Assessment of Sleep Quantity and Sleep Disturbances During Recovery From Sports-Related Concussion in Youth Athletes

The relationship between multiple concussions and multidimensional sleep quality in collegiate-aged, active athletes

OBJECTIVES

Determine the association of cumulative concussion and repetitive head impacts with self-reported sleep quality in healthy collegiate-aged athletes.

METHODS

Collegiate-aged athletes (N = 212; mean age 21.00, 62.7% male) completed semistructured interviews for sport and concussion history and the Pittsburgh Sleep Quality Index (PSQI). Number of concussions was retrospectively determined based on the 1993 American Congress of Rehabilitation Medicine (ACRM) criteria; repetitive head impact was measured based on the cumulative years of contact sport exposure. Associations of number of concussions and repetitive head impact exposure with global PSQI score, overall poor (PSQI >5) vs. good sleep, and binarized subscale scores were tested. Secondary analyses were conducted using alternative concussion criteria and metrics of repetitive head impact.

RESULTS

The number of prior concussions was associated with higher PSQI global scores (B(SE)= 0.50(0.13), p < .001). Participants with more concussions were more likely to be poor sleepers (OR=1.52, p < .001), report poorer sleep quality (OR=1.29, p = .037), longer sleep latency (OR=1.34, p = .005), more sleep disturbances (OR=1.56, p = .001), increased use of sleep medications or sleep aids (OR=1.35, p = .008), and more sleep-related daily dysfunction (OR=1.38, p = .002). Similar results were observed for alternative definitions of concussion. No metric of repetitive head impact was associated with any sleep quality metric.

CONCLUSIONS

More prior concussions, but not repetitive head impact exposure, are associated with worse self-reported sleep, with subscale analyses showing concussion history associated with multiple aspects of subjective sleep quality rather than sleep quantity. Sleep represents an important factor to consider for future research aimed at characterizing and ultimately preventing adverse long-term health outcomes associated with concussion history.

Exercising More Than 150 min/wk After Concussion Is Associated With Sleep Quality Improvements

OBJECTIVE

To examine whether a high volume of aerobic exercise after concussion (>150 min/wk) is associated with improved sleep quality over a 1-month period. We hypothesized that more than 150 min/wk of exercise would be associated with improved sleep quality across concussion recovery.

DESIGN

Prospective cohort observational study.

SETTING

Sports medicine clinic.

PARTICIPANTS

Adolescents initially tested 8.4 ± 3.5 (range, 2-18) days postconcussion who returned for a follow-up assessment 34.3 ± 7.7 (range: 20-49) days postconcussion.

MAIN OUTCOME MEASURES

Participants completed the Pittsburgh Sleep Quality Index and the Post-Concussion Symptom Inventory. No specific exercise or sleep recommendations were given beyond what their treating physician provided. Between study visits, participants recorded exercise performed via wrist-worn actigraphy. We calculated average exercise minutes per week and grouped participants as those who exercised more than 150 min/wk versus those who exercised 150 min/wk or less.

RESULTS

Thirty-six adolescents participated. Fifteen (42%) recorded more than 150 min/wk of aerobic exercise (age = 14.0 ± 1.7 years; 47% female; mean = 5.6 ± 1.2 d/wk of exercise; mean = 49.2 ± 17.5 min/session), and 21 recorded 150 min/wk or less of aerobic exercise (age = 15.0 ± 1.9 years; 76% female; mean = 2.7 ± 1.6 d/wk of exercise; mean = 30.2 ± 7.8 min/session). There were no significant group differences in the proportion of those who self-reported beginning physical activity prior to enrollment (47% vs 33%; P = .42) or for initial sleep quality rating (8.0 ± 3.7 vs 8.6 ± 4.1; P = .67) or initial concussion symptom severity rating (34.9 ± 28.0 vs 42.6 ± 25.9; P = .40). The group that exercised more than 150 min/wk between visits demonstrated significantly greater median PSQI rating improvements than those who exercised 150 min/wk or less, with a large effect size noted (median change [interquartile range] = 5 [3, 7] vs 1 [0, 4]; P = .008; Cohen d = 0.96).

CONCLUSION

Current recommendations suggest that subsymptom aerobic exercise can be beneficial after concussion. Our findings indicate that an exercise volume of more than 150 min/wk led to greater sleep quality improvements than those who exercised below this level.

Concussion and the Sleeping Brain

BACKGROUND

Emerging research has suggested sleep to be a modifier of the trajectory of concussion recovery in adolescent and adult populations. Despite the growing recognition of the relationship between sleep and concussion, the mechanisms and physiological processes governing this association have yet to be established.

MAIN BODY

Following a concussion, a pathophysiologic cascade of events occurs, characterized by numerous factors including microglia activation, ionic imbalance, and release of excitatory neurotransmitters. Importantly, each of these factors plays a role in the regulation of the sleep-wake cycle. Therefore, dysregulation of sleep following injury may be a function of the diffuse disruption of cerebral functioning in the wake of both axonal damage and secondary physiological events. As the onset of sleep-related symptoms is highly variable following a concussion, clinicians should be aware of when and how these symptoms present. Post-injury changes in sleep have been reported in the acute, sub-acute, and chronic phases of recovery and can prolong symptom resolution, affect neurocognitive performance, and influence mood state. Though these changes support sleep as a modifier of recovery, limited guidance exists for clinicians or their patients in the management of sleep after concussion. This may be attributed to the fact that research has correlated sleep with concussion recovery but has failed to explain why the correlation exists. Sleep is a complex, multifactorial process and the changes seen in sleep that are seen following concussion are the result of interactions amongst numerous processes that regulate the sleep-wake cycle.

SHORT CONCLUSION

The assessment and management of sleep by identifying and considering the biological, sociological, and psychological interactions of this multifactorial process will allow for clinicians to address the dynamic nature of changes in sleep following concussion.

The Association Among Clinical Profiles, Modifiers, and Prolonged Recovery in Adolescents With Sport-Related Concussion

OBJECTIVE

The purposes were to (1) describe the prevalence of clinical profiles and modifiers, (2) examine the association between clinical profiles and prolonged recovery, and (3) examine the interaction between clinical profiles and modifiers and prolonged recovery in adolescents with sport-related concussion (SRC).

DESIGN

Retrospective, cross-sectional.

SETTING

Interdisciplinary specialty sports concussion clinic.

PATIENTS

Patients (n = 299) aged 12 to 19 years who were diagnosed with SRC within 30 days of injury.

INDEPENDENT VARIABLES

Clinical profiles and modifiers were decided by the clinical judgment of the clinical neuropsychologist and sports medicine physician, using data from the Clinical Profile Screen and information gathered from the clinical interview, neurocognitive, and vestibular and ocular motor testing.

MAIN OUTCOME MEASURES

Prolonged recovery was defined as ≥28 days from the date of injury to the date of clearance.

RESULTS

The most common clinical profiles were migraine (34.8%) and cognitive-fatigue (23.4%). There were no significant relationships between clinical profiles and prolonged recovery (Wald = 5.89, df = 4, P = 0.21). The presence of a modifier did not significantly affect the relationship between clinical profiles and prolonged recovery ( = 6.5, df = 5, P = 0.26). The presence of any modifier yielded a 10-day increase in median recovery time within the cognitive/fatigue clinical profile (Wilcoxon rank-sum = 268.5, P = 0.01).

CONCLUSIONS

Although patients with a clinical profile and modifier may not experience prolonged recovery, they may experience longer recovery time than patients with a clinical profile and no modifier.

Influence of sleep symptoms on recovery from concussion in collegiate athletes: a LIMBIC MATARS consortium investigation

OBJECTIVE

Changes in sleep quality and quantity are commonly endorsed by individuals following a concussion. Limited data exists examining the role of sleep disturbances within 72 hours, and throughout recovery, from concussion. The objective of this study was to determine if the number of days to symptom resolution varied between collegiate athletes with or without sleep-related symptoms following a concussion.

DESIGN

Retrospective chart review.

METHODS

Collegiate athletes (n = 539) who were diagnosed with a concussion between the 2015-2020 sport seasons participated in this retrospective chart review. Participants were divided into groups based on the presence or absence of sleep symptoms within 72 hours of a diagnosed concussion. A Mann-Whitney U test was used to compare days to symptom resolution between groups with α = 0.05.

RESULTS

Of the 539 participants, 250 (46.3%) reported sleep-related symptoms. Participants with sleep-related symptoms took significantly longer (U = 30656, p = 0.002) to report symptom resolution at rest (median [full range] = 8.00[0-423]) as compared to participants who did not report sleep-related symptoms (6.00[0-243] days).

CONCLUSION

Collegiate athletes that report sleep-related symptoms immediately following concussion (<72 hours) were observed to take, on median, two days longer to achieve symptom resolution at rest when compared to athletes who did not endorse the same symptoms.

Association between days for concussion recovery and initial specialty clinic evaluation within 48 hours

BACKGROUND

Researchers have highlighted the importance of early access to concussion care within one week of injury in reducing recovery times. However, a persisting question for concussion researchers is "just how early is important?" The purpose of this study was to examine differences in recovery time as predicted by the number of days elapsed since injury (DSI) to initial evaluation among patients who had access to a specialty concussion clinic within seven days. We hypothesized that DSI group membership, even within seven days, would significantly predict risk of protracted recovery (i.e., beyond 21 days).

METHODS

In this archival study, retrospective data were gathered from electronic medical records between September 2020 to March 2022. Records of participants between ages 12-18, those diagnosed with a sports-related concussion based on initial clinic visit diagnosis by a medical provider and those who established care within seven days of injury at a large pediatric specialty concussion clinic were examined. Participants were divided into three DSI groups (patients seen in < 48 h: "acute", patients seen between 49 h < and < 96 h: "sub-acute", and patients seen between 97 < and < 168 h: "post-acute"). A general linear model was constructed to examine relationships between relevant concussion factors (e.g., Post Concussion Scale Score, neurodevelopmental history, psychiatric history, concussion history, migraine history, overall VOMS change score, cognitive testing, sex, age, race, and ethnicity) that were either significant in the preliminary analysis or in clinical judgement and recovery time. Adjusted odds ratios (OR) were derived from a binary logistic regression model, in which recovery time was normal (≤ 21 recovery days) or protracted (> 21 recovery days).

RESULTS

A total of 856 participants were eligible. Adolescents in the acute group (M = 15.12, SD = 8.04) had shorter recovery times in days compared to those in the sub-acute (M = 17.98, SD = 10.18) and post-acute (M = 21.12, SD = 10.12; F = 26.00, p < .001) groups. Further, participants in the acute (OR = 4.16) and sub-acute (OR = 1.37) groups who accessed specialty concussion clinics within 48 h were 4 times more likely to have a normal recovery and recovered approximately 6 days faster than the post-acute care group.

CONCLUSIONS

Earlier concussion care access predicted recovery times and was associated with lower risk for protracted recovery.

Pediatric Sport-Related Concussion: Recommendations From the Amsterdam Consensus Statement 2023

The 6th International Consensus Conference on Concussion in Sport, Amsterdam 2022, addressed sport-related concussion (SRC) in adults, adolescents, and children. We highlight the updated evidence-base and recommendations regarding SRC in children (5-12 years) and adolescents (13-18 years). Prevention strategies demonstrate lower SRC rates with mouthguard use, policy disallowing bodychecking in ice hockey, and neuromuscular training in adolescent rugby. The Sport Concussion Assessment Tools (SCAT) demonstrate robustness with the parent and child symptom scales, with the best diagnostic discrimination within the first 72 hours postinjury. Subacute evaluation (>72 hours) requires a multimodal tool incorporating symptom scales, balance measures, cognitive, oculomotor and vestibular, mental health, and sleep assessment, to which end the Sport Concussion Office Assessment Tools (SCOAT6 [13+] and Child SCOAT6 [8-12]) were developed. Rather than strict rest, early return to light physical activity and reduced screen time facilitate recovery. Cervicovestibular rehabilitation is recommended for adolescents with dizziness, neck pain, and/or headaches for greater than 10 days. Active rehabilitation and collaborative care for adolescents with persisting symptoms for more than 30 days may decrease symptoms. No tests and measures other than standardized and validated symptom rating scales are valid for diagnosing persisting symptoms after concussion. Fluid and imaging biomarkers currently have limited clinical utility in diagnosing or assessing recovery from SRC. Improved paradigms for return to school were developed. The variable nature of disability and differences in evaluating para athletes and those of diverse ethnicity, sex, and gender are discussed, as are ethical considerations and future directions in pediatric SRC research.

Sleep/Wake Disorders After Sports Concussion: Risks, Revelations, and Interventions

SUMMARY

Sleep-wake disturbances (SWDs) are among the most prevalent, persistent, and often disregarded sequelae of traumatic brain injury. Identification and treatment of SWDs in patients with traumatic brain injury is important and can complement other efforts to promote maximum functional recovery. SWDs can accentuate other consequences of traumatic brain injury, negatively affect mood, exacerbate pain, heighten irritability, and diminish cognitive abilities and the potential for recovery. The risk for sports injuries increases when athletes are sleep deprived. Sleep deprivation increases risk-taking behaviors, predisposing to injuries. SWDs are an independent risk factor for prolonged recovery after sports-related concussion. SWDs following sports-related concussion have been shown to impede recovery, rehabilitation, and return to preinjury activities.

Beyond acute concussion assessment to office management: a systematic review informing the development of a Sport Concussion Office Assessment Tool (SCOAT6) for adults and children

OBJECTIVES

To systematically review the scientific literature regarding the assessment of sport-related concussion (SRC) in the subacute phase (3-30 days) and provide recommendations for developing a Sport Concussion Office Assessment Tool (SCOAT6).

DATA SOURCES

MEDLINE, Embase, PsycINFO, Cochrane CENTRAL, CINAHL, SPORTDiscus and Web of Science searched from 2001 to 2022. Data extracted included study design, population, definition of SRC diagnosis, outcome measure(s) and results.

ELIGIBILITY CRITERIA

(1) Original research, cohort studies, case-control studies, diagnostic accuracy and case series with samples >10; (2) SRC; (3) screening/technology that assessed SRC in the subacute period and (4) low risk of bias (ROB). ROB was performed using adapted Scottish Intercollegiate Guidelines Network criteria. Quality of evidence was evaluated using the Strength of Recommendation Taxonomy classification.

RESULTS

Of 9913 studies screened, 127 met inclusion, assessing 12 overlapping domains. Results were summarised narratively. Studies of acceptable (81) or high (2) quality were used to inform the SCOAT6, finding sufficient evidence for including the assessment of autonomic function, dual gait, vestibular ocular motor screening (VOMS) and mental health screening.

CONCLUSION

Current SRC tools have limited utility beyond 72 hours. Incorporation of a multimodal clinical assessment in the subacute phase of SRC may include symptom evaluation, orthostatic hypotension screen, verbal neurocognitive tests, cervical spine evaluation, neurological screen, Modified Balance Error Scoring System, single/dual task tandem gait, modified VOMS and provocative exercise tests. Screens for sleep disturbance, anxiety and depression are recommended. Studies to evaluate the psychometric properties, clinical feasibility in different environments and time frames are needed.

PROSPERO REGISTRATION NUMBER

CRD42020154787.

When should an athlete retire or discontinue participating in contact or collision sports following sport-related concussion? A systematic review

OBJECTIVE

To systematically review the scientific literature regarding factors to consider when providing advice or guidance to athletes about retirement from contact or collision sport following sport-related concussion (SRC), and to define contraindications to children/adolescent athletes entering or continuing with contact or collision sports after SRC.

DATA SOURCES

Medline, Embase, SPORTSDiscus, APA PsycINFO, CINAHL and Cochrane Central Register of Controlled Trials were searched systematically.

STUDY ELIGIBILITY CRITERIA

Studies were included if they were (1) original research, (2) reported on SRC as the primary source of injury, (3) evaluated the history, clinical assessment and/or investigation of findings that may preclude participation in sport and (4) evaluated mood disturbance and/or neurocognitive deficits, evidence of structural brain injury or risk factors for increased risk of subsequent SRC or prolonged recovery.

RESULTS

Of 4355 articles identified, 93 met the inclusion criteria. None of the included articles directly examined retirement and/or discontinuation from contact or collision sport. Included studies examined factors associated with increased risk of recurrent SRC or prolonged recovery following SRC. In general, these were low-quality cohort studies with heterogeneous results and moderate risk of bias. Higher number and/or severity of symptoms at presentation, sleep disturbance and symptom reproduction with Vestibular Ocular Motor Screen testing were associated with prolonged recovery and history of previous concussion was associated with a risk of further SRC.

CONCLUSION

No evidence was identified to support the inclusion of any patient-specific, injury-specific or other factors (eg, imaging findings) as absolute indications for retirement or discontinued participation in contact or collision sport following SRC.

PROSPERO REGISTRATION NUMBER

CRD42022155121.

Association of Sleep Disturbance With Neurocognition, Symptom Severity, and Recovery in Pediatric Concussion: A 10-Year Retrospective Analysis of a Tertiary Referral Concussion Clinic

OBJECTIVES

To investigate the relationship between sleep disturbance, neurocognition, symptom severity, and recovery in children and adolescents with concussion. Sex-related comparisons were also examined.

SETTING

Pediatric tertiary referral concussion clinic.

PARTICIPANTS

Children and adolescents (aged 6-18 years; n = 554) diagnosed with concussion.

DESIGN

Cross-sectional retrospective study.

MAIN MEASURES

Assessment data were obtained from Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) Applications. Sleep disturbance was quantified using the sleep-related domains of the Post-Concussion Symptom Scale (PCSS) and self-report sleep duration. Sleep duration was categorized as short (<7 hours), intermediate (7-9 hours), and long (≥9 hours). Outcome measures included neurocognition, measured via composite scores of ImPACT cognitive domains (verbal memory, visual memory, visual motor speed, reaction time); symptom severity, using the PCSS; and concussion recovery time (days).

RESULTS

Short sleep resulted in significantly poorer verbal memory ( P = .03), visual memory ( P = .02), and reaction time ( P = .01). Sleep disturbance was strongly associated with total symptom burden (ρ = 0.90, P < .001). Recovery time, median (interquartile range), was significantly prolonged with short sleep, 61 (30-136) days, compared with intermediate, 38 (21-72) days, and long, 34 (19-71) days, sleep ( P < .001). Overall, female participants demonstrated significantly longer recovery times than male participants (mean 91 ± 95 vs 58 ± 85 days, P < .001). Females exhibited similar concussion recovery times irrespective of reported sleep duration ( P = .95), whereas mean recovery time in males was significantly longer with short sleep (84 ± 82 days) than with intermediate (61 ± 106 days) and long (49 ± 62 days) sleep ( P < .001).

CONCLUSION

Sleep disturbance following concussion poses as a promising modifiable risk factor to alleviate postinjury impairments, including cognitive deficits and symptom burden. Female children were found to experience more severe concussion symptoms and protracted recovery times than their male counterparts. Investigations into the factors that may contribute to sex-related differences following concussion are warranted.

Primary and Secondary Risk Factors Associated With Concussion Symptom Clusters in Collegiate Athletes: Results From the NCAA-DoD Grand Alliance CARE Consortium

Background

There is a broad and diverse range of symptoms after a concussion, from irritability to nausea. This heterogeneity of symptoms is a challenge for clinicians managing the different presentations among injuries. Prior research has investigated the structure of postconcussive symptoms to determine if they can be grouped into clusters of related symptoms.

Purpose/Hypothesis

The purpose of this study was to identify symptom clusters during the acute phase after a sports-related concussion using exploratory factor analysis and to understand the relationship between risk factors for postconcussion symptoms (ie, demographics, injury characteristics, mental health, and sleep qualities) and different symptom clusters. We hypothesized that certain factors would be predictive of specific symptom clusters.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Collegiate athletes (N = 1104) from the Concussion, Assessment, Research, and Education (CARE) Consortium completed the Sport Concussion Assessment Tool-Third Edition symptom assessment tool 24 to 48 hours after concussion. Exploratory factor analysis was conducted on the symptom evaluation to determine symptom clusters 24 to 48 hours after concussion. Regression analysis was used to examine the effects of pre- and postinjury characteristics.

Results

Exploratory factor analysis revealed a 4-cluster structure for acute postconcussive symptoms that explained 62% of the variance in symptom reporting: vestibular-cognitive, migrainous, cognitive fatigue, and affective. Delayed reporting, less sleep before assessment, female sex, and being hurt outside of competition (during practice/training) was correlated with increased symptoms for 4 symptom clusters. Depression predicted higher vestibular-cognitive and affective symptoms. Amnesia was correlated with higher vestibular-cognitive and migrainous symptoms, whereas migraine history was associated with more migrainous and affective symptoms.

Conclusion

Symptoms can be grouped into 1 of 4 distinct clusters. Certain variables were associated with increased symptoms across multiple clusters and may be indicative of greater injury severity. Other factors (ie, migraine history, depression, amnesia) were associated with a more specific symptom presentation and may be mechanistically related to concussion outcomes and biological markers.

Effect of Sleep-Related Symptoms on Recovery From a Sport-Related Concussion

Background

Sleep issues are commonly reported in athletes after a sport-related concussion (SRC). Further studies are needed to evaluate screening methods for sleep disturbances and the risk of persisting symptoms after an SRC.

Purpose

To evaluate the association between the Sport Concussion Assessment Tool 5 (SCAT5) symptoms of trouble falling asleep, fatigue (or low energy), and drowsiness and the risk of persisting symptoms (≥28 days to recovery) in adolescent athletes.

Study Design

Cohort study; Level of evidence, 3.

Methods

A total of 519 athletes aged 13 to 18 years reported any sleep-related symptoms with an SRC, scored as none (0), mild (1-2), moderate (3-4), or severe (5-6), at their initial office visit (median, 5.4 days after an SRC). Scores were correlated with the risk of persisting symptoms. A composite "sleep cluster" score (range, 0-18) was calculated by summing the SCAT5 component items for trouble falling asleep, fatigue, and drowsiness.

Results

The results indicated that, compared with athletes who reported that they did not have each symptom, (1) athletes who reported mild, moderate, or severe trouble falling asleep were 3.0, 4.6, and 6.7 times more likely to have persisting symptoms, respectively; (2) athletes reporting mild, moderate, or severe fatigue (or low energy) were 2.6, 4.8, and 7.6 times more likely to have persisting symptoms, respectively; and (3) athletes reporting mild, moderate, or severe drowsiness were 1.9, 4.6, and 6.8 times more likely to have persisting symptoms, respectively (P < .001 for all). For every 1-point increase in the sleep cluster score, there was a 1.2-fold increased risk of persisting symptoms and an additional 2.4 days of recovery required (P < .001 for both).

Conclusion

Athletes who reported mild, moderate, or severe sleep-related symptoms on the SCAT5 were at a proportionally increased risk of persisting symptoms at the initial office visit.

Norm-Based Cutoffs as Predictors of Prolonged Recovery After Adolescent Sport-Related Concussion

OBJECTIVES

To identify predictors of prolonged recovery (ie, >28 days) using patient demographic factors and healthy, norm-based cutoffs on a multimodal test battery in adolescents after sport-related concussions (SRCs).

DESIGN

Retrospective cohort. Patients were deemed recovered after successful completion of return-to-play/school protocols and received medical clearance.

SETTING

Community concussion clinic.

PATIENTS

Male and female adolescent student athletes diagnosed with a SRC and evaluated within 1 week of injury.

INDEPENDENT VARIABLES

Patient demographics, medical history, injury description, computerized neurocognitive testing, vestibular/ocular testing, and symptoms at initial clinical visit.

MAIN OUTCOME MEASURES

Performance on clinical testing to predict recovery duration, classified as normal (<28 days) or prolonged (>28 days).

RESULTS

A total of 201 adolescent student athletes (age = 15.3 ± 1.4 years) were included (female 35%). Average recovery duration for the entire cohort was 22.3 ± 13.3 days, with 22% (n = 45) of adolescent student athletes taking >28 days to recover. The final model was 88.3% accurate in classifying normal and prolonged recovery. Predictor variables included sex, loss of consciousness, history of ocular disorder, history of concussion, performance on visual motor speed composite, visual motion sensitivity symptom provocation and near point of convergence distance, number-naming total time, and symptom count.

CONCLUSIONS

These findings suggest that using norm-based cutoffs from cognitive, oculomotor, and vestibulo-ocular testing and symptom reporting, clinicians can accurately predict a prolonged recovery (sensitivity = 81%) and normal recovery (specificity = 83%) in an adolescent, SRC cohort.

Sleep Dysfunction in Adolescents With Prolonged Postconcussion Symptoms: A Reciprocal Coupling of Traumatic Brain Injury and Sleep-Related Problems

CLINICAL SCENARIO

Concussions are often neglected injuries that affect children and adolescents. Two physiological responses to a concussion are an ionic flux and an increased indiscriminate release of glutamate, which leads to an increase of intracellular calcium and extracellular potassium. This can ultimately result in sleep dysfunction, which often occurs after concussion and has long been thought of as simply another concussion symptom.

FOCUSED CLINICAL QUESTION

Does the likelihood of prolonged postconcussion symptoms increase with reported sleep-related problems (SRPs) in young athletes (8-18 y) compared to concussed young athletes without SRPs and healthy controls?

SUMMARY OF KEY FINDINGS

Four cohort studies with level 2/3 evidence measured subjective and objective sleep dysregulations in concussed and healthy populations. Overall, there was a difference in subjective SRPs between concussed and healthy patients. This correlated with other studies where worse sleep scores during the acute phase of concussion and increased SRPs led to worse ImPACT scores in patients 3 to 12 months postconcussion and longer overall recovery. Objective sleep dysfunction measures were significantly worse in concussed patients than in healthy controls, but no significant difference existed in melatonin measures.

CLINICAL BOTTOM LINE

There is strong evidence that sleep dysfunction is both a symptom of concussion as well as a causal factor of prolonged postconcussion symptoms. These studies show that sleep dysregulation is not always evident in objective measurements, leading to the strong possibility of a functional dysregulation of the sleep-wake cycle that is evident solely from subjective reports.

STRENGTH OF RECOMMENDATION

While there are strong cohort studies researching the role of sleep in those with postconcussion symptoms, the nature of sleep studies prevents the production of strong, high-level evidence studies such as randomized control trials. Thus, there is level B evidence that the likelihood of prolonged postconcussion symptoms is increased by a higher amount of SRPs.

Characterizing Sleep and Wakefulness in the Acute Phase of Concussion in the General Population: A Naturalistic Cohort from the Toronto Concussion Study

Growing literature links concussion to changes in sleep and wakefulness in humans and in rodent models. Sleep has been linked with synaptic reorganization under other conditions; however, the characterization and role of sleep after acute concussion remains poorly understood. While much research has focused on insomnia among patients with chronic or persistent concussion symptoms, there is limited understanding of sleep and acute concussion, its potential role in recovery, and associated risk factors for the development of chronic sleep disturbance. Studies to date are limited by small sample sizes of primarily athlete or military populations. Additional studies among the general population are critical to inform best practice guidelines. We examined the sleep and daytime wakefulness of 472 adults from a naturalistic general population cohort (mean age, 33.3 years, females = 60.8%) within seven days of diagnosed concussion, using a validated, condition-specific measure, the Sleep and Concussion Questionnaire. Participants identified immediate changes in sleep characterized by hypersomnia and difficulty maintaining daytime wakefulness; 35% considered these changes as moderate to severe and 79% required monitoring or follow-up. Females experienced significantly greater severity of changes in sleep compared with males. Positive correlations between severity of sleep and pain and headache were identified. Differences by sex are an important consideration for early intervention and long-term monitoring. Because sleep was compromised by pain, pain management is also an integral part of early intervention. Our findings suggest that assessment of sleep beginning in the acute stage is a critical component of concussion management in the general population.

Influence of Sleep Dysfunction on Concussion Assessment Outcomes Among Adolescent Athletes After Concussion and Healthy Controls

BACKGROUND

Sleep dysfunction (SD) is associated with a high symptom burden and lower neurocognitive performance after concussion and on baseline testing without injury. However, few studies have compared concussed athletes and controls with and without SD on clinical outcomes.

OBJECTIVE

To evaluate differences in clinical outcomes among both concussed athletes and matched controls with and without SD.

DESIGN

Retrospective cross-sectional study.

PARTICIPANTS

Participants aged 12 to 20 years were recruited from a concussion clinic (n = 50 patients) and research registry/flyers (n = 50 healthy age-/sex-matched controls). Participants were categorized by self-reported SD into one of 4 groups: sport-related concussion (SRC) + SD, SRC only, SD only, and controls.

MAIN OUTCOME MEASURES

Post-Concussion Symptom Scale (PCSS), Vestibular/Oculomotor Screening (VOMS), and neurocognitive testing (Immediate Postconcussion Assessment Cognitive Test).

RESULTS

Compared with the SRC only group, the SRC + SD group performed worse on all neurocognitive domains, had a higher total symptom score, and endorsed more symptoms on most VOMS items. In addition, the SRC + SD group was at an increased likelihood of having at least 1 abnormal VOMS item compared with SRC only group. The SRC only group had neurocognitive test scores and symptom reports statistically similar to the SD only group.

CONCLUSION

Sleep dysfunction after concussion is related to worse neurocognitive performance and higher concussion symptom reporting. This study extended findings to suggest vestibular symptomology is worse among athletes with SD after injury compared to injured athletes without SD. Similar performances on concussion assessments for the SRC only and SD only groups suggest SD may appear similar to clinical presentation of concussion, even at baseline in the absence of SRC.

Link between Mild Traumatic Brain Injury, Poor Sleep, and Magnetic Resonance Imaging: Visible Perivascular Spaces in Veterans

Impaired clearance of perivascular waste in the brain may play a critical role in morbidity after mild traumatic brain injury (mTBI). We aimed to determine the effect of mTBI on the burden of magnetic resonance imaging (MRI)-visible perivascular spaces (PVSs) in a cohort of U.S. military veterans and whether sleep modulates this effect. We also investigated the correlation between PVS burden and severity of persistent post-concussive symptoms. Fifty-six Iraq/Afghanistan veterans received 3 Tesla MRI as part of a prospective cohort study on military blast mTBI. White matter PVS burden (i.e., number and volume) was calculated using an established automated segmentation algorithm. Multi-variate regression was used to establish the association between mTBIs sustained in the military and PVS burden. Covariates included age, blood pressure, number of impact mTBIs outside the military, and blast exposures. Correlation coefficients were calculated between PVS burden and severity of persistent post-concussive symptoms. There was a significant positive relationship between the number of mTBIs sustained in the military and both PVS number and volume (p = 0.04). A significant interaction was found between mTBI and poor sleep on PVS volume (p = 0.04). A correlation was found between PVS number and volume, as well as severity of postconcussive symptoms (p = 0.03). Further analysis revealed a moderate correlation between PVS number and volume, as well as balance problems (p < 0.001). In Iraq/Afghanistan veterans, mTBI is associated with an increase in PVS burden. Further, an interaction exists between mTBI and poor sleep on PVS burden. Increased PVS burden, which may indicate waste clearance dysfunction, is associated with persistent post-concussive symptom severity.

Making a Difference: Affective Distress Explains Discrepancy Between Objective and Subjective Cognitive Functioning After Mild Traumatic Brain Injury

OBJECTIVE

To assess the relationship between subjective cognitive symptoms and objective cognitive test scores in patients after concussion. We additionally examined factors associated with subjective and objective cognitive dysfunction, as well as their discrepancy.

PARTICIPANTS

Eighty-six individuals (65.1% female; 74.4% adult) from an interdisciplinary concussion clinic.

METHODS

Subjective and objective cognitive functioning was measured via the SCAT-Symptom Evaluation and the CNS Vital Signs Neurocognition Index (NCI), respectively. Cognitive discrepancy scores were derived by calculating standardized residuals (via linear regression) using subjective symptoms as the outcome and NCI score as the predictor. Hierarchical regression assessed predictors (age, education, time postinjury, attention-deficit/hyperactivity disorder, affective distress, and sleep disturbance) of cognitive discrepancy scores. Nonparametric analyses evaluated relationships between predictor variables, subjective symptoms, and NCI.

RESULTS

More severe affective and sleep symptoms (large and medium effects), less time postinjury (small effect), and older age (small effect) were associated with higher subjective cognitive symptoms. Higher levels of affective distress and less time since injury were associated with higher cognitive discrepancy scores (β = .723, P < .001; β = -.204, P < .05, respectively).

CONCLUSION

Clinical interpretation of subjective cognitive dysfunction should consider these additional variables. Evaluation of affective distress is warranted in the context of higher subjective cognitive complaints than objective test performance.

Association Between Preinjury Symptoms and Postconcussion Symptoms at 4 Weeks in Youth

OBJECTIVE

To investigate whether preinjury physical, emotional, cognitive, and sleep symptoms on the Post-Concussion Symptoms Inventory (PCSI) are associated with persistent postconcussion symptoms (PPCS) at 4 weeks and whether any associations are moderated by sex or age.

STUDY SETTING AND PARTICIPANTS

A total of 3063 participants with acute concussion, presenting to 9 Canadian pediatric emergency departments, were enrolled from August 2013 to June 2015.

DESIGN

A planned secondary analysis of a prospective, multicenter cohort study (Predicting Persistent Post-concussive Problems in Pediatrics or 5P). Primary outcome was PPCS at 4 weeks, defined as 3 or more new or worsening individual symptoms compared with the preinjury score at 28 days on the PCSI. The association between preinjury scores and PPCS was analyzed with a multivariable logistic regression analysis that included preinjury, sex, age, sex × preinjury, and age × preinjury interactions as predictors. Missing baseline covariates were imputed.

RESULTS

A total of 2123 (n = 844 [39.8%] girls; median [IQR] age = 12.9 [10.7, 15.0] participants were included in the analysis. Preinjury physical symptom score was associated with PPCS at 4 weeks (χ2 = 13.87, df = 6, P = .031). The preinjury emotional score also contributed to the variability in PPCS (χ2 = 11.79, df = 6, P = .067). While girls reported higher preinjury physical, emotional, and cognitive scores than boys, neither sex nor age interacted with preinjury to predict PPCS at 4 weeks. Independent of age and sex, preinjury physical symptoms were associated with PPCS at 4 weeks (OR = 1.40; 95% CI, 1.15-1.70).

CONCLUSION

Preinjury physical symptoms are associated with the probability of having PPCS at 4 weeks postconcussion independent of age and sex. Providers should consider preinjury symptoms to inform prognosis and recovery management.

Is the glymphatic system the missing link between sleep impairments and neurological disorders? Examining the implications and uncertainties

Until recently, both the purpose of the biological need for sleep and the mechanism by which the central nervous system eliminated metabolic waste products were unknown. The glymphatic system is the recently discovered macroscopic waste clearance system for the CNS, which predominantly functions during sleep states. Important implications for the glymphatic system exist for a significant proportion of neurological disorders, including traumatic brain injury, epilepsy, stroke, migraine, and Alzheimer's disease. Within the limited amount of research pertaining to this novel system there exists controversy regarding several of the key structural and functional aspects of the glymphatic system. In this review we address evidence from both standpoints regarding the prominent debates surrounding the glymphatic system, including the functional differences in wakefulness vs. sleep, the role of glial aquaporin-4 water channels, and whether it reflects a convective flow or a passive diffusion process. The answers that underlie these questions will have crucial and distinct outcomes for the future of the glymphatic system and the disorders it has been implicated in. However, this review also summarizes the potential role of the glymphatic system in the development and progression of the aforementioned neurological disorders. Furthermore, the possible contribution of the orexinergic system to this relationship between the glymphatic system, sleep, and these neurological disorders is also explored. Overall, in order to develop and utilize therapeutic interventions centred around the glymphatic system we must first dedicate further investigation to elucidating these discrepancies and unanswered questions.

Increased Risk of Musculoskeletal Injury Following Sport-Related Concussion: A Perception-Action Coupling Approach

Recent studies have concluded that athletes have increased risk of musculoskeletal injury following sport-related concussion. While an underlying explanation is still unknown, perceptual-motor control may be implicated in this increased risk. Some authors have purported that indirect perception (i.e., a "top-down" view of neuromuscular control) may be disrupted following sport-related concussion. Direct perception theory states that the athlete and environment are inextricably linked in a continuous perception-action coupling loop. That is, the athlete is able to directly perceive opportunities for action (e.g., "affordances") in the environment. Based on these notions, the aim of the current paper was to introduce a theoretical model that argues that sport-related concussion may dysregulate the direct perception process, potentially increasing behavioral risk of musculoskeletal injury during sport. Our model is integrated with a sport-related concussion clinical treatment model, which highlights individualized profiles that characterize the heterogeneous response to sport-related concussion. These profiles have a typical constellation of symptoms (e.g., anxiety, fatigue, ocular dysfunction, etc.), which themselves have been associated with disrupted perception-action coupling, independent of sport-related concussion. Therefore, we argue that athletes who have not re-established perception-action coupling loops following sport-related concussion may be at increased risk of subsequent musculoskeletal injury.

Association of sleep symptoms with mood and vestibular subtypes following sport-related concussion

Sport-related concussion (SRC) is a heterogenous injury with diverse symptoms and impairments that can be aggregated into clinical subtypes (cognitive, headache/migraine, vestibular, ocular-motor, anxiety/mood). Sleep disruption has been defined as potential exacerbating conditions that may accompany the five clinical subtypes. The authors sought to better characterize the role of impaired sleep in each clinical subtype and to identify other risk factors for sleep impairment after SRC. 281 patients (15.3 ± 2.1 years) aged 10-22 years within 21 days of SRC completed the Post-Concussion Symptom Scale (PCSS), the Vestibular/Ocular Motor Screening (VOMS), and a clinical assessment to identify clinical subtype. Subjects were then divided into HIGH (≥7; n = 82) and LOW (≤3; n = 132) sleep symptom groups for comparison. HIGH participants had greater proportions of females (p < 0.001), history of psychiatric disorder (p < 0.001); total PCSS (p < 0.001); and impairment on all VOMS items (p < 0.001). HIGH participants were associated with mood/anxiety (p < 0.001), vestibular (p = 0.003) and ocular (p = 0.03) subtypes. Results of a logistic regression (LR) model with adjusted odds ratios (OR) to predict HIGH sleep symptoms supported anxiety/mood profile (OR = 2.98), vestibular profile (OR = 2.81), psychiatric history (OR = 4.99), and history of motion sickness (OR = 2.13) as significant predictors. Prescribing behavioral and sleep interventions may improve outcomes in cases where these factors co-occur.

Sleep and stress in the acute phase of concussion in youth

This study sought to address the complex interplay between both biological and psychological perceptions of stress and sleep in the acute stages following a mild traumatic brain injury. A secondary goal was to identify potential targets for intervention. Eleven acutely injured youth (mean age 12 years) were studied at home with overnight actigraphy, salivary cortisol and melatonin assays, and subjective ratings of stress and fatigue (injured group). Nine matched control youth also were assessed (control group). Results suggested longer sleep latencies (time to fall asleep) and higher levels of fatigue in the injured group exist (p = 0.025 and p = 0.004, respectively). In the injured group, stress and sleep onset were significantly related with most subjects meeting criteria for Acute Stress Disorder. Melatonin levels were lower at bedtime in the injured group. Saliva samples were collected via passive drool at three time points: ∼1 h before bed ("bedtime" or T1), immediately upon waking (time 2: T2), and 30 min post-waking (time 3: T3). Overnight increases in cortisol (T1 to T2) were greater for the injured group; however, post-sleep changes in cortisol (T2 to T3) were reversed with control concentrations increasing. These findings are unique in using actigraphy and salivary hormone levels in an acutely injured youth while in their homes. The differences in sleep latency and the presence of injury-related stress point to potential treatment targets in acute concussion.

Sleep Disturbances in the Acute Stage of Concussion are Associated With Poorer Long-Term Recovery: A Systematic Review

OBJECTIVE

To examine the association between sleep during the acute stage of concussion and long-term outcomes.

LITERATURE SURVEY

Literature searches were performed 1 July 2018 to 1 August 2018 in Ovid MEDLINE, CINAHL, and Web of Science, along with hand searching for gray literature and cited references. Of the 610 search results, 359 unique references were reviewed after duplicates were removed.

METHODOLOGY

Two reviewers independently reviewed and came to consensus on which titles/abstracts met inclusion/exclusion criteria (n = 23). The 23 full-text articles were assessed independently by the same two reviewers for eligibility. Consensus was achieved, leaving four articles for quality assessment and data extraction. One person extracted relevant data from each study using a standard data-extraction table. The data extraction table was reviewed by two reviewers and consensus was achieved for completeness and accuracy. Quality appraisal was conducted to assess the risk for potential bias and quality of included articles.

SYNTHESIS

Two of the articles included children younger than 16 years old and two included a wide age range. In general, poorer sleep was associated with poorer outcomes following concussion at reassessments across any age population. In addition, poorer sleep in the acute stage of concussion was associated with poorer long-term outcomes and recovery.

CONCLUSIONS

The variability in sleep assessments used, symptoms assessed, length of time to reassessments, and comparator group included made data synthesis challenging. The use of standard valid and reliable sleep assessments is recommended. Future studies may consider if addressing sleep disturbances early following concussion will improve longer-term outcomes.

Repetitive Mild Traumatic Brain Injury Alters Glymphatic Clearance Rates in Limbic Structures of Adolescent Female Rats

The glymphatic system is the macroscopic waste clearance system for the central nervous system. Glymphatic dysfunction has been linked to several neurological conditions, including traumatic brain injury (TBI). Adolescents are at particularly high risk for experiencing a TBI, particularly mild TBI (mTBI) and repetitive mTBI (RmTBI); however, glymphatic clearance, and how it relates to behavioral outcomes, has not been investigated in this context. Therefore, this study examined glymphatic function in the adolescent brain following RmTBI. Female adolescent Sprague Dawley rats were subjected to either three mTBIs or sham injuries spaced three days apart. One-day after their final injury, the animals underwent a beam walking task to assess sensorimotor function, and contrast-enhanced MRI to visualize glymphatic clearance rate. Behavioural measures indicated that the RmTBI group displayed an increase in loss of consciousness as well as motor coordination and balance deficits consistent with our previous studies. The contrast-enhanced MRI results indicated that the female adolescent glymphatic system responds to RmTBI in a region-specific manner, wherein an increased influx but reduced efflux was observed throughout limbic structures (hypothalamus, hippocampus, and amygdala) and the olfactory bulb but neither the influx or efflux were altered in the cortical structures (primary motor cortex, insular cortex, and dorsolateral prefrontal cortex) examined. This may indicate a role for an impaired and/or inefficient glymphatic system in the limbic structures and cortical structures, respectively, in the development of post-concussive symptomology during adolescence.

A Longitudinal Investigation of Sleep and Daytime Wakefulness in Children and Youth With Concussion

A high proportion of adults who sustain a concussion identify changes in their sleep during the acute stage, typically reporting an increased need for sleep or nonrestful sleep. Our understanding of sleep following concussion is less well understood within a pediatric population. In this study, we investigated the trajectory of sleep and daytime sleepiness in a prospective cohort of 40 children and youth (6-18 years old) with concussion, 40 age-and sex-matched healthy children and youth, and 40 with upper-extremity orthopedic injury. Evaluations occurred during the acute stage (<2 weeks) and at 3-, 6-, and 12-month postinjury using the Sleep Disturbance Scale for Children and the Postconcussion Symptom Scale. There were no significant differences within- or between-group differences in sleep across all four time points with analysis of the groups as a whole. When groups were divided by age (6-11 and 12- < 18 years), there was a significant difference in the ability to initiate sleep for the younger concussed group during the acute stage, compared with healthy controls, as well as significantly greater daytime nap duration that decreased over time. Significant correlations were also found between the frequency and duration of daytime naps and Postconcussion Symptom Scale total score and subscores (cognitive, physical/migraine, mood, and sleep) in the concussed group during the acute stage. Our results suggest that in a group with noncomplicated concussion, children and youth have transient alterations in daytime sleepiness that are related to concussion symptoms. Younger children may be more vulnerable to disturbances in sleep and daytime wakefulness.

Utility of Brief Psychological Measures for Prediction of Prolonged Symptom Clearance in Concussed Student Athletes

Objective

Variability in recovery time following sport-related concussion (SRC) is poorly understood. We explored the utility of brief mood, anxiety, and sleep questionnaires as postinjury predictors of SRC symptom clearance in adolescents.

Method

At initial visit 0–2 weeks postinjury, concussed athletes aged 12–18 years self-reported injury/medical factors (prior concussion, loss of consciousness, amnesia, and concussion symptom severity) and were administered psychological symptom measures. At 3 months, medical record review determined return-to-play (RTP) date. Subjects were divided into two datasets, with the first utilized for developing cutoff scores and then validated with the second dataset.

Results

A total of 64% of the 141 participants had early RTP (within 21 days postinjury), and 23% had late RTP (postinjury day 30 or later). The Generalized Anxiety Disorder Screener (GAD-7, M = 2.1, SD = 3.1) was the only significant predictor (p = .001), with a 1.4-fold [95% CI 1.2–1.8] increased risk for every point. No other factors in the full model discriminated recovery groups (ps &gt; .05). Receiver operating characteristic curve analysis derived a GAD-7 cut score ≥3 (sensitivity= 56.7%, specificity = 74.2%, AUCs = 0.63–0.79, ps &lt; .001).

Conclusions

Postconcussion anxiety symptoms may help identify individuals at increased risk for prolonged recovery.

Association Between Sleep Quality and Recovery Following Sport-Related Concussion in Pediatrics

Our objective was to determine the association between sleep quality, symptom severity, and recovery following sport-related concussion in pediatric athletes. A review of data from the North Texas Concussion Network Prospective Registry (ConTex) was performed. Participants were diagnosed with a sport-related concussion and were ≤18 years old. Participants were categorized based on their initial clinic visit Pittsburgh Sleep Quality Index composite score (0-21) into good sleep quality (GS≤5) and poor sleep quality (PS>5) groups. The PS group reported higher median total symptom scores at 3-month follow-up (3.0 vs 0.0, P < .01) and took more than a median of 2 weeks longer to recover compared to the GS group (35.0 days vs 20.0 days, P < .01). Poor sleep quality was strongly associated with greater symptom severity and longer time to recovery following sport-related concussion. Early recognition of concussed athletes with poor sleep quality at initial clinic visit may help predict prolonged recovery.

Acute Post-Traumatic Sleep May Define Vulnerability to a Second Traumatic Brain Injury in Mice

Chronic neurological impairments can manifest from repetitive traumatic brain injury (rTBI), particularly when subsequent injuries occur before the initial injury completely heals. Herein, we apply post-traumatic sleep as a physiological biomarker of vulnerability, hypothesizing that a second TBI during post-traumatic sleep worsens neurological and histological outcomes compared to one TBI or a second TBI after post-traumatic sleep subsides. Mice received sham or diffuse TBI by midline fluid percussion injury; brain-injured mice received one TBI or rTBIs at 3- or 9-h intervals. Over 40 h post-injury, injured mice slept more than shams. Functional assessments indicated lower latencies on rotarod and increased Neurological Severity Scores for mice with rTBIs within 3 h. Anxiety-like behaviors in the open field task were increased for mice with rTBIs at 3 h. Based on pixel density of silver accumulation, neuropathology was greater at 28 days post-injury (DPI) in rTBI groups than sham and single TBI. Cortical microglia morphology was quantified and mice receiving rTBI were de-ramified at 14 DPI compared to shams and mice receiving a single TBI, suggesting robust microglial response in rTBI groups. Orexin-A-positive cells were sustained in the lateral hypothalamus with no loss detected, indicating that loss of wake-promoting neurons did not contribute to post-traumatic sleep. Thus, duration of post-traumatic sleep is a period of vulnerability that results in exacerbated injury from rTBI. Monitoring individual post-traumatic sleep is a potential clinical tool for personalized TBI management, where regular sleep patterns may inform rehabilitative strategies and return-to-activity guidelines.

Natural Progression of Symptom Change and Recovery From Concussion in a Pediatric Population

IMPORTANCE

The natural progression of symptom change and recovery remains poorly defined in children after concussion.

OBJECTIVES

To describe the natural progression of symptom change by age group (5-7, 8-12, and 13-18 years) and sex, as well as to develop centile curves to inform families about children after injury recovery.

DESIGN, SETTING, AND PARTICIPANTS

Planned secondary analysis of a prospective multicenter cohort study (Predicting Persistent Postconcussive Problems in Pediatrics). The setting was 9 pediatric emergency departments within the Pediatric Emergency Research Canada (PERC) network. Participants were aged 5 to 18 years with acute concussion, enrolled from August 1, 2013, to May 31, 2015, and data analyses were performed between January 2018 and March 2018.

EXPOSURES

Participants had a concussion consistent with the Zurich Consensus Statement on Concussion in Sport diagnostic criteria and 85% completeness of the Postconcussion Symptom Inventory (PCSI) at each time point.

MAIN OUTCOMES AND MEASURES

The primary outcome was symptom change, defined as current rating minus preinjury rating (delta score), at presentation and 1, 2, 4, 8, and 12 weeks after injury, measured using the PCSI. Symptoms were self-rated for ages 8 to 18 years and rated by the child and parent for ages 5 to 7 years. The secondary outcome was recovery, defined as no change in symptoms relative to current preinjury PCSI ratings (delta score = 0). Mixed-effects models incorporated the total score, adjusting for random effects (site and participant variability), fixed-effects indicators (age, sex, time, age by time interaction, and sex by time interaction), and variables associated with recovery. Recovery centile curves by age and sex were computed.

RESULTS

A total of 3063 children (median age, 12.0 years [interquartile range, 9.2-14.6 years]; 60.7% male) completed the primary outcome; 2716 were included in the primary outcome analysis. For the group aged 5 to 7 years, symptom change primarily occurred the first week after injury; by 2 weeks, 75.6% of symptoms had improved (PCSI change between 0 and 2 weeks, -5.3; 95% CI, -5.5 to -5.0). For the groups aged 8 to 12 years and 13 to 18 years, symptom change was prominent the first 2 weeks but flattened between 2 and 4 weeks. By 4 weeks, 83.6% and 86.2% of symptoms, respectively, had improved for the groups aged 8 to 12 years (PCSI change between 0 and 4 weeks, -9.0; 95% CI, -9.6 to -8.4) and 13 to 18 years (PCSI change between 0 and 4 weeks, -28.6; 95% CI, -30.8 to -26.3). Sex by time interaction was significant only for the adolescent group (β = 0.32; 95% CI, 0.21-0.43; P < .001). Most adolescent girls had not recovered by week 12.

CONCLUSIONS AND RELEVANCE

Symptom improvement primarily occurs in the first 2 weeks after concussion in children and in the first 4 weeks after concussion in preadolescents and male adolescents. Female adolescents appear to have protracted recovery. The derived recovery curves may be useful for evidence-based anticipatory guidance.