The effect of sleep restriction therapy for insomnia on REM sleep fragmentation: A secondary analysis of a randomised controlled trial

Rapid eye movement sleep fragmentation is hypothesised to be a reliable feature of insomnia, which may contribute to emotion dysregulation. Sleep restriction therapy, an effective intervention for insomnia, has the potential to reduce rapid eye movement sleep fragmentation through its manipulation of basic sleep-wake processes. We performed secondary data analysis of a randomised controlled trial to examine whether sleep restriction therapy reduces rapid eye movement sleep fragmentation in comparison to a matched control arm. Participants (n = 56; 39 female, mean age = 40.78 ± 9.08 years) were randomly allocated to 4 weeks of sleep restriction therapy or 4 weeks of time in bed regularisation. Ambulatory polysomnographic recordings were performed at baseline, week 1 and week 4. Arousals during rapid eye movement and non-rapid eye movement sleep were scored blind to group allocation. The following rapid eye movement sleep fragmentation index was the primary outcome: index 1 = (rapid eye movement arousals + rapid eye movement awakenings + non-rapid eye movement intrusions)/rapid eye movement duration in hours. Secondary outcomes were two further indices of rapid eye movement sleep fragmentation: index 2 = (rapid eye movement arousals + rapid eye movement awakenings)/rapid eye movement duration in hours; and index 3 = rapid eye movement arousals/rapid eye movement duration in hours. A non-rapid eye movement fragmentation index was also calculated (non-rapid eye movement arousals/non-rapid eye movement duration in hours). Linear-mixed models were fitted to assess between-group differences. There was no significant group difference for the primary rapid eye movement fragmentation index at week 1 (p = 0.097, d = -0.31) or week 4 (p = 0.741, d = -0.06). There was some indication that secondary indices of rapid eye movement fragmentation decreased more in the sleep restriction therapy group relative to control at week 1 (index 2: p = 0.023, d = -0.46; index 3: p = 0.051, d = -0.39), but not at week 4 (d ≤ 0.13). No group effects were found for arousals during non-rapid eye movement sleep. We did not find clear evidence that sleep restriction therapy modifies rapid eye movement sleep fragmentation. Small-to-medium effect sizes in the hypothesised direction, across several indices of rapid eye movement fragmentation during early treatment, demand further investigation in future studies.

Associations between self-reported sleep, overnight memory consolidation, and emotion perception: A large-scale online study in the general population

Experimental studies suggest that short or disrupted sleep impairs memory consolidation, mood, and perception of emotional stimuli. However, studies have chiefly relied on laboratory-based study designs and small sample sizes. The aim of this fully online and pre-registered study was to investigate the association between sleep and overnight memory consolidation, emotion perception, and affect in a large, self-selected UK sample. A total of 1646 participants (473 completed) took part in an online study, where they completed a declarative (word-pairs) memory task, emotion perception task (valence ratings of images), and rated their affect within 2 h of bed-time. The following morning, participants reported on their state affect, sleep for the previous night, completed a cued recall task for the previously presented word-pairs, rated the valence of previously viewed images, and completed a surprise recognition task. Demographic data and habitual sleep quality and duration (sleep traits) were also recorded. Habitual sleep traits were associated with immediate recall for the word-pairs task, while self-reported sleep parameters for the specific night were not associated with overnight memory consolidation. Neither habitual sleep traits, nor nightly sleep parameters were associated with unpleasantness ratings to negative stimuli or overnight habituation. Habitual poor sleep was associated with less positive and more negative affect, and morning affect was predicted by the specific night's sleep. This study suggests that overnight emotional processing and declarative memory may not be associated with self-reported sleep across individuals. More work is needed to understand how findings from laboratory-based studies extrapolate to real-world samples and contexts.

The effect of sleep continuity disruption on multimodal emotion processing and regulation: a laboratory-based, randomised, controlled experiment in good sleepers

Previous research shows that experimental sleep deprivation alters emotion processing, suggesting a potential mechanism linking sleep disruption to mental ill-health. Extending previous work, we experimentally disrupted sleep continuity in good sleepers and assessed next-day emotion processing and regulation using tasks with established sensitivity to depression. In a laboratory-based study, 51 good sleepers (37 female; mean [SD] age 24 [3.63] years), were randomised to 1 night of uninterrupted sleep (n = 24) or sleep continuity disruption (n = 27). We assessed emotion perception, attention, and memory the following day. Participants also completed an emotion regulation task and measures of self-reported affect, anxiety, sleepiness, overnight declarative memory consolidation, and psychomotor vigilance. Confirming the effects of the manipulation, sleep continuity disruption led to a marked decrease in polysomnography-defined total sleep time (229.98 versus 434.57 min), increased wake-time after sleep onset (260.66 versus 23.84 min), and increased sleepiness (d = 0.81). Sleep continuity disruption led to increased anxiety (d = 0.68), decreased positive affect (d = -0.62), reduced overnight declarative memory consolidation (d = -1.08), and reduced psychomotor vigilance (longer reaction times [d = 0.64] and more lapses [d = 0.74]), relative to control. However, contrary to our hypotheses, experimental sleep disruption had no effect on perception of, or bias for, emotional facial expressions, emotional memory for words, or emotion regulation following worry induction. In conclusion, 1 night of sleep continuity disruption had no appreciable effect on objective measures of emotion processing or emotion regulation in response to worry induction, despite clear effects on memory consolidation, vigilance, and self-reported affect and anxiety.

The Teensleep study: the effectiveness of a school-based sleep education programme at improving early adolescent sleep

Objective

To evaluate the impact of a school-based sleep education programme on adolescent sleep and sleep knowledge.

Methods

This is the first outcome report on ‘Teensleep’: a novel, teacher-led programme, comprising ten lessons that can be delivered flexibly. Students in Year 10 (n = 1504; mean age = 14.14 ± 0.35 years) from ten UK state (non-fee-paying) secondary schools received the lessons and parents received a leaflet. Effectiveness was assessed using measures across two time points (pre- and post-intervention). Students completed questionnaires on sleep knowledge, sleep quality, sleep behaviour, sleep hygiene, daytime sleepiness and health-related quality of life. A sub-sample provided objective (actigraphy, n = 84) and subjective (sleep diary, n = 74) sleep measures.

Results

Large improvements in sleep knowledge (d = 0.78), and smaller improvements in sleep quality (d = 0.15) and sleep hygiene (d = 0.11) were observed, but not in daytime sleepiness or health-related quality of life. Small and limited changes in subjective and objective sleep patterns were found. Baseline sleep quality was differentially associated with key outcomes, with those initially self-reporting poor sleep demonstrating an improvement in sleep quality, sleep hygiene and sleepiness.

Conclusion

Teensleep was effective at improving sleep knowledge but sleep changes were small. Such interventions have traditionally focused on gains for all students, but this study suggests that poor sleepers may be the most likely to experience immediate direct sleep benefits. Follow-up studies are required to investigate whether or not sleep education provides long-term benefits as a step towards preventative sleep medicine.

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‘Teensleep’ is a teacher-led, school-based sleep education programme for adolescents.

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Large-scale study: students received lessons in ten UK schools.

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Programme effectiveness was evaluated using questionnaires and actigraphy.

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Sleep knowledge, self-reported sleep quality and sleep hygiene improved after lessons.

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Study suggests poor sleepers may be most likely to experience immediate benefits.

Isolating the role of time in bed restriction in the treatment of insomnia: a randomized, controlled, dismantling trial comparing sleep restriction therapy with time in bed regularization

Study Objectives

Sleep restriction therapy (SRT) is one of the most effective treatments for insomnia. Restriction of time in bed (TIB) is assumed to be the central mechanism through which SRT improves sleep consolidation and reduces insomnia symptoms. This hypothesis has never been directly tested. We designed a randomized, controlled, dismantling trial in order to isolate the role of TIB restriction in driving both clinical and polysomnographic sleep outcomes.

Methods

Participants aged 25–55 who met diagnostic criteria for insomnia disorder were block-randomized (1:1) to 4 weeks of SRT or time in bed regularization (TBR), a treatment that involves the prescription of a regular but not reduced TIB. The primary outcome was assessed with the insomnia severity index (ISI) at baseline, 4-, and 12-weeks post-randomization. Secondary outcomes included sleep continuity (assessed via polysomnography, actigraphy, and diary) and quality of life. We performed intention-to-treat analyses using linear mixed models.

Results

Fifty-six participants (39 females, mean age = 40.78 ± 9.08) were assigned to SRT (n = 27) or TBR (n = 29). Daily monitoring of sleep via diaries and actigraphy confirmed large group differences in TIB (d range = 1.63–1.98). At 4-weeks post-randomization, the adjusted mean difference for the ISI was −4.49 (d = −1.40) and −4.35 at 12 weeks (d = −1.36), indicating that the SRT group reported reduced insomnia severity relative to TBR. Robust treatment effects in favor of SRT were also found for objective and self-reported sleep continuity variables (d range = 0.40–0.92) and sleep-related quality of life (d = 1.29).

Conclusions

For the first time, we demonstrate that TIB restriction is superior to the regularization of TIB on its own. Our results underscore the centrality of the restriction component in reducing insomnia symptoms and consolidating sleep.

0548 Overnight Memory Consolidation in Insomnia versus Normal and Experimentally Disrupted Sleep

Introduction

Healthy sleep is assumed to play an important role in the consolidation of newly acquired memories. Evidence suggest that periods of sleep after learning facilitates memory consolidation relative to wakefulness. Insomnia is associated with cognitive impairment but few studies have assessed overnight memory consolidation. We compared overnight consolidation in people with insomnia to a group of good sleepers who were randomised to either a normal night of sleep (uninterrupted sleep, US) or one night of sleep continuity disruption via forced awakenings (FA).

Methods

51 good sleepers (37 female; mean age: 24 years, SD: 3.63), randomised to either one night of US (n=24) or one night of FA (n=27), were compared to 27 participants meeting criteria for insomnia disorder (23 female; mean age: 53 years, SD: 8.34) who were assessed at baseline as part of a randomised controlled trial of digital cognitive-behavioural therapy. Overnight memory consolidation (difference in correctly recalled word pairs between evening and morning recall) was assessed using the same word-pair task and protocol in the two lab-based studies.

Results

Overnight memory consolidation was significantly lower in the insomnia (mean: 5.4, SD: 5.8, p=0.001) and the FA (mean: 6.7, SD: 4.1, p<0.001) group compared to the US group (mean: 11.6, SD: 5.3). However, when adjusted for age only the FA group, but not the insomnia group, showed significantly lower memory performance than the US group.

Conclusion

While our findings suggest that overnight memory consolidation is impaired in insomnia relative to normal sleep we cannot rule out an age-related explanation given the difference in ages between the study samples. Future work will assess whether overnight consolidation improves following cognitive behavioural therapy.

Support

The research was supported by the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC) and the Dr Mortimer and Theresa Sackler Foundation. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health.

Prebiotic supplementation does not affect reading and cognitive performance in children: A randomised placebo-controlled study

Based on the emerging interest in the effects of gut microbiota on cognition, this proof-of-concept study assessed how children aged 7 to 9 with low reading scores responded to the ingestion of a 3-month prebiotic supplement versus a placebo. As a secondary aim, the effects of the prebiotic on cognition, sleep, behaviour, mood, anxiety, and cortisol were assessed. In this sample, the prebiotic did not affect any of the outcome measures.

Challenges in implementing and assessing outcomes of school start time change in the UK: experience of the Oxford Teensleep study

OBJECTIVE

Later school start times for adolescents have been implemented in the US and associated benefits found, although no randomised controlled trials (RCT) have been undertaken. The objective of this study was to evaluate the impact of two school interventions in the UK, a delayed start time and a sleep education programme, on students' academic performance, sleep outcomes and health-related quality of life.

METHODS

The study had an RCT design to enable an investigation into the differential effects of two interventions or a combination of both: schools were to delay their start time to 10:00am and/or provide a classroom-based sleep education programme. The recruitment target was 100 state (non-fee-paying) secondary schools. Participants were to be students in Year 10/11 (14-16-year-olds).

RESULTS

Despite much media coverage, only two schools volunteered to take part in the RCT. The main challenges faced in recruitment fell under three categories: research design, school, and project-specific issues. The delayed start time and prospect of randomisation to this intervention were the overwhelming reasons cited for not taking part. Facilitators and barriers to research were identified. Recommendations include carrying out a feasibility study prior to a main trial, allowing adequate time for recruitment, involving stakeholders throughout the decision-making process, incorporating independent (fee-paying) schools in recruitment, focusing on students not taking important examinations or involving an older year group with greater independence.

CONCLUSION

The Teensleep study provides supporting evidence that evaluating the effects of a change in school start times through an RCT is unfeasible in the UK.

Exploration of potential objective and subjective daily indicators of sleep health in normal sleepers

PURPOSE

While the concept of "sleep health" has only recently been defined, how it relates to both subjective and objective sleep parameters is yet to be determined. The current study aimed to identify potential indicators of poorer sleep health, from subjective and objective daily sleep characteristics, in normal sleepers.

PARTICIPANTS AND METHODS

Eighty-three individuals aged 18-65 years with no history of sleep disorders, chronic physical or psychiatric illnesses, or substance misuse were recruited from the North of England. Secondary analysis of a series of standardized studies, which included psychometrics, actigraphy, and an in-lab polysomnography (PSG) component, was undertaken. Questions from several psychometric sleep scales were combined to create an aggregate measure of sleep health status. Subjective sleep continuity was assessed by 2-week sleep diary. Objective measures comprised two continuous weeks of actigraphy and two nights of in-lab PSG.

RESULTS

Significant negative correlations were evident between sleep health scores and both diary-derived subjective sleep latency (SL; diary) and actigraphy-derived SL (actigraphy). This was reflected by independent samples t-test between high and low sleep health groups. No relationships between sleep health and PSG parameters were observed. Regression analyses indicated sleep latencies from both the sleep diary and actigraphy as significant predictors, explaining 28.2% of the variance in sleep health.

CONCLUSION

Perceived increases in SL appear to be a primary indicator of declining sleep health in normal sleepers. The majority of objective sleep parameters, including gross PSG sleep parameters, appear not to be sensitive to sleep health status in normal sleepers. Future research is needed to understand the physical and psychological correlates of sleep health in larger samples.

Altered Perception of Facially Expressed Tiredness in Insomnia

The present study compared normal sleepers and individuals displaying insomnia symptoms in their ratings for the expression intensity of tiredness and alertness whilst observing tired and neutral faces. Fifty-six normal sleepers and 58 individuals with insomnia symptoms observed 98 facial photographs (49 neutral, 49 tired). Using a visual analogue scale, participants were required to rate the extent to which each face appeared as tired and alert. Tired faces were created by manipulating neutral photographs to include previously identified facial tiredness cues. All participants rated sleep-related faces as more tired and less alert relative to neutral photographs. A significant Group × Face × Rating interaction demonstrated that, compared with normal sleepers, the insomnia symptoms group showed lower ratings for the expression of tiredness, but not alertness, whilst observing the tired faces. The findings suggest that the presence of insomnia symptoms is associated with reduced ratings of expression intensity for sleep-related facial photographs displaying tiredness. These outcomes add to the body of literature on how facial cues of tiredness are perceived by those with insomnia symptoms. Further work is required to elucidate the mechanisms underlying the relationship between insomnia symptoms and reduced perceptions of facially expressed tiredness.

Executive function in adolescents with PKU and their siblings: Associations with biochemistry

Previous research shows consistent and marked executive function impairment in children with early and continuously treated phenylketonuria. This between groups analysis (phenylketonuria group vs sibling controls) found no significant differences in executive function (although adolescents with phenylketonuria performed slightly worse than their siblings). Biochemical relationships with executive function were confined to long-term measures of high phenylalanine:tyrosine ratio exposure, as well as tyrosine exposure independent of phenylalanine. This study suggests that early and continuously treated PKU results in non-significant EF differences (compared to siblings), although the influence of long-term exposure to poorer metabolic control is still evident.

Wrongful life actions: the legal and ethical hurdles

This article discusses the various legal and ethical issues arising out of the cause of action for wrongful life. This action involves a claim by a child that but for the negligence of the doctor, hospital or other medical institution, his or her mother would have terminated the pregnancy and he or she would not have been born. The courts have generally rejected this cause of action on the basis of legal, ethical and policy considerations. The author proposes that the legal hurdles can be overcome and that the ethical and policy considerations do not outweigh the desirability of upholding wrongful life claims.

Metabolic fluctuation during a muscle contraction cycle

Gated 31P-nuclear magnetic resonance followed the metabolic fluctuation in rat gastrocnemius muscle during a contraction cycle. Within 16 ms after stimulation, the phosphocreatine (PCr) level drops 11.3% from its reference state. The PCr minimum corresponds closely to the time of maximum force contraction. Pi increases stoichiometrically, while ATP remains constant. During a twitch, PCr hydrolysis produces 3.1 mumol ATP/g tissue, which is substantially higher than the reported 0.3 mumol ATP.twitch-1.g tissue-1 derived from steady-state experiments. The results reveal that a substantial energy fluctuation accompanies a muscle twitch.

Notes on the preparation and assay of anti-lymphocytic serum for use in mice

The `activity' of rabbit anti-mouse ALS was measured in terms of its power to prolong the life of A-strain homografts on CBA mice. Antisera raised by lymphocytes from mice of other strains were active in CBA mice, and conversely antisera raised by CBA lymphocytes were active in mice of other strains. All active sera were cytotoxic to mouse lymphocytes in the presence of mouse complement, but not all cytotoxic sera were active. ALS raised in species (chicken, duck) of which the sera do not bind with mouse complement were inactive in mice. Neither cytotoxicity nor the power to circumvent graft-versus-host reactions give adequate measures of the activity of impure antisera.

Good antiserum (`two-pulse' ALS) for use in mice could be raised in New Zealand White rabbits by the intravenous injection of 10⁹ mouse thymocytes on two occasions 14 days apart, followed by bleeding out 7 days after the second injection. Further injections of antigen increased the titre of undesirable contaminants in ALS (e.g. red cell agglutinins) but usually did not increase (and sometimes lowered) activity. ALS raised with adjuvants, though powerful, was highly toxic and required extensive absorption.