Plasma Biomarker Concentrations Associated With Return to Sport Following Sport-Related Concussion in Collegiate Athletes—A Concussion Assessment, Research, and Education (CARE) Consortium Study

Importance: Identifying plasma biomarkers associated with the amount of time an athlete may need before they return to sport (RTS) following a sport-related concussion (SRC) is important because it may help to improve the health and safety of athletes. Objective: To examine whether plasma biomarkers can differentiate collegiate athletes who RTS in less than 14 days or 14 days or more following SRC. Design, Setting, and Participants: This multicenter prospective diagnostic study, conducted by the National Collegiate Athletics Association–Department of Defense Concussion Assessment, Research, and Education Consortium, included 127 male and female athletes who had sustained an SRC while enrolled at 6 Concussion Assessment, Research, and Education Consortium Advanced Research Core sites as well as 2 partial–Advanced Research Core military service academies. Data were collected between February 2015 and May 2018. Athletes with SRC completed clinical testing and blood collection at preseason (baseline), postinjury (0-21 hours), 24 to 48 hours postinjury, time of symptom resolution, and 7 days after unrestricted RTS. Main Outcomes and Measures: A total of 3 plasma biomarkers (ie, total tau protein, glial fibrillary acidic protein [GFAP], and neurofilament light chain protein [Nf-L]) were measured using an ultrasensitive single molecule array technology and were included in the final analysis. RTS was examined between athletes who took less than 14 days vs those who took 14 days or more to RTS following SRC. Linear mixed models were used to identify significant interactions between period by RTS group. Area under the receiver operating characteristic curve analyses were conducted to examine whether these plasma biomarkers could discriminate between RTS groups. Results: The 127 participants had a mean (SD) age of 18.9 (1.3) years, and 97 (76.4%) were men; 65 (51.2%) took less than 14 days to RTS, and 62 (48.8%) took 14 days or more to RTS. Linear mixed models identified significant associations for both mean (SE) plasma total tau (24-48 hours postinjury, <14 days RTS vs ≥14 days RTS: −0.65 [0.12] pg/mL vs −0.14 [0.14] pg/mL; P = .008) and GFAP (postinjury, 14 days RTS vs ≥14 days RTS: 4.72 [0.12] pg/mL vs 4.39 [0.11] pg/mL; P = .04). Total tau at the time of symptom resolution had acceptable discrimination power (area under the receiver operating characteristic curve, 0.75; 95% CI, 0.63-0.86; P < .001). We also examined a combined plasma biomarker panel that incorporated Nf-L, GFAP, and total tau at each period to discriminate RTS groups. Although the analyses did reach significance at each time period when combined, results indicated that they were poor at distinguishing the groups (area under the receiver operating characteristic curve, <0.7). Conclusions and Relevance: The findings of this study suggest that measures of total tau and GFAP may identify athletes who will require more time to RTS. However, further research is needed to improve our ability to determine recovery following an SRC.This publication was made possible with support from the Grand Alliance Concussion Assessment, Research, and Education (CARE) Consortium, funded, in part by the NCAA and the Department of Defense. The US Army Medical Research Acquisition Activity, 820 Chandler St, Ft Detrick, MD 21702, is the awarding and administering acquisition office. This work was supported by the Office of the Assistant Secretary of Defense for Health Affairs through the Psychological Health and Traumatic Brain Injury Program under award No. W81XWH-14-2-0151

Weight status of young children: Exploring the relationship with sleep and light exposure

The problem of paediatric obesity remains significant. This study investigated the potential influence of two environmental mechanisms proposed to affect children's weight status, sleep and light exposure. Collectively this body of research has made significant contributions to current understanding of child weight status in three ways: 1) documentation of current methodologies used to classify body mass in young children; 2) adding to understanding of the potential role of sleep parameters for child weight; and 3) the first documentation of the significant influence of environmental light exposure on the weight of preschool aged children. This study elucidates new directions for intervention

Risk of dementia after TBI - a cause of growing concern

Moderate and severe traumatic brain injuries (TBIs) have long been recognized as risk factors for dementia, but the relationship between mild TBI (mTBI) and dementia is unclear. New research demonstrates that even an mTBI without loss of consciousness is associated with a twofold increase in the risk of dementia

Mandatory naptimes in childcare do not reduce children's cortisol levels

The majority of preschool children (aged 3-5 years) no longer habitually nap, yet in childcare settings daily mandated naptimes in which children lie down without alternative activity remains a common practice. Mandated naptimes are associated with observed reductions in emotional climate and increased incidence of distress. While intended to be restful, mandatory naptimes may induce stress in those children unable to sleep. To examine this possibility, we applied a 2 (mandated/flexible practice) × 2 (nap/no-nap) design to test group difference in stress responses of children (N = 43, mean age 56.3 months). Salivary cortisol level was measured at 4 time-points (waking, pre-naptime, post-naptime, and bedtime) across two days at childcare. Overall our results show a significant decline in cortisol level from wake to pre-naptime and from post-naptime to bedtime. No significant change in cortisol level was observed from pre- to post- naptime. Significant group differences in cortisol patterns were observed. Notably, children under mandatory naptime conditions who did not nap showed no significant reduction in cortisol level from post-naptime to bedtime. While cortisol measurement suggests naptime is neither stressful nor restful for children in any group, implications for bedtime arousal are raised for those unable to sleep under conditions of mandated naptimes

Correlates of naptime behaviors in preschool aged children

Purpose: Major changes in the timing, duration, and function of sleep occur during childhood. These changes include the transition from habitual napping to infrequent napping. This transition is likely to reflect, at least in part, neurocognitive development. This study sought to identify factors that discriminate between four groups of children with different teacher-reported responses to naptime in childcare: those who nap (nappers), sometimes nap (transitioners), do not nap (resters), and neither nap, nor lie still (problem nappers).Methods: Standardized observations of sleep and sleep behaviors, daytime behaviors across a number of domains, and direct neurocognitive assessment of 158 preschool aged children (aged 49-72 months; 54% male) attending childcare centers in Queensland (QLD), Australia, were adopted as part of a large longitudinal study of early childhood, the Effective Early Education Experiences (E4Kids) study. Discriminant function analysis was used to examine how age, parent education, nighttime sleep duration, cognitive functioning, behavior problems, and temperament differentiated the four groups.Results: Three discriminant functions were identified and defined as maturation (strong loadings of nighttime sleep duration, cognitive function, and age), socioeconomic status (parental cation), and behavioral problems (externalizing behavior, temperament, and internalizing behavior). These functions accounted for 62.9%, 32.6%, and 4.5% of the between-groups variance, respectively. Children defined as nappers (n= 44) had significantly shorter duration of nighttime sleep, were younger, and had lower cognitive functioning scores than did other groups. Problem nappers, (n= 25) were more likely to have parents with lower levels of education than did transitioners (n= 41). Standard behavior and temperament measures did not significantly differentiate the groups.Conclusion: The findings support an interaction between cognitive development, sleep behaviors, and the individual needs and circumstances of children. Further research in this area could make a strong contribution to theory and practice in early childhood education, and a strong contribution to understanding of children's development

Investigating the association between sleep parameters and the weight status of children: night sleep duration matters

To examine the associations between sleep parameters and weight status in a large sample of preschool children.Cross-sectional survey data from the Effective Early Educational Experiences for children (E4Kids) study were analyzed.1111 children aged 3 to 6 years from Queensland and Victoria, Australia.General linear modeling, with adjustment for significant control variables, assessed the impact of night sleep duration, total sleep duration, napping frequency, sleep timing (onset, offset and midpoint), and severity of sleep problems on standardized body mass index (BMI z score). General linear modeling was conducted for the total sample and then separately by sex.For the total sample, there was a significant association between short sleep duration (≤10 hours) and increased BMI z score. No other sleep parameters were associated with BMI z score in this sample. Analyses by sex revealed that, among girls, there were no associations between any sleep parameter and BMI z score. However, among boys, short night sleep duration and napping frequency were both significantly associated with weight status even after adjustment for controls.Night sleep duration is a consistent independent predictor of body mass in young children. These results identify a complex relationship between sleep and body mass that implicates sex. Potential mechanisms that might explain sex differences warrant further investigation

What parents want: parent preference regarding sleep for their preschool child when attending early care and education

Background: While most children cease napping between the ages of 2 and 5 years, across a range of international settings the allocation of a mandatory naptime is a common feature of the daily routine in Early Care and Education (ECE) programs for children of this age. Evidence regarding the developmental effects of napping is limited but, beyond age 2, is consistently associated with delayed night sleep onset and increased number of awakenings. Objectives: The present study examined parent preferences towards napping in ECE. Methods: Participants were 750 parents of preschool-aged children attending a representative sample of Australian ECE programs across metropolitan, regional and rural sites in 2011. We analysed quantitative and open-ended questionnaire data from a large, longitudinal study of the effectiveness of Australian early education programs (E4Kids). Statistical analyses examined prevalence of parent preference for sleep and demographic correlates. Thematic analyses were employed to identify parents' rationale for this preference. Results: The majority of parents (78.7%) preferred that their children did not regularly sleep while attending ECE. The dominant explanation provided by parents was that regular naps were no longer appropriate and adversely impacted their children's health and development. Parents of younger children were more likely to support regular naps. Conclusions: The results highlight a disjuncture between parent preferences and current sleep policy and practices in ECE. Further research is needed to establish evidence-based guidelines to support healthy sleep-rest practices in ECE. Such evidence will guide appropriate practice and support parent-educator communication regarding sleep and rest

Concurrent mild traumatic brain injury and posttraumatic stress disorder is associated with elevated tau concentrations in peripheral blood plasma

Concurrent mild traumatic brain injury (mTBI) and posttraumatic stress disorder (PTSD) are common in U.S. military service members and veterans. Tau and amyloid-beta-42 (A beta 42) are proteins that have been linked to cognitive impairment, neurological hallmarks of Alzheimer's disease, and may also relate to recovery from mTBI. However, the role of these proteins in the maintenance or resolution of chronic symptoms has not yet been determined. Participants in the current study were 102 service members and veterans who had sustained an mTBI (n = 84) or injured controls (IC) without TBI (n = 18). They were categorized into three groups based on the presence or absence of mTBI and PTSD: IC/PTSD-Absent (n = 18), mTBI/PTSD-Absent (n = 63), and mTBI/PTSD-Present (n = 21). Concentrations of tau and A beta 42 in peripheral blood plasma were measured using Simoa(TM), an ultrasensitive technology, and compared across groups. Tau concentrations were highest in the mTBI/PTSD-Present group, F(2, 99) = 4.33, p = .016, compared to the other two groups. Linear multiple regression was conducted to determine the independent effects of PTSD and mTBI on tau concentrations, controlling for gender and sleep medication. PTSD was a significant and independent predictor of tau concentrations, beta = .25, p = .009, eta(2)(p) = .26. A beta 42 concentrations did not differ between the groups. The results indicated that PTSD was associated with an elevation of tau in peripheral blood and suggest that there may be increased biological effects of PTSD in this young cohort of service members and veterans following mTBI

Smoothed 7-day light exposure plots from three individual participants.

<p>Light exposure data (measured in lux) were smoothed and shown on a logarithmic scale for three representative children across 7 measurement days (plotted in hours). The horizontal yellow shaded area represents a threshold of ≥200 lux. Points where lux is registered as zero are not shown, as the log of zero is not defined.</p

Representative light exposure profiles (log linear lux) for two individual participants with “Early” and “Late” light exposure.

<p>The black dashed line depicts the mean light exposure of all participants across the recording period (<i>N</i> = 48); the blue line depicts the light exposure of a participant classified as having an “Early MLiT²⁰⁰”; the red line depicts the light exposure of a participant classified as having a “Late MLiT²⁰⁰”. The horizontal line represents the 200 lux threshold.</p