Actigraphy in sleep research with infants and young children: Current practices and future benefits of standardized reporting

Reliability and validity of instruments containing reported sleep measures among children from birth to <5 years of age: A systematic review

Valid and reliable sleep measures during the early years are crucial for practitioners and researchers seeking accurate evaluation methods. The authors in this review systematically examined the psychometric properties of instruments containing reported sleep measures in children from birth to <5 years of age. The search was conducted using several electronic databases, including MEDLINE, EMBASE, PsycINFO, Web of Science, CINAHL, SPORTDiscus, Scopus and HaPI, with the most recent update on August 30, 2022. The quality of the included studies was assessed using the COSMIN methodology. A total of 79 studies were analyzed. However, none of these measures had undergone a comprehensive evaluation of all psychometric properties. Unfortunately, suitable reported sleep measures for children aged 0-4.99 years could not be identified through this review. Further research is needed to develop and validate psychometrically robust sleep assessment tools for this specific age group.

Sleep quality in children with hepatic glycogen storage diseases, a prospective observational pilot study

Background

Hepatic glycogen storage diseases (GSDs) are characterised by enzyme defects affecting liver glycogen metabolism, where carbohydrate supplementation to prevent overnight hypoglycaemia is common. Concerns around sleep quality in hepatic GSDs relate to emerging evidence that overnight dysglycaemia impacts sleep quality.

Methods

This prospective observational study reported sleep quality and duration in children with hepatic GSDs over 7 days utilising: actigraphy (Actiwatch 2 by Phillips Respironics), sleep diaries, proxy reported age-appropriate sleep and quality-of-life (QoL) questionnaires, in the context of nocturnal glycaemic profiles continuous glucose monitor (CGM, Dexcom G6) and nocturnal dietary management strategies. Significant hypo- and hyperglycaemia were defined as ≥1% of sleep diary documented nocturnal period, recording <3.5 and >10.0 mmol/L, respectively.

Results

Seven children with hepatic GSD (aged 1-17 years) participated. Objective sleep quality was poor, with actigraphy demonstrating that no child achieved the minimum sleep duration recommended for age. Subjective sleep quality was also poor, with 4/5 documenting significant daytime sleepiness and 6/6 reporting poor sleep hygiene. Children prescribed overnight bolus feeds (OBF) (n = 2) recorded shorter sleep duration compared to other nocturnal management strategies. Parent-reported QoL suggested poor disease-related QoL outcomes for this cohort.

Conclusion

Objective and subjective sleep disturbances and reduced QoL are common within our sample of children with hepatic GSD. From our observations these outcomes may be linked to nutritional overnight interventions, especially OBFs, rather than overnight glucose levels. Consideration of the impacts of overnight feeding strategies on sleep quality and QoL in children with hepatic GSD should inform future management strategies.

Toddler Screen Use Before Bed and Its Effect on Sleep and Attention: A Randomized Clinical Trial

Importance

Toddler screen time has been associated with poorer sleep and differences in attention. Understanding the causal impact of screen time on early development is of the highest importance.

Objective

To test (1) the feasibility of the 7-week parent-administered screen time intervention (PASTI) in toddlers (aged 16-30 months) who have screen time in the hour before bed and (2) the impact of PASTI on toddlers' sleep and attention.

Design, Setting, and Participants

This assessor-blinded, UK-based randomized clinical trial was conducted between July 2022 and July 2023. This was a single-site study that enrolled families with a toddler aged between 16 and 30 months, living within 75 miles of the Babylab, and with 10 minutes or more of screen time in the hour before bed on 3 or more days a week. Exclusion criteria were (1) a genetic or neurological condition, (2) premature birth (<37 weeks), and (3) current participation in another study.

Interventions

Families were randomized (1:1:1) to (1) PASTI: caregivers removed toddler screen time in the hour before bed and used activities from a bedtime box instead (eg, reading, puzzles); (2) bedtime box (BB only): used matched before-bed activities, with no mention of screen time; or (3) no intervention (NI): continued as usual.

Main Outcomes and Measures

Feasibility outcomes: participation rate, intervention adherence, retention, family experiences, and assessment acceptability. Efficacy outcomes: screen use, actigraphy-measured sleep, and eye-tracking attention measures.

Results

A total of 427 families were screened, 164 were eligible (38.4%), and 105 families were randomized (mean [SD] age, 23.7 [4.6] months; 60 male [57%]). The trial was feasible, with 99% participant (104 of 105) retention and 94% of families (33 of 35) adhering to PASTI. PASTI showed reductions in parent-reported screen time (vs NI: Cohen d = -0.96; 95% CI, -1.32 to -0.60; vs BB only: Cohen d = -0.65; 95% CI, -1.03 to -0.27). PASTI showed small to medium improvements in objectively measured sleep efficiency (vs NI: Cohen d = 0.27; 95% CI, -0.11 to 0.66; vs BB only: Cohen d = 0.56; 95% CI, 0.17-0.96), night awakenings (vs NI: Cohen d = -0.28; 95% CI, -0.67 to 0.12; vs BB only: Cohen d = -0.31; 95% CI, -0.71 to 0.10), and reduced daytime sleep (vs NI: Cohen d = -0.30; 95% CI, -0.74 to 0.13) but no difference compared with BB only. There was no observable effect of PASTI on objective measures of attention. Compared with BB only, PASTI showed a difference on parent-reported effortful control (Cohen d = -0.40; 95% CI, -0.75 to -0.05) and inhibitory control (Cohen d = -0.48; 95% CI, -0.77 to -0.19), due to an increase in BB-only scores.

Conclusions and Relevance

Results of this randomized clinical trial show that, supporting pediatric recommendations, removing screen time before toddler bedtime was feasible and showed modest preliminary beneficial effects on sleep. A future full confirmatory trial is needed before PASTI's adoption by parents and pediatricians.

Trial Registration

ISRCTN.org Identifier: ISRCTN58249751.

Evaluating the performance of open-source and proprietary processing of actigraphy sleep estimation in children with suspected sleep disorders: A comparison with polysomnography

STUDY OBJECTIVES

Evaluate the performance of actigraphy-based open-source and proprietary sleep algorithms compared to polysomnography in children with suspected sleep disorders.

METHODS

In a sleep clinic, 110 children (5-12 years, 54% female, 50% Black, 82% with sleep disorders) wore wrist-placed ActiGraph GT9X during overnight polysomnography. Actigraphy data were scored as sleep or wake using open-source GGIR and proprietary ActiLife software. Discrepancy and epoch-by-epoch analyses were conducted to assess agreement between algorithms and polysomnography, along with equivalence testing.

RESULTS

The open-source vanHees2015 algorithm showed good accuracy (79.5% ± 12.0%), sensitivity (81.1% ± 13.5%), and specificity (66.0% ± 23.8%) for sleep detection but was outperformed by the proprietary ActiLife algorithms. The magnitude and trend of bias for total sleep time, sleep efficiency, sleep onset latency, and wake after sleep onset were similar between algorithms. Total sleep time and sleep efficiency were statistically equivalent for the Cole-Kripke (Actilife) and vanHees2015 algorithms compared to the Sadeh (Actilife) algorithm. The Cole-Kripke (ActiLife) demonstrated higher sensitivity (90.5%) to detect sleep but lower specificity (61.2%) than Cole-Kripke (GGIR) (sensitivity: 62.7%, specificity: 79.9%). Sadeh and Cole-Kripke estimated sleep outcomes were not statistically equivalent between implementations in ActiLife and GGIR.

CONCLUSIONS

The open-source vanHees2015 algorithm performed well but slightly worse than the proprietary ActiLife algorithms in children. The open-source nature vanHees2015 makes it ideal for clinical pediatric use. Implementation of the Sadeh and Cole-Kripke algorithms in the proprietary ActiLife and open-source GGIR software yield different sleep estimates, so comparisons between studies using these different implementations should be avoided.

Longitudinal Associations Between Physical Activity and Sleep Duration in Infants and Toddlers

PURPOSE

This study examined longitudinal associations between average physical activity (PA) levels in children and their sleep duration, and whether changes in PA levels are associated with their sleep duration.

METHODS

Data were collected on 108 children at 4 time points: when children were 6, 12, 18, and 24 months of age (44% female, 50% Non-Hispanic White). PA was assessed using accelerometry. Children's daytime, nighttime, and 24-hour sleep duration were measured with actigraphy. Linear mixed model analyses estimated the associations between average PA levels over time and changes in PA over time, treating each sleep duration variable as an outcome in separate linear mixed model analyses.

RESULTS

Children with higher total PA levels slept less during the day compared with children with lower total PA levels over the 2-year period. The strength of the relationship between a child's PA levels and their 24-hour sleep duration decreased as they approached 24 months of age.

CONCLUSIONS

The results suggest that while PA may be developmentally beneficial overall, it appears that its relationship with sleep duration is not clinically relevant in very young children.

Leveraging biosocial methods to examine and address structural determinants of health and promote health equity

BACKGROUND

Biosocial approaches in nursing research have largely focused on the ways that social determinants of health influence individual-level outcomes, including symptom management, family and social support, and educational interventions.

PURPOSE

Theoretical, methodological, and practical strategies are needed to expand current biosocial methods for nursing science and focus on upstream, structural determinants of health and the policies that underlie health inequities.

METHODS

This paper summarizes presentations given at the 2023 Council for the Advancement of Nursing Science Advanced Methods Conference, Biosocial Methods to Advance Health Equity, in a panel titled "Individual, community, systems and policy related to biosocial methods."

DISCUSSION

Nurses are uniquely positioned to examine upstream, structural determinants of health by leveraging expertise in biosocial methods, collaborating with interdisciplinary researchers and community members, and advocating for policy change. By conducting theory-grounded biosocial research, nurse researchers can significantly advance scientific knowledge and promote health equity for individuals and communities.

CONCLUSION

Nurse scientists are conducting research using biosocial methods and provide recommendations for expansion of this approach in the field.

Characterising the motion and cardiorespiratory interaction of preterm infants can improve the classification of their sleep state

AIM

This study aimed to classify quiet sleep, active sleep and wake states in preterm infants by analysing cardiorespiratory signals obtained from routine patient monitors.

METHODS

We studied eight preterm infants, with an average postmenstrual age of 32.3 ± 2.4 weeks, in a neonatal intensive care unit in the Netherlands. Electrocardiography and chest impedance respiratory signals were recorded. After filtering and R-peak detection, cardiorespiratory features and motion and cardiorespiratory interaction features were extracted, based on previous research. An extremely randomised trees algorithm was used for classification and performance was evaluated using leave-one-patient-out cross-validation and Cohen's kappa coefficient.

RESULTS

A sleep expert annotated 4731 30-second epochs (39.4 h) and active sleep, quiet sleep and wake accounted for 73.3%, 12.6% and 14.1% respectively. Using all features, and the extremely randomised trees algorithm, the binary discrimination between active and quiet sleep was better than between other states. Incorporating motion and cardiorespiratory interaction features improved the classification of all sleep states (kappa 0.38 ± 0.09) than analyses without these features (kappa 0.31 ± 0.11).

CONCLUSION

Cardiorespiratory interactions contributed to detecting quiet sleep and motion features contributed to detecting wake states. This combination improved the automated classifications of sleep states.

State of the science and recommendations for using wearable technology in sleep and circadian research

Wearable sleep-tracking technology is of growing use in the sleep and circadian fields, including for applications across other disciplines, inclusive of a variety of disease states. Patients increasingly present sleep data derived from their wearable devices to their providers and the ever-increasing availability of commercial devices and new-generation research/clinical tools has led to the wide adoption of wearables in research, which has become even more relevant given the discontinuation of the Philips Respironics Actiwatch. Standards for evaluating the performance of wearable sleep-tracking devices have been introduced and the available evidence suggests that consumer-grade devices exceed the performance of traditional actigraphy in assessing sleep as defined by polysomnogram. However, clear limitations exist, for example, the misclassification of wakefulness during the sleep period, problems with sleep tracking outside of the main sleep bout or nighttime period, artifacts, and unclear translation of performance to individuals with certain characteristics or comorbidities. This is of particular relevance when person-specific factors (like skin color or obesity) negatively impact sensor performance with the potential downstream impact of augmenting already existing healthcare disparities. However, wearable sleep-tracking technology holds great promise for our field, given features distinct from traditional actigraphy such as measurement of autonomic parameters, estimation of circadian features, and the potential to integrate other self-reported, objective, and passively recorded health indicators. Scientists face numerous decision points and barriers when incorporating traditional actigraphy, consumer-grade multi-sensor devices, or contemporary research/clinical-grade sleep trackers into their research. Considerations include wearable device capabilities and performance, target population and goals of the study, wearable device outputs and availability of raw and aggregate data, and data extraction, processing, and analysis. Given the difficulties in the implementation and utilization of wearable sleep-tracking technology in real-world research and clinical settings, the following State of the Science review requested by the Sleep Research Society aims to address the following questions. What data can wearable sleep-tracking devices provide? How accurate are these data? What should be taken into account when incorporating wearable sleep-tracking devices into research? These outstanding questions and surrounding considerations motivated this work, outlining practical recommendations for using wearable technology in sleep and circadian research.

Kairos study protocol: a multidisciplinary approach to the study of school timing and its effects on health, well-being and students' performance

Recent evidence from chronobiology, chssronomedicine and chronopsychology shows that the organisation of social time (e.g., school schedules) generally does not respect biological time. This raises concerns about the impact of the constant mismatch between students' social and internal body clocks on their health, well-being and academic performance. The present paper describes a protocol used to investigate the problem of (de) synchronisation of biological times (chronotypes) in childhood and youth in relation to school times. It studies the effects of student chronotype vs. school schedule matches/mismatches on health behaviours (e.g., how many hours students sleep, when they sleep, eat, do physical activity, spend time outdoors in daylight) and learning (verbal expression, spatial structuring, operations) and whether alert-fatigue levels mediate this effect alignments/misalignments on learning (verbal expression, spatial structuring, operations) and their mediation by alert-fatigue levels. The novelty of our protocol lies in its multidisciplinary and mixed methodology approach to a relevant and complex issue. It draws on up-to-date knowledge from the areas of biology, medicine, psychology, pedagogy and sociology. The methods employed include a varied repertoire of techniques from hormonal analysis (cortisol and melatonin), continuous activity and light monitoring, self-registration of food intake, sleep timings, exercise and exposure to screens, alongside with systematic application of cognitive performance tests (e.g., memory, reasoning, calculation, attention) and self-reported well-being. This comprehensive and interdisciplinary protocol should support evidence-based education policy measures related to school time organisation. Appropriate and healthier school timetables will contribute to social change, healthier students and with more efficient learning. The results of studies using a similar methodology in other countries would ensure replication and comparability of results and contribute to knowledge to support policy making.

Infant sleep interventions with sleep measurements using actigraphy: A systematic review

AIM

This review investigated the outcomes and methodological quality of infant sleep intervention studies utilizing actigraphy.

BACKGROUND

Parents need appropriate support for infant sleep from nurses. There are few methodological reports of actigraphy in infant sleep intervention studies that objectively measure infant sleep in a natural setting.

DESIGN

This was a systematic review study.

DATA SOURCES

Ovid MEDLINE, Embase, Cochrane, CINAHL and PsycINFO were searched from database establishment to 30 December 2021.

REVIEW METHODS

This systematic review utilized the Cochrane Collaboration review guidelines.

RESULTS

Eleven sleep intervention studies were reviewed. Three used extinction-based behavioural interventions, and eight included parental education programs. The infant sleep interventions positively affected the sleep outcomes of both infants and parents. Fairly consistent effects were found on infants' number of awakenings and sleep onset latency. However, parental psychosocial outcomes were inconsistent. All studies reported device placement, the algorithm for analysis, the use of a sleep diary and number of days/nights, but external movements affecting infants' sleep records were insufficiently reported. Only two studies had a low risk of bias.

CONCLUSIONS

The infant sleep interventions had positive effects on both infants and their parents. Comprehensive methodological considerations are required for more standardized assessments using actigraphy for infant sleep evaluation.

Post-PICU sleep efficiency and quality of life in infants and toddlers with acquired brain injury

STUDY OBJECTIVES

We aimed to investigate the use of sleep efficiency (SE) as a measure of sleep disturbance in infants and toddlers with acquired brain injury (ABI) and evaluate associations between SE and child health-related quality of life and family outcomes.

METHODS

Retrospective cohort study of 101 children ages 3-36 months who survived critical care for ABI. SE was quantified from the Brief Infant Sleep Questionnaire as a ratio of nighttime sleep to total time in bed; poor SE was defined as < 80%. Outcome measures included the Pediatric Quality of Life Inventory Core Total Score (health-related quality of life) and Family Impact Module Total Score. Spearman's correlation quantified associations between SE and outcomes. Multivariable linear regression tested association between poor SE and health-related quality of life controlling for significant covariates (age, diagnosis, comorbidities, worsening Functional Status Scale).

RESULTS

Following ABI, median SE was 91.7 (interquartile range = 83.3, 95.5). Nineteen (19%) children had poor SE (< 80%). SE correlated significantly with quality of life (Spearman's correlation = .307) and Family Impact Module (Spearman's correlation = .309; both P < .01). When controlling for covariates, poor SE significantly increased risk for lower health-related quality of life (β-coefficient = -7.0; 95% confidence interval= -13.4, -0.6).

CONCLUSIONS

One in five infants and young children with ABI have poor SE that is associated with poorer child and family health outcomes. Our study underscores the potential importance of sleep following ABI to optimize recovery and the need for additional investigation of SE in infants and young children.

CITATION

Klapp JM, Hall TA, Riley AR, Janzen D, Williams CN. Post-PICU sleep efficiency and quality of life in infants and toddlers with acquired brain injury. J Clin Sleep Med. 2024;20(1):75-83.

Ethical considerations in using sensors to remotely assess pediatric health behaviors

Sensors, including accelerometer-based and electronic adherence monitoring devices, have transformed health data collection. Sensors allow for unobtrusive, real-time sampling of health behaviors that relate to psychological health, including sleep, physical activity, and medication-taking. These technical strengths have captured scholarly attention, with far less discussion about the level of human touch involved in implementing sensors. Researchers face several subjective decision points when collecting health data via sensors, with these decisions posing ethical concerns for users and the public at large. Using examples from pediatric sleep, physical activity, and medication adherence research, we pose critical ethical questions, practical dilemmas, and guidance for implementing health-based sensors. We focus on youth given that they are often deemed the ideal population for digital health approaches but have unique technology-related vulnerabilities and preferences. Ethical considerations are organized according to Belmont principles of respect for persons (e.g., when sensor-based data are valued above the subjective lived experiences of youth and their families), beneficence (e.g., with sensor data management and sharing), and justice (e.g., with sensor access and acceptability among minoritized pediatric populations). Recommendations include the need to increase transparency about the extent of subjective decision making with sensor data management. Without greater attention to the human factors involved in sensor research, ethical risks could outweigh the scientific promise of sensors, thereby negating their potential role in improving child health and care. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Effects of caffeine therapy for apnea of prematurity on sleep and neurodevelopment of preterm infants at 6 months of corrected age

STUDY OBJECTIVES

To determine the differences in sleep patterns between preterm infants who received caffeine and those who did not and to evaluate the effects of caffeine therapy on early neurodevelopment. Secondarily, actigraphy and polysomnography were compared to evaluate the sleep of preterm infants.

METHODS

Twenty-eight preterm infants ages 28-34 weeks admitted to a single-center Level III neonatal intensive care unit between May 2020 and May 2021 were included. Sleep was assessed by actigraphy for 72 hours with Respironics Mini-Mitter® Actiwatch-2 and Brief Infant Sleep Questionnaire at 6 months corrected age. On the first day of actigraphy, infants underwent polysomnography between 10:00 am and 3:00 pm. Neurodevelopment was evaluated by the Bayley Scales of Infant and Toddler Development-III, the Ages & Stages Questionnaire, and the Hammersmith Infant Neurological Examination.

RESULTS

There were no significant differences in sleep parameters measured by actigraphy, the Brief Infant Sleep Questionnaire, and polysomnography between infants in the caffeine group (n = 12) and no-caffeine group (n = 16). Sensitivity (91.07%) and agreement rate (77.21%) for the actigraphy against polysomnography were highest at the automatic threshold. No significant differences were observed in the neurodevelopment of infants in the caffeine group compared to the no-caffeine group.

CONCLUSIONS

Sleep parameters and neurodevelopmental outcomes were not different in infants at 6 months of corrected age with regard to caffeine therapy. Actigraphy at the automatic threshold can be used in infants for sleep pattern assessment.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Influence of Caffeine Therapy in Preterm Infants; URL: https://www.clinicaltrials.gov/ct2/show/NCT04376749; Identifier: NCT04376749.

CITATION

Atalah YEY, Barış HE, Akdere SK, et al. Effects of caffeine therapy for apnea of prematurity on sleep and neurodevelopment of preterm infants at 6 months of corrected age. J Clin Sleep Med. 2023;19(12):2075-2085.

From early birds to night owls: a longitudinal study of actigraphy-assessed sleep trajectories during the transition from pre- to early adolescence

STUDY OBJECTIVES

Pre- and early adolescence are believed to constitute periods of important age-related changes in sleep. However, much of the research on these presumed developmental changes has used cross-sectional data or subjective measures of sleep, limiting the quality of the evidence. In addition, little is known about the development of certain features of the sleep-wake cycle pertaining to regularity (e.g. weekend-weekday differences and intra-individual variability) or circadian rhythms (e.g. sleep midpoint).

METHODS

This study examined the sleep trajectories of 128 typically developing youth (69 girls) from ages 8 to 12 years on four sleep characteristics: sleep onset, sleep offset, total sleep time (TST), and sleep midpoint. For each of these characteristics, actigraphy-derived estimates of typical (i.e. mean) sleep and sleep regularity were obtained at each time point. Multilevel growth curves were modeled.

RESULTS

Overall, the sleep-wake cycle significantly changed between 8 and 12 years. Mean sleep onset, offset and midpoint exhibited an ascending curvilinear growth pattern that shifted later with age, while mean TST decreased linearly. Weekend-weekday differences (social jetlag) for sleep offset and midpoint became more pronounced each year. Weekday TST was longer than weekend TST, though this difference became smaller over time. Finally, intra-individual variability increased over time for all sleep characteristics, with variability in TST ascending curvilinearly. Important between-person and sex differences were also observed.

CONCLUSION

This study reveals the marked changes that occur in the sleep of typically developing pre- and early adolescents. We discuss the potential implications of these trajectories.

A longitudinal study of infant 24-hour sleep: comparisons of sleep diary and accelerometer with different algorithms

STUDY OBJECTIVES

To longitudinally compare sleep/wake identification and sleep parameter estimation from sleep diaries to accelerometers using different algorithms and epoch lengths in infants.

METHODS

Mothers and other caregivers from the Nurture study (southeastern United States, 2013-2018) reported infants' 24-hour sleep in sleep diaries for 4 continuous days, while infants concurrently wore accelerometers on the left ankle at 3, 6, 9, and 12 months of age. We applied the Sadeh, Sadeh Infant, Cole, and Count-scaled algorithm to accelerometer data at 15 and 60 seconds epochs. For sleep/wake identification, we assessed agreement by calculating epoch-by-epoch percent agreement and kappas. We derived sleep parameters from sleep diaries and accelerometers separately and evaluated agreement using Bland-Altman plots. We estimated longitudinal trajectories of sleep parameters using marginal linear and Poisson regressions with generalized estimation equation estimation.

RESULTS

Among the 477 infants, 66.2% were black and 49.5% were female. Agreement for sleep/wake identification varied by epoch length and algorithm. Relative to sleep diaries, we observed similar nighttime sleep offset, onset, and total nighttime sleep duration from accelerometers regardless of algorithm and epoch length. However, accelerometers consistently estimated about 1 less nap per day using the 15 seconds epoch, 70 and 50 minutes' shorter nap duration per day using the 15 and 60 seconds epoch, respectively; but accelerometers estimated over 3 times more wake after nighttime sleep onset (WASO) per night. Some consistent sleep parameter trajectories from 3 to 12 months from accelerometers and sleep diaries included fewer naps and WASOs, shorter total daytime sleep, longer total nighttime sleep, and higher nighttime sleep efficiency.

CONCLUSIONS

Although there is no perfect measure of sleep in infancy, our findings suggest that a combination of accelerometer and diary may be needed to adequately measure infant sleep.

Concordance of objective and subjective measures of sleep in children with neurodevelopmental conditions: A systematic review and meta-analysis

The purpose of this systematic review and meta-analysis is to delineate the concordance of objective and subjective measures of sleep in children with neurodevelopmental conditions (NDCs). A systematic literature search identified 31 studies that compare objective and subjective estimates of sleep parameters in autism, ADHD or rare genetic syndromes associated with intellectual disability. The meta-analyses revealed smaller mean differences and larger correlations indicative of greater concordance for parameters associated with sleep scheduling compared to parameters associated with sleep duration and night awakenings. Relative to objective measures, subjective measures produced: 1) greater estimates of total sleep time, sleep efficiency and time in bed; and 2) lower estimates of wake after sleep onset and number of night awakenings. Subgroup analyses also revealed differences in concordance between measurement comparison types (e.g., stronger correlations between actigraphy and sleep diaries, compared to actigraphy and questionnaires) and NDC diagnostic groups. The results predominantly replicate concordance trends observed in typically-developing samples, although some NDC-specific patterns of concordance were identified. This indicates that objective and subjective sleep measures retain broadly similar properties across populations, although researchers and clinicians should be cautious of the impact of NDC-related characteristics on sleep parameter estimates. These findings should inform sleep assessment design and the interpretation of sleep parameter estimates in NDCs, increasing the rigour of sleep parameter description across research and clinical settings.

Circadian rhythm disorders in patients with advanced cancer: a scoping review

Circadian rhythms can be demonstrated in several biomarkers and behavioural activities, with rhythmical patterns occurring roughly over a 24-h period. Circadian disorders occur in patients with cancer and may be associated with poor clinical outcomes. This scoping review aimed to identify circadian rhythm research and reporting practices, circadian rhythm patterns, circadian rhythm disorders, and relevant associations of circadian rhythm disorders in patients with advanced cancer. Studies involved adult patients with locally advanced or metastatic cancer and used objective measures of circadian rhythmicity. Two independent authors completed initial screening of title and abstracts, full text reviews, data extraction, and data checking. A total of 98 articles were highlighted in the scoping review, which utilised physical activity measures (actigraphy and polysomnography), biomarkers (cortisol and melatonin), or a combination. Several circadian rhythms are commonly disordered amongst patients with advanced cancer and have significant implications for symptom burden, quality of life, and survival. It remains unclear which patients are most at risk of a circadian rhythm disorder. Significant heterogeneity exists in research and reporting practices. Standardising this approach may address discrepancies in the current literature and allow for research to focus on the most relevant parameters and approaches to improving circadian rhythmicity.

Sleep and 24-hour rhythm characteristics in preschool children born very preterm and full term

STUDY OBJECTIVES

Sleep impacts the quality of life and is associated with cardiometabolic and neurocognitive outcomes. Little is known about the sleep of preterm-born children at preschool age. We, therefore, studied sleep and 24-hour rhythms of preschool children born very preterm compared with full-term children.

METHODS

This was a prospective cohort study comparing sleep quality and quantity of children born very preterm (gestational age [GA] < 30 weeks) with full-term children at the (corrected) age of 3 years, using (1) 2 parent-reported questionnaires (Brief Infant Sleep Questionnaire and The Munich Chronotype Questionnaire) and (2) at least 3 days of triaxial wrist actigraphy combined with sleep diary. We performed regression analyses with adjustment for sex (corrected), age, and birth weight standard deviation (SD) score.

RESULTS

Ninety-seven very-preterm-born (median GA 27+5; interquartile range 26 + 3;29 + 0 weeks) and 92 full-term children (GA 39 + 3; 38 + 4;40 + 4 weeks) were included. Sleep problems and other reported sleep parameters were not different between groups. As measured with actigraphy, sleep and 24-hour rhythm were similar between groups, except for very-preterm born children waking up 21 minutes (4;38) minutes later than full-term children (adjusted P = .001).

CONCLUSIONS

Based on parent reports and actigraphy, very-preterm-born children sleep quite similar to full-term controls at the corrected age of 3 years. Reported sleep problems were not different between groups. Actigraphy data suggest that preterm-born children may wake up later than children born full term. Further studies are needed to explore how sleep relates to cardiometabolic and neurodevelopmental outcomes after preterm birth and whether early interventions are useful to optimize 24-hour rhythm and sleep.

CITATION

Bijlsma A, Beunders VAA, Dorrepaal DJ, et al. Sleep and 24-hour rhythm characteristics in preschool children born very preterm and full term. J Clin Sleep Med. 2023;19(4):685-693.

A novel method to increase specificity of sleep-wake classifiers based on wrist-worn actigraphy

The knowledge of the distribution of sleep and wake over a 24-h day is essential for a comprehensive image of sleep-wake rhythms. Current sleep-wake scoring algorithms for wrist-worn actigraphy suffer from low specificities, which leads to an underestimation of the time staying awake. The goal of this study (ClinicalTrials.gov Identifier: NCT03356938) was to develop a sleep-wake classifier with increased specificity. By artificially balancing the training dataset to contain as much wake as sleep epochs from day- and nighttime measurements from 12 subjects, we optimized the classification parameters to an optimal trade-off between sensitivity and specificity. The resulting sleep-wake classifier achieved high specificity of 80.4% and sensitivity of 88.6% on the balanced dataset containing 3079.9 h of actimeter data. In the validation on night sleep of separate adaptation recordings from 19 healthy subjects, the sleep-wake classifier achieved 89.4% sensitivity and 64.6% specificity and estimated accurately total sleep time and sleep efficiency with a mean difference of 12.16 min and 2.83%, respectively. This new, device-independent method allows to rid sleep-wake classifiers from their bias towards sleep detection and lay a foundation for more accurate assessments in everyday life, which could be applied to monitor patients with fragmented sleep-wake rhythms.

Actigraphy evaluation before and after intravenous ferric carboxymaltose in 3 children with restless sleep disorder

Restless sleep disorder has been described in the literature as a disorder affecting children and presenting with large muscle movements during sleep with an index of 5 events/h or more, leading to daytime impairment including sleepiness or behavioral problems. Children with restless sleep disorder have been found to have low ferritin levels. Studies with iron supplementation both oral or intravenous have been shown effective in clinically improving both nighttime and daytime symptoms. However objective data of the improvement is lacking. Repeating polysomnography is expensive, and alternative methods of assessing large muscle movements are needed. In this small case series we present actigraphy results in 3 children with restless sleep disorder collected for 1 week, a week before and 8 weeks after intravenous iron supplementation. Although actigraphy parameters were not highly consistent between our 3 patients, improvement in symptoms tend to parallel sleep parameters in actigraphy.

CITATION

Chu ZYB, DelRosso LM, Mogavero MP, Ferri R. Actigraphy evaluation before and after intravenous ferric carboxymaltose in 3 children with restless sleep disorder. J Clin Sleep Med. 2023;19(3):633-637.

Insomnia in Infancy, Childhood, and Adolescence

Insomnia is the most prevalent sleep disorder in youth, tends to persist over time, and is associated with a myriad of adverse outcomes. This paper synthesizes the current evidence regarding the phenomenology, prevalence, assessment, consequences, cause, and treatment of pediatric insomnia, highlighting areas that warrant further research and addressing the unique characteristics of this disorder in infants, children, and adolescents.

Links between Daytime Napping, Night-Time Sleep Quality and Infant Attention: An Eye-Tracking, Actigraphy and Parent-Report Study

The current study explored the potential influence of infant sleep, measured by parental report and actigraphy, and family functioning on attention development using eye tracking. The use of actigraphy in parallel with parental report, has the advantage of measuring participant’s sleep throughout the night without parental observation and the ability to objectively assess sleep quality. An eye-tracking version of the Gap-Overlap task was used to measure visual attention. Questionnaires and behavioural assessment were used to assess family function, and general cognitive development. Fifty infants (Mean age = 13.44 months, SD = 3.10) participated in the study, 23 of which had full final datasets. Results show that daytime sleep duration, as measured by parental report, and proportion of light sleep at night, as measured by actigraphy, are linked to visual attention. A higher proportion of light sleep, a marker of poorer sleep quality, and less daytime sleep were negatively linked with facilitation and disengagement on the Gap-Overlap task. Family functioning was not associated with attention. The results provide initial evidence that in addition to the amount of daytime sleep; quality of night-time sleep as measured by proportion of light sleep, is a potentially useful sleep variable which requires further focus in the study of attention development.

Lower Serum Calcium Levels Associated with Disrupted Sleep and Rest–Activity Rhythm in Shift Workers

Vitamin D deficiency is prevalent in many developed countries, and several studies suggest that vitamin D plays an essential role in brain function. A recent study showed that vitamin D deficiency was closely associated with daytime sleepiness and shorter sleep time. The relationshipbetween vitamin D levels and calcium levels is well established, and calcium level regulates slow-wave sleep generation. It is conceivable that the sleep disturbance in vitamin D deficiency may be due to an altered calcium level. Nonetheless, calcium levels, sleep disturbances, and activity rhythms have not been investigated directly. Therefore, we hypothesized that calcium and vitamin D levels might be important in regulating sleep and activity rhythm, and we analyzed the correlation with calcium levels by actigraphy analysis. Interestingly, a negative correlation was found between calcium level and sleep latency, total sleep time, use of sleep medicine, and daytime dysfunction among shift workers. In contrast, non-shift workers showed a negative correlation between the calcium level and the circadian phase. These findings suggest that low serum calcium levels may disrupt sleep–wake control and rest–activity rhythm, even if they are within the normal range.

Digital Health Technologies in Pediatric Trials

BACKGROUND

Advances in the miniaturization of sensors and other technologies provide opportunities to collect physiological and/or functional data directly from patients participating in clinical trials. The use of such technologies in children is particularly promising. Objective, quantifiable measurements made by these technologies, often on a continuous or frequent basis, may provide more robust data than the episodic reports from caregivers that are used in traditional pediatric trials.

METHODS

We reviewed the pros and cons of these technologies for use in a variety of pediatric diseases, including seizure and neuromuscular disorders, cardiorespiratory diseases, and metabolic disorders.

RESULTS

Correlation between sensor measurements and patient observations or traditional clinical measurements varied depending on the disease being evaluated. There was a notable dearth of reports on the use of digital health technology in pediatric patients. Given the range of sensors and measurements that can be made by DHTs, selection of the design, metrics and types of sensors best suited to disease evaluation presents challenges for adoption of these technologies in clinical trials.

CONCLUSION

Traditional measurements of drug effects are often deficient, particularly in the evaluation of infants and young children. The opportunity to make objective, frequent measurements may increase our power to detect and quantify responses to therapy in these populations. Further research and evaluation are needed to realize the full scientific potential of remote monitoring in pediatric clinical trials.

Verification, analytical validation and clinical validation (V3) of wearable dosimeters and light loggers

Background

Light exposure is an important driver and modulator of human physiology, behavior and overall health, including the biological clock, sleep-wake cycles, mood and alertness. Light can also be used as a directed intervention, e.g., in the form of light therapy in seasonal affective disorder (SAD), jetlag prevention and treatment, or to treat circadian disorders. Recently, a system of quantities and units related to the physiological effects of light was standardized by the International Commission on Illumination (CIE S 026/E:2018). At the same time, biometric monitoring technologies (BioMeTs) to capture personalized light exposure were developed. However, because there are currently no standard approaches to evaluate the digital dosimeters, the need to provide a firm framework for the characterization, calibration, and reporting for these digital sensors is urgent.

Objective

This article provides such a framework by applying the principles of verification, analytic validation and clinical validation (V3) as a state-of-the-art approach for tools and standards in digital medicine to light dosimetry.

Results

This article describes opportunities for the use of digital dosimeters for basic research, for monitoring light exposure, and for measuring adherence in both clinical and non-clinical populations to light-based interventions in clinical trials.

Individual differences and diversity in human physiological responses to light

Exposure to light affects our physiology and behaviour through a pathway connecting the retina to the circadian pacemaker in the hypothalamus - the suprachiasmatic nucleus (SCN). Recent research has identified significant individual differences in the non-visual effects of light,mediated by this pathway. Here, we discuss the fundamentals and individual differences in the non-visual effects of light. We propose a set of actions to improve our evidence database to be more diverse: understanding systematic bias in the evidence base, dedicated efforts to recruit more diverse participants, routine deposition and sharing of data, and development of data standards and reporting guidelines.

Multi-Night at-Home Evaluation of Improved Sleep Detection and Classification with a Memory-Enhanced Consumer Sleep Tracker

PURPOSE

To evaluate the benefits of applying an improved sleep detection and staging algorithm on minimally processed multi-sensor wearable data collected from older generation hardware.

PATIENTS AND METHODS

58 healthy, East Asian adults aged 23-69 years (M = 37.10, SD = 13.03, 32 males), each underwent 3 nights of PSG at home, wearing 2^nd Generation Oura Rings equipped with additional memory to store raw data from accelerometer, infra-red photoplethysmography and temperature sensors. 2-stage and 4-stage sleep classifications using a new machine-learning algorithm (Gen3) trained on a diverse and independent dataset were compared to the existing consumer algorithm (Gen2) for whole-night and epoch-by-epoch metrics.

RESULTS

Gen 3 outperformed its predecessor with a mean (SD) accuracy of 92.6% (0.04), sensitivity of 94.9% (0.03), and specificity of 78.5% (0.11); corresponding to a 3%, 2.8% and 6.2% improvement from Gen2 across the three nights, with Cohen's d values >0.39, t values >2.69, and p values <0.01. Notably, Gen 3 showed robust performance comparable to PSG in its assessment of sleep latency, light sleep, rapid eye movement (REM), and wake after sleep onset (WASO) duration. Participants <40 years of age benefited more from the upgrade with less measurement bias for total sleep time (TST), WASO, light sleep and sleep efficiency compared to those ≥40 years. Males showed greater improvements on TST and REM sleep measurement bias compared to females, while females benefitted more for deep sleep measures compared to males.

CONCLUSION

These results affirm the benefits of applying machine learning and a diverse training dataset to improve sleep measurement of a consumer wearable device. Importantly, collecting raw data with appropriate hardware allows for future advancements in algorithm development or sleep physiology to be retrospectively applied to enhance the value of longitudinal sleep studies.

Sleep and Actigraphy Research Trends: A Bibliometric and Keyword Network Analysis From 2004 to 2020

Background and Objective As sleep is a predictor of quality of life, studying sleep health and measurement is important. Actigraphy as a physiologic measure based on monitoring an individual’s movement has also been increasing in use as it has several advantages over traditional self-reports. This study aimed to report the research trends of sleep and actigraphy using a bibliometric and keyword analysis.Methods Using topic search queries, this study collected data from 3955 publications published between 2004 and 2020 and listed in the Web of Science Core Collection. A text-mining unstructured data analysis was performed using author keywords and a bibliographic analysis.Results Studies on sleep and actigraphy have been actively conducted in the fields of neurosciences and neurology but not in other fields. A gradual increase in publication and the steep increase in citations related to this topic occurring during the period considered. By clustering the author keywords, the analysis revealed five clusters: 1) monitoring physical activity and blood pressure, 2) measuring sleep quality, 3) insomnia and cognitive behavioral therapy for adolescents and children, 4) disorders and circadian rhythms, and 5) shift work. The leading research cluster has changed over the time.Conclusions With the increase in the number of studies and citations on sleep and actigraphy over the past 16 years, the trend of sleep and actigraphy studies have shifted from a focus on sleeprelated psychiatric disorders to a focus on cognitive behavioral therapy for children and adolescents and, more recently, the measurement of sleep quality.

Concordance between subjective and objective measures of infant sleep varies by age and maternal mood: Implications for studies of sleep and cognitive development

Infant habitual sleep has been proposed as an important moderator of development in domains such as attention, memory or temperament. To test such hypotheses, we need to know how to accurately and consistently assess habitual sleep in infancy. Common assessment methods include easy to deploy but subjective parent-report measures (diary/sleep questionnaire); or more labour-intensive but objective motor movement measures (actigraphy). Understanding the degree to which these methods provide converging insights is important, but cross-method agreement has yet to be investigated longitudinally. Moreover, it is unclear whether concordance systematically varies with infant or maternal characteristics that could represent confounders in observational studies. This longitudinal study (up to 4 study visits/participant) investigated cross-method concordance on one objective (7-day actigraphy) and three commonly used subjective (7-day sleep diary, Brief Infant Sleep Questionnaire, Sleep & Settle Questionnaire) sleep measures in 76 typically developing infants (age: 4–14 months) and assessed the impact of maternal characteristics (stress, age, education) and infant characteristics (age) on cross-method concordance. In addition, associations between objective and subjective sleep measures and a measure of general developmental status (Ages & Stages Questionnaire) were investigated. A range of equivalence analyses (tests of equivalence, correlational analyses, Bland-Altman plots) showed mixed agreement between sleep measures. Most importantly, cross-method agreement was associated with maternal stress levels and infant age. Specifically, agreement between different measures of night waking was better for mothers experiencing higher stress levels and was higher for younger than older infants; the reverse pattern was true for day sleep duration. Interestingly, objective and subjective measures did not yield the same patterns of association with developmental domains, indicating that sleep method choice can influence which associations are found between sleep and cognitive development. However, results converged across day sleep and problem-solving skills, highlighting the importance of studying day sleep in future studies. We discuss implications of sleep method choice for investigating sleep in the context of studying infant development and behaviour.

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A range of equivalence analyses showed mixed agreement between subjective and objective sleep measures.

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Cross-method agreement was associated with maternal stress levels and infant age.

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Objective and subjective measures did not yield the same patterns of association with developmental domains except for day sleep duration.

Actigraphy in mechanically ventilated pediatric ICU patients: comparison to PSG and evaluation of behavioral circadian rhythmicity

Sleep disruption is common in pediatric intensive care unit (PICU) patients, but measuring sleep in this population is challenging. We aimed to evaluate the utility of actigraphy for estimating circadian rhythmicity in mechanically ventilated PICU patients and its accuracy for measuring sleep by comparing it to polysomnogram (PSG). We conducted a single-center prospective observational study of children 6 months - 17 years of age receiving mechanical ventilation and standard, protocolized sedation for acute respiratory failure, excluding children with acute or historical neurologic injury. We enrolled 16 children and monitored them with up to 14 days of actigraphy and 24 hours of simultaneous limited (10 channel) PSG. Daily actigraphy-based activity profiles demonstrated that patients had a high level of nighttime activity (30-41% of total activity), suggesting disrupted circadian activity cycles. Among n = 12 patients with sufficient actigraphy and PSG data overlap, actigraphy-based sleep estimation showed poor agreement with PSG-identified sleep states, with good sensitivity (94%) but poor specificity (28%), low accuracy (70%,) and low agreement (Cohen's kappa = 0.2, 95% CI = 0.08-0.31). Using univariate linear regression, we identified that Cornell Assessment of Pediatric Delirium scores were associated with accuracy of actigraphy but that other clinical factors including sedative medication doses, activity levels, and restraint use were not. In this population, actigraphy did not reliably discern between sleep and wake states. However, in select patients, actigraphy was able to distinguish diurnal variation in activity patterns, and therefore may be useful for evaluating patients' response to circadian-oriented interventions.

Validation of actigraphy in hospitalised newborn infants using video polysomnography

Actigraphy has been established as a reliable sleep assessment tool in adults; however, its utility in newborns remains unknown. Validation of actigraphy in newborns may provide a significant insight into the physiological and pathological acquisition process of mature diurnal sleep patterns and subsequent morbidities in both newborns and their mothers. Thus, the present study aimed to evaluate the accuracy of sleep-wake detection by overnight actigraphy in a cohort of newborns. Simultaneous recording of polysomnography and actigraphy data was performed in 40 newborns admitted to a tertiary neonatal intensive care unit (NICU). A mixed-effects logistic regression model to explain the sleep state identified by polysomnography was employed using the actigraphic activity score as a fixed independent variable and the individual newborn's identity as a random effect. To evaluate the usefulness of the actigraphic activity score as a surrogate marker of sleep, a receiver operating characteristic (ROC) curve analysis was performed using the variables that were used in the mixed-effects logistic regression model, and the area under the curve (AUC) was assessed. The results showed that polysomnography-determined sleep epochs were associated with a smaller activity index on actigraphy (odds ratio per 10 activity indices increase 0.81, 95% confidence interval [CI] 0.79-0.84). The AUC for the ROC curve was 0.87 (95% CI 0.87-0.88, range 0.54-0.99). An activity score of 124 showed the maximum overall accuracy (90.2%, 95% CI 87.7-92.1). Our present study suggests that sleep-wake states of NICU-hospitalised newborns can be precisely determined using actigraphy on the ankle.

Actigraphy in sleep research with infants and young children: Current practices and future benefits of standardized reporting

Actigraphy is a cost-efficient method to estimate sleep-wake patterns over long periods in natural settings. However, the lack of methodological standards in actigraphy research complicates the generalization of outcomes. A rapidly growing methodological diversity is visible in the field, which increasingly necessitates the detailed reporting of methodology. We address this problem and evaluate the current state of the art and recent methodological developments in actigraphy reporting with a special focus on infants and young children. Through a systematic literature search on PubMed (keywords: sleep, actigraphy, child *, preschool, children, infant), we identified 126 recent articles (published since 2012), which were classified and evaluated for reporting of actigraphy. Results show that all studies report on the number of days/nights the actigraph was worn. Reporting was good with respect to device model, placement and sleep diary, whereas reporting was worse for epoch length, algorithm, artefact identification, data loss and definition of variables. In the studies with infants only (n = 58), the majority of articles (62.1%) reported a recording of actigraphy that was continuous across 24 hr. Of these, 23 articles (63.9%) analysed the continuous 24-hr data and merely a fifth used actigraphy to quantify daytime sleep. In comparison with an evaluation in 2012, we observed small improvements in reporting of actigraphy methodology. We propose stricter adherence to standards in reporting methodology in order to streamline actigraphy research with infants and young children, to improve comparability and to facilitate big data ventures in the sleep community.

Associations of diarised sleep onset time, period and duration with total and central adiposity in a biethnic sample of young children: the Born in Bradford observational cohort study

OBJECTIVES

To investigate associations of parent-reported sleep characteristics with adiposity levels in a biethnic sample of young children.

DESIGN

A cross-sectional observational study.

SETTING

The Born in Bradford 1000 study, UK.

PARTICIPANTS

Children aged approximately 18 months (n=209; 40.2% South Asian; 59.8% white) and 36 months (n=162; 40.7% South Asian; 59.3% white).

PRIMARY AND SECONDARY OUTCOME MEASURES

Children's body mass index (BMI) z-score, sum of two-skinfolds (triceps and subscapular) and waist circumference. Adjusted regression was used to quantify associations of sleep parameters with adiposity stratified by ethnicity and age group. The results are beta coefficients (95% CIs) and unless otherwise stated represent the difference in outcomes for every 1-hour difference in sleep parameters.

RESULTS

The average sleep onset time was markedly later in South Asian (21:26±68 min) than white children (19:41±48 min). Later sleep onset was associated with lower BMI z-score (-0.3 (-0.5 to -0.0)) and sum of two-skinfolds (-1.5 mm (-2.8 mm to -0.2 mm)) in white children aged 18 months and higher BMI z-score in South Asian children aged 36 months (0.3 (0.0-0.5)). Longer sleep duration on weekends than weekdays was associated with higher BMI z-score (0.4 (0.1-0.8)) and waist circumference (1.2 cm (0.3-2.2 cm)) in South Asian children aged 18 months, and later sleep onset on weekends than weekdays was associated with larger sum of two-skinfolds (1.7 mm (0.3-3.1 mm)) and waist circumference (1.8 cm (0.6-2.9 cm)). Going to sleep ≥20 min later on weekends than weekdays was associated with lower waist circumference in white children aged 18 months (-1.7 cm (-3.2 cm to -0.1 cm)).

CONCLUSIONS

Sleep timing is associated with total and central adiposity in young children but associations differ by age group and ethnicity. Sleep onset times and regular sleep schedules may be important for obesity prevention.

Sleep Dysregulation and Daytime Electrodermal Patterns in Children With Autism: A Descriptive Study

Sleep deficiency influences emotion and behavior regulation but the mechanisms of influence are poorly understood. Emotion, behavioral, and sleep theories highlight differences in autonomic function as a potential pathway of influence and research in typical populations draw links between sleep deficiency and autonomic dysregulation (e.g., elevated reactivity within the sympathetic nervous system). In populations at elevated risk for sleep deficiency/problems (i.e., individuals with autism), greater variability in sleep and autonomic/arousal profiles may be particularly informative. Using electrodermal activity (EDA) as an indicator of sympathetic nervous system activation, this descriptive pilot study aimed to document daytime EDA patterns in children with autism and to explore their relations with sleep dysregulation/deficiency. EDA and sleep were measured using ankle and wrist worn sensors in 13 children (Mean_age 6.11 years). EDA indices included nonspecific skin conductance responses (NSSCR) and tonic skin conductance levels (SCL). Descriptively, children in the dysregulated sleep group had fewer NSSCRs and lower SCL in the afternoon. This blunted physiological arousal profile/pattern is consistent with previous research, but this is the first study to explore how sleep may be linked. Notably, this pattern may not reflect sleep but an overall dysregulation profile which in this sample included: dysregulated sleep, a blunted afternoon arousal profile, and elevated ASD symptom severity. Replication with larger, more diverse samples is needed to disentangle the complex relations among sleep, arousal, and ASD behavioral features. However, this study represents an important first step in documenting extended daytime arousal patterns.

Daytime nap and nighttime breastfeeding are associated with toddlers' nighttime sleep

The purpose of the present study is to examine the association between toddlers' sleep arrangements and their nighttime sleep duration and other sleep variables. For this investigation, we performed a study in which child activity and sleep levels were recorded using actigraphy. The parents of 1.5-year-old toddlers (n = 106) were asked to attach an actigraphy unit to their child’s waist with an adjustable elastic belt and complete a sleep diary for 7 consecutive days. Questionnaires were used to assess the sleep arrangements of the toddlers. There was a significant negative correlation between nap duration and nighttime sleep duration, suggesting that longer nap sleep induces shorter nighttime sleep duration. Among the sleep arrangements, such as nighttime breastfeeding or co-sleeping, only nighttime breastfeeding predicted shorter nighttime sleep duration. Our findings indicate that shorter naps induce a longer nighttime sleep in 1.5-year-old toddlers while nighttime breastfeeding decreases their nighttime sleep duration.

The Validity, Reliability, and Feasibility of Measurement Tools Used to Assess Sleep of Pre-school Aged Children: A Systematic Rapid Review

Background: Sleep of pre-school aged children is important for their health and development, but there are currently no standards for measuring sleep in this age group. We aimed to examine the validity, reliability and feasibility of tools used to assess sleep of pre-school aged children. Methods: Studies were eligible for inclusion if they examined the validity and/or reliability and/or feasibility of a measurement tool used to examine sleep of pre-school aged children (aged 3-7 years). We systematically searched six electronic databases, grey literature and trial registries. We manually searched topic specific journals, reference and citations of included studies, and reference lists of existing reviews. We extracted data and conducted a risk of bias assessment on the included studies using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) risk of bias checklist. We used a narrative synthesis to present the results. Results: Sixteen studies met the inclusion criteria: these explored accelerometers (n = 3) and parental reported tools (n = 13; nine questionnaires, six diaries). Studies assessed construct validity (n = 3), criterion validity (n = 1), convergent validity (n = 13), test-retest reliability (n = 2), internal consistency (n = 4) and feasibility (n = 12). Most studies assessed the convergent validity of questionnaires and diaries compared with accelerometers, but the validity of accelerometers for sleep in this age group is unknown. Of studies with a low risk of bias, one sleep diary was shown to be valid for measuring sleep duration. No measurement tools were appropriate for determining sleep quality. Reporting of reliability and feasibility was minimal. Discussion: The evidence base in this field is limited, and most studies had high risk of bias. Future research on sleep in pre-school aged children should focus on assessing the validity, reliability and feasibility of accelerometers, which in turn will improve the quality of studies that assess questionnaires and diaries against accelerometers. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021230900; PROSPERO: CRD42021230900.

Sleep behavior of infants with infantile hemangioma treated with propranolol-a cohort study

Sleep problems are frequently reported in infants treated with propranolol for infantile hemangiomas, possibly serving as a marker for a negative impact on central nervous system function. In this cohort study, we objectively investigate the sleep behavior of infants with infantile hemangiomas on propranolol compared to a healthy, untreated control group. Sleep of propranolol-treated infants and controls was investigated using ankle actigraphy and a 24-h diary for 7-10 days at ages 3 and 6 months. The main outcome measures were the Number of Nighttime Awakenings and Sleep Efficiency. The main secondary outcome measures included 24-hour Total Sleep, daytime sleep behavior, and parent-rated infant sleep quality and behavioral development based on the Brief Infant Sleep Questionnaire (BISQ) and the age-appropriate Ages-and-Stages Questionnaire (ASQ), respectively. Fifty-four term-born infants were included in each cohort. No group difference in any investigated parameter was seen at age 3 months. At age 6 months, the propranolol group exhibited a decrease in Sleep Efficiency and a trend towards an increased Number of Nighttime Awakenings compared to the control group. Treated infants at 6 months also had shorter daytime waking periods. 24-hour Total Sleep was unaffected by propranolol. No negative impact of propranolol on subjective sleep quality and behavioral development was noted.Conclusion: Propranolol exerts a measurable yet mild impact on objectively assessed infants' sleep measures. Behavioral developmental scores were unaffected. Our results support propranolol as first-line therapy for complicated infantile hemangiomas. What is Known: • Sleep disorders are frequently reported in infants with infantile hemangiomas treated with propranolol and often lead to treatment discontinuation. • Investigations of the sleep pattern in this patient group using objective measures are lacking. What is New: • The sleep pattern of propranolol-treated infants is assessed using actigraphy and a 24-h sleep diary and compared to healthy, untreated controls. • Propranolol leads to a decreased sleep efficiency at night and an increased demand of daytime sleep, yet effects are mild overall.

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.