Mild traumatic brain injury and fatigue: a prospective longitudinal study

A study protocol for risk stratification in children with concussion (RSiCC): Theoretical framework, design, and methods

Research shows that one in five children will experience a concussion by age 16. Compared to adults, children experience longer and more severe postconcussive symptoms (PCS), with severity and duration varying considerably among children and complicating management of these patients. Persistent PCS can result in increased school absenteeism, social isolation, and psychological distress. Although early PCS diagnosis and access to evidence-based interventions are strongly linked to positive health and academic outcomes, symptom severity and duration are not fully explained by acute post-injury symptoms. Prior research has focused on the role of neuroinflammation in mediating PCS and associated fatigue; however relationship between inflammatory biomarkers and PCS severity, has not examined longitudinally. To identify which children are at high risk for persistent PCS and poor health, academic, and social outcomes, research tracking PCS trajectories and describing school-based impacts across the entire first year postinjury is critically needed. This study will 1) define novel PCS trajectory typologies in a racially/ethnically diverse population of 500 children with concussion (11-17 years, near equal distribution by sex), 2) identify associations between these typologies and patterns of inflammatory biomarkers and genetic variants, 3) develop a risk stratification model to identify children at risk for persistent PCS; and 4) gain unique insights and describe PCS impact, including fatigue, on longer-term academic and social outcomes. We will be the first to use NIH's symptom science model and patient-reported outcomes to explore the patterns of fatigue and other physical, cognitive, psychological, emotional and academic responses to concussion in children over a full year. Our model will enable clinicians and educators to identify children most at risk for poor long-term health, social, and academic outcomes after concussion. This work is critical to meeting our long-term goal of developing personalized concussion symptom-management strategies to improve outcomes and reduce disparities in the health and quality of life of children.

Too tired to think: Relationship between post-COVID-19 fatigue and cognition in a veteran sample

COVID-19 survivors often endorse persistent physical and neuropsychiatric problems following disease recovery, a phenomenon described as "long COVID." Research exploring long-COVID continues to evolve in large-scale studies but remains limited among smaller populations (e.g., veterans). We explored the relationship between persistent post-COVID-19 fatigue and cognition among a sample of 246 veterans who voluntarily enrolled in a COVID-19 Convalescence Programme and completed a mental health evaluation of post-illness mood (depression, anxiety, PTSD), cognition (subjective complaints, Modified Telephone Interview for Cognitive Status [TICS-M] performance), fatigue, pain, and sleep. In concert with our hypotheses, subjective cognitive complaints are not significantly correlated with TICS-M performance, but rather are strongly correlated with long-COVID fatigue. Although cognitive changes are common post-COVID complaints, these are likely better predicted by other factors, (e.g., fatigue, mood, pain, and sleep disruption). Furthermore, comorbid mood, sleep, and pain complaints appeared to mediate the relationship between subjective cognitive complaints and fatigue. Limitations to this study included use of retrospective chart review data, limited access to pre-disease data for comparison, and lack of healthy controls. Clinicians should consider the impact of modifiable conditions associated with cognitive and functional decline, as these conditions may be targets for interdisciplinary treatment in a long-COVID veteran population.

Dynamic Prevalence of and Factors Associated With Fatigue Following Traumatic Brain Injury: A Systematic Review and Meta-analysis of Observational Studies

OBJECTIVE

To implement a systematic review and meta-analysis to comprehensively synthesize the prevalence of and factors associated with fatigue following traumatic brain injury (TBI).

METHODS

We systematically searched the PubMed, EMBASE, Cochrane Library, Cumulated Index to Nursing and Allied Health Literature, PsycINFO, and ProQuest Dissertations and Theses A&I databases in all fields from their inception to March 31, 2021. We included observational studies investigating fatigue at specific time points following TBI or factors associated with post-TBI fatigue. All data were analyzed using a random-effects model.

RESULTS

This meta-analysis included 29 studies that involved 12 662 patients with TBI and estimated the prevalence of post-TBI fatigue (mean age = 41.09 years); the meta-analysis also included 23 studies that involved 6681 patients (mean age = 39.95 years) and investigated factors associated with post-TBI fatigue. In patients with mild-to-severe TBI, the fatigue prevalence rates at 2 weeks or less, 1 to 3 months, 6 months, 1 year, and 2 years or more after TBI were 52.2%, 34.6%, 36.0%, 36.1%, and 48.8%, respectively. Depression ( r = 0.48), anxiety ( r = 0.49), sleep disturbance ( r = 0.57), and pain ( r = 0.46) were significantly associated with post-TBI fatigue. No publication bias was identified among the studies, except for those assessing fatigue prevalence at 6 months after TBI.

CONCLUSION

The pooled prevalence rates of post-TBI fatigue exhibited a U-shaped pattern, with the lowest prevalence rates occurring at 1 to 3 months after TBI. Depression, anxiety, sleep disturbance, and pain were associated with post-TBI fatigue. Younger patients and male patients were more likely to experience post-TBI fatigue. Our findings can assist healthcare providers with identifying appropriate and effective interventions targeting post-TBI fatigue at specific periods.

High-salt diet induces microbiome dysregulation, neuroinflammation and anxiety in the chronic period after mild repetitive closed head injury in adolescent mice

The associations between human concussions and subsequent sequelae of chronic neuropsychiatric and cardiovascular diseases such as hypertension have been reported; however, little is known about the underlying biological processes. We hypothesized that dietary changes, including a high-salt diet, disrupt the bidirectional gut-brain axis, resulting in worsening neuroinflammation and emergence of cardiovascular and behavioural phenotypes in the chronic period after repetitive closed head injury in adolescent mice. Adolescent mice were subjected to three daily closed head injuries, recovered for 12 weeks and then maintained on a high-salt diet or a normal diet for an additional 12 weeks. Experimental endpoints were haemodynamics, behaviour, microglial gene expression (bulk RNA sequencing), brain inflammation (brain tissue quantitative PCR) and microbiome diversity (16S RNA sequencing). High-salt diet did not affect systemic blood pressure or heart rate in sham or injured mice. High-salt diet increased anxiety-like behaviour in injured mice compared to sham mice fed with high-salt diet and injured mice fed with normal diet. Increased anxiety in injured mice that received a high-salt diet was associated with microgliosis and a proinflammatory microglial transcriptomic signature, including upregulation in interferon-gamma, interferon-beta and oxidative stress-related pathways. Accordingly, we found upregulation of tumour necrosis factor-alpha and interferon-gamma mRNA in the brain tissue of high salt diet-fed injured mice. High-salt diet had a larger effect on the gut microbiome composition than repetitive closed head injury. Increases in gut microbes in the families Lachnospiraceae, Erysipelotrichaceae and Clostridiaceae were positively correlated with anxiety-like behaviours. In contrast, Muribaculaceae, Acholeplasmataceae and Lactobacillaceae were negatively correlated with anxiety in injured mice that received a high-salt diet, a time-dependent effect. The findings suggest that high-salt diet, administered after a recovery period, may affect neurologic outcomes following mild repetitive head injury, including the development of anxiety. This effect was linked to microbiome dysregulation and an exacerbation of microglial inflammation, which may be physiological targets to prevent behavioural sequelae in the chronic period after mild repetitive head injury. The data suggest an important contribution of diet in determining long-term outcomes after mild repetitive head injury.

Heterogeneity of health-related quality of life after mild traumatic brain injury with systemic injury: a cluster analytic approach

PURPOSE

Health-related quality of life (HRQoL) is a key component of evaluating outcome after mild traumatic brain injury (mTBI). As outcome is heterogeneous following mTBI, it is relevant to examine individual differences in HRQoL. This study investigated whether multiple homogenous subgroups could be meaningfully identified, 10 weeks after hospitalised mTBI with systemic injury, on the basis of HRQoL profiles.

METHODS

Ninety-one adults were assessed for HRQoL, pain, fatigue, sleep quality, psychological distress, cognition and post-concussion symptoms.

RESULTS

Cluster analyses revealed three separate subgroups based on physical, mental, social and energy HRQoL. One group (42%) demonstrated normative levels of HRQoL on all subdomains. The remaining two groups demonstrated significantly reduced HRQoL on all subdomains. These groups had equivalently poor mental, social and energy HRQoL, but the smallest group (27%) had significantly poorer physical HRQoL. Multinomial logistic regression revealed that pain significantly and independently predicted group membership for the particularly poor physical HRQoL group. Fatigue was the only significant independent predictor of group membership for the remaining group with reduced HRQoL.

CONCLUSION

These findings suggest more than 50% of hospitalised individuals with mTBI and systemic injury, have reduced HRQoL, 10 weeks after mTBI. Pain and fatigue warrant clinical attention in these individuals.IMPLICATIONS FOR REHABILITATIONMild traumatic brain injury is a common event that has been shown to be associated with persistently reduced health-related quality of life in approximately 50% of individuals 6 to 12 months after injury.Health-related quality of life likely varies between individuals after injuryRelative to the "normal" population, most individuals in this cohort of individuals with mTBI and systemic injury had reduced mental, social and energy quality of life 10 weeks after injury.Fatigue and pain are important factors in reduced health-related quality of life after mTBI with systemic injury.Further research is needed to determine whether these fatigue and pain issues are related to mTBI-factors, such as headache, and/or related to systemic injury factors, which are common in the mTBI population.

Trajectories of fatigue and related outcomes following mild acquired brain injury: a multivariate latent class growth analysis

OBJECTIVE

Fatigue is a common symptom following acquired brain injury although the severity and course differs for many individuals. This longitudinal study aimed to identify latent trajectory classes of fatigue and associated outcomes following mild brain injury.

METHODS

204 adults with mild traumatic brain injury (159; 78%) or minor stroke (45; 22%) were assessed 4 times over 1 year. Subjective measures of fatigue, anxiety, depression, cognitive complaints and societal participation were collected. Multivariate Latent Class Growth Analysis identified classes of participants with similar longitudinal patterns. Demographic and injury characteristics were used to predict class membership.

RESULTS

Analysis revealed four classes. Class 1 (53%) had mild, decreasing fatigue with no other problems. Class 2 (29%) experienced high persistent fatigue, moderate cognitive complaints and societal participation problems. Class 3 (11%) had high persistent fatigue with anxiety, depression, cognitive complaints and participation problems. Class 4 (7%) experienced decreasing fatigue with anxiety and depression but no cognitive or participation problems. Women and older individuals were more likely to be in class 2.

CONCLUSION

Half the participants had a favourable outcome while the remaining classes were characterised by persistent fatigue with cognitive complaints (class 2), decreasing fatigue with mood problems (class 4) or fatigue with both cognitive and mood problems (class 3). Fatigue treatment should target combinations of problems in such individual trajectories after mild brain injury.

Stressful life events are associated with self-reported fatigue and depressive symptoms in patients with mild traumatic brain injury

OBJECTIVE

To examine the associations between recent stressful life events and self-reported fatigue and depressive symptoms in patients with mild traumatic brain injury.

DESIGN

Observational cohort study.

PARTICIPANTS

Patients (aged 18-68 years) with mild traumatic brain injury (n = 99) or lower extremity orthopaedic injury (n = 34).

METHODS

Data on stressful life events and self-reported symptoms were collected 3 months post-injury. Stressful life events in the last 12 months were assessed as part of a structured interview using a checklist of 11 common life events, self-reported fatigue with Barrow Neurological Institute Fatigue Scale, and depressive symptoms with Beck Depression Inventory - Fast Screen.

RESULTS

Median number of stressful life events was 1 (range 0-7) in the mild traumatic brain injury group and 1.5 (range 0-6) in the orthopaedic injury group. The groups did not differ significantly in terms of fatigue or depressive symptoms. In the mild traumatic brain injury group, the total number of recent stressful life events correlated significantly with self-reported fatigue (rs = 0.270, p = 0.007) and depressive symptoms (rs = 0.271, p = 0.007).

CONCLUSION

Stressful life events are associated with self-reported fatigue and depressive symptoms in patients with mild traumatic brain injury. Clinicians should consider stressful life events when managing patients who experience these symptoms, as this may help identifying potential targets for intervention.

Biopsychosocial correlates of fatigue in young adult survivors of childhood traumatic brain injury: A prospective cohort study

This prospective cohort study aimed to evaluate the potential role of injury, socio-demographic and individual psychological factors in predicting long-term fatigue outcomes in young adult survivors of childhood TBI at 16-years post-injury. The study included 51 young adults diagnosed with childhood TBI from 2-12 years of age. Twenty age-and-sex-matched controls were included for comparison. Findings showed that almost one-in-four TBI participants (24%) endorsed clinically elevated fatigue at 16-years post-injury. Despite the relatively large proportion of TBI participants endorsing clinically significant fatigue, group comparisons revealed that the TBI and control groups did not significantly differ on fatigue symptom severity or rates of clinically elevated fatigue. For the TBI group, post-injury fatigue was significantly associated with socio-demographic and psychological factors, including lower educational level, higher depression symptom severity, and more frequent substance use. Higher fatigue was also associated with lower self-reported quality of life (QoL) in the physical, psychological, and environmental domains, even after controlling for depressive symptom severity, socio-demographic, and injury-related factors. Overall, findings show that a substantial proportion of young adults with a history of childhood TBI experience clinically elevated fatigue at 16-years post-injury. Identification and treatment of modifiable risk-factors (e.g. depression symptoms, substance use) has potential to reduce fatigue.

Exploring the status and associated factors of the readiness for return-to-work in young and middle-aged stroke patients

Stroke increasingly affects individuals of working age. An accurate assessment of Readiness for Return-to-Work (RRTW) can help determine the optimal timing for RRTW and facilitate an early reintegration into society. This study investigates the current state of RRTW and the influencing factors among young and middle-aged stroke patients in China. A sample of young and middle-aged stroke patients hospitalized in a tertiary hospital in Henan Province between December 2021 and May 2022 were included in this study. A general information questionnaire and the Readiness for RRTW scale, the Social Support Rate Scale, the Stroke Self-Efficacy Scale, and the Fatigue Severity Scale were administered to the patients. Of the 203 patients successfully surveyed, 60 (29.6%) were in the pre-contemplation stage, 35 (17.2%) in the contemplation stage, 81 (39.9%) in the prepared for action-self-evaluative stage, and 27 (13.3%) in the prepared for action- behavior stage. Logistic regression analysis identified education level, monthly income, time to start rehabilitation therapy, social support, stroke self-efficacy, and fatigue severity as key factors affecting RRTW scale readiness in young and middle-aged stroke patients. The readiness of young and middle-aged stroke patients to Return-to-Work needs to be increased further. Healthcare professionals should consider the influencing factors of RRTW and design targeted intervention programs to facilitate a successful Return-to-Work and normal life.

Network analysis and relationship of symptom factors to functional outcomes and quality of life following mild traumatic brain injury: a TRACK-TBI study

Introduction

Mild traumatic brain injury (mTBI) is a heterogenous injury which can be difficult to characterize and manage. Using cross-sectional network analysis (NA) to conceptualize mTBI symptoms offers an innovative solution to identify how mTBI symptoms relate to each other. The centrality hypothesis of network theory posits that certain symptoms in a network are more relevant (central) or have above average influence over the rest of the network. However, no studies have used NA to characterize the interrelationships between symptoms in a cohort of patients who presented with mTBI to a U.S. Level 1 trauma center emergency department and how subacute central symptoms relate to long-term outcomes.

Methods

Patients with mTBI (Glasgow Coma Scale = 13-15) evaluated across 18 U.S. Level 1 trauma centers from 2013 to 2019 completed the Rivermead Post-Concussion Symptoms Questionnaire (RPQ) at 2 weeks (W2) post-injury (n = 1,593) and at 3 months (M3), 6 months (M6), and 12 months (M12) post-injury. Network maps were developed from RPQ subscale scores at each timepoint. RPQ scores at W2 were associated with M6 and M12 functional and quality of life outcomes.

Results

Network structure did not differ across timepoints, indicating no difference in symptoms/factors influence on the overall symptom network across time. The cognitive factor had the highest expected influence at W2 (1.761), M3 (1.245), and M6 (1.349). Fatigue had the highest expected influence at M12 (1.275). The emotional factor was the only other node with expected influence >1 at any timepoint, indicating disproportionate influence of emotional symptoms on overall symptom burden (M3 = 1.011; M6 = 1.076).

Discussion

Several symptom factors at 2-weeks post-injury were more strongly associated with incomplete recovery and/or poorer injury-related quality of life at 6 and 12 months post-injury than previously validated demographic and clinical covariates. The network analysis suggests that emotional, cognitive, and fatigue symptoms may be useful treatment targets in this population due to high centrality and activating potential of the overall symptom network.

The executive functions among patients with an initial Glasgow coma scale score of 15

Executive functions (EF) were the critical neuropsychological functions linked to long-term adaptation. Given the heterogeneous prognosis trajectories of mild traumatic brain jury (mTBI), the mildest TBI may not always be benign in the chronic stage. The present study explored the long-term EF in patients with chronic complicated mTBI and a Glasgow Coma Scale (GCS) score of 15. Fifty patients with complicated mTBI and GCS scores of 15 and 35 control participants were recruited in this study. Medical records were retrospectively analyzed, and neuropsychological assessments and subjective measures examined the neuropsychological functions. Compared with healthy controls, complicated mTBI patients with a GCS score of 15 performed significantly worse on most EF assessments, including longer reaction time (RT) and poor cognitive flexibility and abstract reasoning performances. Patients also reported more EF problems and lower quality of life (QoL) than healthy controls. Females and those with subdural hematoma (SDH) had significantly longer reaction times (RT) on executive attention tests. This study found that complicated mTBI with a GCS score of 15 had incomplete recovery of EF, even in the chronic stage. We suggest that early neuropsychological assessment and rehabilitation should be arranged for such patients.

Brain Fog: a Narrative Review of the Most Common Mysterious Cognitive Disorder in COVID-19

It has been more than three years since COVID-19 impacted the lives of millions of people, many of whom suffer from long-term effects known as long-haulers. Notwithstanding multiorgan complaints in long-haulers, signs and symptoms associated with cognitive characteristics commonly known as "brain fog" occur in COVID patients over 50, women, obesity, and asthma at excessive. Brain fog is a set of symptoms that include cognitive impairment, inability to concentrate and multitask, and short-term and long-term memory loss. Of course, brain fog contributes to high levels of anxiety and stress, necessitating an empathetic response to this group of COVID patients. Although the etiology of brain fog in COVID-19 is currently unknown, regarding the mechanisms of pathogenesis, the following hypotheses exist: activation of astrocytes and microglia to release pro-inflammatory cytokines, aggregation of tau protein, and COVID-19 entry in the brain can trigger an autoimmune reaction. There are currently no specific tests to detect brain fog or any specific cognitive rehabilitation methods. However, a healthy lifestyle can help reduce symptoms to some extent, and symptom-based clinical management is also well suited to minimize brain fog side effects in COVID-19 patients. Therefore, this review discusses mechanisms of SARS-CoV-2 pathogenesis that may contribute to brain fog, as well as some approaches to providing therapies that may help COVID-19 patients avoid annoying brain fog symptoms.

Quality of Life Differences in Children and Adolescents With 0, 1 to 2, or 3+ Persistent Postconcussion Symptoms

CONTEXT

Persistent postconcussion symptoms (PPCSs) are associated with lower health-related quality of life (HRQoL) in children and adolescents. Despite commonly cited criteria for PPCSs involving 3 or more complaints, many individuals experience just 1 or 2 symptoms that may still negatively affect HRQoL.

OBJECTIVE

To determine differences in HRQoL between children and adolescents with 0, 1 to 2, or 3+ parent-reported persistent symptoms at 1 month postconcussion.

DESIGN

Prospective cohort study.

SETTING

Community practice clinics.

PATIENTS OR OTHER PARTICIPANTS

Individuals aged 8 to 18 years presented for the initial visit within 3 days of a sport- or recreation-related concussion. One month later, parents or guardians reported persistent symptoms using the Rivermead Post Concussion Symptoms Questionnaire (RPQ). Individuals with complete symptom data were analyzed (n = 236/245, n = 97 females, age = 14.3 ± 2.1 years). Participants were grouped by the number of discrete RPQ symptoms reported as worse than preinjury (0, 1-2, or 3+).

MAIN OUTCOME MEASURE(S)

Total summary and subscale scores on the Pediatric Quality of Life Inventory (PedsQL) 23-item HRQoL inventory and 18-item Multidimensional Fatigue Scale (MDFS).

RESULTS

Kruskal-Wallis rank sum tests highlighted differences in PedsQL HRQoL and MDFS total scores across symptom groups (PedsQL HRQoL: χ22 = 85.53, P < .001; MDFS: χ22 = 93.15, P < .001). Dunn post hoc analyses indicated all 3 groups were statistically significantly different from each other (P < .001). The median (interquartile range) values for the Peds QL Inventory HRQoL totals were 93.5 (84.2-98.8) for those with 0 symptoms; 84.8 (73.9-92.4) for those with 1 to 2 symptoms; and 70.7 (58.7-78.0) for those with 3+ symptoms. The median (interquartile range) values for the MDFS totals were 92.4 (76.4-98.6) for those with 0 symptoms; 78.5 (65.6-88.9) for those with 1 to 2 symptoms; and 54.2 (46.2-65.3) for those with 3+ symptoms. Similar group differences were observed for each PedsQL HRQoL and MDFS subscale score.

CONCLUSIONS

Children and adolescents whose parents reported 1 to 2 PPCSs had lower HRQoL and more fatigue than those with 0 symptoms. Across all 3 groups, those with 3+ persistent symptoms had the lowest HRQoL and most fatigue. These findings indicate the continued need for intervention in this age group to prevent and address PPCSs.

Recovery of clinical, cognitive and cortical activity measures following mild traumatic brain injury (mTBI): A longitudinal investigation

The mechanisms that underpin recovery following mild traumatic brain injury (mTBI) remain poorly understood. Identifying neurophysiological markers and their functional significance is necessary to develop diagnostic and prognostic indicators of recovery. The current study assessed 30 participants in the subacute phase of mTBI (10-31 days post-injury) and 28 demographically matched controls. Participants also completed 3 month (mTBI: N = 21, control: N = 25) and 6 month (mTBI: N = 15, control: N = 25) follow up sessions to track recovery. At each time point, a battery of clinical, cognitive, and neurophysiological assessments was completed. Neurophysiological measures included resting-state electroencephalography (EEG) and transcranial magnetic stimulation combined with EEG (TMS-EEG). Outcome measures were analysed using mixed linear models (MLM). Group differences in mood, post-concussion symptoms and resting-state EEG resolved by 3 months, and recovery was maintained at 6 months. On TMS-EEG derived neurophysiological measures of cortical reactivity, group differences ameliorated at 3 months but re-emerged at 6 months, while on measures of fatigue, group differences persisted across all time points. Persistent neurophysiological changes and greater fatigue in the absence of measurable cognitive impairment may suggest the impact of mTBI on neuronal communication may leads to increased neural effort to maintain efficient function. Neurophysiological measures to track recovery may help identify both temporally optimal windows and therapeutic targets for the development of new treatments in mTBI.

"My head feels like it has gone through a mixer" - a qualitative interview study on recovery 1 year after aneurysmal subarachnoid hemorrhage

PURPOSE

To describe patients' perceived and expected recovery 1 year after aneurysmal subarachnoid hemorrhage (aSAH).

MATERIALS AND METHODS

Semi-structured interviews were conducted with 16 persons 1 year after aSAH. Inductive manifest qualitative content analysis was used.

RESULTS

The analysis resulted in two categories and seven subcategories. The category "A spectrum of varying experiences of recovery" includes four subcategories describing physical recovery, mental recovery, alterations in social life, and perceived possibilities to return to normality. Some informants felt that life was almost as before, while others described a completely different life, including a new view of self, altered relationships, not being able to return to work, and effects on personal finances. The category "A spectrum of reflections and expectations of recovery" comprises three subcategories depicturing that expectations of recovery were influenced by existential thoughts, describing what they based own expectations of recovery on, and how expectations from others influenced them.

CONCLUSIONS

aSAH was perceived as a life-changing event. The changes impacted on informants' view of self and relationships, and they perceived new barriers in their living conditions. Lack of information on expected recovery was expressed and expectations of recovery were at times unrealistic.IMPLICATIONS FOR REHABILITATIONContracting an aneurysmal subarachnoid hemorrhage (aSAH) is a life-changing event with possible impact on a variety of areas in daily life.There is a need for improved information to aSAH survivors and their significant others on the course of the recovery and possible long-term consequences.aSAH survivors may need assistance to balance unrealistic expectations on recovery.

Relationship between psychosocial and psychiatric risk factors and poor long-term outcome following mild traumatic brain injury: A systematic review

BACKGROUND AND PURPOSE

Mild traumatic brain injury (mTBI) has an estimated worldwide incidence of >60 million per year, and long-term persistent postconcussion symptoms (PPCS) are increasingly recognized as being predicted by psychosocial variables. Patients at risk for PPCS may be amenable to closer follow-up to treat modifiable symptoms and prevent chronicity. In this regard, similarities seem to exist with psychosocial risk factors for chronicity in other health-related conditions. However, as opposed to other conditions, no screening instruments exist for mTBI.

METHODS

A systematic search of the literature on psychological and psychiatric predictors of long-term symptoms in mTBI was performed by two independent reviewers using PubMed, Embase, and Web of Science.

RESULTS

Fifty papers were included in the systematic analysis. Anxiety, depressive symptoms, and emotional distress early after injury predict PPCS burden and functional outcome up to 1 year after injury. In addition, coping styles and preinjury psychiatric disorders and mental health also correlate with PPCS burden and functional outcome. Associations between PPCS and personality and beliefs were reported, but either these effects were small or evidence was limited.

CONCLUSIONS

Early psychological and psychiatric factors may negatively interact with recovery potential to increase the risk of chronicity of PPCS burden after mTBI. This opens opportunities for research on screening tools and early intervention in patients at risk.

The incidence and severity of symptoms similiar to peristing concussion symptoms in neurologically healthy individuals in aotearoa New Zealand

The non-specificity of persisting concussion symptoms (PCS) following concussion can make treatment and rehabilitation a complex and challenging endeavour for clinicians. International studies have demonstrated that in neurologically healthy individuals similar symptoms also exist. This study aimed to examine the presence and frequency of symptoms similar to PCS in neurologically healthy adults in Aotearoa New Zealand and compare these to PCS following concussion. 252 neurologically healthy adults (34.22 years); completed the Rivermead Post-Concussion Questionnaire (RPQ). Scores on this measure were evaluated and compared with 146 individuals who were at least three months post-injury (34.62 years). 25.79% (n = 65) of the neurologically healthy individuals had scores on the RPQ of ≥16. Fatigue was the most commonly endorsed symptom (67.9%), followed by sleep disturbances (59.9%). Certain demographic factors (age, education history and gender) were associated with higher endorsement but only on specific symptoms. The concussion group had significantly higher scores on the RPQ and significantly more individuals with PCS. However, at the individual item level, just over half of PCS symptoms were significantly higher in the concussion group. These symptoms were predominately neurological, with only forgetfulness and irritability significantly different between the concussion and neurologically healthy groups. Symptoms similar to PCS are prevalent in neurologically healthy individuals in Aotearoa New Zealand. The implications of these findings on the rehabilitation and management of PCS are discussed.

Fatigue in young patients with acquired brain injury in the rehabilitation setting: Categorizing and interpreting fatigue severity levels

PURPOSE

Fatigue in patients with acquired brain injury (ABI) is common. However, to better target fatigue, clear ways to categorize/interpret fatigue-severity in individual patients are lacking. This study aims to determine/categorize fatigue severity among children, adolescents, and young adults with ABI.

METHODS

This cross-sectional study included young patients admitted to outpatient rehabilitation and their parents. To determine fatigue, the PedsQL™Multidimensional-Fatigue-Scale was used (MFS, scores 0-100, lower scores = higher fatigue, patient-/parent-reported). Based on scores from a reference population, four categories were formed: "1 = no/little fatigued" to "4 = severely-more fatigued."

RESULTS

All scores were lower than those from the reference population, with comparisons in the adolescent and young adult groups reaching statistical significance (p < .05). The proportions of patients in category 4 were: 9%/50%/58% among children/adolescents/young adults, showing that many patients were "severely-more fatigued"-than the reference population.

CONCLUSIONS

Measuring fatigue and categorizing fatigue severity looks promising for clinical practice and could help to better target fatigue.

Post-Concussion Symptoms Rule: Derivation and Validation of a Clinical Decision Rule for Early Prediction of Persistent Symptoms after a Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) is a common problem. Depending on diagnostic criteria, 13 to 62% of those patients develop persistent post-concussion symptoms (PPCS). The main objective of this prospective multi-center study is to derive and validate a clinical decision rule (CDR) for the early prediction of PPCS. Patients aged ≥14 years were included if they presented to one of our seven participating emergency departments (EDs) within 24 h of an mTBI. Clinical data were collected in the ED, and symptom evolution was assessed at 7, 30 and 90 days post-injury using the Rivermead Post-Concussion Questionnaire (RPQ). The primary outcome was PPCS at 90 days after mTBI. A predictive model called the Post-Concussion Symptoms Rule (PoCS Rule) was developed using the methodological standards for CDR. Of the 1083 analyzed patients (471 and 612 for the derivation and validation cohorts, respectively), 15.6% had PPCS. The final model included the following factors assessed in the ED: age, sex, history of prior TBI or mental health disorder, headache in ED, cervical sprain and hemorrhage on computed tomography. The 7-day follow-up identified additional risk factors: headaches, sleep disturbance, fatigue, sensitivity to light, and RPQ ≥21. The PoCS Rule had a sensitivity of 91.4% and 89.6%, a specificity of 53.8% and 44.7% and a negative predictive value of 97.2% and 95.8% in the derivation and validation cohorts, respectively. The PoCS Rule will help emergency physicians quickly stratify the risk of PPCS in mTBI patients and better plan post-discharge resources.

Therapeutic Approaches to the Neurologic Manifestations of COVID-19

As of May 2022, there have been more than 527 million infections with severe acute respiratory disease coronavirus type 2 (SARS-CoV-2) and over 6.2 million deaths from Coronavirus Disease 2019 (COVID-19) worldwide. COVID-19 is a multisystem illness with important neurologic consequences that impact long-term morbidity and mortality. In the acutely ill, the neurologic manifestations of COVID-19 can include distressing but relatively benign symptoms such as headache, myalgias, and anosmia; however, entities such as encephalopathy, stroke, seizures, encephalitis, and Guillain-Barre Syndrome can cause neurologic injury and resulting disability that persists long after the acute pulmonary illness. Furthermore, as many as one-third of patients may experience persistent neurologic symptoms as part of a Post-Acute Sequelae of SARS-CoV-2 infection (Neuro-PASC) syndrome. This Neuro-PASC syndrome can affect patients who required hospitalization for COVID-19 or patients who did not require hospitalization and who may have had minor or no pulmonary symptoms. Given the large number of individuals affected and the ability of neurologic complications to impair quality of life and productivity, the neurologic manifestations of COVID-19 are likely to have major and long-lasting personal, public health, and economic consequences. While knowledge of disease mechanisms and therapies acquired prior to the pandemic can inform us on how to manage patients with the neurologic manifestations of COVID-19, there is a critical need for improved understanding of specific COVID-19 disease mechanisms and development of therapies that target the neurologic morbidities of COVID-19. This current perspective reviews evidence for proposed disease mechanisms as they inform the neurologic management of COVID-19 in adult patients while also identifying areas in need of further research.

Surfing-Related Craniofacial Injuries: A NEISS Database Study

INTRODUCTION

Surfing is a popular pastime in coastal areas around the world with increasing numbers of participants. There is a lack of detailed data in the literature regarding surfing-related head and neck (HN) injuries.

MATERIALS AND METHODS

We queried the National Electronic Injury Surveillance System (NEISS) database to characterize patient demographics, injury types, injury subsite, and emergency department (ED) disposition status associated with surfing-related HN injuries between 2009 and 2020 in the United States.

RESULTS

A total of 54,978 estimated national cases were reported from 2009 to 2020. Injuries to the head (36.0%) and neck (35.8%) were most common. Young adults (ages 18-35) made up most ED visits, whereas older adults (>35) made up most (63.5%) admissions. Laceration (46.1%) was the most common injury among ED visits, whereas fracture (30.5%) and internal injury (29.2%) were most common in admitted patients. Concussions represented 7.5% of injuries overall, 9.1% of pediatric injuries, and 9.9% of young adult injuries.

CONCLUSIONS

When treating a patient who presents with injury suffered during surfing, a thorough examination of the HN should be performed. Specific attention should be given to evaluation of lacerations, fractures, internal ear injuries, and concussions. Pediatric and young adult patients are at increased risk of concussion. The majority of surfing injuries can be treated in an outpatient context.

Screening Method for Assessment of Work Ability for Patients Suffering From Mental Fatigue

Pathological mental fatigue adversely affects endurance in the performance of tasks over time, with negative impact on work ability. There are currently no methods for objectively assessing work ability for patients suffering from mental fatigue. In this study, work ability in relation to mental fatigue as a screening method was evaluated, using the Work Ability Index (WAI) and Mental Fatigue Scale (MFS). Included participants represented three patient groups commonly affected by mental fatigue; acquired brain injury (n = 49, traumatic brain injury, stroke), burn-out syndrome (55) and hypothyroidism (50). The results showed a significant correlation between WAI and MFS (r = –0.754) and status in the workplace (WAI r = 0.722, MFS r = –0.443) for all groups. The WAI and MFS were significant predictors for status in the workplace (p < 0.001) and explained 53% of the variance. This screening method can help health care professionals to identify people who are mentally fatigued with a reduced ability to work or return to work after illness, and who are in need of in-depth investigation. It is important to initiate treatment early with the aim of promoting a sustainable working life and general well-being of the individual.

Association of Traumatic Brain Injury With the Risk of Developing Chronic Cardiovascular, Endocrine, Neurological, and Psychiatric Disorders

IMPORTANCE

Increased risk of neurological and psychiatric conditions after traumatic brain injury (TBI) is well-defined. However, cardiovascular and endocrine comorbidity risk after TBI in individuals without these comorbidities and associations with post-TBI mortality have received little attention.

OBJECTIVE

To assess the incidence of cardiovascular, endocrine, neurological, and psychiatric comorbidities in patients with mild TBI (mTBI) or moderate to severe TBI (msTBI) and analyze associations between post-TBI comorbidities and mortality.

DESIGN, SETTING, AND PARTICIPANTS

This prospective longitudinal cohort study used hospital-based patient registry data from a tertiary academic medical center to select patients without any prior clinical comorbidities who experienced TBI from 2000 to 2015. Using the same data registry, individuals without head injuries, the unexposed group, and without target comorbidities were selected and age-, sex-, and race-frequency-matched to TBI subgroups. Patients were followed-up for up to 10 years. Data were analyzed in 2021.

EXPOSURES

Mild or moderate to severe head trauma.

MAIN OUTCOMES AND MEASURES

Cardiovascular, endocrine, neurologic, and psychiatric conditions were defined based on International Classification of Diseases, Ninth Revision (ICD-9) or International Statistical Classification of Diseases and Related Health Problems, Tenth Revision (ICD-10). Associations between TBI and comorbidities, as well as associations between the comorbidities and mortality, were analyzed.

RESULTS

A total of 4351 patients with mTBI (median [IQR] age, 45 [29-57] years), 4351 patients with msTBI (median [IQR] age, 47 [30-58] years), and 4351 unexposed individuals (median [IQR] age, 46 [30-58] years) were included in analyses. In each group, 45% of participants were women. mTBI and msTBI were significantly associated with higher risks of cardiovascular, endocrine, neurologic, and psychiatric disorders compared with unexposed individuals. In particular, hypertension risk was increased in both mTBI (HR, 2.5; 95% CI, 2.1-2.9) and msTBI (HR, 2.4; 95% CI, 2.0-2.9) groups. Diabetes risk was increased in both mTBI (HR, 1.9; 95% CI, 1.4-2.7) and msTBI (HR, 1.9; 95% CI, 1.4-2.6) groups, and risk of ischemic stroke or transient ischemic attack was also increased in mTBI (HR, 2.2; 95% CI, 1.4-3.3) and msTBI (HR, 3.6; 95% CI, 2.4-5.3) groups. All comorbidities in the TBI subgroups emerged within a median (IQR) of 3.49 (1.76-5.96) years after injury. Risks for post-TBI comorbidities were also higher in patients aged 18 to 40 years compared with age-matched unexposed individuals: hypertension risk was increased in the mTBI (HR, 5.9; 95% CI, 3.9-9.1) and msTBI (HR, 3.9; 95% CI, 2.5-6.1) groups, while hyperlipidemia (HR, 2.3; 95% CI, 1.5-3.4) and diabetes (HR, 4.6; 95% CI, 2.1-9.9) were increased in the mTBI group. Individuals with msTBI, compared with unexposed patients, had higher risk of mortality (432 deaths [9.9%] vs 250 deaths [5.7%]; P < .001); postinjury hypertension (HR, 1.3; 95% CI, 1.1-1.7), coronary artery disease (HR, 2.2; 95% CI, 1.6-3.0), and adrenal insufficiency (HR, 6.2; 95% CI, 2.8-13.0) were also associated with higher mortality.

CONCLUSIONS AND RELEVANCE

These findings suggest that TBI of any severity was associated with a higher risk of chronic cardiovascular, endocrine, and neurological comorbidities in patients without baseline diagnoses. Medical comorbidities were observed in relatively young patients with TBI. Comorbidities occurring after TBI were associated with higher mortality. These findings suggest the need for a targeted screening program for multisystem diseases after TBI, particularly chronic cardiometabolic diseases.

Neurocognitive Rehabilitation in COVID-19 Patients: A Clinical Review

Abstract: COVID-19 has affected many people all around the world for more than two years now have suffered many long-term consequences which is commonly referred to as long-haulers. Despite multiorgan complaints in long haulers, symptoms related to cognitive functions commonly referred as brain fog are seen in the high risk covid patients with age more than 50, women more than men, obesity, asthma and those who experienced more than five symptoms during the first week of covid illness. Long term isolation has certainly contributed to high level of anxiety and stress calling for an empathetic response to this group of covid patients as there is no specific test to detect long haulers and no specific cognitive rehabilitation techniques available as of today.

Symptom Frequency and Persistence in the First Year after Traumatic Brain Injury: A TRACK-TBI Study

Symptom endorsement after traumatic brain injury (TBI) is common acutely post-injury and is associated with other adverse outcomes. Prevalence of persistent symptoms has been debated, especially in mild TBI (mTBI). A cohort of participants ≥17 years with TBI (n = 2039), 257 orthopedic trauma controls (OTCs), and 300 friend controls (FCs) were enrolled in the TRACK-TBI study and evaluated at 2 weeks and 3, 6, and 12 months post-injury using the Rivermead Post-Concussion Symptoms Questionnaire (RPQ). TBI participants had significantly higher symptom burden than OTCs or FCs at all times, with average scores more than double. TBI cases showed significant decreases in RPQ score between each evaluation (p < 0.001), decreasing ∼1.7 points per month between 2 weeks and 3 months and 0.2 points per month after that. More than 50% of the TBI sample, including >50% of each of the mild and moderate/severe TBI subsamples, continued to endorse three or more symptoms as worse than pre-injury through 12 months post-injury. A majority of TBI participants who endorsed a symptom at 3 months or later did so at the next evaluation as well. Contrary to reviews that report symptom resolution by 3 months post-injury among those with mTBI, this study of participants treated at level 1 trauma centers and having a computed tomography ordered found that persistent symptoms are common to at least a year after TBI. Additionally, although symptom endorsement was not specific to TBI given that they were also reported by OTC and FC participants, TBI participants endorsed over twice the symptom burden compared with the other groups.

Cognitive-Linguistic outcome in moderate to severe diffuse axonal injury and association with fatigue

PURPOSE

Individuals with traumatic brain injury (TBI) often have persistent cognitive-linguistic deficits that negatively influence their life. Our objective was to examine the cognitive-linguistic outcome in individuals with moderate to severe diffuse axonal injury (DAI) with a novel test battery. As fatigue is a common symptom affecting the lives of individuals with DAI, we also wanted to assess whether the self-reported fatigue was associated with cognitive-linguistic abilities.

METHODS

Selected cognitive-linguistic subtests of the Finnish KAT test and The Mental Fatigue Scale (MFS) were applied to 48 adults with moderate to severe DAI and 27 healthy controls. The majority of the participants with DAI were in the chronic stage. The groups were compared using ANCOVA. Linear regressions were used to analyze the association between MFS and cognitive-linguistic outcomes.

RESULTS

The participants with DAI had significantly poorer scores than the controls in most cognitive-linguistic variables and reported significantly more fatigue. Two of the four cognitive-linguistic composite variables were associated with the degree of self-reported fatigue.

CONCLUSIONS

Cognitive-linguistic deficits are common in individuals with moderate to severe DAI, and The Finnish KAT test is a valuable tool to detect those. Fatigue was associated with linguistic working memory and language production.

Effect of early tranexamic acid treatment on fatigue in patients with mild traumatic brain injury: data from the CRASH-3 clinical trial

Background: Each year world-wide about 65 million people sustain a mild traumatic brain injury (mTBI). Fatigue is a common and distressing symptom after mTBI. We examine the effect of tranexamic acid (TXA) on fatigue in patients with mTBI using data from the CRASH-3 trial. Methods: The CRASH-3 trial randomised 9,202 patients with traumatic brain injury and no significant extracranial bleeding to receive TXA or placebo within 3 hours of injury. The primary outcome was death from head injury within 28 days of injury. The methods and results are presented elsewhere. Fatigue was recorded as “None”, “Moderate” or “Extreme.” This study examines the effect of TXA on extreme fatigue in the 2,632 patients with mTBI (Glasgow Coma Scale [GCS] score≥13). Our analyses were not prespecified. Results: Our study primary outcome, extreme fatigue, was reported for 10 (0.8%) of 1,328 patients receiving TXA and 19 (1.5%) of 1,288 patients receiving placebo (risk ratio [RR]=0.51, 95% confidence interval [CI] 0.24-1.09). Death within 28 days of injury was reported for 34 (2.6%) of 1,328 patients receiving TXA versus 47 (3.6%) of 1,288 patients receiving placebo (RR=0.70, 95% CI 0.45-1.08). Among patients allocated to TXA, 44 (3.3%) patients either died or reported extreme fatigue versus 66 (5.1%) patients among those allocated to placebo (RR=0.65, 95% CI 0.44-0.94). Conclusions: Early tranexamic acid treatment may reduce fatigue in mTBI patients, but these results need to be confirmed in a larger trial. Registration: ISRCTN (ISRCTN15088122, 19/07/2011), ClinicalTrials.gov (NCT01402882, 26/07/2011), EudraCT (2011-003669-14, 25/07/2011), Pan African Clinical Trial Registry (PACTR20121000441277, 30/10/2012).

Fatigue following mild traumatic brain injury relates to visual processing and effort perception in the context of motor performance

INTRODUCTION

Following mild traumatic brain injury (mTBI), a substantial number of patients experience disabling fatigue for months after the initial injury. To date, the underlying mechanisms of fatigue remain unclear. Recently, it was shown that mTBI patients with persistent fatigue do not demonstrate increased performance fatigability (i.e., objective performance decline) during a sustained motor task. However, it is not known whether the neural activation required to sustain this performance is altered after mTBI.

METHODS

Blood oxygen level-dependent (BOLD) fMRI data were acquired from 19 mTBI patients (>3 months post-injury) and 19 control participants during two motor tasks. Force was recorded from the index finger abductors of both hands during submaximal contractions and a 2-minute maximal voluntary contraction (MVC) with the right hand. Voluntary muscle activation (i.e., CNS drive) was indexed during the sustained MVC using peripheral nerve stimulation. Fatigue was quantified using the Fatigue Severity Scale (FSS) and Modified Fatigue Impact Scale (MFIS). Questionnaire, task, and BOLD data were compared across groups, and linear regression was used to evaluate the relationship between BOLD-activity and fatigue in the mTBI group.

RESULTS

The mTBI patients reported significantly higher levels of fatigue (FSS: 5.3 vs. 2.6, p < 0.001). Both mTBI- and control groups demonstrated significant performance fatigability during the sustained MVC, but no significant differences in task performance or BOLD-activity were observed between groups. However, mTBI patients reporting higher FSS scores showed increased BOLD-activity in the bilateral visual cortices (mainly extrastriate) and the left midcingulate gyrus. Furthermore, across all participants mean voluntary muscle activation during the sustained MVC correlated with long lasting post-contraction BOLD-activation in the right insula and midcingulate cortex.

CONCLUSION

The fMRI findings suggest that self-reported fatigue in mTBI may relate to visual processing and effort perception. Long lasting activation associated with high levels of CNS drive might be related to changes in cortical homeostasis in the context of high effort.

Trajectories of Fatigue, Psychological Distress, and Coping Styles After Mild Traumatic Brain Injury: A 6-Month Prospective Cohort Study

OBJECTIVE

To analyze fatigue after mild traumatic brain injury (TBI) with latent class growth analysis (LCGA) to determine distinct recovery trajectories and investigate influencing factors, including emotional distress and coping styles.

DESIGN

An observational cohort study design with validated questionnaires assessing fatigue, anxiety, depression, posttraumatic stress, and coping at 2 weeks and 3 and 6 months postinjury.

SETTING

Three level 1 trauma centers.

PARTICIPANTS

Patients with mild TBI (N=456).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Fatigue was measured with the fatigue severity subscale of the Checklist Individual Strength, including 8 items (sum score, 8-56). Subsequently, 3 clinical categories were created: high (score, 40-56), moderate (score, 26-38), and low (score, 8-25).

RESULTS

From the entire mild TBI group, 4 patient clusters with distinct patterns for fatigue, emotional distress, and coping styles were found with LCGA. Clusters 1 and 2 showed favorable recovery from fatigue over time, with low emotional distress and the predominant use of active coping in cluster 1 (30%) and low emotional distress and decreasing passive coping in cluster 2 (25%). Clusters 3 and 4 showed unfavorable recovery, with persistent high fatigue and increasing passive coping together with low emotional distress in cluster 3 (27%) and high emotional distress in cluster 4 (18%). Patients with adverse trajectories were more often women and more often experiencing sleep disturbances and pain.

CONCLUSIONS

The prognosis for recovery from posttraumatic fatigue is favorable for 55% of mild TBI patients. Patients at risk for chronic fatigue can be signaled in the acute phase postinjury based on the presence of high fatigue, high passive coping, and, for a subgroup of patients, high emotional distress. LCGA proved to be a highly valuable and multipurpose statistical method to map distinct courses of disease-related processes over time.

Persistent neurologic symptoms and cognitive dysfunction in non-hospitalized Covid-19 "long haulers"

OBJECTIVE

Most SARS-CoV-2-infected individuals never require hospitalization. However, some develop prolonged symptoms. We sought to characterize the spectrum of neurologic manifestations in non-hospitalized Covid-19 "long haulers".

METHODS

This is a prospective study of the first 100 consecutive patients (50 SARS-CoV-2 laboratory-positive (SARS-CoV-2+ ) and 50 laboratory-negative (SARS-CoV-2- ) individuals) presenting to our Neuro-Covid-19 clinic between May and November 2020. Due to early pandemic testing limitations, patients were included if they met Infectious Diseases Society of America symptoms of Covid-19, were never hospitalized for pneumonia or hypoxemia, and had neurologic symptoms lasting over 6 weeks. We recorded the frequency of neurologic symptoms and analyzed patient-reported quality of life measures and standardized cognitive assessments.

RESULTS

Mean age was 43.2 ± 11.3 years, 70% were female, and 48% were evaluated in televisits. The most frequent comorbidities were depression/anxiety (42%) and autoimmune disease (16%). The main neurologic manifestations were: "brain fog" (81%), headache (68%), numbness/tingling (60%), dysgeusia (59%), anosmia (55%), and myalgias (55%), with only anosmia being more frequent in SARS-CoV-2+ than SARS-CoV-2- patients (37/50 [74%] vs. 18/50 [36%]; p < 0.001). Moreover, 85% also experienced fatigue. There was no correlation between time from disease onset and subjective impression of recovery. Both groups exhibited impaired quality of life in cognitive and fatigue domains. SARS-CoV-2+ patients performed worse in attention and working memory cognitive tasks compared to a demographic-matched US population (T-score 41.5 [37, 48.25] and 43 [37.5, 48.75], respectively; both p < 0.01).

INTERPRETATION

Non-hospitalized Covid-19 "long haulers" experience prominent and persistent "brain fog" and fatigue that affect their cognition and quality of life.

Concussion and Risk of Chronic Medical and Behavioral Health Comorbidities

While chronic neurological effects from concussion have been studied widely, little is known about possible links between concussion and long-term medical and behavioral comorbidities. We performed a retrospective cohort study of 9205 adult patients with concussion, matched to non-concussion controls from a hospital-based electronic medical registry. Patients with comorbidities before the index visit were excluded. Behavioral and medical comorbidities were defined by International Classification of Diseases, Ninth and Tenth Revision codes. Groups were followed for up to 10 years to identify comorbidity incidence after a concussion. Cox proportional hazards models were used to calculate associations between concussion and comorbidities after multi-variable adjustment. Patients with concussion were 57% male (median age: 31; interquartile range [IQR] = 23-48 years) at enrollment with a median follow-up time of 6.1 years (IQR = 4.2-9.1) and well-matched to healthy controls. Most (83%) concussions were evaluated in outpatient settings (5% inpatient). During follow-up, we found significantly higher risks of cardiovascular risks developing including hypertension (hazard ratio [HR] = 1.7, 95% confidence interval [CI]: 1.5-1.9), obesity (HR = 1.7, 95% CI: 1.3-2.0), and diabetes mellitus (HR = 1.8, 95% CI: 1.4-2.3) in the concussion group compared with controls. Similarly, psychiatric and neurological disorders such as depression (HR = 3.0, 95% CI: 2.6-3.5), psychosis (HR = 6.0, 95% CI: 4.2-8.6), stroke (HR = 2.1 95% CI: 1.5-2.9), and epilepsy (HR = 4.4, 95% CI: 3.2-5.9) were higher in the concussion group. Most comorbidities developed less than five years post-concussion. The risks for post-concussion comorbidities were also higher in patients under 40 years old compared with controls. Patients with concussion demonstrated an increased risk of development of medical and behavioral health comorbidities. Prospective studies are warranted to better describe the burden of long-term comorbidities in patients with concussion.

Cardiorespiratory Functioning in Youth with Persistent Post-Concussion Symptoms: A Pilot Study

Dysregulation of the autonomic nervous system (ANS) may play an important role in the development and maintenance of persistent post-concussive symptoms (PPCS). Post-injury breathing dysfunction, which is influenced by the ANS, has not been well-studied in youth. This study evaluated cardiorespiratory functioning at baseline in youth patients with PPCS and examined the relationship of cardiorespiratory variables with neurobehavioral outcomes. Participants were between the ages of 13-25 in two groups: (1) Patients with PPCS (concussion within the past 2-16 months; n = 13) and (2) non-injured controls (n = 12). Capnometry was used to obtain end-tidal CO2 (EtCO2), oxygen saturation (SaO2), respiration rate (RR), and pulse rate (PR) at seated rest. PPCS participants exhibited a reduced mean value of EtCO2 in exhaled breath (M = 36.3 mmHg, SD = 2.86 mmHg) and an altered inter-correlation between EtCO2 and RR compared to controls. Neurobehavioral outcomes including depression, severity of self-reported concussion symptoms, cognitive catastrophizing, and psychomotor processing speed were correlated with cardiorespiratory variables when the groups were combined. Overall, results from this study suggest that breathing dynamics may be altered in youth with PPCS and that cardiorespiratory outcomes could be related to a dimension of neurobehavioral outcomes associated with poorer recovery from concussion.

Long-Term Presentation of Postconcussion Symptoms and Associated Factors: Analysis of Latent Class Modeling

OBJECTIVE

Postconcussion symptoms (PCS) are commonly reported by patients with mild traumatic brain injury (MTBI). Although PCS significantly recovered by 3-month postinjury, a number of patients still experienced persistent PCS for >1 year. As few researchers investigated long-term PCS endorsement, the present study thus aims to show the latent structure of long-term PCS and further uncover its associating factors.

METHODS

In total, 110 patients with MTBI and 32 healthy participants were prospectively enrolled. PCS was evaluated at 2 weeks and long-term evaluations (mean = 2.90 years) after MTBI. In addition, cognitive functions, which include memory, executive function, and information processing, and emotional disturbances, which include depression, anxiety, and irritability, were also examined at 2-week postinjury.

RESULTS

Patients reported significantly more PCS at 2-week postinjury than healthy participants did, but PCS significantly improved at long-term evaluations when comparing with PCS at acute stage after MTBI. Both of PCS at 2 weeks and long-term evaluations can be further subdivided into subgroups based on the severity of PCS, in which specific PCS (e.g., fatigue, loss of energy, insomnia, slowness of information processing, irritability, and blurred vision) can be well differentiated among subgroups at long-term evaluations.

CONCLUSIONS

This study directly showed the characteristics of long-term PCS and associating factors. It further evidenced that specific physical, cognitive, and emotional symptoms might be determinant to identify the subgroups of patients with long-term PCS endorsement.

The Prevalence and Stability of Sleep-Wake Disturbance and Fatigue throughout the First Year after Mild Traumatic Brain Injury

In this prospective, longitudinal study, we aimed to determine the prevalence and stability of sleep-wake disturbance (SWD) and fatigue in a large representative sample of patients (Trondheim mild traumatic brain injury [mTBI] follow-up study). We included 378 patients with mTBI (age 16-60), 82 matched trauma controls with orthopedic injuries, and 83 matched community controls. Increased sleep need, poor sleep quality, excessive daytime sleepiness, and fatigue were assessed at 2 weeks, 3 months, and 12 months after injury. Mixed logistic regression models were used to evaluate clinically relevant group differences longitudinally. Prevalence of increased sleep need, poor sleep quality, and fatigue was significantly higher in patients with mTBI than in both trauma controls and community controls at all time points. More patients with mTBI reported problems with excessive daytime sleepiness compared to trauma controls, but not community controls, at all time points. Patients with complicated mTBI (intracranial findings on computed tomography or magnetic resonance imaging) had more fatigue problems compared to those with uncomplicated mTBI, at all three time points. In patients with mTBI who experienced SWDs and fatigue 2 weeks after injury, around half still had problems at 3 months and approximately one third at 12 months. Interestingly, we observed limited overlap between the different symptom measures; a large number of patients reported one specific problem with SWD or fatigue rather than several problems. In conclusion, our results provide strong evidence that mTBI contributes significantly to the development and maintenance of SWDs and fatigue.

Headache- and Dizziness-Specific Health-Related Quality-of-Life Impairments Persist for 1 in 4 Amateur Athletes Who Are Cleared to Return to Sporting Activity Following Sport-Related Concussion: A Prospective Matched-Cohort Study

OBJECTIVES

To prospectively investigate the recovery of athlete-reported symptoms and the condition-specific health-related quality of life (HRQoL) following sport-related concussion.

DESIGN

Prospective matched-cohort study.

METHODS

We recruited amateur athletes who were diagnosed with sport-related concussion by emergency department physicians. Study participants were assessed at 3 time points following sport-related concussion. At each assessment, participants completed 5 condition-specific HRQoL patient-reported outcome measures to evaluate participants' perceptions of the effects of specific concussion-related symptoms on their HRQoL. We performed log-linear analyses to assess the proportion of concussed participants with clinically impaired condition-specific HRQoL compared with the proportion of participants in the control group with clinically impaired condition-specific HRQoL.

RESULTS

Fifty participants with sport-related concussion and 50 control participants matched by sex, age, and activity completed the study. Upon return to sporting activity, there was a significantly greater proportion of participants in the concussion group who perceived that headache, neck pain, and dizziness had an adverse effect on their HRQoL compared with the control group. Two weeks after return to sporting activity, there was still a significantly greater proportion of participants in the concussion group who perceived that headache (χ²₁ = 9.0; odds ratio [OR] = 4.4; 95% confidence interval [CI]: 1.5, 15.2; P = .003) and dizziness (χ²₁ = 9.5; OR = 13.5; 95% CI: 1.8, 604.9; P = .006) had an adverse effect on their HRQoL compared with the proportion of clinically impaired participants in the control group.

CONCLUSION

Of concussed participants, 1 in 4 perceived that headache and dizziness had adverse effects on their HRQoL after returning to sporting activity following sport-related concussion compared with nonconcussed, control participants. J Orthop Sports Phys Ther 2020;50(12):692-701. doi:10.2519/jospt.2020.9485.

Sex differences in reporting of concussion symptoms in adults

OBJECTIVE

To examine differences in concussion symptom reporting between female and male adults considering current psychological symptoms such as anxiety and depression and pre-injury factors in order to identify sex differences which may guide treatment efforts. Method: This prospective study is part of the North Texas Concussion Registry (ConTex). Subjects (N = 132) age 19 to 78 years had sustained a concussion within 30 days of clinic visit. The independent variable was sex and covariates included age, ethnicity, current anxiety and depression ratings, history of attention deficit disorder, history of headache/migraine, and time to clinic. The dependent variables were 22 post-concussion symptoms as measured by the Sport Concussion Assessment Tool-5 Post-Concussion Symptom Scale. Results: Analysis of covariance and ordinal logistic regression results both revealed that females had a greater likelihood of reporting increased symptom severity for 15/22 concussion symptoms. The largest risk ratios (effect size) in symptom reporting between sexes (higher symptoms in females) included: feeling more emotional 4.05 (0.72), fatigue or low energy 4.05 (0.72), sensitivity to light 3.74 (0.69), headache 3.65 (0.57), balance problems 3.31 (0.53), pressure in head 3.06 (0.51), and neck pain 2.97 (0.60). Conclusions: Adult females in our sample reported higher levels of many concussion symptoms than males and showed an increased risk of developing these same symptoms following concussion. Examination of the magnitude of sex difference in concussion symptom reporting will better inform medical staff to anticipate and address symptoms that may present greater challenges for adult females.

Frequency of fatigue and its changes in the first 6 months after traumatic brain injury: results from the CENTER-TBI study

Background

Fatigue is one of the most commonly reported subjective symptoms following traumatic brain injury (TBI). The aims were to assess frequency of fatigue over the first 6 months after TBI, and examine whether fatigue changes could be predicted by demographic characteristics, injury severity and comorbidities.

Methods

Patients with acute TBI admitted to 65 trauma centers were enrolled in the study Collaborative European NeuroTrauma Effectiveness Research in TBI (CENTER-TBI). Subjective fatigue was measured by single item on the Rivermead Post-Concussion Symptoms Questionnaire (RPQ), administered at baseline, three and 6 months postinjury. Patients were categorized by clinical care pathway: admitted to an emergency room (ER), a ward (ADM) or an intensive care unit (ICU). Injury severity, preinjury somatic- and psychiatric conditions, depressive and sleep problems were registered at baseline. For prediction of fatigue changes, descriptive statistics and mixed effect logistic regression analysis are reported.

Results

Fatigue was experienced by 47% of patients at baseline, 48% at 3 months and 46% at 6 months. Patients admitted to ICU had a higher probability of experiencing fatigue than those in ER and ADM strata. Females and individuals with lower age, higher education, more severe intracranial injury, preinjury somatic and psychiatric conditions, sleep disturbance and feeling depressed postinjury had a higher probability of fatigue.

Conclusion

A high and stable frequency of fatigue was found during the first 6 months after TBI. Specific socio-demographic factors, comorbidities and injury severity characteristics were predictors of fatigue in this study.

Electronic supplementary material

The online version of this article (10.1007/s00415-020-10022-2) contains supplementary material, which is available to authorized users.

Influence of Sociodemographic, Premorbid, and Injury-Related Factors on Post-Concussion Symptoms after Traumatic Brain Injury

BACKGROUND

Post-concussion symptoms (PCS) are often reported as consequences of mild and moderate traumatic brain injury (TBI), but these symptoms are not well documented in severe TBI. There is a lack of agreement as to which factors and covariates affect the occurrence, frequency, and intensity of PCS among TBI severity groups. The present study therefore aims to examine the association between sociodemographic, premorbid, and injury-related factors and PCS.

METHODS

A total of 1391 individuals (65% male) from the CENTER-TBI study were included in the analyses. The occurrence, frequency (number of PCS), and intensity (severity) of PCS were assessed using the Rivermead Post-concussion Symptoms Questionnaire (RPQ) at six months after TBI. To examine the association between selected factors (age, sex, living situation, employment status, educational background, injury and TBI severity, and premorbid problems) and PCS, a zero-inflated negative binomial model (ZINB) for occurrence and frequency of PCS and a standard negative binomial regression (NB) for intensity were applied.

RESULTS

Of the total sample, 72% of individuals after TBI reported suffering from some form of PCS, with fatigue being the most frequent among all TBI severity groups, followed by forgetfulness, and poor concentration. Different factors contributed to the probability of occurrence, frequency, and intensity of PCS. While the occurrence of PCS seemed to be independent of the age and sex of the individuals, both the frequency and intensity of PCS are associated with them. Both injury and TBI severity influence the occurrence and frequency of PCS, but are associated less with its intensity (except "acute" symptoms such as nausea, vomiting, and headaches). Analyses focusing on the mTBI subgroup only yielded results comparable to those of the total sample.

DISCUSSION

In line with previous studies, the results support a multifactorial etiology of PCS and show the importance of differentiating between their occurrence, frequency, and intensity to better provide appropriate treatment for individual subgroups with different symptoms (e.g., multiple PCS or more intense PCS). Although PCS often occur in mild to moderate TBI, individuals after severe TBI also suffer from PCS or post-concussion-like symptoms that require appropriate treatment. The chosen statistical approaches (i.e., ZINB and NB models) permit an ameliorated differentiation between outcomes (occurrence, frequency, and intensity of PCS) and should be used more widely in TBI research.

An observational study of the association between sleep disturbance, fatigue and cognition in the post-acute period after mild traumatic brain injury in prospectively studied premorbidly healthy adults

The literature examining the relationship between sleep disturbance, fatigue, and cognition in premorbidly healthy civilian adults after mTBI is very limited. The current study aimed to investigate the relationships of sleep disturbance and fatigue with cognition while controlling for psychological distress and age. Using a prospective observational design, we assessed 60 premorbidly healthy individuals approximately 8 weeks after mTBI. Participants were assessed with the Pittsburgh Sleep Quality Index and the Multidimensional Fatigue Inventory as well as measures of speed of information processing, attention, memory, and executive function; depression and anxiety were also assessed. Findings revealed associations between sleep disturbance and cognition (r²= .586, p < .001) as well as between fatigue and cognition (r²= .390, p < .01), independent of the impact of psychological status and age. Associations were evident in the domains of processing speed, attention, and memory, but were most consistently apparent on measures of executive function. Greater sleep disturbance was most consistently associated with poorer cognitive function. Unexpectedly, higher levels of fatigue were associated with better cognitive function, which may be explained by the coping hypothesis. Given sleep interventions have been shown to improve sleep disturbance, these findings suggest that sleep intervention may also result in improved cognition after mTBI.

Injuries to the Head and Face From Skateboarding: A 10-Year Analysis From National Electronic Injury Surveillance System Hospitals

PURPOSE

To estimate the incidence of patients presenting to emergency departments (EDs) as a result of facial trauma sustained from skateboarding.

PATIENTS AND METHODS

The National Electronic Injury Surveillance System (NEISS) database was queried for skateboard-related head and face fractures, contusions, abrasions, and lacerations from 2009 through 2018. We identified 2,519 reported injuries, extrapolating to a national incidence of 100,201 injuries. Fractures accounted for 14.1% of these visits. There were 355 ED visits for fractures, extrapolating to an estimated 11,893 visits nationally. Entries were tabulated for demographic information, fracture type, mechanism of injury, and disposition.

RESULTS

Patients sustaining injury to the head and face were aged 16 years, on average, and predominantly male patients (85.9%). Most patients sustaining fractures were male patients (87.9%), with a mean age of 18 years. The most common fracture types included unspecified skull fractures (31%), nasal fractures (29%), and mandibular fractures (18%). The most common mechanism of injury was falling off the skateboard while riding (76.9%). Collisions with motor vehicles also accounted for a substantial proportion of the injuries (7.3%).

CONCLUSIONS

A substantial number of ED visits were a result of skateboarding-related facial trauma. Given the neurologic outcomes of head trauma and functional consequences of facial fractures, especially among adolescents, our findings suggest that injury prevention programs and more aggressive helmet use may be necessary to reduce morbidity and hospitalization.

Predicting Concussion Outcome by Integrating Finite Element Modeling and Network Analysis

Concussion is a significant public health problem affecting 1.6-2.4 million Americans annually. An alternative to reducing the burden of concussion is to reduce its incidence with improved protective equipment and injury mitigation systems. Finite element (FE) models of the brain response to blunt trauma are often used to estimate injury potential and can lead to improved helmet designs. However, these models have yet to incorporate how the patterns of brain connectivity disruption after impact affects the relay of information in the injured brain. Furthermore, FE brain models typically do not consider the differences in individual brain structural connectivities and their purported role in concussion risk. Here, we use graph theory techniques to integrate brain deformations predicted from FE modeling with measurements of network efficiency to identify brain regions whose connectivity characteristics may influence concussion risk. We computed maximum principal strain in 129 brain regions using head kinematics measured from 53 professional football impact reconstructions that included concussive and non-concussive cases. In parallel, using diffusion spectrum imaging data from 30 healthy subjects, we simulated structural lesioning of each of the same 129 brain regions. We simulated lesioning by removing each region one at a time along with all its connections. In turn, we computed the resultant change in global efficiency to identify regions important for network communication. We found that brain regions that deformed the most during an impact did not overlap with regions most important for network communication (Pearson's correlation, ρ = 0.07; p = 0.45). Despite this dissimilarity, we found that predicting concussion incidence was equally accurate when considering either areas of high strain or of high importance to global efficiency. Interestingly, accuracy for concussion prediction varied considerably across the 30 healthy connectomes. These results suggest that individual network structure is an important confounding variable in concussion prediction and that further investigation of its role may improve concussion prediction and lead to the development of more effective protective equipment.

Reward presentation reduces on-task fatigue in traumatic brain injury

While cognitive fatigue is experienced by up to 80% of individuals with traumatic brain injury (TBI), little is known about its neural underpinnings. We previously hypothesized that presentation of rewarding outcomes leads to cognitive fatigue reduction and activation of the striatum, a brain region shown to be associated with cognitive fatigue in clinical populations and processing of rewarding outcomes. We have demonstrated this in individuals with multiple sclerosis. Here, we tested this hypothesis in individuals with TBI. Twenty-one individuals with TBI and 24 healthy participants underwent functional magnetic resonance imaging. Participants performed a task during which they were presented with 1) the Outcome condition where they were exposed to monetary rewards, and 2) the No Outcome condition that served as the control condition and was not associated with monetary rewards. In accordance with our hypothesis, results showed that attainment of rewarding outcomes leads to cognitive fatigue reduction in individuals with TBI, as well as activation of the striatum. Specifically, we observed a significant group by condition interaction on fatigue scores driven by the TBI group reporting lower levels of fatigue after the Outcome condition. fMRI data revealed a significant main-effect of condition in regions previously implicated in outcome processing, while a significant group by condition interaction was observed in the left ventral striatum as revealed by a priori region of interest analysis. Results suggest that a salient motivator can significantly reduce fatigue and that outcome presentation leads to increased activation of the ventral striatum in TBI. These findings can inform the development of future non-pharmacological cognitive fatigue treatment methods and contribute to the growing body of evidence showing the association between cognitive fatigue and the striatum.

Physiological and pathological covariates of persistent concussion-related fatigue: results from two regression methodologies

BACKGROUND

Fatigue severity in persons with mild traumatic brain injury (mTBI) has received little research attention, despite its typically positively skewed nature. Investigation of covariates across a range of fatigue severity may provide insight into important contributors.

OBJECTIVE

To assess the relative significance of a priori-hypothesized covariates of physiological and pathological (mental and physical) fatigue in persons with mTBI/concussion, applying ordinary least squares (OLS) and quantile regression (QR) approaches.

METHODS

We conducted a cross-sectional investigation in 80 participants with mTBI/concussion (mean age 45.4 ± 10.1 years, 59% male). The fatigue severity scale (FSS) was used as an outcome measure. Predictors of this outcome, grouped into physiological and pathological models of fatigue were assessed using OLS and QR.

RESULTS

The mean total FSS score was 46.13 ± 14.59, and the median was 49 (interquartile range 37-57), demonstrating positive skewness. Fatigue severity was associated with variables within the mental, psychological and psychiatric domains at different levels of the fatigue score distribution.

CONCLUSION

Results highlighted that some covariates had a significant impact on the FSS total score at non-central parts of its distribution, while others exhibited significant impact across the entire distribution. Addressing covariates of fatigue across the severity continuum can enhance research and clinical management.

Self-Reported Fatigue After Mild Traumatic Brain Injury Is Not Associated With Performance Fatigability During a Sustained Maximal Contraction

Patients with mild traumatic brain injury (mTBI) are frequently affected by fatigue. However, hardly any data is available on the fatigability of the motor system. We evaluated fatigue using the Fatigue Severity Scale (FSS) and Modified Fatigue Impact Scale (MFIS) questionnaires in 20 participants with mTBI (>3 months post injury; 8 females) and 20 age- and sex matched controls. Furthermore, index finger abduction force and electromyography of the first dorsal interosseous muscle of the right hand were measured during brief and sustained maximal voluntary contractions (MVC). Double pulse stimulation (100 Hz) was applied to the ulnar nerve to evoke doublet-forces before and after the sustained contraction. Seven superimposed twitches were evoked during the sustained MVC to quantify voluntary muscle activation. mTBI participants reported higher FSS scores (mTBI: 5.2 ± 0.8 SD vs. control: 2.8 ± 0.8 SD; P < 0.01). During the sustained MVC, force declined to similar levels in mTBI (30.0 ± 9.9% MVC) and control participants (32.7 ± 9.8% MVC, P = 0.37). The decline in doublet-forces after the sustained MVC (mTBI: to 37.2 ± 12.1 vs. control: to 41.4 ± 14.0% reference doublet, P = 0.32) and the superimposed twitches evoked during the sustained MVC (mTBI: median 9.3, range: 2.2-32.9 vs. control: median 10.3, range: 1.9-31.0% doublet_pre, P = 0.34) also did not differ between groups. Force decline was associated with decline in doublet-force (R ² = 0.50, P < 0.01) for both groups. Including a measure of voluntary muscle activation resulted in more explained variance for mTBI participants only. No associations between self-reported fatigue and force decline or voluntary muscle activation were found in mTBI participants. However, the physical subdomain of the MFIS was associated with the decline in doublet-force after the sustained MVC (R ² = 0.23, P = 0.04). These results indicate that after mTBI, increased levels of self-reported physical fatigue reflected increased fatigability due to changes in peripheral muscle properties, but not force decline or muscle activation. Additionally, muscle activation was more important to explain the decline in voluntary force (performance fatigability) after mTBI than in control participants.

Sleep and fatigue after TBI

BACKGROUND

Whilst post traumatic brain injury fatigue (PTBIF) and sleep disturbance are common sequelae following brain injury, underlying mechanisms, and the potential for targeted interventions remain unclear.

OBJECTIVE

To present a review of recent studies exploring the epidemiology of PTBIF and sleep disturbance, the relationship and neuropsychological correlates of these issues, potential approaches to intervention, and implications for neurorehabilitation.

METHODS

A review of relevant literature was undertaken, with a focus on PTBIF relating to sleep disturbance, the neuropsychological correlates of these issues and implications for neurorehabilitation. This paper does not set out to provide a systematic review.

RESULTS

Multidimensional approaches to assessment and treatment of sleep disturbance and PTBIF are required.

CONCLUSIONS

There is a need for more robust findings in determining the complex nature of relationships between PTBIF, sleep disturbance, and correlates. Longitudinal prospective data is required to increase our understanding of the nature and course of PTBIF and sleep disturbance post TBI. Large scale clinical trials are required in evaluating the potential benefits of interventions.

Post-stroke fatigue as an indicator of underlying bioenergetics alterations

Approximately half of stroke survivors suffer from clinically significant fatigue, contributing to poor quality of life, depression, dependency, and increased mortality. The etiology of post-stroke fatigue is not well understood and treatment is limited. This study tested the hypothesis that systemic aerobic energy metabolism, as reflected by platelet oxygen consumption, is negatively associated with fatigue and systemic inflammation is positively associated with fatigue in chronic ischemic stroke survivors. Data on self-reported level of fatigue, platelet oxygen consumption rates (OCR) and plasma inflammatory markers were analyzed from 20 ischemic stroke survivors. DNA copy number for two mitochondrial genes was measured as a marker of platelet mitochondrial content. Basal and protonophore-stimulated maximal platelet OCR showed a biphasic relationship to fatigue. Platelet OCR was negatively associated with low to moderate fatigue but was positively associated with moderate to high fatigue. DNA copy number was not associated with either fatigue or platelet OCR. Fatigue was negatively associated with C-reactive protein but not with other inflammatory markers. Post-stroke fatigue may be indicative of a systemic cellular energy dysfunction that is reflected in platelet energy metabolism. The biphasic relationship of fatigue to platelet OCR may indicate an ineffective bioenergetic compensatory response that has been observed in other pathological states.

Concussion education in Canadian medical schools: a 5 year follow-up survey

BACKGROUND

Despite concussion now being recognized as a public health priority in Canada, recent studies-including our 2012 survey of Canadian medical schools-have revealed major gaps in concussion education at the undergraduate medical school level.

METHODS

We re-surveyed all 17 Canadian medical schools using a questionnaire divided in two categories: (1) concussion-specific education (2) head injury education incorporating a concussion component to determine whether there have been any improvements in concussion education at the medical school level during the last five years. For each year of medical school, respondents were asked to provide the estimated number of hours and teaching format for each category.

RESULTS

We received replies from 13 of the 17 medical schools (76%). 11 of the 13 (85%) medical schools now reported providing concussion-specific education compared to 29% in our 2012 survey. The mean number of hours dedicated to category 1 learning in 2017 was 2.65 h compared to 0.57 in 2012, and the mean number of hours of category 2 increased to 7.5 from 1.54.

CONCLUSION

Our follow-up study reveals increased exposure to concussion-related teaching in Canadian medical schools during the last five years. Persistent deficiencies in a minority of schools are highlighted. These should be addressed by reiterating the importance of concussion education for undergraduate medical students and by developing clear concussion-specific objectives at the national licensure level.