Prefrontal Cortex Activity During Gait in People With Persistent Symptoms After Concussion.

BACKGROUND: Concussions result in transient symptoms stemming from a cortical metabolic energy crisis. Though this metabolic energy crisis typically resolves in a month, symptoms can persist for years. The symptomatic period is associated with gait dysfunction, the cortical underpinnings of which are poorly understood. Quantifying prefrontal cortex (PFC) activity during gait may provide insight into post-concussion gait dysfunction. The purpose of this study was to explore the effects of persisting concussion symptoms on PFC activity during gait. We hypothesized that adults with persisting concussion symptoms would have greater PFC activity during gait than controls. Within the concussed group, we hypothesized that worse symptoms would relate to increased PFC activity during gait, and that increased PFC activity would relate to worse gait characteristics. METHODS: The Neurobehavior Symptom Inventory (NSI) characterized concussion symptoms. Functional near-infrared spectroscopy quantified PFC activity (relative concentration changes of oxygenated hemoglobin [HbO2]) in 14 people with a concussion and 25 controls. Gait was assessed using six inertial sensors in the concussion group. RESULTS: Average NSI total score was 26.4 (13.2). HbO2 was significantly higher (P = .007) for the concussed group (0.058 [0.108]) compared to the control group (-0.016 [0.057]). Within the concussion group, HbO2 correlated with NSI total symptom score (ρ = .62; P = .02), sagittal range of motion (r = .79; P = .001), and stride time variability (r = -.54; P = .046). CONCLUSION: These data suggest PFC activity relates to symptom severity and some gait characteristics in people with persistent concussion symptoms. Identifying the neurophysiological underpinnings to gait deficits post-concussion expands our knowledge of motor behavior deficits in people with persistent concussion symptoms.

Relationship between severity of concussion's symptoms and functional performance in children.

INTRODUCTION: Concussion is a common brain injury that has significant effects on multiple functional domains in children. However, limited research exists on the relationship between concussion severity and functional performance in this population. This study aimed to examine the relationship between the severity of concussion symptoms and children's balance and functional performance. METHODS: This cross-sectional study recruited 23 children (9 males and 14 females; mean age 13.9 ± 2.2 years) with clinically diagnosed concussions from a tertiary balance center in 2016. Participants underwent clinical and functional evaluations by specialized physical therapists. Symptom severity was assessed using the Post-Concussion Symptom Scale (PCSS), while functional performance was measured using the Functional Gait Assessment (FGA). RESULTS: There was a trend suggesting a negative correlation between symptom severity (PCSS) and functional performance (FGA), indicating potentially better performance in individuals with milder symptoms. However, this trend was not significant (rs (21) = -.072, p = 0.744). Furthermore, no significant correlation was found between FGA scores and the severity of individual symptoms. CONCLUSION: The findings suggest that concussion symptom severity may not be directly related to functional performance in children. Therefore, it is crucial to incorporate functional performance measures alongside symptom assessment for comprehensive concussion management.

Effects of phytocannabinoids on heart rate variability and blood pressure variability in female post-concussion syndrome patients: case series.

Cannabidiol (CBD) can exert neuroprotective effects without being intoxicating, and in combination with Δ9-tetrahydrocannabinol (THC) CBD has shown to protect against THC psychosis. Acute concussion and post-concussion syndrome (PCS) can result in autonomic dysfunction in heart rate variability (HRV), but less information is available on blood pressure variability (BPV). Furthermore, the effects of phytocannabinoids on HRV and BPV in PCS are unknown. The purpose of this study was to observe the influence of daily administration of CBD or a combination of CBD and THC on HRV and BPV parameters in four female PCS participants. Participants completed a seated 5-min rest followed by six breaths-per-minute paced breathing protocol. Data was collected prior to phytocannabinoid intake and continued over 54 to 70 days. High frequency systolic BPV parameter increased every assessment period, unless altered due to external circumstances and symptoms. HRV parameters showed less consistent and varying responses. These results suggest that CBD can help to improve the altered autonomic dysfunction in those with PCS, and that responses to the drug administration was individualized. Double blinded, randomized controlled trials with greater sample sizes are required to better understand the influences of the varying dosages on human physiology and in PCS.

Cerebrovascular Responses to O2-CO2 Exchange Ratio under Brief Breath-Hold Challenge in Patients with Chronic Mild Traumatic Brain Injury.

Breath-by-breath oxygen-carbon dioxide (O2-CO2) exchange ratio (bER) is a respiratory gas exchange (RGE) metric, which is the ratio of the changes in the partial pressure of O2 (ΔPO2) to CO2 (ΔPCO2) between end-inspiration and end-expiration, has been demonstrated to characterize the cerebrovascular responses to breath-hold challenge in healthy individuals. We aimed to explore whether bER could characterize cerebrovascular responses in patients with chronic mild traumatic brain injury (mTBI) under breath-hold challenge. We also investigated the correlation between bER and the severity of post-concussion symptoms. Blood-oxygenation-level-dependent (BOLD) images were acquired using functional magnetic resonance imaging (fMRI) on 10 patients with chronic mTBI and 10 controls without brain injury history when performing a breath-hold task. Time series of RGE metrics of ΔPO2, ΔPCO2, and bER were computed, and their cross-correlation with regional change in BOLD (ΔBOLD) was calculated. Symptom burden was assessed using the Rivermead Post Concussion Questionnaire (RPQ), and its correlation with RGE changes was also measured. Compared with controls, a diffuse decrease in the correlation between regional ΔBOLD and bER was found in the brain of patients with mTBI (pfdr < 0.05). No significant difference was found between patients and controls for the correlation of regional ΔBOLD with ΔPO2 and ΔPCO2. Symptom severity indicated by RPQ scores increased with a decrease in the averaged changes of bER (ρ = 0.79, p = 0.01) and ΔPO2 (ρ = 0.70, p = 0.03) in breath-hold epochs. Our imaging and symptom severity findings suggest that bER can be used to characterize cerebrovascular responses to breath hold in patients with mTBI. The RGE may contribute to the post-concussive symptom severity.

Characterizing Physical Activity and Sedentary Behavior in Adults With Persistent Postconcussive Symptoms After Mild Traumatic Brain Injury.

OBJECTIVE: To evaluate physical activity (PA) and sedentary behavior and their associations with symptom and quality of life outcomes in adults with persistent postconcussive symptoms (PPCS) after mild traumatic brain injury (mTBI). DESIGN: Cross-sectional cohort study. SETTING: Outpatient brain injury clinic. PARTICIPANTS: Consecutive sample of adults (N=180) with a diagnosis of mTBI and PPCS. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: PA and sedentary behavior were assessed using the Godin Leisure-Time Exercise Questionnaire and Rapid Assessment Disuse Index, respectively. Participants were dichotomized according to whether they completed 150 minutes of moderate-to-vigorous PA per week, based on Canadian guidelines. Postinjury moderate-to-vigorous PA was also analyzed as a continuous variable. RESULTS: Prior to injury, 85% of participants reported meeting PA guidelines, compared with 28% postinjury. Individuals meeting PA guidelines postinjury reported higher quality of life (η2p=0.130; P<.001) and lower scores on measures of functional impact of headache (η2p=0.065; P=.009), fatigue (η2p=0.080; P=.004), depression (η2p=0.085; P=.001), and anxiety (η2p=0.046; P=.031), compared with those not meeting guidelines. Sedentary behavior postinjury was negatively correlated with quality of life (rs[127]=-0.252; P=.004) and positively correlated with symptom burden (rs[167]=0.227; P=.003), fatigue (rs[127]=0.288; P=.001), depression (rs[174]=0.319; P<.001), and anxiety (rs[127]=0.180; P=.042). CONCLUSIONS: PA was significantly decreased in individuals with PPCS compared to preinjury levels. Meeting PA guidelines postinjury was associated with better clinical outcomes, suggesting that returning individuals to PA should be considered in the treatment of this patient population.

Effect of Collaborative Care on Persistent Postconcussive Symptoms in Adolescents: A Randomized Clinical Trial.

Importance: Despite the high level of impairment for adolescents with persistent postconcussive symptoms, few studies have tested whether such problems can be remediated. Objective: To examine whether collaborative care treatment is associated with improvements in postconcussive, quality of life, anxiety, and depressive symptoms over 1 year, compared with usual care. Design, Setting, and Participants: The Collaborative Care Model for Treatment of Persistent Symptoms After Concussion Among Youth II Trial was a randomized clinical trial conducted from March 2017 to May 2020 with follow-up assessments at 3, 6, and 12 months. Participants were recruited from pediatric primary care, sports medicine, neurology, and rehabilitation clinics in western Washington. Adolescents aged 11 to 18 years with a diagnosed sports-related or recreational-related concussion within the past 9 months and with at least 3 symptoms persisting at least 1 month after injury were eligible. Data analysis was performed from June to September 2020. Interventions: The collaborative care intervention included cognitive behavioral therapy and care management, delivered mostly through telehealth, throughout the 6-month treatment period, with enhanced medication consultation when warranted. The comparator group was usual care provided in specialty clinics. Main Outcomes and Measures: Primary outcomes were adolescents' reports of postconcussive, quality of life, anxiety, and depressive symptoms. Secondary outcomes were parent-reported symptoms. Results: Of the 390 eligible adolescents, 201 (51.5%) agreed to participate, and 200 were enrolled (mean [SD] age, 14.7 [1.7] years; 124 girls [62.0%]), with 96% to 98% 3- to 12-month retention. Ninety-nine participants were randomized to usual care, and 101 were randomized to collaborative care. Adolescents who received collaborative care reported significant improvements in Health Behavior Inventory scores compared with usual care at 3 months (3.4 point decrease; 95% CI, -6.6 to -0.1 point decrease) and 12 months (4.1 point decrease; 95% CI, -7.7 to -0.4 point decrease). In addition, youth-reported Pediatric Quality of Life Inventory scores at 12 months improved by a mean of 4.7 points (95% CI, 0.05 to 9.3 points) in the intervention group compared with the control group. No differences emerged by group over time for adolescent depressive or anxiety symptoms or for parent-reported outcomes. Conclusions and Relevance: Although both groups improved over time, youth receiving the collaborative care intervention had fewer symptoms and better quality of life over 1 year. Intervention delivery through telehealth broadens the reach of this treatment. Trial Registration: ClinicalTrials.gov Identifier: NCT03034720.

Effect of Video Discharge Instructions for Patients With Mild Traumatic Brain Injury in the Emergency Department: A Randomized Controlled Trial.

STUDY OBJECTIVE: We measure the effect of video discharge instructions on postconcussion symptoms in patients with mild traumatic brain injury in the emergency department. METHODS: A multicenter randomized controlled trial was conducted in which patients with mild traumatic brain injury were randomly assigned to either intervention (verbal, written, and video discharge information) or control (verbal and written discharge information only). All patients were interviewed 1 week and 3 months from randomization. Primary outcome measure was the Rivermead Post-Concussion Symptoms Questionnaire at 3 months. Secondary outcomes were correct recall, Hospital Anxiety and Depression Scale score, health-related quality of life (12-Item Short Form Health Survey), return visits, and patient satisfaction. RESULTS: A total of 2,883 patients were assessed for eligibility, of whom 381 were included in the control group and 390 in the video intervention group. Difference in mean total Rivermead Post-Concussion Symptoms Questionnaire score between the 2 groups was 0.2 at 1 week and 0.3 at 3 months after traumatic brain injury (estimated effect -0.7; 95% confidence interval -2.1 to 0.7). There was also no difference in Hospital Anxiety and Depression Scale score, recall, 12-Item Short Form Health Survey score, return visits, and patient satisfaction between the control and intervention group. CONCLUSION: Severity of postconcussion symptoms in patients with mild traumatic brain injury did not improve by adding video information to standard care. Also, there was no difference in recall, health-related quality of life, return visits, and patient satisfaction between the control and intervention groups.

Neurocognitive Outcomes and Their Diffusion Tensor Imaging Correlates in Children With Mild Traumatic Brain Injury.

This study aimed to assess the neurocognitive outcomes and their diffusion tensor imaging correlates in children (aged 6-16 years) with mild traumatic brain injury. This prospective analysis included 74 children with mild traumatic brain injury (52 boys; mean age: 9.5 [±2.7] years). Wechsler Intelligence Scale for Children-Indian adaptation (WISC-IV), Child Behavior Checklist, and Children's Sleep Habits Questionnaire were administered for 57 cases (at 3 months postinjury) and 51 controls of similar age. The findings of diffusion tensor imaging (done within 7 days of injury) were correlated with various WISC-IV indices. The presenting features at the time of injury were loss of consciousness (53%), confusion or disorientation (47%), and post-traumatic amnesia (10%). Other features in the acute phase included drowsiness (86%), headache (78%), balance problems (62%), nausea (47%), fatigue (45%), vomiting (35%), nasal or ear bleed (12%), sensitivity to sound and light (12%), etc. At 3 months postinjury, the children with mild traumatic brain injury performed poorly in terms of Intelligence Quotient, perceptual reasoning index, and processing speed index as compared to controls. Based on the Child Behavior Checklist, 17% of children with mild traumatic brain injury had internalizing behavioral problems in comparison with 4% of controls. Prevalence of poor sleepers in the mild traumatic brain injury cohort and controls was 12.3% and 2% respectively. Headache, reduced attention span, and fatigue were common postconcussion symptoms. There was a positive correlation between right uncinate fasciculus fractional anisotropy and verbal comprehension index (r = 0.32; P < .05).

Do fear and catastrophizing about mental activities relate to fear-avoidance behavior in a community sample? An experimental study.

Introduction: Healthy people often experience headache, cognitive failures, or mental fatigue. Some people even experience these symptoms on a level comparable to patients with mild spectrum brain injuries. In these individuals, the fear-avoidance model explains symptoms as a consequence of catastrophizing and fear-avoidance toward mental activities. This experimental study investigated in healthy adults whether fear-avoidance and catastrophizing about mental activities are related to fear-avoidance behavior (i.e., behavioral avoidance of mental activities) according to the fear-avoidance model.Method: A randomized crossover within-subject design was used with two measurements and 80 participants. Participants were exposed to three demanding cognitive tasks and their simplified counterparts. Post-concussion symptoms, catastrophizing, fear-avoidance, behavioral avoidance (time spent working on cognitive tasks), exposure to mental activity, depression, heart rate, and state-trait anxiety were assessed.Results: Significant correlations between the variables of the fear-avoidance model were found. Furthermore, catastrophizers spent less time on difficult tasks compared to easy tasks. Both catastrophizing and female sex predicted time spent on difficult tasks, whereas only female sex predicted time spent on easy tasks.Conclusions: This study found that, according to the fear-avoidance model, catastrophizing is related to behavioral avoidance of cognitively challenging tasks in a community sample.

Altered Processing of Complex Visual Stimuli in Patients with Postconcussive Visual Motion Sensitivity.

BACKGROUND AND PURPOSE: Vestibular symptoms are common after concussion. Vestibular Ocular Motor Screening identifies vestibular impairment, including postconcussive visual motion sensitivity, though the underlying functional brain alterations are not defined. We hypothesized that alterations in multisensory processing are responsible for postconcussive visual motion sensitivity, are detectable on fMRI, and correlate with symptom severity. MATERIALS AND METHODS: Twelve patients with subacute postconcussive visual motion sensitivity and 10 healthy control subjects underwent vestibular testing and a novel fMRI visual-vestibular paradigm including 30-second "neutral" or "provocative" videos. The presence of symptoms/intensity was rated immediately after each video. fMRI group-level analysis was performed for a "provocative-neutral" condition. Z-statistic images were nonparametrically thresholded using clusters determined by Z > 2.3 and a corrected cluster significance threshold of P = .05. Symptoms assessed on Vestibular Ocular Motor Screening were correlated with fMRI mean parameter estimates using Pearson correlation coefficients. RESULTS: Subjects with postconcussive visual motion sensitivity had significantly more Vestibular Ocular Motor Screening abnormalities and increased symptoms while viewing provocative videos. While robust mean activation in the primary and secondary visual areas, the parietal lobe, parietoinsular vestibular cortex, and cingulate gyrus was seen in both groups, selective increased activation was seen in subjects with postconcussive visual motion sensitivity in the primary vestibular/adjacent cortex and inferior frontal gyrus, which are putative multisensory visual-vestibular processing centers. Moderate-to-strong correlations were found between Vestibular Ocular Motor Screening scores and fMRI activation in the left frontal eye field, left middle temporal visual area, and right posterior hippocampus. CONCLUSIONS: Increased fMRI brain activation in visual-vestibular multisensory processing regions is selectively seen in patients with postconcussive visual motion sensitivity and is correlated with Vestibular Ocular Motor Screening symptom severity, suggesting that increased visual input weighting into the vestibular network may underlie postconcussive visual motion sensitivity.

Cerebral Blood Flow Predicts Recovery in Children with Persistent Post-Concussion Symptoms after Mild Traumatic Brain Injury.

Persistent post-concussion symptoms (PPCS) following pediatric mild traumatic brain injury (mTBI) are associated with differential changes in cerebral blood flow (CBF). Given its potential as a therapeutic target, we examined CBF changes during recovery in children with PPCS. We hypothesized that CBF would decrease and that such decreases would mirror clinical recovery. In a prospective cohort study, 61 children and adolescents (mean age 14 [standard deviation = 2.6] years; 41% male) with PPCS were imaged with three-dimensional (3D) pseudo-continuous arterial spin-labelled (pCASL) magnetic resonance imaging (MRI) at 4-6 and 8-10 weeks post-injury. Exclusion criteria included any significant past medical history and/or previous concussion within the past 3 months. Twenty-three participants had clinically recovered at the time of the second scan. We found that relative and mean absolute CBF were higher in participants with poor recovery, 44.0 (95% confidence interval [CI]: 43.32, 44.67) than in those with good recovery, 42.19 (95% CI: 41.77, 42.60) mL/min/100 g gray tissue and decreased over time (ß = -1.75; p < 0.001). The decrease was greater in those with good recovery (ß = 2.29; p < 0.001) and predicted outcome in 77% of children with PPCS (odds ratio [OR] 0.54, 95% CI: 0.36, 0.80; p = 0.002). Future studies are warranted to validate the utility of CBF as a useful predictive biomarker of outcome in PPCS.

Quantitative Multimodal Assessment of Concussion Recovery in Youth Athletes.

OBJECTIVE: To evaluate recovery trajectories among youth athletes with a concussion and healthy controls across different domains using a quantitative and multifaceted protocol. STUDY DESIGN: Prospective repeated measures. PARTICIPANTS: Youth athletes diagnosed with a concussion between the ages of 8 and 18 years were evaluated (1) within 10 days after injury, (2) approximately 3 weeks after injury, and (3) after return-to-play clearance. Control participants completed the same protocol. SETTING: Sport concussion clinic. INTERVENTIONS: N/A. MAIN OUTCOME MEASURES: Participants underwent a multifaceted protocol that assessed symptoms (postconcussion symptom scale [PCSS]), dual-task gait, event-related potentials (ERPs), and eye tracking. RESULTS: Sixty-seven athletes participated: 36 after concussion (age = 14.0 ± 2.6 years; 44% female) and 31 controls (age = 14.6 ± 2.2 years; 39% female). Concussion symptoms were higher for the concussion group compared with controls at the first (PCSS = 31.7 ± 18.8 vs 1.9 ± 2.9; P < 0.001) and second time points (PCSS = 10.8 ± 11.2 vs 1.8 ± 3.6; P = 0.001) but resolved by the final assessment (PCSS = 1.7 ± 3.6 vs 2.0 ± 3.8; P = 0.46). The concussion group walked slower during dual-task gait than controls at all 3 tests including after return-to-play clearance (0.83 ± 0.19 vs 0.95 ± 0.15 m/s; P = 0.049). There were no between-group differences for ERP connectivity or eye tracking. Those with concussions had a decrease in ERP connectivity recovery over the 3 time points, whereas control participants' scores increased (concussion Δ = -8.7 ± 28.0; control Δ = 13.9 ± 32.2; χ2 = 14.1, P = 0.001). CONCLUSIONS: Concussion is associated with altered dual-task gait speeds after resolution of concussion symptoms, but ERP and eye tracking measures did not demonstrate between-group differences across time. Some objective approaches to concussion monitoring may support with identifying deficits after concussion, but further work is required to delineate the role of gait, electrophysiological, and eye tracking methods for clinical decision-making.

Cortical Volume and Thickness in Youth Several Years After Concussion.

OBJECTIVE: The long-term effects of pediatric concussion on brain morphometry remain poorly delineated. This study used magnetic resonance imaging (MRI) to investigate cortical volume and thickness in youth several years after concussion. METHODS: Participants aged 8-19 years old with a history of concussion (n = 37) or orthopedic injury (n = 20) underwent MRI, rated their postconcussion symptoms, and completed cognitive testing on average 2.6 years (SD = 1.6) after injury. FreeSurfer was used to obtain cortical volume and thickness measurements as well as determine any significant correlations between brain morphometry, postconcussion symptoms (parent and self-report), and cognitive functioning. RESULTS: No significant group differences were found for either cortical volume or thickness. Youth with a history of concussion had higher postconcussion symptom scores (both parent and self-report Postconcussion Symptom Inventory) than the orthopedic injury group, but symptom ratings did not significantly correlate with cortical volume or thickness. Across both groups, faster reaction time on a computerized neurocognitive test battery (CNS Vital Signs) was associated with a thinner cortex in the left pars triangularis of the inferior frontal gyrus and the left caudal anterior cingulate. Better verbal memory was associated with a thinner cortex in the left rostral middle frontal gyrus. CONCLUSION: Findings do not support differences in cortical volume or thickness approximately 2.5 years postconcussion in youth, suggesting either long-term cortical recovery or no cortical differences as a result of injury. Further research using a longitudinal study design and larger samples is needed.

Second Impact Syndrome. Myth or reality?

INTRODUCTION: Second impact syndrome (SIS) is a devastating condition occurring in sport-induced mild brain injury. SIS is drastically defined by anamnestic, clinical and radiological criteria, which is unusual in the field of cranial traumatology. The purpose of this study was to provide a literature review of this syndrome. MATERIAL AND METHODS: We conducted a literature review of all published studies on PubMed. The keywords were "second impact syndrome and catastrophic head injury", "second impact syndrome and sport", "repeat concussion and catastrophic brain injury", "catastrophic head injury and concussion", "catastrophic head injury", "concussion and second impact syndrome", "concussion and repetitive head injury". RESULTS: Eighty-two full-text articles were assessed for eligibility. Finally, 41 studies were included in qualitative synthesis and 21 were included in quantitative synthesis. DISCUSSION: The number of cases reported in the literature was extremely small compared to the population at risk, i.e., the number of athletes exposed to repeated concussions. SIS was similar to talk and die syndrome, with which it shares certain characteristics. If we consider SIS according to "talk and deteriorate tables", it opens up interesting perspectives because they are specific in children and adolescents. Taking into account the scarcity of this syndrome, one may question whether athlete-intrinsic features may be involved in at least some cases of SIS. On a pathophysiological level, many explanations remained unsatisfactory because they were unable to explain all the clinical phenomena and observed lesions. Triggering the trigeminocardiac reflex is a crucial element in explaining the sequence of clinical events. Its association with a state of neurogenic inflammation provides an almost complete explanation for this particular condition. Finally, on a practical level, a concussion occurring during the playing of a sport must be considered as any other injury before allowing a return to play.

Changes in exertion-related symptoms in adults and youth who have sustained a sport-related concussion.

OBJECTIVES: To identify the symptoms responsible for cessation of exercise testing and evaluate changes in post-concussion symptom scores on the Post-Concussion Symptom Scale (PCSS) from the Sport-Concussion Assessment Tool (SCAT5) immediately, 1-4h, and 6-12h following completion of the Buffalo Concussion Treadmill Test (BCTT) in youth and adults who have sustained a sport-related concussion. DESIGN: Prospective case-series. METHODS: Individuals who were diagnosed with a sport-related concussion and self-reported difficulties with exertion were referred to perform an exertional treadmill test. Individuals were recruited from a university sports medicine clinic. Change in PCSS symptom severity scores were operationally defined as a change ≥4 points. RESULTS: Forty-five individuals aged 13-57 years consented to participate. A total of 14/24 (58.3%) female and 13/21 (61.9%) male participants reported an increase in symptom severity scores immediately following the BCTT. At 1-4h, 5/10 (50.0%) males and 5/14 (35.7%) females who completed the PCSS had elevated symptom severity scores compared to pre-exertion. Only 24.2% (3/17 males and 5/16 females) of participants completing the PCSS at 6-12h reported increased symptom severity scores. CONCLUSION: Exertional testing is an important component of a multifaceted assessment following concussion; however, previous research evaluating symptom responses to exertion is limited. This study provides evidence to suggest individuals who experience an exacerbation of concussion-associated symptoms after exertion are likely to return to pre-exertion levels within the same day. Future research monitoring symptoms following exertion and throughout recovery should be performed in tandem with physiological measures to better understand the source of symptoms.

Impaired eye tracking is associated with symptom severity but not dynamic postural control in adolescents following concussion.

PURPOSE: The purpose of the study was to (1) examine the relationship between self-reported symptoms and concussion-related eye tracking impairments, and (2) compare gait performance between (a) adolescents with a concussion who have normal eye tracking, (b) adolescents with a concussion who have abnormal eye tracking, and (c) healthy controls. METHODS: A total of 30 concussed participants (age: 14.4 ± 2.2 years, mean ± SD, 50% female) and 30 controls (age: 14.2 ± 2.2 years, 47% female) completed eye tracking and gait assessments. The BOX score is a metric of pupillary disconjugacy, with scores <10 classified as normal and ≥10 abnormal. Symptoms were collected using the Post-Concussion Symptom Scale (PCSS), and gait speed was measured with triaxial inertial measurement units. We conducted a linear regression to examine the relationship between PCSS and BOX scores and a two-way mixed effects analysis of variance to examine the effect of group (abnormal BOX, normal BOX, and healthy control) on single- and dual-task gait speed. RESULTS: There was a significant association between total PCSS score and BOX score in the concussion group (ß = 0.16, p = 0.004, 95% confidence interval (95%CI): 0.06‒0.27), but not in the control group (ß = 0.21, p = 0.08, 95%CI: -0.03 to 0.45). There were no significant associations between PCSS symptom profiles and BOX scores in the concussion or control groups. There were also no significant differences in single-task (Abnormal: 1.00 ± 0.14 m/s; Normal: 1.11 ± 0.21 m/s; Healthy: 1.14 ± 0.18 m/s; p = 0.08) or dual-task (Abnormal: 0.77 ± 0.15 m/s; Normal: 0.84 ± 0.21 m/s; Healthy: 0.90 ± 0.18 m/s; p = 0.16) gait speed. CONCLUSION: The concussed group with impaired eye tracking reported higher total symptom severity, as well as worse symptom severity across the 5 PCSS symptom domain profiles. However, eye tracking deficits did not appear to be driven by any particular symptom domain. While not statistically significant, the slower gait speeds in those with abnormal BOX scores may still be clinically relevant since gait-related impairments may persist beyond clinical recovery.

Perceived Recovery and Self-Reported Functioning in Adolescents with Mild Traumatic Brain Injury: The Role of Sleep, Mood, and Physical Symptoms.

Purpose: To determine the contributions of anxiety, depressive, and concussion symptoms and sleep quality to self-perceived recovery in adolescents with concussion.Method: Adolescents aged 12-20 (n = 298) completed anxiety, depression, concussion symptoms, and sleep measures at an initial concussion clinic visit and three-month follow-up. At follow-up, they reported self-perceived recovery as percent back to normal.Results: Injury-related factors alone did not predict self-perceived recovery (R2Adj =.017, p =.074). More concurrent physical, mental health, and sleep symptoms explained 18.8% additional variance in poorer self-perceived recovery (R2Adj Change =.188, p <.05). Physical symptoms (Bstand = -.292) and anxiety (Bstand = -.260) accounted for the most variance in self-perceived recovery.Conclusion: Post-concussive symptoms, in particular anxiety and self-reported physical symptoms, seem to characterize protracted recovery. Self-perceived recovery as an outcome measure may provide a more holistic understanding of adolescents' experiences after concussion.

Sex-specific differences in resting-state functional connectivity of large-scale networks in postconcussion syndrome.

Concussions are associated with a range of cognitive, neuropsychological and behavioral sequelae that, at times, persist beyond typical recovery times and are referred to as postconcussion syndrome (PCS). There is growing support that concussion can disrupt network-based connectivity post-injury. To date, a significant knowledge gap remains regarding the sex-specific impact of concussion on resting state functional connectivity (rs-FC). The aims of this study were to (1) investigate the injury-based rs-FC differences across three large-scale neural networks and (2) explore the sex-specific impact of injury on network-based connectivity. MRI data was collected from a sample of 80 concussed participants who fulfilled the criteria for postconcussion syndrome and 31 control participants who did not have any history of concussion. Connectivity maps between network nodes and brain regions were used to assess connectivity using the Functional Connectivity (CONN) toolbox. Network based statistics showed that concussed participants were significantly different from healthy controls across both salience and fronto-parietal network nodes. More specifically, distinct subnetwork components were identified in the concussed sample, with hyperconnected frontal nodes and hypoconnected posterior nodes across both the salience and fronto-parietal networks, when compared to the healthy controls. Node-to-region analyses showed sex-specific differences across association cortices, however, driven by distinct networks. Sex-specific network-based alterations in rs-FC post concussion need to be examined to better understand the underlying mechanisms and associations to clinical outcomes.