Is it Time to Include Wearable Sleep Trackers in the Applied Psychologists' Toolbox?

Wearable sleep trackers are increasingly used in applied psychology. Particularly, the recent boom in the fitness tracking industry has resulted in a number of relatively inexpensive consumer-oriented devices that further enlarge the potential applications of ambulatory sleep monitoring. While being largely positioned as wellness tools, wearable sleep trackers could be considered useful health devices supported by a growing number of independent peer-reviewed studies evaluating their accuracy. The inclusion of sensors that monitor cardiorespiratory physiology, diurnal activity data, and other environmental signals allows for a comprehensive and multidimensional approach to sleep health and its impact on psychological well-being. Moreover, the increasingly common combination of wearable trackers and experience sampling methods has the potential to uncover within-individual processes linking sleep to daily experiences, behaviors, and other psychosocial factors. Here, we provide a concise overview of the state-of-the-art, challenges, and opportunities of using wearable sleep-tracking technology in applied psychology. Specifically, we review key device profiles, capabilities, and limitations. By providing representative examples, we highlight how scholars and practitioners can fully exploit the potential of wearable sleep trackers while being aware of the most critical pitfalls characterizing these devices. Overall, consumer wearable sleep trackers are increasingly recognized as a valuable method to investigate, assess, and improve sleep health. Incorporating such devices in research and professional practice might significantly improve the quantity and quality of the collected information while opening the possibility of involving large samples over representative time periods. However, a rigorous and informed approach to their use is necessary.

Methods used to assess sleep in children who attend community-based mental health programmes: A systematic review

Sleep quality and sleep duration are important for children's physical and mental health. Mental health diagnoses and sleep disturbances may be interlinked. We sought to identify the methods used to assess sleep in paediatric community-based mental health programmes. A systematic review was conducted using an a priori protocol to ascertain the sleep assessment methods used in paediatric community-based mental health programmes. Children for this review were defined as any person under the age of 19. Cochrane Library, CINAHL, Web of Science, ProQuest, APA PsycInfo, and PubMed databases were searched from January 2021 to March 2022. Of the 320 records screened, 314 records were excluded. Six studies were included for analysis. A variety of validated and non-validated sleep instruments were used to measure sleep quality and a range of sleep disturbances in community health programmes for children. There were a limited number of studies associated with sleep assessment in paediatric community-based settings suggesting this is an area of research that may be understudied. Sleep questionnaires were predominately completed by parents or guardians. Further research is required to establish the most effective method for screening sleep behaviour in paediatric community mental health programmes to understand the impact of sleep in the recovery of children and adolescents with mental health disorders.

Diet quality and associated factors in Brazilian undergraduates during the COVID-19 pandemic

Background

Diet quality is associated with psychobiological, psychological, biological, and physiological factors of individuals, and in the context of prolonged stress, such as the COVID-19 pandemic, it can lead to a worsening of the quality of food for undergraduates. This study aimed to analyze diet quality and associated factors in Brazilian undergraduates.

Methods

Data were collected from 4,799 undergraduate students from all Brazilian regions, from August 2020 to February 2021. The online questionnaire contained socioeconomic variables, the ESQUADA scale to assess diet quality, self-referred changes in weight, the Brazilian food insecurity scale (EBIA), sleep assessment and the perceived stress scale. Unconditional multiple logistic regression analysis was performed to study variables associated with poor and very poor diet quality.

Results

Most of participants presented a good diet quality (51.7%), while 9.8% had a poor or very poor diet quality and only 1.1% had an excellent diet quality. 58.2% of undergraduates reported to have an increase in weight during the pandemic and 74.3% of the students presented elevated stress during the pandemic. Logistic regressions showed students who gained weight during the pandemic presented the highest AOR = 1.56 (95% CI = 1.12-2.20) for poor or very poor diet quality. The elevated perceived stress was also associated with a higher AOR = 2.85 (95% CI = 1.71-4.74) for poor or very poor diet quality.

Conclusion

Most of the studied undergraduates presented a good diet quality. Nevertheless, poor/very poor diet quality was associated with higher perceived stress and weight gain. Our study indicated that policies should beaimed at the socioeconomically most vulnerable undergraduates, those in a situation of food and nutritional insecurity, high perceived stress, and who gained weight during the pandemic.

Subjective sleep assessment compared to polysomnography in mechanically ventilated critically ill ICU patients

Sleep deprivation is expected in the intensive care unit (ICU) and is associated with delirium and increased mortality. Polysomnography (PSG) is the gold standard for sleep assessment, but practical issues limit the method. Hence, many ICUs worldwide use subjective sleep assessment (SSA) for sleep monitoring, but the agreement between SSA and PSG is unknown. The hypothesis was that the level of agreement between SSA and PSG was low and that total sleep time (TST) assessed with SSA would be overestimated compared to PSG in this existing cohort database. In this sub-analysis, 30 consecutive study participants underwent 15-h PSG recordings during two consecutive nights. The attending nurse performed an hourly subjective observer rating of sleep quantity during both nights, and the agreement between SSA and PSG was determined along with mean TST. Primary outcome: The level of agreement between SSA and PSG determined by Bland-Altman analysis. Secondary outcome: (1) The overall mean TST estimated by SSA compared to PSG in all study participants enrolled in the main study during both study nights, (2) TST for all study participants evaluated hourly during both study nights, (3) TST assessed with SSA compared to PSG in study participants sedated with dexmedetomidine during the second night and for study participants treated with placebo or non-sedation the first and second nights. The level of agreement between SSA and PSG was low. Mean TST estimated by SSA during the time interval 4.00 p.m. to 7.00 a.m. was 481 min (428;534, 95% CI) vs. PSG at 437 min (386;488, 95% CI) (p = .05). When sedated with dexmedetomidine, TST estimated using SSA was 650 min (571;729, 95% CI) versus PSG which was 588 min (531;645, 95% CI) (p = 0.56). For participants treated with placebo or non-sedation TST estimated with SSA was 397 min (343;450, 95% CI) versus PSG at 362 min (302;422, 95% CI) versus (p = 0.17). In mechanically ventilated critically ill ICU patients, the level of agreement between SSA and PSG was low, and there was a significant overestimation of mean TST. SSA should only be used under awareness that it is imprecise and overestimates TST.

Sleep Management within Skilled Nursing Facilities: A Practice Survey

A cross-sectional descriptive survey of 105 occupational therapy practitioners examined the practice patterns in sleep management within skilled nursing facilities. All participants viewed sleep as essential to address in their settings, since clients frequently reported inadequate sleep, daytime sleepiness, difficulty staying asleep, and situational interruption. Majority of the practitioners reported not screening, assessing, treating, or documenting sleep issues and lack the use of standardized assessments and evidence-based interventions for sleep. Results suggest that practitioners need more training, education, and advocacy skills to promote the role of occupational therapy in addressing sleep management in skilled nursing facilities.

Agreement of Sleep Measures-A Comparison between a Sleep Diary and Three Consumer Wearable Devices

Nowadays, self-tracking and optimization are widely spread. As sleep is essential for well-being, health, and peak performance, the number of available consumer technologies to assess individual sleep behavior is increasing rapidly. However, little is known about the consumer wearables' usability and reliability for sleep tracking. Therefore, the aim of the present study was to compare the sleep measures of wearable devices with a standardized sleep diary in young healthy adults in free-living conditions. We tracked night sleep from 30 participants (19 females, 11 males; 24.3 ± 4.2 years old). Each wore three wearables and simultaneously assessed individual sleep patterns for four consecutive nights. Wearables and diaries correlated substantially regarding time in bed (Range CCC_Lin: 0.74-0.84) and total sleep time (Range CCC_Lin: 0.76-0.85). There was no sufficient agreement regarding the measures of sleep efficiency (Range CCC_Lin: 0.05-0.34) and sleep interruptions (Range CCC_Lin: -0.02-0.10). Finally, these results show wearables to be an easy-to-handle, time- and cost-efficient alternative to tracking sleep in healthy populations. Future research should develop and empirically test the usability of such consumer sleep technologies.

Can insomnia be fatal? An Australian case of fatal familial insomnia

Fatal familial insomnia (FFI) is a rare prion disease with autosomal dominant inheritance. Currently, there is only one published case study of FFI in Australia. FFI is universally fatal, with the disease duration ranging from 8 to 72 months. Clinically, it manifests with disordered sleep-wake cycle, dysautonomia, motor disturbances and neuropsychiatric disorders. We describe a case of FFI detailing the investigative process, including the importance of sleep assessment and polysomnography in obtaining a diagnosis.

A primer on sleep for MFTs: Implications and practical considerations

Despite many marriage and family therapists (MFTs) utilizing the Biopsychosocial-Spiritual (BPSS) framework in assessment and treatment, there is still a lack of education on sleep and the implications for mental, emotional, and relational health. Newer research within many fields highlights the far-reaching spillover effects of short or poor-quality sleep that can affect our clients. MFTs need to know how to assess, how to provide proper psychoeducation, how to apply this knowledge in clinical settings, and how to collaborate with other healthcare providers. As such, the purpose of this article is threefold: (a) review the biopsychosocial-spiritual importance of sleep; (b) equip MFTs with information on sleep assessment, how to identify situations for referral, and how to provide psychoeducation on sleep hygiene; and (c) review important considerations for research and practice for MFTs.

Self-reported sleep duration and timing: A methodological review of event definitions, context, and timeframe of related questions

Study Objectives

Clinical and population health recommendations are derived from studies that include self-report. Differences in question wording and response scales may significantly affect responses. We conducted a methodological review assessing variation in event definition(s), context (i.e., work- versus free-day), and timeframe (e.g., "in the past 4 weeks") of sleep timing/duration questions.

Methods

We queried databases of sleep, medicine, epidemiology, and psychology for survey-based studies and/or publications with sleep duration/timing questions. The text of these questions was thematically analyzed.

Results

We identified 53 surveys with sample sizes ranging from 93 to 1,185,106. For sleep duration, participants reported nocturnal sleep (24/44), sleep in the past 24-hours (14/44), their major sleep episode (3/44), or answered unaided (3/44). For bedtime, participants reported time into bed (19/47), first attempt to sleep (16/40), or fall-asleep time (12/47). For wake-time, participants reported wake-up time (30/43), the time they "get up" (7/43), or their out-of-bed time (6/43). Context guidance appeared in 18/44 major sleep duration, 35/47 bedtime, and 34/43 wake-time questions. Timeframe was provided in 8/44 major sleep episode duration, 16/47 bedtime, and 10/43 wake-time questions. One question queried the method of awakening (e.g., by alarm clock), 18 questions assessed sleep latency, and 12 measured napping.

Conclusion

There is variability in the event definition(s), context, and timeframe of questions relating to sleep. This work informs efforts at data harmonization for meta-analyses, provides options for question wording, and identifies questions for future surveys.

Associations between parent-reported and objectively measured sleep duration and timing in infants at age 6 months

STUDY OBJECTIVES

To compare the estimates of sleep duration and timing from survey, diary, and actigraphy in infants at age 6 months, overall and by select demographics and other factors.

METHODS

In total, 314 infants participating in the Rise & SHINE (Sleep Health in Infancy & Early Childhood study) cohort in Boston, MA, USA, wore an actigraph on their left ankle for 7 days. Parents concurrently completed a sleep diary and the expanded version of the Brief Infant Sleep Questionnaire. Concordance between parent-reported and objective sleep estimates was assessed using Bland-Altman plots, Spearman's rank correlations, intraclass correlations, and linear regression models.

RESULTS

Mean infant age was 6.4 (0.6 SD) months; 51% were female and 42% were Non-Hispanic white. Mean total sleep duration using actigraphy was 526 (67 SD) minutes per night, 143 (42 SD) minutes per day, and 460 (100 SD) minutes during the longest nighttime sleep period. Relative to actigraphy, parent-completed survey and diary overestimated total day (by 29 and 31 minutes, respectively) and night sleep duration (67 and 43 minutes, respectively) and underestimated the longest sleep (58 minutes), with the highest agreement for sleep onset and offset timing (differences < 30 minutes). There was a tendency toward greater bias among short- and long-sleeping infants. Self-reporting bias for diary-measured longest nighttime sleep and total night sleep duration was higher in infants of parents reporting a problem with their baby's night awakenings and in low-income families, respectively.

CONCLUSIONS

Our findings underscore the need to be cautious when comparing findings across studies using different sleep assessment methods.

Which are the Central Aspects of Infant Sleep? The Dynamics of Sleep Composites across Infancy

Sleep during infancy is important for the well-being of both infant and parent. Therefore, there is large interest in characterizing infant sleep with reliable tools, for example by combining actigraphy with 24-h-diaries. However, it is critical to select the right variables to characterize sleep. In a longitudinal investigation, we collected sleep data of 152 infants at ages 3, 6, and 12 months. Using principal component analysis, we identified five underlying sleep composites from 48 commonly-used sleep variables: Sleep Night, Sleep Day, Sleep Activity, Sleep Timing, and Sleep Variability. These composites accurately reflect known sleep dynamics throughout infancy as Sleep Day (representing naps), Sleep Activity (representing sleep efficiency and consolidation), and Sleep Variability (representing day-to-day stability) decrease across infancy, while Sleep Night (representing nighttime sleep) slightly increases, and Sleep Timing becomes earlier as one ages. We uncover interesting dynamics between the sleep composites and demonstrate that infant sleep is not only highly variable between infants but also dynamic within infants across time. Interestingly, Sleep Day is associated with behavioral development and therefore a potential marker for maturation. We recommend either the use of sleep composites or the core representative variables within each sleep composite for more reliable research.

Applied behavior analysis measurement, assessment, and treatment of sleep and sleep-related problems

This discussion article considers applied behavior analysis measurement, assessment, and treatment of sleep and sleep-related problems among infants, children, and youth who are typically developing and have neurodevelopmental disabilities. Measurement has concentrated on designing practitioner-implemented methods and improving fidelity of data recording through sleep-monitoring instrumentation. The emphasis of assessment is identifying antecedent and consequence variables that promote sleep and evoke and maintain sleep-related problems. Treatment research has evaluated several effective interventions for problems such as delayed sleep-onset, night and early morning waking, bedtime resistance, and unwanted co-sleeping. Early and contemporary applied behavior analysis research is reviewed relative to function-based treatment formulation, intervention integrity, social validity, and research-to-practice translation.

An Arabic Translation, Reliability, Validity, and Feasibility of the Richards-Campbell Sleep Questionnaire for Sleep Quality Assessment in ICU: Prospective-Repeated Assessments

BACKGROUND AND PURPOSE

To translate Richards-Campbell Sleep Questionnaire (RCSQ) into the Arabic language (RCSQ-A), to assess content validity of the translated tool, to analyze the internal consistency, and to evaluate its feasibility.

METHODS

A rigorous translation was completed using the process of translation by World Health Organization. Cognitive debriefing interviews were performed. Repeated assessments using RCSQ-A was conducted in critical care patients in Saudi Arabia.

RESULT

Cronbach's alpha of .89 was seen in the RCSQ-A. The cognitive interviews showed that the RCSQ-A well understood and interpreted correctly and consistently. Fifty-seven participants reported their sleep using RCSQ-A a total of 110 times.

CONCLUSION

RCSQ-A has adequate translation validity, provided good internal consistency and content validity, making it suitable for use as a measurement tool in practice and research in Arabic-speaking countries.

Event marker compliance in actigraphy

Actigraphy is a versatile tool for evaluating sleep-wake cycles over time in the home-environment. Patients using the Phillips Actiwatch place an event marker when going to sleep and upon awakening. We investigate compliance in pressing the Actiwatch event marker button for patients referred for insomnia, hypersomnia and disorders of circadian rhythm. We retrospectively analysed event markers from 150 patients undergoing actigraphy for 2,117 nights combined. Compliance was evaluated from inspection of actigraphy records, and coded as full or partial. From patient records, a construct called the C-factor, designed to describe poor social resources and chronic unemployment, was used together with age and sex to predict compliance. We found a mean compliance between 54.0% and 76.3% for a median monitoring duration of 14 days. There was an overall insignificant effect of age (p = .081), but when analysed only for females there was a significant effect of 0.56% pr. year (p = .0038). Compliance was higher for women, Cohen's d = 0.65 (p = .01). The C-factor predicts 18.3% (confidence interval 9%-27.5%) lower compliance. Morning and evening compliance are correlated at r = .65. In conclusion, actigraphy event marker compliance is generally moderate or high, with older women exhibiting the highest compliance. C-factor predicts lower compliance, and this pattern may further translate to other circumstances. If compliance is important, clinicians may want to consider the effects of age, sex and C-factor.

Sleep Evaluation in the Assessment of Pediatric Attention Deficit Disorders

INTRODUCTION

Examining the impact of appropriate sleep evaluation on diagnosis of attention deficit disorders can improve the standard of care in pediatrics. This quality improvement project examined current practice and subsequent implementation of a validated standardized sleep evaluation tool in the assessment of children with symptoms of attention deficit.

METHODS

Retrospective chart review and implementation of the Children's Sleep Habits Questionnaire (CSHQ) for children 6 to 14years old with attention deficit symptoms.

MEASURES

Rates of sleep screening, sleep referrals, diagnosis of sleep and attention deficit disorders, Vanderbilt scores, CSHQ scores.

RESULTS

In the retrospective group (n = 41), 76% of patients had attention deficit disorder/attention deficit hyperactivity disorder, 19.5% had sleeping disorders. There were significant provider differences in diagnosing sleep problems (p = .007). In the intervention group (n = 5), 60% had abnormal CSHQ scores.

DISCUSSION

There was considerable incidence of sleeping problems in children with symptoms of attention deficit and provider variation in sleep evaluation and diagnosis, with minimal referral to specialist care. Our findings support a more comprehensive and standardized evaluation of sleep when assessing for attention deficit disorders to improve appropriate referrals, diagnosis, and treatment in pediatrics.

A Pilot Study of Impulse Radio Ultra Wideband Radar Technology as a New Tool for Sleep Assessment

STUDY OBJECTIVES

To validate Impulse radio ultra wideband pulse-doppler radar technology against polysomnography (PSG) for sleep assessment.

METHODS

In all, 12 participants were recruited and their overnight sleep was assessed both by a Novelda XeThru radar and PSG. Two subjects had two nightly recordings, whereas 10 had one recording. Epoch by epoch (30 seconds) comparisons from bedtime to rise time were conducted. Concordance was estimated in terms of the mean difference between the radar and the PSG estimates regarding sleep onset latency, wake time after sleep onset and total sleep time. In addition, accuracy, sensitivity, specificity and Cohen kappa were calculated.

RESULTS

The mean difference (minutes) between the radar and the PSG registrations was -5.7 minutes (standard deviation [SD] = 22.1 minutes) for sleep onset latency, 6.4 minutes (SD = 32.5 minutes) for wake after sleep onset, and 1.5 minutes (SD = 24.6 minutes) for total sleep time. The mean values obtained for accuracy, sensitivity, specificity and Cohen kappa were 0.931, 0.961, 0.695 and 0.670, respectively.

CONCLUSION

Impulse radio ultra wideband radar technology is a promising tool in terms of affordable and practical objective sleep assessment. Further technical development and more validation studies are needed in order to conclude about the utility potential of this device.

Exploration of sleep disorders in the elderly: which particularities?

There are many reasons to take into consideration the sleep disorders in the elderly. The sleep quality degrades with age and is strongly affected by medical conditions, intrinsic sleep disorders, or by a combination of these factors. Other age-related conditions such as severe dementia, dependence or living in institution worsen sleep disturbances in older people. When living alone elderly people, being cognitively impaired and medically disabled, may not be able to complain about sleep problems. Sleep disorders are thus underdiagnosed, unmarked, and insufficiently investigated in the elderly. In this heterogeneous population, sleep assessment should include a global geriatric approach and be individually adapted for each subject. The sleep interview must specially include medical comorbidities, medication uses, and aged-related changes of lifestyle such as retirement, loss of spouse, hospitalization or institutionalization. In the elderly with loss of autonomy, standard sleep assessment is not always adequate and must be replaced by shorter, simpler or observation-based tests such as the Sleep disorders inventory, Observation-based nocturnal sleep inventory, Observation and interview based diurnal sleepiness inventory. When sleep log is impossible, actimetry is an excellent alternative for studying sleep-wake rhythm. Ventilatory polygraphy is a simpler test for detecting sleep apnea than polysomnography. Utilization of sophisticated investigations should be discussed when the feasibility and usefulness is limited.

Alterations and Interdependence in Self-Reported Sleep-Wake Parameters of Patient-Caregiver Dyads During Adjuvant Chemotherapy for Breast Cancer

PURPOSE/OBJECTIVES

To longitudinally explore changes, similarities, differences, and interrelations in the sleep-wake parameters of patient-caregiver dyads throughout adjuvant chemotherapy for breast cancer.
.

DESIGN

Observational, repeated-measures, dyadic study.
.

SETTING

Four ambulatory oncology clinics in Scotland.
.

SAMPLE

48 dyads consisting of patients and their primary informal caregivers.
.

METHODS

Four dyadic, self-reported sleep-wake assessments took place before chemo-therapy (T0), during chemotherapy cycles 1 (T1) and 4 (T2), and after chemotherapy (T3). Dyads completed the Pittsburgh Sleep Quality Index. Multilevel hierarchical linear modeling was used to explore dyadic data.
.

MAIN RESEARCH VARIABLES

Perceived sleep quality, sleep onset latency (SOL), total sleep time, habitual sleep efficiency, wake after sleep onset, daily disturbance, daytime napping duration, overall sleep-wake impairment.
.

FINDINGS

The majority of dyads had at least one poor sleeper throughout the study; 25%-35% were dyads of concurrent poor sleepers. Curvilinear patterns of change were evident for patients' (but not caregivers') sleep-wake parameters, steadily deteriorating from pre- to midtreatment, then leveling off close to baseline. Average trajectories were significantly different between the dyad members but indicative of a trend for concurrent deterioration at T2. Dyad members' perceived sleep quality, SOL, and overall sleep-wake impairment were closely interrelated; wake variables remained uncoupled.
.

CONCLUSIONS

Despite overall differences in magnitude, sleep problems may be concurrently present in both dyad members, covary, and peak midway through chemotherapy. 
.

IMPLICATIONS FOR NURSING

Dyadic sleep assessments can shed light on potential areas of sleep interaction to enable interventions to support care dyads at risk of sleep distress during chemotherapy for breast cancer.

Gastrointestinal motility during sleep assessed by tracking of telemetric capsules combined with polysomnography - a pilot study

Studies of gastrointestinal function during sleep are hampered by lack of applicable techniques. Recent development of a novel ambulatory telemetric capsule system, which can be used in conjunction with polysomnography, offers a solution to this problem. The 3D-Transit system consists of ingestible electromagnetic capsules traceable through a portable extracorporeal receiver while traversing the gut. During sleep monitored by polysomnography, gastrointestinal motility was concurrently investigated using 3D-Transit in nine healthy subjects. Overall, the amplitude of gastric contractions decreased with depth of sleep (light sleep, N2 versus deep sleep, N3; P<0.05). Progression through the small intestine did not change with depth of sleep (Kruskal–Wallis probability =0.1), and there was no association between nocturnal awakenings or arousals and the occurrence of colonic or small intestinal propagating movements. Basal colonic activity was suppressed during both deep sleep (P<0.05) and light sleep (P<0.05) when compared with nocturnal wake periods. In conclusion, the novel ambulatory 3D-Transit system combined with polysomnography allows minimally invasive and completely ambulatory investigation of associations between sleep patterns and gastrointestinal motility.

The consensus sleep diary: standardizing prospective sleep self-monitoring

STUDY OBJECTIVES

To present an expert consensus, standardized, patient-informed sleep diary.

METHODS AND RESULTS

Sleep diaries from the original expert panel of 25 attendees of the Pittsburgh Assessment Conference(1) were collected and reviewed. A smaller subset of experts formed a committee and reviewed the compiled diaries. Items deemed essential were included in a Core sleep diary, and those deemed optional were retained for an expanded diary. Secondly, optional items would be available in other versions. A draft of the Core and optional versions along with a feedback questionnaire were sent to members of the Pittsburgh Assessment Conference. The feedback from the group was integrated and the diary drafts were subjected to 6 focus groups composed of good sleepers, people with insomnia, and people with sleep apnea. The data were summarized into themes and changes to the drafts were made in response to the focus groups. The resultant draft was evaluated by another focus group and subjected to lexile analyses. The lexile analyses suggested that the Core diary instructions are at a sixth-grade reading level and the Core diary was written at a third-grade reading level.

CONCLUSIONS

The Consensus Sleep Diary was the result of collaborations with insomnia experts and potential users. The adoption of a standard sleep diary for insomnia will facilitate comparisons across studies and advance the field. The proposed diary is intended as a living document which still needs to be tested, refined, and validated.

Absence of effects of prolonged simvastatin therapy on nocturnal sleep in a large randomized placebo-controlled study. Oxford Cholesterol Study Group

1. It has been suggested that lipophilic HMG CoA reductase inhibitors, like lovastatin and simvastatin, may cause sleep disturbance. 2. Six hundred and twenty-one patients at increased risk of coronary heart disease were randomized in a single centre to receive 40 mg daily simvastatin, 20 mg daily simvastatin or matching placebo. To assess the effects of prolonged use of simvastatin on nocturnal sleep quality and duration, a sleep questionnaire was administered to 567 patients (95% of 595 survivors) at an average of 88 weeks (range: 44-129 weeks) after randomization. 3. The main outcome measures were sleep-related problems and use of sleep-enhancing medications reported during routine study follow-up visits, and responses to the sleep questionnaire about changes in sleep duration and about various sleep events during the preceding month. 4. No differences were observed between the treatment groups in the frequency of sleep-related problems reported, in the proportion of follow-up visits at which such problems were reported, or in the use of sleep-enhancing medications. The numbers who stopped study treatment were similar in the different treatment groups, and no patient stopped principally because of insomnia. In response to the sleep questionnaire, there were no significant differences between the treatment groups in reports of various sleep events during the preceding month, except that slightly fewer patients allocated simvastatin reported waking often. No differences in sleep duration were observed. 5. This placebo-controlled trial does not indicate any adverse effects of prolonged treatment with simvastatin on systematically sought measures of sleep disturbance.