:

A reduction in core temperature and an increase in the distal-proximal skin gradient (DPG) are reported to be associated with shorter sleep onset latencies (SOL) and better sleep quality. Ramelteon is a melatonin MT-1/MT-2 agonist approved for the treatment of insomnia. At night, ramelteon has been reported to shorten SOL. In the present study we tested the hypothesis that ramelteon would reduce core temperature, increase the DPG, as well as shorten SOL, reduce wakefulness after sleep onset (WASO), and increase total sleep time (TST) during a daytime sleep opportunity.

Design:

Randomized, double-blind, placebo-controlled, cross-over design. Eight mg ramelteon or placebo was administered 2 h prior to a 4-h daytime sleep opportunity.

Setting:

Sleep and chronobiology laboratory.

Participants:

Fourteen healthy adults (5 females), aged (23.2 ± 4.2 y).

Measurements and Results:

Primary outcome measures included core body temperature, the DPG and sleep physiology (minutes of total sleep time [TST], wake after sleep onset [WASO], and SOL). We also assessed as secondary outcomes, proximal and distal skin temperatures, sleep staging and subjective TST. Repeated measures ANOVA revealed ramelteon significantly reduced core temperature and increased the DPG (both P < 0.05). Furthermore, ramelteon reduced WASO and increased TST, and stages 1 and 2 sleep (all P < 0.05). The change in the DPG was negatively correlated with SOL in the ramelteon condition.

Conclusions:

Ramelteon improved daytime sleep, perhaps mechanistically in part by reducing core temperature and modulating skin temperature. These findings suggest that ramelteon may have promise for the treatment of insomnia associated with circadian misalignment due to circadian sleep disorders.

Citation:

Markwald RR; Lee-Choing TL; Burke TM; Snider JA; Wright KP. Effects of the melatonin MT-1/MT-2 agonist ramelteon on daytime body temperature and sleep. SLEEP 2010;33(6):825-831     

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.     

Sleep Disordered Breathing,Daytime Symptoms,and Functional Performance in Stable Heart Failure

Study Objectives:

To evaluate characteristics of sleep disordered breathing (SDB); clinical and demographic correlates of SDB; and the extent to which SDB explains functional performance and symptoms in stable heart failure patients receiving care in structured HF disease management programs.

Design:

Cross-sectional, observational study.

Setting:

Structured heart failure disease management programs.

Participants:

170 stable chronic heart failure patients (mean age = 60.3 ± 16.8 years; n = 60 [35%] female; n = 50 [29%] African American; left ventricular ejection fraction mean = 32 ± 14.6).

Interventions:

N/A

Measurements and Results:

Full polysomnography was obtained for one night on participants in their homes. Participants completed the 6-minute walk, 3 days of actigraphy, MOS-SF 36, Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, Multi-Dimensional Assessment of Fatigue Scale, and the Centers for the Epidemiological Studies of Depression Scale. Fifty-one percent had significant SDB; Sixteen (9%) of the total sample had central sleep apnea. Severe SDB was associated with a 4-fold increase in the likelihood of poor self-reported physical function (OR = 4.15, 95%CI = 1.19–14.57) and CSA was associated with low levels of daytime mobility (OR = 4.09, 95%CI = 1.23–13.62) after controlling for clinical and demographic variables. There were no statistically significant relationships between SDB and daytime symptoms or self-reported sleep, despite poorer objective sleep quality in patients with SDB.

Conclusions:

Severe SDB is associated with poor physical function in patients with stable HF but not with daytime symptoms or self-reported sleep, despite poorer objective sleep quality in patients with SDB.

Citation:

Redeker NS; Muench U; Zucker MJ; Walsleben J; Gilbert M; Freudenberger R; Chen M; Campbell D; Blank L; Berkowitz R; Adams L; Rapoport DM. Sleep disordered breathing, daytime symptoms, and functional performance in stable heart failure. SLEEP 2010;33(4):551-560.     

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.     

Nonrestorative Sleep as a Distinct Component of Insomnia

Study Objectives:

Explore characteristics of nonrestorative sleep (NRS) in prospectively defined subgroups of individuals with NRS symptoms, investigate whether NRS can occur independently of difficulties initiating and maintaining sleep (DIS/DMS), and determine its effect on waking function.

Design:

Cross-sectional and longitudinal population-based study comparing patterns of daytime symptoms, and their persistence, in cohorts of subjects with NRS symptoms grouped according to presence or absence of DIS and DMS.

Setting:

28 sleep centers in the US.

Participants:

Subjects reporting awakening unrestored or unrefreshed at least 3 times weekly over the previous 3 months were classified, based on self-reported sleep problems, to DIS (n = 138), DMS (n = 44), DIS+DMS (n = 125), and NRS-only (no DIS or DMS; n = 192) cohorts. Eighty healthy volunteers formed a control group.

Interventions:

None.

Measurements and Results:

Polysomnography confirmed DIS and/or DMS in 56/138 (41%), 18/44 (41%), and 37/125 (30%) subjects in DIS, DMS, and DIS+DMS cohorts, respectively; and absence of DIS or DMS in 115/192 (60%) NRS-only subjects and 52/80 (65%) healthy volunteers. Multiple subject-reported endpoints including the Endicott Work Productivity Scale, Pittsburgh Insomnia Rating Scale, Restorative Sleep Questionnaire, and SF-36, showed that NRS-only subjects had significantly impaired daytime function relative to healthy volunteers, comparable to impairment affecting subjects with DIS and/or DMS. Symptoms persisted over 3 months.

Conclusions:

This study confirms that NRS can occur independently of other components of insomnia. Daytime symptoms were as severe in individuals with NRS-only as those whose NRS symptoms were combined with DIS or DMS.

Citation:

Roth T; Zammit G; Lankford A; Mayleben D; Stern T; Pitman V; Clark D; Werth JL. Nonrestorative sleep as a distinct component of insomnia. SLEEP 2010;33(4):449-458.     

A Video Method to Study Drosophila Sleep

Study Objectives:

To use video to determine the accuracy of the infrared beam-splitting method for measuring sleep in Drosophila and to determine the effect of time of day, sex, genotype, and age on sleep measurements.

Design:

A digital image analysis method based on frame subtraction principle was developed to distinguish a quiescent from a moving fly. Data obtained using this method were compared with data obtained using the Drosophila Activity Monitoring System (DAMS). The location of the fly was identified based on its centroid location in the subtracted images.

Measurements and Results:

The error associated with the identification of total sleep using DAMS ranged from 7% to 95% and depended on genotype, sex, age, and time of day. The degree of the total sleep error was dependent on genotype during the daytime (P < 0.001) and was dependent on age during both the daytime and the nighttime (P < 0.001 for both). The DAMS method overestimated sleep bout duration during both the day and night, and the degree of these errors was genotype dependent (P < 0.001). Brief movements that occur during sleep bouts can be accurately identified using video. Both video and DAMS detected a homeostatic response to sleep deprivation.

Conclusions:

Video digital analysis is more accurate than DAMS in fly sleep measurements. In particular, conclusions drawn from DAMS measurements regarding daytime sleep and sleep architecture should be made with caution. Video analysis also permits the assessment of fly position and brief movements during sleep.

Citation:

Zimmerman JE; Raizen DM; Maycock MH; Maislin G; Pack AI. A video method to study drosophila sleep. SLEEP 2008;31(11):1587–1598.     

Longitudinal Evaluation of Sleep-Disordered Breathing and Sleep Symptoms with Change in Quality of Life: The Sleep Heart Health Study (SHHS)

Study Objectives:

Findings from population studies evaluating the progression and incidence of sleep disordered breathing have shown evidence of a longitudinal increase in the severity of sleep disordered breathing. The present study evaluates the association among changes in sleep disordered breathing, sleep symptoms, and quality of life over time.

Design:

Prospective cohort study. Data were from the Sleep Heart Health Study.

Setting:

Multicenter study.

Participants:

Three thousand seventy-eight subjects aged 40 years and older from the baseline and follow-up examination cycles were included.

Measurements:

The primary outcomes were changes in the Physical Component Summary and Mental Component Summary scales obtained from the Medical Outcomes Study Short-Form Health Survey. The primary exposure was change in the respiratory disturbance index obtained from unattended overnight polysomnograms performed approximately 5 years apart. Other covariates included measures of excessive daytime sleepiness and difficulty initiating and maintaining sleep.

Results:

Mean respiratory disturbance index increased from 8.1 ± 11 SD at baseline to 10.9 ± 14 (P < 0.0001) at follow-up. The mean Physical Component Summary and Mental Component Summary scores were 48.5 and 54.1 at baseline and 46.3 and 54.8 at follow-up. No associations between change in respiratory disturbance index and changes in Physical Component Summary or Mental Component Summary scores were seen. However, worsening of difficulty initiating and maintaining sleep and excessive daytime sleepiness were significantly associated with lower quality of life.

Conclusions:

A slight increase in severity of sleep disordered breathing was seen over 5 years; this was not associated with worsening of quality of life. However, subjective symptoms of quality of sleep and daytime sleepiness were associated with declining quality of life.

Citation:

Silva GE; An MW; Goodwin JL; Shahar E; Redline S; Resnick H; Baldwin CM; Quan SF. Longitudinal evaluation of sleep-disordered breathing and sleep symptoms with change in quality of life: the Sleep Heart Health Study (SHHS). SLEEP 2009;32(8):1049-1057.     

Early Developmental Changes in Sleep in Infants: The Impact of Maternal Depression

Objectives:

This study evaluated whether sleep over the first 6 months of life was more disturbed in infants born to mothers who were depressed compared with infants from nondepressed mothers.

Design:

Actigraphy was recorded for 7 consecutive days starting at 2 weeks postpartum and monthly thereafter until 6 months of age. Mothers completed daily sleep/wake diaries. Sleep data at 2 weeks and 6 months postpartum are presented here.

Setting:

The home environment.

Participants:

Eighteen healthy, full-term infants, 9 males and 9 females. Seven infants were born to women with no personal or family history of depression; 11 infants were born to women diagnosed with depression or with elevated levels of depression symptoms.

Interventions:

N/A.

Measurements and Results:

Total sleep time, sleep latency, sleep efficiency, and number and duration of sleep episodes were computed for nocturnal and daytime sleep in each 24-hour block. Data were coded for risk group (1 = low risk, 2 = high risk), and repeated-measures multivariate analysis of variance contrasted changes in sleep measures at Week 2 and Week 24, between risk groups. The high-risk infants took longer to fall asleep, had lower sleep efficiencies, and had more sleep bouts in the nocturnal sleep period than did low-risk infants. These effects persisted at 6 months postpartum.

Conclusions:

Maternal depression is associated with significant sleep disturbance in infancy at 2 weeks postpartum that continues through 24 weeks. It remains to be determined if sleep disturbance in infancy confers a greater risk of developing early-onset depression in childhood.

Citation:

Armitage R; Flynn H; Hoffmann R; Vazquez D; Lopez J; Marcus S. Early developmental changes in sleep in infants: the impact of maternal depression. SLEEP 2009;32(5):693-696.     

Insomnia with Objective Short Sleep Duration is Associated with Deficits in Neuropsychological Performance: A General Population Study

Study Objectives:

To examine the joint effect of insomnia and objective short sleep duration on neuropsychological performance.

Design:

Representative cross-sectional study.

Setting:

Sleep laboratory.

Participants:

1,741 men and women randomly selected from central Pennsylvania.

Interventions:

None.

Measurements:

Insomnia (n = 116) was defined by a complaint of insomnia with a duration ≥ 1 year and the absence of sleep disordered breathing (SDB), while normal sleep (n = 562) was defined as the absence of insomnia, excessive daytime sleepiness, and SDB. Both groups were split according to polysomnographic sleep duration into 2 categories: ≥ 6 h of sleep (“normal sleep duration”) and < 6 h of sleep (“short sleep duration”). We compared the groups'' performance on a comprehensive neuropsychological battery that measured processing speed, attention, visual memory, and verbal fluency, while controlling for age, race, gender, education, body mass index, and physical and mental health.

Results:

No significant differences were detected between insomniacs and controls. However, the insomnia with short sleep duration group compared to the control with normal or short sleep duration groups showed poorer neuropsychological performance in variables such as processing speed, set-switching attention, and number of visual memory errors and omissions. In contrast, the insomnia with normal sleep duration group showed no significant deficits.

Conclusions:

Insomnia with objective short sleep duration is associated with deficits in set-switching attentional abilities, a key component of the “executive control of attention.” These findings suggest that objective sleep duration may predict the severity of chronic insomnia, including its effect on neurocognitive function.

Citation:

Fernandez-Mendoza J; Calhoun S; Bixler EO; Pejovic S; Karataraki M; Liao D; Vela-Bueno A; Ramos-Platon MJ; Sauder KA; Vgontzas AN. Insomnia with objective short sleep duration is associated with deficits in neuropsychological performance: a general population study. SLEEP 2010;33(4):459-465.     

EEG Sleep Spectra in Older Adults Across All Circadian Phases During NREM Sleep

Study Objectives:

Healthy aging is associated with changes in sleep-wake regulation, and those changes often lead to problems sleeping, both during the night and during daytime. We aimed to examine the electroencephalographic (EEG) sleep spectra during non-rapid eye movement (NREM) sleep when sleep was scheduled at all times of day.

Design/Interventions:

After three 24-h baseline (BL) days, participants were scheduled to live on 20-hour “days” consisting of 6.7 hours of bed rest and 13.3 hours of wakefulness for 12 consecutive days (forced desynchrony, FD). The EEG was recorded from a central derivation during all scheduled sleep episodes, with subsequent visual scoring and spectral analysis.

Setting:

Intensive Physiological Monitoring Unit of the Brigham & Women''s Hospital General Clinical Research Center.

Participants:

Twenty-four healthy older subjects (64.2 ± 6.3 yr; 13 women, 11 men)

Measurements and Results:

Compared with BL nights, EEG activity in the slow wave (0.5 to 5.25 Hz), theta (6 to 6.25 and 7 Hz), alpha (10 to 11.25 Hz), and high spindle range (14.5 to 15.5 Hz) was significantly greater during FD, when subjects slept across many times of day and night. During FD, there was a significant interaction between homeostatic and circadian factors, such that EEG delta activity (0.5 to 1.5 Hz) was higher in the biological morning/early afternoon than at other times. EEG activity was significantly increased in almost all frequency ranges (0.5 to 21 Hz) during the biological day, as compared with the biological night, except for the lower EEG spindle range (12.25 to 14 Hz). Overall, EEG beta activity was positively correlated with wakefulness and negatively correlated with total sleep time.

Conclusion:

Our findings provide some new evidence for the underlying mechanisms that contribute to age-related difficulties in sleep consolidation, especially when sleep occurs during the daytime.

Citation:

Münch M; Silva EJ; Ronda JM; Czeisler CA; Duffy JF. EEG sleep spectra in older adults across all circadian phases during NREM sleep. SLEEP 2010;33(3):389-401.     

Airway Dilator Muscle Activity and Lung Volume During Stable Breathing in Obstructive Sleep Apnea

Study Objectives:

Many patients with obstructive sleep apnea (OSA) have spontaneous periods of stable flow limited breathing during sleep without respiratory events or arousals. In addition, OSA is often more severe during REM than NREM and more severe during stage 2 than slow wave sleep (SWS). The physiological mechanisms for these observations are unknown. Thus we aimed to determine whether the activity of two upper airway dilator muscles (genioglossus and tensor palatini) or end-expiratory lung volume (EELV) differ between (1) spontaneously occurring stable and cyclical breathing and (2) different sleep stages in OSA.

Design:

Physiologic observation.

Setting:

Sleep physiology laboratory.

Study Participants:

15 OSA patients with documented periods of spontaneous stable breathing.

Intervention:

Subjects were instrumented with intramuscular electrodes for genioglossus and tensor palatini electromyograms (EMG_GG and EMG_TP), chest and abdominal magnetometers (EELV measurement), an epiglottic pressure catheter (respiratory effort), and a mask and pneumotachograph (airflow/ventilation). Patients slept supine overnight without CPAP.

Measurements and Results:

Peak and Tonic EMG_GG were significantly lower during cyclical (85.4 ± 2.7 and 94.6 ± 4.7 % total activity) than stable breathing (109.4 ± 0.4 and 103 ± 0.8 % total activity, respectively). During respiratory events in REM, tonic EMG_GG activity was lower than during respiratory events in stage 2 (71.9 ± 5.1 and 119.6 ± 5.6 % total activity). EMG_GG did not differ between stable stage 2 and stable SWS (98.9 ± 3.2 versus 109.7 ± 4.4 % total activity), nor did EMG_TP or EELV differ in any breathing condition/sleep stage.

Conclusions:

Increased genioglossus muscle tone is associated with spontaneous periods of stable flow limited breathing in the OSA subjects studied. Reductions in genioglossus activity during REM may explain the higher severity of OSA in that stage. Increased lung volume and tensor palatini activity do not appear to be major mechanisms enabling spontaneous stable flow limited breathing periods.

Citation:

Jordan AS; White DP; Lo YL; Wellman A; Eckert DJ; Yim-Yeh S; Eikermann M; Smith SA; Stevenson KE; Malhotra A. Airway dilator muscle activity and lung volume during stable breathing in obstructive sleep apnea. SLEEP 2009;32(3):361–368.