A Randomized Controlled Trial Comparing Neurofeedback and Cognitive-Behavioral Therapy for Insomnia Patients: Pilot Study

Insomnia is a common disease that negatively affects patients both mentally and physically. While insomnia disorder is mainly characterized by hyperarousal, a few studies that have directly intervened with cortical arousal. This study was conducted to investigate the effect of a neurofeedback protocol for reducing cortical arousal on insomnia compared to cognitive-behavioral treatment for insomnia (CBT-I). Seventeen adults with insomnia, free of other psychiatric illnesses, were randomly assigned to neurofeedback or CBT-I. All participants completed questionnaires on insomnia [Insomnia Severity Index (ISI)], sleep quality [Pittsburgh Sleep Quality Index (PSQI)], and dysfunctional cognition [Dysfunctional Beliefs and Attitudes about Sleep Scale (DBAS-16)]. The neurofeedback group showed decreases in beta waves and increases in theta and alpha waves in various areas of the electroencephalogram (EEG), indicating lowered cortical arousal. The ISI and PSQI scores were significantly decreased, and sleep efficiency and sleep satisfaction were increased compared to the pre-treatment scores in both groups. DBAS scores decreased only in the CBT-I group (NF p?=?0.173; CBT-I p?=?0.012). This study confirmed that neurofeedback training could alleviate the symptoms of insomnia by reducing cortical hyperarousal in patients, despite the limited effect in reducing cognitive dysfunction compared to CBT-I.

     

Neurofeedback for Insomnia: A Pilot Study of <Emphasis Type="Italic">Z</Emphasis>-Score SMR and Individualized Protocols

Insomnia is an epidemic in the US. Neurofeedback (NFB) is a little used, psychophysiological treatment with demonstrated usefulness for treating insomnia. Our objective was to assess whether two distinct Z-Score NFB protocols, a modified sensorimotor (SMR) protocol and a sequential, quantitative EEG (sQEEG)-guided, individually designed (IND) protocol, would alleviate sleep and associated daytime dysfunctions of participants with insomnia. Both protocols used instantaneous Z scores to determine reward condition administered when awake. Twelve adults with insomnia, free of other mental and uncontrolled physical illnesses, were randomly assigned to the SMR or IND group. Eight completed this randomized, parallel group, single-blind study. Both groups received fifteen 20-min sessions of Z-Score NFB. Pre-post assessments included sQEEG, mental health, quality of life, and insomnia status. ANOVA yielded significant post-treatment improvement for the combined group on all primary insomnia scores: Insomnia Severity Index (ISI p < .005), Pittsburgh Sleep Quality Inventory (PSQI p < .0001), PSQI Sleep Efficiency (p < .007), and Quality of Life Inventory (p < .02). Binomial tests of baseline EEGs indicated a significant proportion of excessively high levels of Delta and Beta power (p < .001) which were lowered post-treatment (paired z-tests p < .001). Baseline EEGs showed excessive sleepiness and hyperarousal, which improved post-treatment. Both Z-Score NFB groups improved in sleep and daytime functioning. Post-treatment, all participants were normal sleepers. Because there were no significant differences in the findings between the two groups, our future large scale studies will utilize the less burdensome to administer Z-Score SMR protocol.     

Treatment of Chronic Insomnia with Yoga: A Preliminary Study with Sleep–Wake Diaries

There is good evidence for cognitive and physiological arousal in chronic insomnia. Accordingly, clinical trial studies of insomnia treatments aimed at reducing arousal, including relaxation and meditation, have reported positive results. Yoga is a multicomponent practice that is also known to be effective in reducing arousal, although it has not been well evaluated as a treatment for insomnia. In this preliminary study, a simple daily yoga treatment was evaluated in a chronic insomnia population consisting of sleep-onset and/or sleep-maintenance insomnia and primary or secondary insomnia. Participants maintained sleep–wake diaries during a pretreatment 2-week baseline and a subsequent 8-week intervention, in which they practiced the treatment on their own following a single in-person training session with subsequent brief in-person and telephone follow-ups. Sleep efficiency (SE), total sleep time (TST), total wake time (TWT), sleep onset latency (SOL), wake time after sleep onset (WASO), number of awakenings, and sleep quality measures were derived from sleep–wake diary entries and were averaged in 2-week intervals. For 20 participants completing the protocol, statistically significant improvements were observed in SE, TST, TWT, SOL, and WASO at end-treatment as compared with pretreatment values.     

Chronotype,bed timing and total sleep time in seniors

Many older adults (seniors) experience problems with getting enough sleep. Because of the link between sleep and circadian rhythms, changes in bedtime lead to changes in the amount of sleep obtained. Although primarily determined genetically, chronotype changes with advancing age towards a more morning-type (M-type) orientation. In a 2006 study, we have found a linear relationship, by which the earlier a senior’s bedtime, the more sleep she/he will obtain. The aim of this study was to see whether this relationship differs for M-type seniors, as compared to seniors outside the M-type category. Retired seniors (n?=?954, 535?M, 410F, 65?years+, mean age 74.4?years) taking part in a telephone interview were divided into M-types and Other types (O-types) using the Composite Scale of Morningness (CSM). The relationship between bedtime and Total Sleep Time (TST), and between rise-time and TST, was tested using linear regression separately for M-types and O-types. For each participant, habitual bedtime, rise-time and total Sleep Time (TST) [after removing time spent in unwanted wakefulness] were obtained using a telephone version of the Sleep Timing Questionnaire (STQ). Both chronotype groups showed a significant linear relationship between bedtime and TST (p?<?0.001); with earlier bedtimes leading to more TST (M-type 5.6?min; O-type 4.4?min per 10?min change [slope difference p?=?0.05]); and an opposite relationship between rise-time and TST with earlier rise-times leading to less TST (M-type 6.7?min; O-type 4.2?min per 10?min change [slope difference p?=?0.001]). M-types retired to bed 56?min earlier (p?<?0.001), awoke 93?min earlier (p?<?0.001) and obtained 23?min less TST (p?<?0.001) than O-types. In conclusion, both chronotypes showed TST to be related in a linear way to bedtime and rise-time; the overall shorter TST in M-types was due to them rising 93?min earlier, but only retiring to bed 56?min earlier than O-types; as well as having a steeper rise-time versus TST relationship.     

Testing the Benefits of Neurofeedback on Selective Attention Measured Through Dichotic Listening

The electrophysiological changes after a single session of neurofeedback training (↑SMR/↓Theta) and its effects on executive attention during a dichotic listening test with forced attentional procedures were measured in a sample of 20 healthy women. A pre–post moment test double blind design, with the inclusion of a group receiving sham neurofeedback, allowed for minimization of alien influences. The interaction of Moment × Group was significant, indicating an enhancement of SMR band after the real neurofeedback. The dichotic listening scores were correlated with the amplitude of Beta band in baseline conditions. The performance on the forced left attentional condition in dichotic listening was significantly improved and correlated positively with the post-training enhancement of the SMR band. The sham neurofeedback group also improved DL scores, so a clear affirmation about the benefits of neurofeedback training over cognitive performance could not be unambiguously established. It is concluded that the protocol showed a good independence and acceptable trainability in modifying the EEG results, but there was limited interpretability regarding cognitive outcomes.     

Neurofeedback Training for Tourette Syndrome: An Uncontrolled Single Case Study

Gilles de la Tourette syndrome (TS) is characterized by motor and vocal tic manifestations, often accompanied by behavioral, cognitive and affective dysfunctions. Electroencephalography of patients with TS has revealed reduced Sensorimotor Rhythm (SMR) and excessive fronto-central Theta activity, that presumably underlie motor and cognitive disturbances in TS. Some evidence exists that neurofeedback (NFB) training aimed at enhancing SMR amplitude is effective for reducing tics. The present report is an uncontrolled single case study where a NFB training protocol, involving combined SMR uptraining/Theta downtraining was delivered to a 17-year-old male with TS. After sixteen SMR-Theta sessions, six additional sessions were administered with SMR uptraining alone. SMR increase was better obtained when SMR uptraining was administered alone, whereas Theta decrease was observed after both trainings. The patient showed a reduction of tics and affective symptoms, and improvement of cognitive performance after both trainings. Overall, these findings suggest that Theta decrease might account for some clinical effects seen in conjunction with SMR uptraining. Future studies should clarify the feasibility of NFB protocols for patients with TS beyond SMR uptraining alone.     

Improvements in Spelling after QEEG-based Neurofeedback in Dyslexia: A Randomized Controlled Treatment Study

Phonological theories of dyslexia assume a specific deficit in representation, storage and recall of phonemes. Various brain imaging techniques, including qEEG, point to the importance of a range of areas, predominantly the left hemispheric temporal areas. This study attempted to reduce reading and spelling deficits in children who are dyslexic by means of neurofeedback training based on neurophysiological differences between the participants and gender and age matched controls. Nineteen children were randomized into an experimental group receiving qEEG based neurofeedback (n = 10) and a control group (n = 9). Both groups also received remedial teaching. The experimental group improved considerably in spelling (Cohen’s d = 3). No improvement was found in reading. An indepth study of the changes in the qEEG power and coherence protocols evidenced no fronto-central changes, which is in line with the absence of reading improvements. A significant increase of alpha coherence was found, which may be an indication that attentional processes account for the improvement in spelling. Consideration of subtypes of dyslexia may refine the results of future studies.     

The longer the better: Sleep–wake patterns during preparation of the World Rowing Junior Championships

Recovery is essential for high athletic performance, and therefore especially sleep has been identified as a crucial source for physical and psychological well-being. However, due to early-morning trainings, which are general practice in many sports, athletes are likely to experience sleep restrictions. Therefore, this study investigated the sleep–wake patterns of 55 junior national rowers (17.7 ± 0.6 years) via sleep logs and actigraphy during a four-week training camp. Recovery and stress ratings were obtained every morning with the Short Recovery and Stress Scale on a 7-point Likert-type scale ranging from 0 (does not apply at all) to 6 (fully applies). The first training session was scheduled for 6:30 h every day. With two to four training sessions per day, the training load was considerably increased from athletes’ home training. Objective sleep measures (n = 14) revealed less total sleep time (TST) in the first two weeks (409.6 ± 19.1 and 416.0 ± 16.3 min), while training volume and intensity were higher. In the second half of the camp, less training sessions were implemented, more afternoons were training free and TSTs were longer (436.3 ± 15.8 and 456.9 ± 25.7 min). A single occasion of 1.5-h delayed bedtime and usual early morning training (6:30 h) resulted in reduced ratings of Overall Recovery (OR) (M = 3.3 ± 1.3) and greater Negative Emotional State (NES) (M = 1.3 ± 1.2, p < .05), which returned to baseline on the next day. Following an extended night due to the only training-free day, sleep-offset times were shifted from ~5:30 to ~8:00 h, and each recovery and stress score improved (p < .01). Moreover, subjective ratings of the first six days were summarised as a baseline score to generate reference data as well as to explore the association between sleep and recovery. Intercorrelations of these sleep parameters emphasised the relationship between restful sleep and falling asleep quickly (r = .34, p < .05) as well as few awakenings (r = .35, p < .05). Overall, the findings highlight the impact of sleep on subjective recovery measures in the setting of a training camp. Providing the opportunity of extended sleep (and a day off) seems the most simple and effective strategy to enhance recovery and stress-related ratings.     

Bruxism and nocturnal groaning

Sleep bruxism (SB) is a sleep-related movement disorder, characterized by tooth grinding and/or clenching. The causes of SB range from psychosocial factors to an excessive sleep arousal response. Some studies showed that SB episodes during sleep are under the influences of transient activity of the brainstem arousal. Nocturnal groaning (NG) is a parasomnia characterized by an expiratory monotonous vocalization occurring during sleep, especially in REM sleep and during the second half of the night. The pathogenesis of NG remains still unclear and many hypotheses arose, ranging from the persistence of a vestigial ventilatory pattern rather than an expiratory upper airways' obstruction. Sleep microstructure fluctuation might modulate the NG, since the end of the NG episode usually is synchronized with a cortical arousal and an autonomic activation. Further studies should clarify the pathophysiology of SB and NG, especially when the two phenomena are associated.     

Comparison of the Effect of Cognitive Rehabilitation and Neurofeedback on Sustained Attention Among Elementary School Students with Specific Learning Disorder: A Preliminary Randomized Controlled Clinical Trial

Specific learning disorder (SLD) can occur along with the problems of attention performance and be complicated by them. Recent studies have reported the positive effects of cognitive rehabilitation (CR) and neurofeedback (NFB) on sustained attention (SA) in SLD. Nevertheless, it has not yet been determinedwhat kind of treatment may be the most appropriate option for this disorder in terms of the different functions of cognitive status, especially SA. This preliminary study aimed to compare CR and NFB effects on SA among elementary school students with SLD using a randomized controlled clinical trial (RCT). Fifty- three eligible students with a DSM-5 SLD diagnosis, aged 7–10, were randomly allocated in NFB (n?=?18), CR (n?=?18), and control groups (n?=?17). All the participants were evaluated for SA by performing the continuous performance test (CPT) on the studied groups at the time of their inclusion in the study and 7 weeks after it. The intervention groups took part in 20 sessions of CR and 20 sessions of NFB. Conversely, the untreated group were evaluated without any intervention.15 boys and 30 girls in 3 groups completed the study (n?=?15 per group). The mean and standard deviation of participants’ age were (8.66?±?1.48) years, (8.40?±?1.73) years and (8.53?±?1.63) years in CR, NFB and untreated groups, respectively. The results showed significant differences between the groups based on the variables of the CPT test (p?<?0.05). Also, the significant effects of the variables represented the higher scores of the CR compared to the NFB group (p?<?0.001). This study provides einitial evidence that CR is more effective than NFB on SA improvement among students with SLD.     

Comparison of escitalopram alone and combined with zolpidem in treating major depression and related sleep impairments

Escitalopram has been shown to be effective for treating major depression (MDD); however, research is lacking regarding its effect on treating MDD-related sleep impairments. The purpose of this study was to assess the efficacy of escitalopram monotherapy and investigate changes in insomnia, depressive symptoms, and quality of life (QOL). Participants were 14 patients with MDD who enrolled in a clinical trial at Jikei University Katsushika Medical Center. Escitalopram monotherapy was used, and hypnotics were administered three times per week for individuals suffering from sleep impairments. The following variables were assessed: (1) sleep quality [Pittsburgh sleep quality index (PSQI)], (2) depression [Zung self-rating depression scale (ZSRDS)], and (3) quality of life (QOL) as determined by the Sheehan disability scale (SDISS) and short form (36) health survey (SF-36). These assessments were conducted prior to any treatment (pre-test) and again 8–12 weeks after treatment (post-test). Monotherapy (E = escitalopram alone; n = 6) and combination therapy (E+ = escitalopram + zolpidem; n = 8) groups were compared. All participants completed the full protocol (average 9.4 ± 1.8 weeks). Regardless of treatment group, participants improved on all assessments (including sleep impairment). However, groups did not differ in their level of improvement. A two-factor ANOVA revealed that the E+ group showed particular improvements in QOL. In treating MDD and associated sleep impairments, zolpidem did not confer additional benefits. Thus, clinicians should consider E monotherapy for patients with MDD-related sleep impairments before prescribing combination therapies.

     

Association Between Thyroid Function and Objective and Subjective Sleep Quality in Older Men: The Osteoporotic Fractures in Men (MrOS) Study

ObjectiveTo determine the association between thyroid hormone levels and sleep quality in community-dwelling men.MethodsAmong 5,994 men aged ≥ 65 years in the Osteoporotic Fractures in Men (MrOS) study, 682 had baseline thyroid function data, normal free thyroxine (FT₄) (0.70 ≤ FT₄ ≤ 1.85 ng/dL), actigraphy measurements, and were not using thyroid-related medications. Three categories of thyroid function were defined: subclinical hyperthyroid (thyroid-stimulating hormone [TSH] < 0.55 mIU/L), euthyroid (TSH, 0.55 to 4.78 mIU/L), and subclinical hypothyroid (TSH > 4.78 mIU/L). Objective (total hours of nighttime sleep [TST], sleep efficiency [SE], wake after sleep onset [WASO], sleep latency [SL], number of long wake episodes [LWEP]) and subjective (TST, Pittsburgh Sleep Quality Index score, Epworth Sleepiness Scale score) sleep quality parameters were measured. The association between TSH and sleep quality was examined using linear regression (continuous sleep outcomes) and log-binomial regression (categorical sleep outcomes).ResultsAmong the 682 men examined, 15 had subclinical hyperthyroidism and 38 had subclinical hypothyroidism. There was no difference in sleep quality between subclinical hypothyroid and euthyroid men. Compared to euthyroid men, subclinical hyperthyroid men had lower mean actigraphy TST (adjusted mean difference [95% confidence interval (CI)], − 27.4 [− 63.7 to 8.9] minutes), lower mean SE (− 4.5% [− 10.3% to 1.3%]), and higher mean WASO (13.5 [− 8.0 to 35.0] minutes]), whereas 41% had increased risk of actigraphy-measured TST < 6 hours (relative risk [RR], 1.41; 95% CI, 0.83 to 2.39), and 83% had increased risk of SL ≥ 60 minutes (RR, 1.83; 95% CI, 0.65 to 5.14) (all P > .05).ConclusionNeither subclinical hypothyroidism nor hyperthyroidism is significantly associated with decreased sleep quality. (Endocr Pract. 2014;20:576-586)     

Impact of tapering and proactive recovery on young elite rugby union players’ repeated high intensity effort ability

To assess the effects of a taper combined with proactive recovery on the repeated high intensity effort (RHIE) of elite rugby union players, and the possible interaction of pre-taper fatigue and sleep. Eighteen players performed a 3-week intensive training block followed by a 7-day exponential taper combined with a multicomponent recovery strategy. Following the intervention, players were divided into 3 groups (Normal Training: NT, Acute Fatigue: AF or Functional Overreaching: F-OR) based on their readiness to perform prior to the taper. Total sprint time [TST], percentage decrement [%D] and the number of sprints ≥90% of the best [N90] were analyzed to assess performance during a RHIE test. Subjective sleep quality was assessed through the Pittsburg Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS). No improvement in TST was reported in either NT or F-OR after the taper, whereas AF tended to improve (-1.58 ± 1.95%; p > 0.05; g = -0.20). F-OR players reported baseline PSQI and ESS indicative of sleep disturbance (6.2 ± 2.2 and 10.6 ± 5.4, respectively). AF displayed a small impairment in PSQI during intensive training (11.5 ± 80.6%; p > 0.05; g = 0.20), which was reversed following the taper (-34.6 ± 62.1%; p > 0.05; g = -0.73). Pre-taper fatigue precluded the expected performance benefits of the combined taper and recovery intervention, likely associated with a lack of strictly controlled intensive training block. Poor sleep quality before the intensive training period appeared to predispose the players to developing functional overreaching.     

Basic Scale on Insomnia complaints and Quality of Sleep (BaSIQS): Reliability,initial validity and normative scores in higher education students

Based on successive samples totaling more than 5000 higher education students, we scrutinized the reliability, structure, initial validity and normative scores of a brief self-report seven-item scale to screen for the continuum of nighttime insomnia complaints/perceived sleep quality, used by our team for more than a decade, henceforth labeled the Basic Scale on Insomnia complaints and Quality of Sleep (BaSIQS). In study/sample 1 (n?=?1654), the items were developed based on part of a larger survey on higher education sleep–wake patterns. The test–retest study was conducted in an independent small group (n?=?33) with a 2–8 week gap. In study/sample 2 (n?=?360), focused mainly on validity, the BaSIQS was completed together with the Pittsburgh Sleep Quality Index (PSQI). In study 3, a large recent sample of students from universities all over the country (n?=?2995) answered the BaSIQS items, based on which normative scores were determined, and an additional question on perceived sleep problems in order to further analyze the scale’s validity. Regarding reliability, Cronbach alpha coefficients were systematically higher than 0.7, and the test–retest correlation coefficient was greater than 0.8. Structure analyses revealed consistently satisfactory two-factor and single-factor solutions. Concerning validity analyses, BaSIQS scores were significantly correlated with PSQI component scores and overall score (r?=?0.652 corresponding to a large association); mean scores were significantly higher in those students classifying themselves as having sleep problems (p?<?0.0001, d?=?0.99 corresponding to a large effect size). In conclusion, the BaSIQS is very easy to administer, and appears to be a reliable and valid scale in higher education students. It might be a convenient short tool in research and applied settings to rapidly assess sleep quality or screen for insomnia complaints, and it may be easily used in other populations with minor adaptations.     

Examining courses of sleep quality and sleepiness in full 2 weeks on/2 weeks off offshore day shift rotations

ABSTRACT

To better understand sleep quality and sleepiness problems offshore, we examined courses of sleep quality and sleepiness in full 2-weeks on/2-weeks off offshore day shift rotations by comparing pre-offshore (1 week), offshore (2 weeks) and post-offshore (1 week) work periods. A longitudinal observational study was conducted among N=42 offshore workers. Sleep quality was measured subjectively with two daily questions and objectively with actigraphy, measuring: time in bed (TIB), total sleep time (TST), sleep latency (SL) and sleep efficiency percentage (SE%). Sleepiness was measured twice a day (morning and evening) with the Karolinska Sleepiness Scale. Changes in sleep and sleepiness parameters during the pre/post and offshore work periods were investigated using (generalized) linear mixed models. In the pre-offshore work period, courses of SE% significantly decreased (p=.038). During offshore work periods, the courses of evening sleepiness scores significantly increased (p<.001) and significantly decreased during post-offshore work periods (p=.004). During offshore work periods, TIB (p<.001) and TST (p<.001) were significantly shorter, SE% was significantly higher (p=.002), perceived sleep quality was significantly lower (p<.001) and level of rest after wake was significantly worse (p<.001) than during the pre- and post-offshore work periods. Morning sleepiness was significantly higher during offshore work periods (p=.015) and evening sleepiness was significantly higher in the post-offshore work period (p=.005) compared to the other periods. No significant changes in SL were observed. Courses of sleep quality and sleepiness parameters significantly changed during full 2-weeks on/2-weeks off offshore day shift rotation periods. These changes should be considered in offshore fatigue risk management programmes.     

Neuro-protective effects of carbamazepine on sleep patterns and head and body shakes in kainic acid-treated rats

The aim of this work was to analyze the effect of carbamazepine (CBZ) on sleep patterns and on “head and body shakes” and to determine the role of serotonin (5-HT) in a model of kainic-induced seizures. Thirty male Wistar rats (280–300 g) were used for polygraphic sleep recording. After a basal recording, the rats were allocated into three groups: kainic acid-treated animals (KA; 10 mg/kg; n = 10), carbamazepine-treated animals (CBZ; 30 mg/kg; n = 10) and animals injected with KA 30 min after pretreatment with CBZ (CBZ + KA; n = 10). Polygraphic recordings were performed for 10 h for 3 days, with the exception of the CBZ group, which were observed for 1 day. In order to measure the head and body shakes that occurred over that time, a behavioral assessment was performed in two additional groups of KA (n = 10) and CBZ + KA (n = 10) animals. After 10 h of behavioral assessment, the rats were sacrificed, and the levels of 5-HT and 5-hydroxy-indol-acetic acid (5-HIAA) were analyzed. We compared these findings with the results from a group of rats without pharmacological intervention (n = 10). All of the recordings were performed from 08:00 to 18:00 h. Data analysis: the electrographic parameters, head and body shake counting and monoamine concentrations were analyzed by an ANOVA test. Differences of *p ≤ 0.01 and **p ≤ 0.001 were considered statistically significant. Our results showed that CBZ exerted a protective effect on sleep pattern alterations induced by KA, which when administered alone caused a complete inhibition of sleep for the first 10 h after administration. Although there was a reduction in the amount of sleep after the administration of KA in CBZ-pretreated animals, sleep inhibition was incomplete. In addition, CBZ decreased the frequency of head and body shakes by 60% as compared to KA. The 5-HT and 5-HIAA levels in the pons were increased in the KA and KA + CBZ groups. Our conclusion is that in addition to decreasing seizure intensity, CBZ facilitates the partial recovery of sleep. These results suggest that CBZ provides neuro-protective effects on sleep and against seizures.     

Arousal and ventilatory responses during sleep in children with obstructive sleep apnea

Abnormal centralregulation of upper airway muscles may contribute to thepathophysiology of the childhood obstructive sleep apnea syndrome(OSAS). We hypothesized that this was secondary to global abnormalitiesof ventilatory control during sleep. We therefore compared the responseto chemical stimuli during sleep between prepubertal children with OSASand controls. Patients with OSAS aroused at a higherPCO₂ (58 ± 2 vs. 60 ± 5 Torr,P < 0.05); those with the highestapnea index had the highest arousal threshold(r = 0.52, P < 0.05). The hypercapnic arousal threshold decreased after treatment. For all subjects, hypoxia was apoor stimulus to arousal, whereas hypercapnia and, particularly, hypoxic hypercapnia were potent stimuli to arousal. Hypercapnia resulted in decreased airway obstruction in OSAS. Ventilatory responseswere similar between patients with OSAS and controls; however, thesample size was small. We conclude that children with OSAS haveslightly blunted arousal responses to hypercapnia. However, the overallventilatory and arousal responses are normal in children with OSAS,indicating that a global deficit in respiratory drive is not a majorfactor in the etiology of childhood OSAS. Nevertheless, subtleabnormalities in ventilatory control may exist.

     

Chronotype and its relationship with sleep disorders in children with attention deficit hyperactivity disorder

Chronotype can be classified as morningness types, people who prefer morning hours for their physical and mental activities; eveningness types, people who prefer the afternoon or evening hours; and intermediate types, those who show characteristics of both morningness and eveningness types. Attention deficit hyperactivity disorder (ADHD) has been linked with disturbances in chronotype, particularly increased eveningness. Despite the possibility of an association between chronotypes, sleep disturbances and ADHD symptoms, there is little evidence of this association considering the child population. The purpose of this study was to examine chronotype preferences in children aged between 7 and 12 years who were diagnosed as having ADHD in the context of sleep disturbances. The Schedule for Affective Disorders and Schizophrenia for School Age Children-Present and Lifetime Version, Conner’s Rating Scales, Children’s Sleep Habit Questionnaire and Children’s Chronotype Questionnaire were used for the evaluation of children with ADHD and healthy controls. The ADHD group was 73% combined-type, and the eveningness scores of the ADHD group (n = 52) were significantly higher than the control group (n = 52) (p < 0.01). There was a positive correlation between the higher scores of eveningness and total scores on resistance to sleep time (p < 0.09), respiratory problems during sleep and daytime sleepiness in the ADHD group. CSHQ total score was found to be a predictive factor for eveningness among children with ADHD (p < 0.01). These findings highlight possible reciprocal links between ADHD symptoms, sleep disturbances and chronotype in children aged 7–12 years, which might lead to individualized treatment options.     

Circadian adaptation of airline pilots during extended duration operations between the USA and Asia

This study tracked circadian adaptation among airline pilots before, during, and after trips where they flew from Seattle (SEA) or Los Angeles (LAX) to Asia (7--9 time zones westward), spent 7--12?d in Asia, and then flew back to the USA. In Asia, pilots' exposures to local time cues and sleep opportunities were constrained by duty (short-haul flights crossing ≤1 time zone/24?h). Fourteen captains and 16 first officers participated (median age?=?56 versus 48 yrs, p.U)?<?0.001). Their sleep was monitored (actigraphy, duty/sleep diaries) from 3?d pre-trip to 5?d post-trip. For every flight, Karolinska Sleepiness and Samn-Perelli Fatigue scales and 5-min psychomotor vigilance task (PVT) tests were completed pre-flight and at top of descent (TOD). Participants had ≥3 d free of duty prior to outbound flight(s). From 72--24?h prior to departure (baseline sleep), mean total sleep/24?h (TST)?=?7.00?h (SD?=?1.18?h) and mean sleep efficiency?=?87% (SD?=?4.9%). Most pilots (23/30) flew direct to and from Asia, but 7 LAX-based pilots flew via a 1-d layover in Honolulu (HNL). On flights with ≥2 pilots, mean total in-flight sleep varied from 0.40 to 2.09?h outbound and from 0.74 to 1.88?h inbound. Duty patterns in Asia were variable, with ≤2 flights/d (mean flight duration?=?3.53?h, SD?=?0.53?h). TST on days 17 in Asia did not differ from baseline (p.F)?=?0.2031). However, mean sleep efficiency was significantly lower than baseline on days 5--7 (p.F)?=?0.0041). More pilots were on duty between 20:00 and 24:00?h on days 57 (mean?=?21%) than on days 24 (mean?=?14%). Sleep propensity distribution phase markers and chi-square periodogram analyses suggest that adaptation to local time was complete by day 4 in Asia. On pre-flight PVT tests in Asia, the slowest 10% of responses improved for flights departing 14:00--19:59?h (p.F)?=?0.0484). At TOD, the slowest 10% of responses improved across days for flights arriving 14:00--19:59?h (p.F)?=?0.0349) and 20:00--01:59?h (p.F)?=?0.0379). Sleepiness and fatigue ratings pre-flight and at TOD did not change across days in Asia. TST on post-trip day 1 was longer than baseline (estimated mean extension?=?1.68?h; adjusted p(t)?<?0.0001). On all post-trip days, sleep efficiency was comparable to baseline. Sleep propensity distribution phase markers and chi-square periodogram analyses suggest complete readaptation in 12?d. Two opposing influences appeared to affect sleep and PVT performance across days in Asia: progressive circadian adaptation to local time and increasing duty during local night, which displaced sleep from the optimal physiological time. Cumulative sleep restriction across the return flight may explain the large rebound in TST on day 1 post-trip. Thereafter TST, sleep efficiency, and sleep timing suggest that readaptation was complete. Rapid post-trip readaptation may be facilitated by pilots having unconstrained nocturnal sleep opportunities, coupled with stronger patterns of family and social cues than in Asia.