Chronic Post-concussion Syndrome Research Articles

Reader Response: Exosomal Neurofilament Light: A Prognostic Biomarker for Remote Symptoms After Mild Traumatic Brain Injury?

Guedes et al.1 measured exosomal and plasma biomarkers in veterans with a history of mild traumatic brain injury (mTBI) and tested their relationships with chronic symptoms. Neurofilament light (NfL) chain, tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, and vascular endothelial growth factor were measured, and the symptoms of postconcussive syndrome (PCS), posttraumatic stress disorder (PTSD), and depression were evaluated. Repetitive mTBIs are associated with elevated exosomal and plasma levels of NfL chain, with the greatest elevations in those with chronic PCS, PTSD, and depression symptoms. The authors speculated that there is a possible neuroinflammatory and axonal disruptive basis for symptoms that persist years after mTBI, especially in repetitive cases. I have a concern about their study.

The Utility of Neuromotor Retraining to Augment Manual Therapy and Vestibular Rehabilitation in a Patient with Post-Concussion Syndrome: A Case Report

Background and PurposeLess than half of patients discharged from the emergency department post-concussion receive patient education or follow-up care, and 10-20% of individuals will develop symptoms that last longer than six months. Current research on interventions for post-concussion syndrome (PCS) shows inconsistent results, and recommendations for effective physical therapy treatment for patients with chronic PCS are lacking. The purpose of this case report is to highlight a successful, multi-system approach to physical therapy examination and treatment of a patient with chronic PCS.Case DescriptionThis case describes a 21-year-old male who sustained a concussion 356 days prior to evaluation. He received no follow-up treatment and reported periods of worsening symptoms since the injury. Impairments in cervical range of motion and accessory mobility, vestibular and vestibulo-ocular function, and postural stability were identified. Both cognitive and emotional symptoms were also present. The patient attended eight, sixty-minute sessions over a five-week period in an outpatient setting. Comprehensive physical therapy interventions included manual therapy, vestibular rehabilitation, and neuromotor retraining aimed at restoring proper sensory integration and midline postural orientation.OutcomesOutcomes included cervical spine goniometric measurements and accessory mobility assessments. Objective measures of postural stability included the Modified Clinical Test of Sensory Interaction in Balance (m-CTSIB) and the Fukuda Step Test. The Rivermead Post-Concussion Symptoms Questionnaire (RPQ) was used to subjectively assess symptom severity. At discharge, goniometric measurements returned to within normal limits except left cervical rotation active range of motion (ROM), and both the m-CTSIB and Fukuda Step Test were within normal ranges. The RPQ score reduced from 20 to 2 demonstrating symptom resolution in all items but “headache.”DiscussionPCS can affect multiple systems, necessitating a comprehensive approach to examination and intervention. Manual therapy was used to restore cervical spine ROM, vestibular rehabilitation was utilized to improve gaze stability and visual motion sensitivity, and neuromotor retraining was implemented to improve postural stability and sensory integration. Physical therapists have the ability to treat multiple systems impacted with PCS, with the potential to reduce the longevity and severity of impairments for patients.Level of EvidenceLevel V

Exosomal neurofilament light: A prognostic biomarker for remote symptoms after mild traumatic brain injury?

To measure exosomal and plasma levels of candidate blood biomarkers in veterans with history of mild traumatic brain injury (mTBI) and test their relationship with chronic symptoms. Exosomal and plasma levels of neurofilament light (NfL) chain, tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10, and vascular endothelial growth factor (VEGF) were measured using an ultrasensitive assay in a cohort of 195 veterans, enrolled in the Chronic Effects of Neurotrauma Consortium Longitudinal Study. We examined relationships between candidate biomarkers and symptoms of postconcussive syndrome (PCS), posttraumatic stress disorder (PTSD), and depression. Biomarker levels were compared among those with no traumatic brain injury (TBI) (controls), 1-2 mTBIs, and repetitive (3 or more) mTBIs. Elevated exosomal and plasma levels of NfL were associated with repetitive mTBIs and with chronic PCS, PTSD, and depression symptoms. Plasma TNF-α levels correlated with PCS and PTSD symptoms. The total number of mTBIs correlated with exosomal and plasma NfL levels and plasma IL-6. Increased number of years since the most recent TBI correlated with higher exosomal NfL and lower plasma IL-6 levels, while increased number of years since first TBI correlated with higher levels of exosomal and plasma NfL, as well as plasma TNF-α and VEGF. Repetitive mTBIs are associated with elevated exosomal and plasma levels of NfL, even years following these injuries, with the greatest elevations in those with chronic PCS, PTSD, and depression symptoms. Our results suggest a possible neuroinflammatory and axonal disruptive basis for symptoms that persist years after mTBI, especially repetitive.

Ensuring and maintaining brain health of the combat sport athlete

Professional boxing and mixed martial arts (MMA) are popular sports with high risk for both acute and chronic traumatic brain injury (TBI). Acute catastrophic neurological injuries include subdural hematoma (SDH), epidural hematoma (EDH), subarachnoid hemorrhage (SAH), intracranial hemorrhage (ICH) and second-impact syndrome (SIS). Late-life neuropsychologic sequelae of repeated brain injury include chronic traumatic encephalopathy (CTE), dementia pugilistica, chronic post-concussion syndrome, posttraumatic dementia, posttraumatic cognitive impairment, posttraumatic Parkinsonism and chronic posttraumatic headache. Urgent measures are needed to ensure and maintain the brain health of the combat sport athlete. In the commentary that follows, some of these measures are discussed.

Impact of Pre-Existing Migraine and Other Co-Morbid or Co-Occurring Conditions on Presentation and Clinical Course Following Deployment-Related Concussion.

To describe the clinical presentation and early clinical course of a sample of deployed U.S. military service members following concussion, underscoring the impact of pre-existing migraine and other co-occurring conditions. It is important to obtain a comprehensive clinical history to identify evidence of underlying migraine and other health conditions which may contribute to an individual's presenting symptoms influencing early management and outcomes following concussion. Early outcome measures assessed include headache treatment response and fitness for return to duty. Acute concussion is reported to result in an array of somatic, cognitive, and behavioral symptoms. It is well established that these symptoms are not specific for concussion and may result from exacerbation of pre-existing or underlying medical conditions and factors. Although most symptoms attributable to concussion resolve within days to weeks, there is evidence that persistent symptoms beyond that specific recovery time may be attributable to factors other than concussion. Military populations are at risk for a number of recognized co-morbid and co-occurring conditions, as well as special situational and psychosocial factors which may influence symptoms and clinical course following concussion. In addition, combat-related concussion frequently occurs in the setting of a blast or military vehicle accidents thus causing concurrent injuries where musculoskeletal injuries may contribute to the clinical presentation. The resultant acute stress reaction, secondary to the traumatic experience associated with concussion, may also cause or aggravate underlying psychological co-morbidities that may influence presenting symptoms. Prior studies identified co-morbidities associated with chronic post-concussive syndrome, which we find are also present during the early phase following deployment-related concussion, thereby influencing presentation and impacting recovery. This retrospective chart review was intended to demonstrate the presence and potential impact of co-morbid and co-occurring conditions contributing to symptoms following concussion, especially migraine due to its high prevalence among post-traumatic headaches. Retrospective chart review was performed by the treating neurologist of 40 service members following concussion in the deployed environment. Clinical symptoms and co-morbid and co-occurring conditions including evidence of pre-existing migraine identified during comprehensive neurologic evaluations were collected. Both pre-deployment/pre-traumatic and post-traumatic headache features supporting migraine and early instituted headache management and treatment response are described. Rates of return to duty in this sample were also tabulated. Headaches were the most frequently reported acute symptom following concussion in this deployed service member population (38/40 patients [98%]), followed by insomnia, tinnitus, impaired concentration, nausea, dizziness, anxiety, impaired balance, depression, and hearing loss. Co-occurring acute injuries, acute stress reaction, and recent onset medication overuse were the most frequent co-occurring conditions identified by the treating neurologist as potentially contributing to the service member's presentation. Chronic co-morbidities identified included chronic headache, anxiety/depression, insomnia, and post-traumatic stress disorder. Service members with 3 or more identified co-morbidities or co-occurring conditions were more likely to require evacuation from theater. Pre-deployment headaches were reported by 25/40 [63%] service members, with 5/40 [12.5%] reporting known prior personal history of migraine. Of those reporting pre-deployment headaches, 21/25 [84%] described migraine features and/or triggers, though most [(15/25) 60%] reported as infrequent. Daily post-traumatic headaches were frequent (26/38 [68%]) and associated with typical migraine features and/or triggers. Of those treated with triptans (16/40 patient [42%]), most (12/16 patient [75%]) showed positive treatment response. Concussion in the deployed settings does not occur in isolation, with co-morbid and co-occurring conditions being common. Presence of multiple co-morbidities appears to influence clinical course and overall recovery. Post-traumatic headaches are often phenotypically fully consistent with migraine, and appear related to pre-existing migraine if supported by detailed pre-deployment headache history suggesting same. Careful and comprehensive history taking and evaluation is invaluable in identifying associated conditions including migraine, potentially helping clinicians with more accurate symptom attribution, diagnoses, and improved clinical management following acute concussion.

A different aspect of the unexpected death of Mozart at the age of 35 years.

The cause of the early death of Wolfgang Amadeus Mozart (1756-1791) at the age of 35 has been the source of much discussion in the medical community. Investigators attributed to Mozart nearly 150 different medical diagnoses. However, the neurosurgical aspect of the early death of Mozart has yet to be well-analyzed, and this subject was investigated herein. The key words "Mozart" and "Mozart's death" were searched in PubMed as well as the libraries of universities. The main source was the archive and website of Internationale Stiftung MOZARTEUM/Salzburg (www.mozarteum.at) and the cranium stored in the Internationale Stiftung Mozarteum in Salzburg/Austria. The linear fracture of the cranium is important, since it shows the neurosurgical aspect of the early death of Mozart. Mozart's disease was most likely a neurotraumatologic one. His fracture likely occurred several months before his death, as evidenced by signs of healing. Intense headaches and declining musical performance in his last year may have been influenced by intracranial hemorrhage induced by the linear fracture. His final disease therefore may have been chronic postconcussion syndrome depending on chronic calcified epidural hematoma.

Scale for retrospective assessment of immediate concussion symptoms.

The retrospective diagnosis of concussion is often missed by clinicians. We present a brief scale for retrospective assessment of the immediate concussion symptoms (ICS) to facilitate the diagnosis of patients without visible head injury or full loss of consciousness. We administered the scale to 90 survivors of car accidents (mean age 42.0, SD=13.6; 33 males, 57 females) at 2 to 33 months after their accident. Our scale consists of 6 items and these were endorsed by the following % of our respondents: feeling dazed (64.4% of our 90 respondents), stunned (73.3%), confused (70.0%), disoriented (62.2%), dizzy (57.8%), and loss of consciousness (22.2%). The statistical properties of the scale are satisfactory (Cronbach alpha = 0.74). The scale correlates with post-accident insomnia (r=0.28), depression (r=0.29), and also with Rivermead measure of the chronic post-concussion syndrome (r=0.34). The ICS scale could be used as a starting point in longitudinal research with brain imaging procedures to evaluate the stages of recovery from the initial concussion. Attached are the English, Spanish, French, German, Italian, Russian, and Czech versions of our scale.

Scale for retrospective assessment of immediate concussion symptoms

The retrospective diagnosis of concussion is often missed by clinicians. We present a brief scale for retrospective assessment of the immediate concussion symptoms (ICS) to facilitate the diagnosis of patients without visible head injury or full loss of consciousness. We administered the scale to 90 survivors of car accidents (mean age 42.0, SD=13.6; 33 males, 57 females) at 2 to 33 months after their accident. Our scale consists of 6 items and these were endorsed by the following % of our respondents: feeling dazed (64.4% of our 90 respondents), stunned (73.3%), confused (70.0%), disoriented (62.2%), dizzy (57.8%), and loss of consciousness (22.2%). The statistical properties of the scale are satisfactory (Cronbach alpha = 0.74). The scale correlates with post-accident insomnia (r=0.28), depression (r=0.29), and also with Rivermead measure of the chronic post-concussion syndrome (r=0.34). The ICS scale could be used as a starting point in longitudinal research with brain imaging procedures to evaluate the stages of recovery from the initial concussion. Attached are the English, Spanish, French, German, Italian, Russian, and Czech versions of our scale.

Head-Eye Vestibular Motion Therapy Affects the Mental and Physical Health of Severe Chronic Postconcussion Patients.

Approximately 1.8-3.6 million annual traumatic brain injuries occur in the United States. An evidence-based treatment for concussions that is reliable and effective has not been available. The objective of this study is to test whether head-eye vestibular motion (HEVM) therapy is associated with decreased symptoms and increased function in postconcussive syndrome (PCS) patients that have been severely impaired for greater than 6 months after a mild traumatic brain injury. Retrospective clinical chart review. Tertiary Specialist Brain Rehabilitation Center. All subjects underwent comprehensive neurological examinations including measurement of eye and head movement. The seven modules of the C3 Logix Comprehensive Concussion Management System were used for pre- and postmeasurements of outcome of HEVM therapy. We utilized an objective validated measurement of physical and mental health characteristics of our patients before and after a 1-week HEVM rehabilitation program. We included only PCS patients that were disabled from work or school for a period of time exceeding 6 months after suffering a sports concussion. These subjects all were enrolled in a 5-day HEVM rehabilitation program at our Institutional Brain Center with pre- and post-C3 Logix testing outcomes. There were statistical and substantive significant decreases in PCS symptom severity after treatment and statistical and substantive significant increases in standardized assessment of concussion scores. The outcomes were associated with positive changes in mental and physical health issues. This is a retrospective review and no control group has been included in this study. These are major limitations with retrospective reviews and further investigations with prospective designs including a randomized controlled study are necessary to further our understanding. Head-eye vestibular motion therapy of 5 days duration is associated with statistical and substantive significant decreases of symptom severity associated with chronic PCS.

Premorbid IQ Predicts Postconcussive Symptoms in OEF/OIF/OND Veterans with mTBI.

Extant literature has demonstrated that symptoms of postconcussive syndrome (PCS) persist well beyond the expected 3-month post-injury recovery period in a minority of individuals with mild traumatic brain injury (mTBI). Suboptimal performance on validity measures and pre- and post-injury psychosocial stressors - rather than actual mTBI or current cognitive functioning - have been identified as predictors of chronic PCS. Whether premorbid IQ has any influence on chronic PCS has been understudied, in the context of established psychogenic etiologies. The sample included 31 veterans, who underwent mTBI neuropsychological evaluations six or more months post-injury in a VA outpatient neuropsychology clinic. A two-step multiple linear regression was conducted to examine the effects on the outcome variable, PCS (Neurobehavioral Symptom Inventory), of the following predictors: cognitive functioning (Repeatable Battery for the Assessment of Neuropsychological Status; Attention, Immediate Memory, and Delayed Memory Indices), performance validity, depression (Beck Depression Inventory-Second Edition), posttraumatic stress disorder (PTSD Checklist, Civilian Version), quality of sleep (Pittsburgh Sleep Quality Index), pain (Brief Pain Inventory), education, and Premorbid IQ (Wechsler Test of Adult Reading). The overall regression model containing all nine predictor variables was statistically significant. Depression (p < .05) and premorbid IQ (p < .05) were the most salient predictors of chronic PCS; in that lower premorbid IQ and greater endorsed symptoms of depression were associated with higher PCS scores. In Step 2 of the multiple linear regression, the WTAR explained an additional 6.7% of the variance in PCS after controlling for psychosocial stressors and current cognitive ability. The findings support premorbid IQ as a unique and relevant predictor of chronic PCS, with significance variance accounted for beyond education, cognitive functioning, and psychosocial variables. Given the predictive relationship between premorbid IQ and PCS, adapting postconcussive interventions to meet the specific needs of individuals with varying levels of intellect may be important in minimizing ongoing symptomatology.

Is There a Gender Bias Involving Impulsivity and Number of Concussions?

- To characterize the relationship between impulsivity and number of concussion during long term recovery from mild head injury (mTBI) as measured by the chronic post-concussion syndrome (CPCS). The ImPACT Neurocognitive test and oculomotor behaviors.

Post mTBI fatigue is associated with abnormal brain functional connectivity.

This study set out to investigate the behavioral correlates of changes in resting-state functional connectivity before and after performing a 20 minute continuous psychomotor vigilance task (PVT) for patients with chronic post-concussion syndrome. Ten patients in chronic phase after mild traumatic brain injury (mTBI) with persisting symptoms of fatigue and ten matched healthy controls participated in the study. We assessed the participants’ fatigue levels and conducted resting-state fMRI before and after a sustained PVT. We evaluated the changes in brain functional connectivity indices in relation to the subject’s fatigue behavior using a quantitative data-driven analysis approach. We found that the PVT invoked significant mental fatigue and specific functional connectivity changes in mTBI patients. Furthermore, we found a significant linear correlation between self-reported fatigue and functional connectivity in the thalamus and middle frontal cortex. Our findings indicate that resting-state fMRI measurements may be a useful indicator of performance potential and a marker of fatigue level in the neural attentional system.

Post-Concussion Syndrome after a Mild Traumatic Brain Injury: A Minefield for Clinical Practice

In this clinical practice review, the controversies and difficulties managing post concussion symptoms following mild traumatic brain injury are discussed. Based on considerable clinical experience in a designated Concussion Clinic, the authors (a neuropsychologist, a psychiatrist, and a neurologist) review relevant literature and issues for clinical practice, particularly with respect to understanding risk factors for and vulnerability to, development of chronic post-concussion symptoms. We contend it is not just the kind of head that matters but also the kind of complications, the kind of outcomes and the kind of management that can influence injury recovery. Given these complexities, a bio-psychosocial conceptualization of chronic post-concussion syndrome is appropriate. Though understanding is still elusive, management should not be biased by physiogenic or psychogenic aetiological theories for management needs to address patient reported outcomes regardless of underpinning aetiology.

Is the Near Point Convergence Test a Valid Assessment of Chronic Post Concussion Recovery?

To characterize relationship between oculomotor convergence insufficiency (CI) during long term recovery from mild head injury (mTBI) as measured by the near-point convergence test (NPCT) and other symptomology common to chronic post-concussion syndrome (CPCS). The NPCT evaluates eye alignment to converge as an object is slowly moved towards the eyes.

Disruptions in Resting State Functional Connectivity and Cerebral Blood Flow in Mild Traumatic Brain Injury Patients.

Mild traumatic brain injury (mTBI) is often occult to conventional imaging techniques. However, there is growing evidence that mTBI patients who lack evidence of structural intracranial injury may develop post-concussive syndrome (PCS). We investigated longitudinal alterations in resting state functional connectivity (rs-FC) in brain networks in a population of 28 patients compared to 28 matched control participants. Rs-FC and cerebral blood flow (CBF) within the nodes of the Default Mode Network (DMN) and Task Positive Network (TPN) were assessed at three time points including acute, sub-acute, and chronic stages following mTBI. Participants received the Automated Neuropsychological Assessment Metrics (ANAM) to assess cognitive performance. Main findings indicate that despite normalized cognitive performance, chronic mTBI patients demonstrate increased rs-FC between the DMN and regions associated with the salience network (SN) and TPN compared to the control populations, as well as reduced strength of rs-FC within the DMN at the acute stage of injury. In addition, chronic mTBI patients demonstrate an imbalance in the ratio of CBF between nodes of the DMN and TPN. Furthermore, preliminary exploratory analysis suggests that compared to those without chronic PCS, patients with chronic PCS reveal an imbalance in the ratio of CBF between the DMN nodes and TPN nodes across multiple stages of recovery. Findings suggest that the altered network perfusion with the associated changes in rs-FC may be a possible predictor of which mTBI patients will develop chronic PCS.

Temporal MRI characterization, neurobiochemical and neurobehavioral changes in a mouse repetitive concussive head injury model

Single and repeated sports-related mild traumatic brain injury (mTBI), also referred to as concussion, can result in chronic post-concussive syndrome (PCS), neuropsychological and cognitive deficits, or chronic traumatic encephalopathy (CTE). However PCS is often difficult to diagnose using routine clinical, neuroimaging or laboratory evaluations, while CTE currently only can be definitively diagnosed postmortem. We sought to develop an animal model to simulate human repetitive concussive head injury for systematic study. In this study, mice received single or multiple head impacts by a stereotaxic impact device with a custom-made rubber tip-fitted impactor. Dynamic changes in MRI, neurobiochemical markers (Tau hyperphosphorylation and glia activation in brain tissues) and neurobehavioral functions such as anxiety, depression, motor function and cognitive function at various acute/subacute (1-7 day post-injury) and chronic (14-60 days post-injury) time points were examined. To explore the potential biomarkers of rCHI, serum levels of total Tau (T-Tau) and phosphorylated Tau (P-Tau) were also monitored at various time points. Our results show temporal dynamics of MRI consistent with structural perturbation in the acute phase and neurobiochemical changes (P-Tau and GFAP induction) in the subacute and chronic phase as well as development of chronic neurobehavioral changes, which resemble those observed in mTBI patients.

Personality and neuroimaging measures differentiate PTSD from mTBI in veterans.

Mild traumatic brain injury (mTBI) is common among recent veterans and often is associated with chronic post-concussive symptoms (PCS). Elevated PCS may also be a consequence of post-traumatic stress disorder (PTSD) which shares symptoms with PCS. Identification of personality, biological, and psychopathology factors that contribute to the relationship between mTBI and PCS could help isolate the sources of chronic post concussive syndrome in veterans. Clinician rated diagnoses (PTSD, Major Depression, Alcohol Dependence), personality characteristics (Multidimensional Personality Questionnaire [MPQ] subscales), white matter brain imaging measures (Mean Diffusivity, Generalized Fractional Anisotropy), and diagnoses of mTBI were collected from 125 American military veterans of Iraq or Afghanistan. Linear and logistic regression models were tested to determine contributions to PCS and whether there were similar contributors to PTSD and mTBI. PCS score was associated with personality characteristics of high Stress Reaction and Traditionalism and low Control as well as mTBI. A diagnosis of PTSD was associated with low Social Closeness, PCS, Alcohol Dependence, and abnormal white matter mean diffusivity. Diagnosis of mTBI was associated with fewer white matter mean diffusivity abnormalities, PCS, and number of deployments. As commonly observed clinically, both PTSD and mTBI were associated with higher rates of PCS, though the contribution of PTSD appears to be secondary to personality traits, particularly Stress Reaction. Furthermore, the observation of factors that are uniquely associated with Blast mTBI (number of deployments) or with PTSD (Lifetime Alcohol Dependence and low Social Closeness), as well as a factor (region of abnormal MD) that had opposite effects on the likelihood of each diagnosis, indicates that the complex relationships between personality, psychopathology, and nature of mTBI need to be considered when interpreting chronic post-concussive symptoms.

Chronic traumatic encephalopathy and other long-term sequelae.

Growing public health concern exists over the incidence of chronic traumatic brain injury (TBI) in athletes participating in contact sports. Chronic TBI represents a spectrum of disorders associated with long-term consequences of single or repetitive TBI and includes chronic traumatic encephalopathy (CTE), chronic postconcussion syndrome, and chronic neurocognitive impairment. Neurologists should be familiar with the different types of chronic TBI and their diagnostic criteria. CTE is the most severe chronic TBI and represents the neurologic consequences of repetitive mild TBI. It is particularly noted among boxers and football players. CTE presents with behavioral, cognitive, and motor symptoms, and can only be definitively diagnosed postmortem. Chronic postconcussion syndrome is defined as postconcussion symptoms that last longer than 1 year and do not appear to resolve; it may develop after a single concussive event. Chronic neurocognitive impairment is an all-encompassing clinical term denoting long-term neurologic sequelae secondary to sports-related trauma and can present either within the postconcussion syndrome or years after a symptom-free interval. This article discusses the diagnostic evaluation of chronic TBI, including clinical history, neurologic examination, neuropsychological testing, neuroimaging, and laboratory testing, as well as the distinctions between CTE, chronic postconcussion syndrome, and chronic neurocognitive impairment. Neurologic impairment among athletes exposed to repetitive brain injury appears to be a real phenomenon. Because CTE has no established treatment, prevention is of paramount importance for athletes participating in contact sports.

The influence of injury cause, contact-sport participation, and personal knowledge on expectation of outcome from mild traumatic brain injury

Objective: This study investigated the influence of injury cause, contact-sport participation, and prior knowledge of mild traumatic brain injury (mTBI) on injury beliefs and chronic symptom expectations of mTBI. Method: A total of 185 non-contact-sport players (non-CSPs) and 59 contact-sport players (CSPs) with no history of mTBI were randomly allocated to one of two conditions in which they read either a vignette depicting a sport-related mTBI (mTBIsport) or a motor-vehicle-accident-related mTBI (mTBIMVA). The vignettes were otherwise standardized to convey the same injury parameters (e.g., duration of loss of consciousness). After reading a vignette, participants reported their injury beliefs (i.e., perceptions of injury undesirability, chronicity, and consequences) and their expectations of chronic postconcussion syndrome (PCS) and posttraumatic stress disorder (PTSD) symptoms. Results: Non-CSPs held significantly more negative beliefs and expected greater PTSD symptomatology and greater PCS affective symptomatology from an mTBIMVA vignette thann mTBIsport vignette, but this difference was not found for CSPs. Unlike CSPs, non-CSPs who personally knew someone who had sustained an mTBI expected significantly less PCS symptomatology than those who did not. Despite these different results for non-CSPs and CSPs, overall, contact-sport participation did not significantly affect injury beliefs and symptom expectations from an mTBIsport. Conclusions: Expectations of persistent problems after an mTBI are influenced by factors such as injury cause even when injury parameters are held constant. Personal knowledge of mTBI, but not contact sport participation, may account for some variability in mTBI beliefs and expectations. These factors require consideration when assessing mTBI outcome.

Hyperbaric oxygen therapy for chronic post-concussive syndrome

In this editorial, the value of hyperbaric oxygen therapy in the management of chronic post-concussive syndrome following mild traumatic brain injury is discussed.