Psychosocial Factors Associated With Time to Recovery After Concussion in Adolescent Ice Hockey Players

OBJECTIVE

To investigate the association between psychosocial factors and physician clearance to return to play (RTP) in youth ice hockey players after sport-related concussion.

DESIGN

Prospective cohort study, Safe to Play (2013-2018).

SETTING

Youth hockey leagues in Alberta and British Columbia, Canada.

PARTICIPANTS

Three hundred fifty-three ice hockey players (aged 11-18 years) who sustained a total of 397 physician-diagnosed concussions.

INDEPENDENT VARIABLES

Psychosocial variables.

MAIN OUTCOME MEASURES

Players and parents completed psychosocial questionnaires preinjury. Players with a suspected concussion were referred for a study physician visit, during which they completed the Sport Concussion Assessment Tool (SCAT3/SCAT5) and single question ratings of distress and expectations of recovery. Time to recovery (TTR) was measured as days between concussion and physician clearance to RTP. Accelerated failure time models estimated the association of psychosocial factors with TTR, summarized with time ratios (TRs). Covariates included age, sex, body checking policy, days from concussion to the initial physician visit, and symptom severity at the initial physician visit.

RESULTS

Self-report of increased peer-related problems on the Strengths and Difficulties Questionnaire (TR, 1.10 [95% CI, 1.02-1.19]), higher ratings of distress about concussion outcomes by participants (TR, 1.06 [95% CI, 1.01-1.11]) and parents (TR, 1.05 [95% CI, 1.01-1.09]), and higher parent ratings of distress about their child's well-being at the time of injury (TR, 1.06 [95% CI, 1.02-1.09]) were associated with longer recovery.

CONCLUSIONS

Greater pre-existing peer-related problems and acute distress about concussion outcomes and youth well-being predicted longer TTR. Treatment targeting these psychosocial factors after concussion may promote recovery.

Longitudinal changes in brain metabolites following pediatric concussion

Concussion is commonly characterized by a cascade of neurometabolic changes following injury. Magnetic Resonance Spectroscopy (MRS) can be used to quantify neurometabolites non-invasively. Longitudinal changes in neurometabolites have rarely been studied in pediatric concussion, and fewer studies consider symptoms. This study examines longitudinal changes of neurometabolites in pediatric concussion and associations between neurometabolites and symptom burden. Participants who presented with concussion or orthopedic injury (OI, comparison group) were recruited. The first timepoint for MRS data collection was at a mean of 12 days post-injury (n = 545). Participants were then randomized to 3 (n = 243) or 6 (n = 215) months for MRS follow-up. Parents completed symptom questionnaires to quantify somatic and cognitive symptoms at multiple timepoints following injury. There were no significant changes in neurometabolites over time in the concussion group and neurometabolite trajectories did not differ between asymptomatic concussion, symptomatic concussion, and OI groups. Cross-sectionally, Choline was significantly lower in those with persistent somatic symptoms compared to OI controls at 3 months post-injury. Lower Choline was also significantly associated with higher somatic symptoms. Although overall neurometabolites do not change over time, choline differences that appear at 3 months and is related to somatic symptoms.

Factors Associated with Transition to Serious Mental Illness

OBJECTIVE

There is increasing interest in early intervention and detection strategies for youth at-risk of developing a serious mental illness (SMI). Little is known about early factors that may be related to the later development of a SMI; thus, the aim of this study was to determine what clinical factors might relate to the development of in this study psychosis, bipolar disorder and severe or recurrent major depression in at-risk youth.

METHOD

The sample consisted of 162 youth aged 12-26 years at different stages of risk. Thirty-one participants developed a SMI during the study. Those who made a transition were compared on a range of baseline clinical and functional measures with those who did not make the transition. A Cox regression model was used to assess the association between measures and later development of a SMI.

RESULTS

Female sex, attenuated psychotic symptoms as assessed with the Scale of Psychosis-Risk Symptoms (SOPS) and ratings on the K-10 Distress Scale, were found to be significantly associated with the later transition to mental illness. Females were 2.77 times more likely to transition compared to males. For the SOPS and K-10 scales, there is a 14% increase in the transition rate relative to a one-scale increase in SOPS and a 7% increase in the transition rate relative to a one-point increase in the K-10.

CONCLUSIONS

Results from these longitudinal data provide further insight into the specific clinical measures that may be pertinent in early detection of mental illnesses.

A dose-response characterization of transcranial magnetic stimulation intensity and evoked potential amplitude in the dorsolateral prefrontal cortex

By combining transcranial magnetic stimulation (TMS) with electroencephalography, human cortical circuits can be directly interrogated. The resulting electrical trace contains TMS-evoked potential (TEP) components, and it is not known whether the amplitudes of these components are stimulus intensity dependent. We examined this in the left dorsolateral prefrontal cortex in nineteen healthy adult participants and extracted TEP amplitudes for the N40, P60, N120, and P200 components at 110%, 120%, and 130% of resting motor threshold (RMT). To probe plasticity of putative stimulus intensity dose-response relationships, this was repeated after participants received intermittent theta burst stimulation (iTBS; 600 pulses, 80% RMT). The amplitude of the N120 and P200 components exhibited a stimulus intensity dose-response relationship, however the N40 and P60 components did not. After iTBS, the N40 and P60 components continued to exhibit a lack of stimulus intensity dose-dependency, and the P200 dose-response was unchanged. In the N120 component, however, we saw evidence of change within the stimulus intensity dose-dependent relationship characterized by a decrease in absolute peak amplitudes at lower stimulus intensities. These data suggest that TEP components have heterogeneous dose-response relationships, with implications for standardizing and harmonizing methods across experiments. Moreover, the selective modification of the N120 dose-response relationship may provide a novel marker for iTBS plasticity in health and disease.

Machine learning using multimodal clinical, electroencephalographic, and magnetic resonance imaging data can predict incident depression in adults with epilepsy: A pilot study

OBJECTIVE

This study was undertaken to develop a multimodal machine learning (ML) approach for predicting incident depression in adults with epilepsy.

METHODS

We randomly selected 200 patients from the Calgary Comprehensive Epilepsy Program registry and linked their registry-based clinical data to their first-available clinical electroencephalogram (EEG) and magnetic resonance imaging (MRI) study. We excluded patients with a clinical or Neurological Disorders Depression Inventory for Epilepsy (NDDI-E)-based diagnosis of major depression at baseline. The NDDI-E was used to detect incident depression over a median of 2.4 years of follow-up (interquartile range [IQR] = 1.5-3.3 years). A ReliefF algorithm was applied to clinical as well as quantitative EEG and MRI parameters for feature selection. Six ML algorithms were trained and tested using stratified threefold cross-validation. Multiple metrics were used to assess model performances.

RESULTS

Of 200 patients, 150 had EEG and MRI data of sufficient quality for ML, of whom 59 were excluded due to prevalent depression. Therefore, 91 patients (41 women) were included, with a median age of 29 (IQR = 22-44) years. A total of 42 features were selected by ReliefF, none of which was a quantitative MRI or EEG variable. All models had a sensitivity > 80%, and five of six had an F1 score ≥ .72. A multilayer perceptron model had the highest F1 score (median = .74, IQR = .71-.78) and sensitivity (84.3%). Median area under the receiver operating characteristic curve and normalized Matthews correlation coefficient were .70 (IQR = .64-.78) and .57 (IQR = .50-.65), respectively.

SIGNIFICANCE

Multimodal ML using baseline features can predict incident depression in this population. Our pilot models demonstrated high accuracy for depression prediction. However, overall performance and calibration can be improved. This model has promise for identifying those at risk for incident depression during follow-up, although efforts to refine it in larger populations along with external validation are required.

Injury Rates, Mechanisms, Risk Factors and Prevention Strategies in Youth Rugby Union: What's All the Ruck-Us About? A Systematic Review and Meta-analysis

BACKGROUND

Rugby Union is a collision team sport played globally. Despite this, significant concerns have been raised regarding the sport's safety, particularly in youth players. Given this, a review of injury rates, risk factors and prevention strategies is required across different youth age groups as well as in males and females.

OBJECTIVE

The objective of this systematic review (SR) and meta-analysis was to investigate injury and concussion rates, risk factors and primary prevention strategies in youth rugby.

METHODS

To be included, studies were required to report either rates, risk factors or prevention strategies in youth rugby and to have a randomised controlled trial, quasi-experimental, cohort, case control, or ecological study design. Exclusion criteria included non-peer-reviewed grey literature, conference abstracts, case studies, previous systematic reviews and studies not written in English. Nine databases were searched. The full search strategy and list of sources are available and pre-registered on PROSPERO (Ref: CRD42020208343). Each study was assessed for risk of bias using the Downs and Black quality assessment tool. Meta-analyses were conducted using a DerSimonian Laird random effect model for each age group and sex.

RESULTS

Sixty-nine studies were included in this SR. The match injury rates (using a 24-h time-loss definition) were 40.2/1000 match hours (95% CI 13.9-66.5) in males and 69.0/1000 match hours (95% CI 46.8-91.2) in females. Concussion rates were 6.2/1000 player-hours (95% CI 5.0-7.4) for males and 33.9/1000 player-hours (95% CI: 24.1-43.7) for females. The most common injury site was lower extremity (males) and the head/neck (females). The most common injury type was ligament sprain (males) and concussion (females). The tackle was the most common event associated with injury in matches (55% male, 71% females). Median time loss was 21 days for males and 17 days for females. Twenty-three risk factors were reported. The risk factors with the strongest evidence were higher levels of play and increasing age. Primary injury prevention strategies were the focus of only eight studies and included law changes (n = 2), equipment (n = 4), education (n = 1) and training (n = 1). The prevention strategy with the most promising evidence was neuromuscular training. The primary limitations included a broad range of injury definitions (n = 9) and rate denominators (n = 11) used, as well as a limited number of studies which could be included in the meta-analysis for females (n = 2).

CONCLUSION

A focus on high-quality risk factor and primary prevention evaluation should be considered in future studies. Targeting primary prevention and stakeholder education remain key strategies in the prevention, recognition and management of injuries and concussions in youth rugby.

Brain metabolites measured with magnetic resonance spectroscopy in pediatric concussion and orthopedic injury: An Advancing Concussion Assessment in Pediatrics (A-CAP) study

Millions of children sustain a concussion annually. Concussion disrupts cellular signaling and neural pathways within the brain but the resulting metabolic disruptions are not well characterized. Magnetic resonance spectroscopy (MRS) can examine key brain metabolites (e.g., N-acetyl Aspartate (tNAA), glutamate (Glx), creatine (tCr), choline (tCho), and myo-Inositol (mI)) to better understand these disruptions. In this study, we used MRS to examine differences in brain metabolites between children and adolescents with concussion versus orthopedic injury. Children and adolescents with concussion (n = 361) or orthopedic injury (OI) (n = 184) aged 8 to 17 years were recruited from five emergency departments across Canada. MRS data were collected from the left dorsolateral prefrontal cortex (L-DLPFC) using point resolved spectroscopy (PRESS) at 3 T at a mean of 12 days post-injury (median 10 days post-injury, range 2-33 days). Univariate analyses for each metabolite found no statistically significant metabolite differences between groups. Within each analysis, several covariates were statistically significant. Follow-up analyses designed to account for possible confounding factors including age, site, scanner, vendor, time since injury, and tissue type (and interactions as appropriate) did not find any metabolite group differences. In the largest sample of pediatric concussion studied with MRS to date, we found no metabolite differences between concussion and OI groups in the L-DLPFC. We suggest that at 2 weeks post-injury in a general pediatric concussion population, brain metabolites in the L-DLPFC are not specifically affected by brain injury.

Multimodal magnetic resonance imaging of youth sport-related concussion reveals acute changes in the cerebellum, basal ganglia, and corpus callosum that resolve with recovery

Magnetic resonance imaging (MRI) can provide a number of measurements relevant to sport-related concussion (SRC) symptoms; however, most studies to date have used a single MRI modality and whole-brain exploratory analyses in attempts to localize concussion injury. This has resulted in highly variable findings across studies due to wide ranging symptomology, severity and nature of injury within studies. A multimodal MRI, symptom-guided region-of-interest (ROI) approach is likely to yield more consistent results. The functions of the cerebellum and basal ganglia transcend many common concussion symptoms, and thus these regions, plus the white matter tracts that connect or project from them, constitute plausible ROIs for MRI analysis. We performed diffusion tensor imaging (DTI), resting-state functional MRI, quantitative susceptibility mapping (QSM), and cerebral blood flow (CBF) imaging using arterial spin labeling (ASL), in youth aged 12-18 years following SRC, with a focus on the cerebellum, basal ganglia and white matter tracts. Compared to controls similar in age, sex and sport (N = 20), recent SRC youth (N = 29; MRI at 8 ± 3 days post injury) exhibited increased susceptibility in the cerebellum (p = 0.032), decreased functional connectivity between the caudate and each of the pallidum (p = 0.035) and thalamus (p = 0.021), and decreased diffusivity in the mid-posterior corpus callosum (p < 0.038); no changes were observed in recovered asymptomatic youth (N = 16; 41 ± 16 days post injury). For recent symptomatic-only SRC youth (N = 24), symptom severity was associated with increased susceptibility in the superior cerebellar peduncles (p = 0.011) and reduced activity in the cerebellum (p = 0.013). Fewer days between injury and MRI were associated with reduced cerebellar-parietal functional connectivity (p < 0.014), reduced activity of the pallidum (p = 0.002), increased CBF in the caudate (p = 0.005), and reduced diffusivity in the central corpus callosum (p < 0.05). Youth SRC is associated with acute cerebellar inflammation accompanied by reduced cerebellar activity and cerebellar-parietal connectivity, as well as structural changes of the middle regions of the corpus callosum accompanied by functional changes of the caudate, all of which resolve with recovery. Early MRI post-injury is important to establish objective MRI-based indicators for concussion diagnosis, recovery assessment and prediction of outcome.

Novel oxygen sensing mechanism in the spinal cord involved in cardiorespiratory responses to hypoxia

As blood oxygenation decreases (hypoxemia), mammals mount cardiorespiratory responses, increasing oxygen to vital organs. The carotid bodies are the primary oxygen chemoreceptors for breathing, but sympathetic-mediated cardiovascular responses to hypoxia persist in their absence, suggesting additional high-fidelity oxygen sensors. We show that spinal thoracic sympathetic preganglionic neurons are excited by hypoxia and silenced by hyperoxia, independent of surrounding astrocytes. These spinal oxygen sensors (SOS) enhance sympatho-respiratory activity induced by CNS asphyxia-like stimuli, suggesting they bestow a life-or-death advantage. Our data suggest the SOS use a mechanism involving neuronal nitric oxide synthase 1 (NOS1) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX). We propose NOS1 serves as an oxygen-dependent sink for NADPH in hyperoxia. In hypoxia, NADPH catabolism by NOS1 decreases, increasing availability of NADPH to NOX and launching reactive oxygen species-dependent processes, including transient receptor potential channel activation. Equipped with this mechanism, SOS are likely broadly important for physiological regulation in chronic disease, spinal cord injury, and cardiorespiratory crisis.

The Impact of Concussion, Sport, and Time in Season on Saliva Telomere Length in Healthy Athletes

To date, sport-related concussion diagnosis and management is primarily based on subjective clinical tests in the absence of validated biomarkers. A major obstacle to clinical validation and application is a lack of studies exploring potential biomarkers in non-injured populations. This cross-sectional study examined the associations between saliva telomere length (TL) and multiple confounding variables in a healthy university athlete population. One hundred eighty-three (108 male and 75 female) uninjured varsity athletes were recruited to the study and provided saliva samples at either pre- or mid-season, for TL analysis. Multiple linear regression was used to determine the associations between saliva TL and history of concussion, sport contact type, time in season (pre vs. mid-season collection), age, and sex. Results showed no significant associations between TL and history of concussion, age, or sport contact type. However, TL from samples collected mid-season were longer than those collected pre-season [β = 231.4, 95% CI (61.9, 401.0), p = 0.008], and males had longer TL than females [β = 284.8, 95% CI (111.5, 458.2), p = 0.001] when adjusting for all other variables in the model. These findings population suggest that multiple variables may influence TL. Future studies should consider these confounders when evaluating saliva TL as a plausible fluid biomarker for SRC.

A metric learning method for estimating myelin content based on T2-weighted MRI from a de- and re-myelination model of multiple sclerosis

Myelin plays a critical role in the pathogenesis of neurological disorders but is difficult to characterize in vivo using standard analysis methods. Our goal was to develop a novel analytical framework for estimating myelin content using T2-weighted magnetic resonance imaging (MRI) based on a de- and re-myelination model of multiple sclerosis. We examined 18 mice with lysolecithin induced demyelination and spontaneous remyelination in the ventral white matter of thoracic spinal cord. Cohorts of 6 mice underwent 9.4T MRI at days 7 (peak demyelination), 14 (ongoing recovery), and 28 (near complete recovery), as well as histological analysis of myelin and the associated cellularity at corresponding timepoints. Our MRI framework took an unsupervised learning approach, including tissue segmentation using a Gaussian Markov random field (GMRF), and myelin and cellularity feature estimation based on the Mahalanobis distance. For comparison, we also investigated 2 regression-based supervised learning approaches, one using our GMRF results, and another using a freely available generalized additive model (GAM). Results showed that GMRF segmentation was 73.2% accurate, and our unsupervised learning method achieved a correlation coefficient of 0.67 (top quartile: 0.78) with histological myelin, similar to 0.70 (top quartile: 0.78) obtained using supervised analyses. Further, the area under the receiver operator characteristic curve of our unsupervised myelin feature (0.883, 95% CI: 0.874–0.891) was significantly better than any of the supervised models in detecting white matter myelin as compared to histology. Collectively, metric learning using standard MRI may prove to be a new alternative method for estimating myelin content, which ultimately can improve our disease monitoring ability in a clinical setting.

Association between concussion education and concussion knowledge, beliefs and behaviours among youth ice hockey parents and coaches: a cross-sectional study

OBJECTIVES

To examine the association between self-reported exposure to concussion education and knowledge, beliefs and self-reported behaviour among parents and coaches of youth ice hockey players.

DESIGN

Cross-sectional.

SETTING

Community ice hockey teams from Calgary and Edmonton, Alberta, Canada.

PARTICIPANTS

Parents and coaches of ice hockey players (ages 11-17, all divisions of play).

PRIMARY AND SECONDARY OUTCOME MEASURES

Participants completed a questionnaire developed and validated to measure concussion knowledge, beliefs and concussion management behaviour (ie, coaches removing athletes from play; parents taking children with suspected concussions to physicians) consistent with the Health Action Process Approach (HAPA). The questionnaire examined specific HAPA constructs (ie, risk perception, outcome expectancies, action self-efficacy, intention, action planning, maintenance self-efficacy, recovery self-efficacy) relevant to concussion management behaviour.

RESULTS

Participants included 786 parents (31.8% with coaching experience) and 10 non-parent coaches. Of the participants, 649 (82.6%) previously received concussion education. Based on a multivariable regression analysis adjusting for coaching experience, previous history of a child sustaining one or more concussions, first aid experience and cluster by team, exposure to concussion education was associated with a mean score difference of 1.36 (95% CI 0.68 to 2.03), p<0.0001, in the knowledge score. Exposure to concussion education was not significantly associated with any of the HAPA constructs based on Wilcoxon rank-sum tests.

CONCLUSION

Exposure to concussion education may be associated with small overall differences in concussion knowledge but may not be associated with significant differences in beliefs or intended behaviours related to concussion management among youth hockey parents and coaches.When providing education or recommendations for concussion education sources to coaches and parents, educational strategies grounded in behavioural change theory that specifically target the motivators of behavioural change should be considered.

Improving symptom burden in adults with persistent post-concussive symptoms: a randomized aerobic exercise trial protocol

BACKGROUND

Persistent post-concussive symptoms (PPCS) affect up to 30% of individuals following mild traumatic brain injury. PPCS frequently includes exercise intolerance. Sub-symptom threshold aerobic exercise has been proposed as a treatment option for symptom burden and exercise intolerance in this population. The primary aim of this study is to evaluate whether a progressive, sub-symptom threshold aerobic exercise program can alleviate symptom burden in adults with PPCS.

METHODS

Fifty-six adults (18-65) with PPCS (>3mos-5 yrs) will be randomized into two groups: an immediate start 12-week aerobic exercise protocol (AEP) or delayed start 6-week placebo-like stretching protocol (SP), followed by AEP. Aerobic or stretching activities will be completed 5x/week for 30 mins during the intervention. Online daily activity logs will be submitted. Exercise prescriptions for the AEP will be 70-80% of heart rate at the point of symptom exacerbation achieved on a treadmill test with heart rate monitoring. Exercise prescription will be updated every 3-weeks with a repeat treadmill test. The Rivermead Post-concussion Symptom Questionnaire will be the primary outcome measure at 6 and 12-weeks of intervention. Secondary outcomes include assessments of specific symptoms (headache, quality of life, mood, anxiety, fatigue, dizziness, sleep parameters, daytime sleepiness) in addition to blood biomarkers and magnetic resonance imaging and spectroscopy data for quantification of brain metabolites including γ-aminobutyric acid (GABA), glutathione, glutamate and N-acetyl aspartate (NAA) all measured at 6 and 12-weeks of intervention.

DISCUSSION

This trial will evaluate the use of aerobic exercise as an intervention for adults with PPCS, thus expanding our knowledge of this treatment option previously studied predominantly for adolescent sport-related concussion.

TRIAL REGISTRATION

ClinicalTrials.gov - NCT03895450 (registered 2019-Feb-11).

Effects of Transcranial Direct Current Stimulation on GABA and Glx in Children: A pilot study

Transcranial direct current stimulation (tDCS) is a form of non-invasive brain stimulation that safely modulates brain excitability and has therapeutic potential for many conditions. Several studies have shown that anodal tDCS of the primary motor cortex (M1) facilitates motor learning and plasticity, but there is little information about the underlying mechanisms. Using magnetic resonance spectroscopy (MRS), it has been shown that tDCS can affect local levels of γ-aminobutyric acid (GABA) and Glx (a measure of glutamate and glutamine combined) in adults, both of which are known to be associated with skill acquisition and plasticity; however this has yet to be studied in children and adolescents. This study examined GABA and Glx in response to conventional anodal tDCS (a-tDCS) and high definition tDCS (HD-tDCS) targeting the M1 in a pediatric population. Twenty-four typically developing, right-handed children ages 12-18 years participated in five consecutive days of tDCS intervention (sham, a-tDCS or HD-tDCS) targeting the right M1 while training in a fine motor task (Purdue Pegboard Task) with their left hand. Glx and GABA were measured before and after the protocol (at day 5 and 6 weeks) using a PRESS and GABA-edited MEGA-PRESS MRS sequence in the sensorimotor cortices. Glx measured in the left sensorimotor cortex was higher in the HD-tDCS group compared to a-tDCS and sham at 6 weeks (p = 0.001). No changes in GABA were observed in either sensorimotor cortex at any time. These results suggest that neither a-tDCS or HD-tDCS locally affect GABA and Glx in the developing brain and therefore it may demonstrate different responses in adults.

Guidelines for the Pharmacotherapy of Schizophrenia in Adults

OBJECTIVE

The present guidelines address the pharmacotherapy of schizophrenia in adults across different stages, phases, and symptom domains.

METHOD

Guidelines were developed using the ADAPTE process, which takes advantage of existing guidelines. Six guidelines were identified for adaptation, with recommendations extracted from each. For those specific to the pharmacotherapy of schizophrenia in adults, a working group selected between guidelines and recommendations to create an adapted guideline.

RESULTS

Recommendations can be categorized into 6 areas that include 1) first-episode schizophrenia, 2) acute exacerbation, 3) relapse prevention and maintenance treatment, 4) treatment-resistant schizophrenia, 5) clozapine-resistant schizophrenia, and 6) specific symptom domains. For each category, recommendations are made based on the available evidence, which is discussed and linked to other established guidelines.

CONCLUSIONS

In most cases, evidence-based recommendations are made that can be used to guide current clinical treatment and decision making. Notably, however, there is a paucity of established evidence to guide treatment decision making in the case of clozapine-resistant schizophrenia, a subsample that represents a sizable proportion of those with schizophrenia.