Postconcussion syndrome: demographics and predictors in 221 patients

Widespread White Matter Abnormalities in Concussed Athletes Detected by 7T Diffusion Magnetic Resonance Imaging

Sports-related concussions may cause white matter injuries and persistent post-concussive symptoms (PPCS). We hypothesized that athletes with PPCS would have neurocognitive impairments and white matter abnormalities that could be revealed by advanced neuroimaging using ultra-high field strength diffusion tensor (DTI) and diffusion kurtosis (DKI) imaging metrics and cerebrospinal fluid (CSF) biomarkers. A cohort of athletes with PPCS severity limiting the ability to work/study and participate in sport school and/or social activities for ≥6 months completed 7T magnetic resonance imaging (MRI) (morphological T1-weighed volumetry, DTI and DKI), extensive neuropsychological testing, symptom rating, and CSF biomarker sampling. Twenty-two athletes with PPCS and 22 controls were included. Concussed athletes performed below norms and significantly lower than controls on all but one of the psychometric neuropsychology tests. Supratentorial white and gray matter, as well as hippocampal volumes did not differ between concussed athletes and controls. However, of the 72 examined white matter tracts, 16% of DTI and 35% of DKI metrics (in total 28%) were significantly different between concussed athletes and controls. DKI fractional anisotropy and axial kurtosis were increased, and DKI radial diffusivity and radial kurtosis decreased in concussed athletes when compared with controls. CSF neurofilament light (NfL; an axonal injury marker), although not glial fibrillary acidic protein, correlated with several diffusion metrics. In this first 7T DTI and DKI study investigating PPCS, widespread microstructural alterations were observed in the white matter, correlating with CSF markers of axonal injury. More white matter changes were observed using DKI than using DTI. These white matter alterations may indicate persistent pathophysiological processes following concussion in sport.

Cause of Concussion With Persisting Symptoms Is Associated With Long-Term Recovery and Symptom Type, Duration, and Number in a Longitudinal Cohort of 600 Patients

It is important for patients and clinicians to know the potential for recovery from concussion as soon as possible after injury, especially in patients who do not recover completely in the first month and have concussion with persisting concussion symptoms (C+PCS). We assessed the association between the causes of concussion and recovery from C+PCS in a consecutive retrospective and prospective cohort of 600 patients referred to the Canadian Concussion Center (CCC) at Toronto Western Hospital. Data were obtained from clinical records and follow-up questionnaires and not from a standardized database. A novel method was used to assess long-term recovery, and multi-variable Cox proportional hazards models were used to assess relationships between cause of concussion and time to recovery. We examined the subsequent recovery of patients who had not recovered after at least one month from the time of concussion. Patients were grouped into the following four causes: sports and recreation (S&R, n = 312, 52%); motor vehicle collisions (MVC, n = 103, 17%); falls (n = 100, 17%); and being struck by an object including violence (SBOV, n = 85, 14%). The MVC group had the highest percentage of females (75.7%), the oldest participants (median: 40.0 [interquartile range (IQR):30.5-49.0] years), the most symptoms (median:11.0 [IQR:8.5-15.0]), and the longest symptom duration (median: 28.0 [IQR:12.0-56.00] months). In contrast, the S&R group had the highest percentage of males (58.1%), the youngest participants (median:20.0 [IQR:17.0-30.0] years), the best recovery outcome, and shortest symptom duration (median:22.0 [IQR:8.0-49.5] months). Significant differences among the four causes included age (p < 0.001), sex (p < 0.001), number of previous concussions (p < 0.001), history of psychiatric disorders (p = 0.002), and migraine (p = 0.001). Recovery from concussion was categorized into three groups: (1) Complete Recovery occurred in only 60 (10%) patients with median time 8.0 (IQR:3.5-18.0) months and included 42 S&R, 7 MVC, 8 falls, and 3 SBOV; (2) Incomplete Recovery occurred in 408 (68.0%) patients with persisting median symptom time of 5.0 (IQR:2.0-12.0) months; and (3) Unknown Recovery occurred in 132 (22.0%) patients and was because of lack of follow-up. In summary, the cause of C+PCS was associated with the type, number, and duration of symptoms and time required for recovery, although all causes of C+PCS produced prolonged symptoms in a large percentage of patients, which emphasizes the importance of concussions as a public health concern necessitating improved prevention and treatment strategies.

A Proposed Mechanism for Visual Vertigo: Post-Concussion Patients Have Higher Gain From Visual Input Into Subcortical Gaze Stabilization

Purpose

Post-concussion syndrome (PCS) is commonly associated with dizziness and visual motion sensitivity. This case-control study set out to explore altered motion processing in PCS by measuring gaze stabilization as a reflection of the capacity of the brain to integrate motion, and it aimed to uncover mechanisms of injury where invasive subcortical recordings are not feasible.

Methods

A total of 554 eye movements were analyzed in 10 PCS patients and nine healthy controls across 171 trials. Optokinetic and vestibulo-ocular reflexes were recorded using a head-mounted eye tracker while participants were exposed to visual, vestibular, and visuo-vestibular motion stimulations in the roll plane. Torsional and vergence eye movements were analyzed in terms of slow-phase velocities, gain, nystagmus frequency, and sensory-specific contributions toward gaze stabilization.

Results

Participants expressed eye-movement responses consistent with expected gaze stabilization; slow phases were fastest for visuo-vestibular trials and slowest for visual stimulations (P < 0.001) and increased with stimulus acceleration (P < 0.001). Concussed patients demonstrated increased gain from visual input to gaze stabilization (P = 0.005), faster slow phases (P = 0.013), earlier nystagmus beats (P = 0.003), and higher relative visual influence over the gaze-stabilizing response (P = 0.001), presenting robust effect sizes despite the limited population size.

Conclusions

The enhanced neural responsiveness to visual motion in PCS, combined with semi-intact visuo-vestibular integration, presented a subcortical hierarchy for altered gaze stabilization. Drawing on comparable animal trials, findings suggest that concussed patients may suffer from diffuse injuries to inhibiting pathways for optokinetic information, likely early in the visuo-vestibular hierarchy of sensorimotor integration. These findings offer context for common but elusive symptoms, presenting a neurological explanation for motion sensitivity and visual vertigo in PCS.

Longitudinal Associations Between Persistent Post-Concussion Symptoms and Blood Biomarkers of Inflammation and CNS-Injury After Mild Traumatic Brain Injury

The aim of our study was to investigate the biological underpinnings of persistent post-concussion symptoms (PPCS) at 3 months following mild traumatic brain injury (mTBI). Patients (n = 192, age 16-60 years) with mTBI, defined as Glasgow Coma Scale (GCS) score between 13 and 15, loss of consciousness (LOC) <30 min, and post-traumatic amnesia (PTA) <24 h were included. Blood samples were collected at admission (within 72 h), 2 weeks, and 3 months. Concentrations of blood biomarkers associated with central nervous system (CNS) damage (glial fibrillary acidic protein [GFAP], neurofilament light [NFL], and tau) and inflammation (interferon gamma [IFNγ], interleukin [IL]-8, eotaxin, macrophage inflammatory protein-1-beta [MIP]-1β, monocyte chemoattractant protein [MCP]-1, interferon-gamma-inducible protein [IP]-10, IL-17A, IL-9, tumor necrosis factor [TNF], basic fibroblast growth factor [FGF]-basic platelet-derived growth factor [PDGF], and IL-1 receptor antagonist [IL-1ra]) were obtained. Demographic and injury-related factors investigated were age, sex, GCS score, LOC, PTA duration, traumatic intracranial finding on magnetic resonance imaging (MRI; within 72 h), and extracranial injuries. Delta values, that is, time-point differences in biomarker concentrations between 2 weeks minus admission and 3 months minus admission, were also calculated. PPCS was assessed with the British Columbia Post-Concussion Symptom Inventory (BC-PSI). In single variable analyses, longer PTA duration and a higher proportion of intracranial findings on MRI were found in the PPCS group, but no single biomarker differentiated those with PPCS from those without. In multi-variable models, female sex, longer PTA duration, MRI findings, and lower GCS scores were associated with increased risk of PPCS. Inflammation markers, but not GFAP, NFL, or tau, were associated with PPCS. At admission, higher concentrations of IL-8 and IL-9 and lower concentrations of TNF, IL-17a, and MCP-1 were associated with greater likelihood of PPCS; at 2 weeks, higher IL-8 and lower IFNγ were associated with PPCS; at 3 months, higher PDGF was associated with PPCS. Higher delta values of PDGF, IL-17A, and FGF-basic at 2 weeks compared with admission, MCP-1 at 3 months compared with admission, and TNF at 2 weeks and 3 months compared with admission were associated with greater likelihood of PPCS. Higher IL-9 delta values at both time-point comparisons were negatively associated with PPCS. Discriminability of individual CNS-injury and inflammation biomarkers for PPCS was around chance level, whereas the optimal combination of biomarkers yielded areas under the curve (AUCs) between 0.62 and 0.73. We demonstrate a role of biological factors on PPCS, including both positive and negative effects of inflammation biomarkers that differed based on sampling time-point after mTBI. PPCS was associated more with acute inflammatory processes, rather than ongoing inflammation or CNS-injury biomarkers. However, the modest discriminative ability of the models suggests other factors are more important in the development of PPCS.

A Narrative Review Of Risk Factors And Predictors For Poor Outcome And Prolonged Recovery After A Mild Traumatic Brain Injury

MATERIAL AND METHODS

A comprehensive search of the main scientific databases (PubMed, Web of Science, Embase, and Cochrane Library) was performed using keywords, such as: "prolonged post-concussion syndrome", combined with "risk factors", "predictors", and "outcomes".

RESULTS

Multiple studies reported more than one risk factor for PPCS development following mTBIs that were generally the results of sports-related concussions and car accidents. The most prevalent risk factor associated with PPCS was the female sex. Social factors/personality traits, anxiety, mental health disorders, or other health conditions from their past medical history, the occurrence of headache/migraines during TBI recovery, somatization, physical activity, and litigation were also reported to contribute to PPCS risk.

CONCLUSIONS

An exhaustive approach is required to mitigate the risk of PPCS and to ensure optimal recovery after concussive events. However, larger prospective cohort studies evaluating patients that were examined and treated with standardized protocols could be needed to further validate these associations and mandate the highest risk factors for delayed recovery.

A Scoping Review on the Use of Non-Invasive Brain Stimulation Techniques for Persistent Post-Concussive Symptoms

BACKGROUND

In the context of managing persistent post-concussive symptoms (PPCS), existing treatments like pharmacotherapy, cognitive behavioral therapy, and physical rehabilitation show only moderate effectiveness. The emergence of neuromodulation techniques in PPCS management has led to debates regarding optimal stimulation parameters and their overall efficacy.

METHODS

this scoping review involved a comprehensive search of PubMed and ScienceDirect databases, focusing on controlled studies examining the therapeutic potential of non-invasive brain stimulation (NIBS) techniques in adults with PPCS.

RESULTS

Among the 940 abstracts screened, only five studies, encompassing 103 patients (12 to 29 per study), met the inclusion criteria. These studies assessed the efficacy of transcranial direct current stimulation (tDCS), or repetitive transcranial magnetic stimulation (rTMS), applied to specific brain regions (i.e., the left dorsolateral pre-frontal cortex (DLPFC) or left motor cortex (M1)) for addressing cognitive and psychological symptoms, headaches, and general PPCSs. The results indicated improvements in cognitive functions with tDCS. In contrast, reductions in headache intensity and depression scores were observed with rTMS, while no significant findings were noted for general symptoms with rTMS.

CONCLUSION

although these pilot studies suggest promise for rTMS and tDCS in PPCS management, further research with larger-scale investigations and standardized protocols is imperative to enhance treatment outcomes for PPCS patients.

Axonal injury mediated by neuronal p75NTR/TRAF6/JNK pathway contributes to cognitive impairment after repetitive mTBI

Repetitive mild traumatic brain injury (rmTBI) is one of the leading causes of cognitive disorders. The impairment of axonal integrity induced by rmTBI is speculated to underlie the progression of cognitive dysfunction. However, few studies have uncovered the cellular mechanism regulating axonal impairment. In this study, we showed that after rmTBI, the activation of neuronal p75NTR signaling contributes to abnormal axonal morphology and impaired axonal transport, which further leads to cognitive dysfunction in mice. By neuron-specific knockdown of p75NTR or treatment with p75NTR inhibitor LM11A-31, we observed better recovery of axonal integrity and cognitive function after brain trauma. Further analysis revealed that p75NTR relies on its adaptor protein TRAF6 to activate downstream signaling via TAK1 and JNK. Overall, our results provide novel insight into the role of neuronal p75NTR in axonal injury and suggest that p75NTR may be a promising target for cognitive function recovery after rmTBI.

Effectiveness of Non-Pharmacological Therapy on Physical Symptoms in Patients With Persistent Concussion Symptoms: A Systematic Review

This systematic review provides a comprehensive overview on the effectiveness of rehabilitation on physical symptoms in patients of all ages with persistent concussion symptoms. PubMed, MEDLINE®, Cochrane library, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Embase were searched from January 1, 2012 to September 1, 2023 using terms related to physical post-concussion symptoms. Eligible articles were critically appraised using the Scottish Intercollegiate Guidelines Network (SIGN) and the Quality Assessment Tool. The Grading of Recommendations Assessment, Development, and Evaluation system was applied to rate the quality of evidence. Thirty-two articles were included. Preliminary evidence suggests that transcranial magnetic stimulation improves symptoms in adults, specifically headaches. Young adults reported a significant decrease in physical symptoms following sub-symptom aerobic training as well as cervical spine manual therapy. Tentatively, adults demonstrated improvements in headache symptoms following neurofeedback sessions, and progressive muscle relaxation resulted in a decrease in monthly headaches. Multimodal therapy in adults produced significant change in physical symptoms when compared with usual care. However, no further reduction in physical symptoms was observed when adult patients received a program of care that afforded cervicovestibular rehabilitation with symptom-limited exercise compared with a symptom-limited exercise program alone. Cognitive behavioral therapy demonstrated inconsistent findings for its effects on physical symptoms, specifically headaches. Veterans had a significant change in post-concussive symptoms, specifically headaches, following 3-month use of an interactive smartphone application as compared with standard care. Finally, in a pediatric population, the use of melatonin did not produce any changes in physical persistent concussion symptoms as compared with placebo. Preliminary evidence suggests that various forms of rehabilitative therapies can improve persistent physical concussive symptoms. However, given the methodological limitations in the majority of trials, the results need to be interpreted with caution.

Clinical performance of a multiparametric MRI-based post concussive syndrome index

Introduction

Diffusion Tensor Imaging (DTI) has revealed measurable changes in the brains of patients with persistent post-concussive syndrome (PCS). Because of inconsistent results in univariate DTI metrics among patients with mild traumatic brain injury (mTBI), there is currently no single objective and reliable MRI index for clinical decision-making in patients with PCS.

Purpose

This study aimed to evaluate the performance of a newly developed PCS Index (PCSI) derived from machine learning of multiparametric magnetic resonance imaging (MRI) data to classify and differentiate subjects with mTBI and PCS history from those without a history of mTBI.

Materials and methods

Data were retrospectively extracted from 139 patients aged between 18 and 60 years with PCS who underwent MRI examinations at 2 weeks to 1-year post-mTBI, as well as from 336 subjects without a history of head trauma. The performance of the PCS Index was assessed by comparing 69 patients with a clinical diagnosis of PCS with 264 control subjects. The PCSI values for patients with PCS were compared based on the mechanism of injury, time interval from injury to MRI examination, sex, history of prior concussion, loss of consciousness, and reported symptoms.

Results

Injured patients had a mean PCSI value of 0.57, compared to the control group, which had a mean PCSI value of 0.12 (p = 8.42e-23) with accuracy of 88%, sensitivity of 64%, and specificity of 95%, respectively. No statistically significant differences were found in the PCSI values when comparing the mechanism of injury, sex, or loss of consciousness.

Conclusion

The PCSI for individuals aged between 18 and 60 years was able to accurately identify patients with post-concussive injuries from 2 weeks to 1-year post-mTBI and differentiate them from the controls. The results of this study suggest that multiparametric MRI-based PCSI has great potential as an objective clinical tool to support the diagnosis, treatment, and follow-up care of patients with post-concussive syndrome. Further research is required to investigate the replicability of this method using other types of clinical MRI scanners.

Prolonged Disability following Re-Exposure after Complete Recovery from Aerotoxic Syndrome: A Case Report

Aerotoxic syndrome is a rarely recognized and poorly defined illness resulting from exposure to products of oil combustion in commercial aircraft bleed air systems. The pathophysiology of this syndrome is not well understood. A 42-year-old male pilot developed duty-limiting symptoms consistent with aerotoxic syndrome following exposure to airline cabin fumes and recurrence of symptoms following re-exposure despite apparent full recovery from the initial exposure event. Given his persistent symptoms and concern for immediate debilitation/incapacitation if re-exposed, the pilot was deemed medically unqualified for return to commercial piloting duties and a disability determination was made. Consideration of aerotoxic syndrome in aircrew members with unusual or episodic symptoms of neuro/cognitive dysfunction is essential for further characterizing this occupational illness, guiding medical management, and understanding its impact on aviation workforce health.

Characterizing the profiles of patients with acute concussion versus prolonged post-concussion symptoms in Ontario

Identifying vulnerability factors for developing persisting concussion symptoms is imperative for determining which patients may require specialized treatment. Using cross-sectional questionnaire data from an Ontario-wide observational concussion study, we compared patients with acute concussion (≤ 14 days) and prolonged post-concussion symptoms (PPCS) (≥ 90 days) on four factors of interest: sex, history of mental health disorders, history of headaches/migraines, and past concussions. Differences in profile between the two groups were also explored. 110 patients with acute concussion and 96 patients with PPCS were included in our study. The groups did not differ on the four factors of interest. Interestingly, both groups had greater proportions of females (acute concussion: 61.1% F; PPCS: 66.3% F). Patient profiles, however, differed wherein patients with PPCS were significantly older, more symptomatic, more likely to have been injured in a transportation-related incident, and more likely to live outside a Metropolitan city. These novel risk factors for persisting concussion symptoms require replication and highlight the need to re-evaluate previously identified risk factors as more and more concussions occur in non-athletes and different risk factors may be at play.

Early vs. delayed evaluation and persisting concussion symptoms during recovery in adults

Objective: Persisting concussion symptoms may adversely affect return to work and functioning in daily activities. This study compared adults who were initially evaluated < 30 days versus those evaluated ≥ 30 days following a concussion at a specialty concussion clinic to determine if delayed initial evaluation is associated with persisting symptoms during recovery. Method: Participants (N = 205) 18 years of age and older who sustained a concussion and presented to a North Texas Concussion Registry (ConTex) clinic were evaluated at two time points: initial clinical visit and three-month follow-up. Participants provided medical history, injury related information, and completed the Sport Concussion Assessment Tool-5 Symptom Evaluation, Generalized Anxiety Disorder 7-item scale (GAD-7), and Patient Health Questionnaire (PHQ-8). Participants were divided into two groups: early and delayed evaluation (±30 days post injury). Results: Number and severity of concussion symptoms were similar between both groups at their initial clinical visit. However, linear regression models showed that a delayed clinical evaluation was associated with a greater number and severity of concussion symptoms along with greater aggravation of symptoms from physical and cognitive activity at three-month follow-up. Conclusions: Individuals who sought care at specialty concussion clinics regardless of previous care 30 or more days following their injury reported more serious persisting concussion symptoms at three month follow-up than those who sought care sooner. Education to improve adults' recognition of concussions when they occur and obtaining earlier clinical evaluation may represent important opportunities in promoting better recovery and reducing persisting concussion symptoms.

Sports Participation and Neurological Injuries in Pediatric Patients With Chiari I Malformation

BACKGROUND

Currently, there is no consensus recommendation regarding the safety of sports participation for pediatric patients with Chiari I malformation (CM-I).

OBJECTIVE

To prospectively survey the treated and untreated patients with CM-I to define the risk of sports-associated neurological injury.

METHODS

A prospective survey was administered to 744 pediatric patients at one neurosurgery clinic between 2010 and 2021. Data were recorded on demographic information, imaging characteristics, treatment, sports participation, and presence of sports-related neurological injury. Patients with incomplete data were called. Two hundred seven patients completed at least 1 subsequent survey and were prospectively followed (mean 1.6 years).

RESULTS

Of 744 patients with completed surveys, 462 participated in sports. Sports participants were more likely to be older at presentation ( P < .001) and have rounded cerebellar tonsil morphology ( P < .001). Seasons of sports played before and after CM-I decompression (CMD) totaled 5918.7 and 936, respectively. There were 84 sports-related concussions among 55 patients; 79 in untreated patients and 5 after CMD. For all sports participants, the concussion rate was 12.3/1000 seasons of all sports, 9.2/1000 seasons of limited-contact sports, and 13.8/1000 of contact sports. The concussion rate after CMD was 5.3/1000 seasons of all sports, 9.2/1000 seasons of limited-contact sports, and 7.1/1000 seasons of contact sports. There were no reports of long-lasting neurological issues postconcussion or of permanent spinal cord injury.

CONCLUSION

No permanent or catastrophic sports-associated neurological injuries were reported. The concussion rates in treated and untreated patients with CM-I were low. Therefore, sports participation in this population should be permitted in most cases.

Persisting Concussion Symptoms from Bodychecking: Unrecognized Toll in Boys' Ice Hockey

OBJECTIVES

Youth hockey is a high-impact sport and can cause concussions with lasting effects. We hypothesized that important injury prevention information would accrue from longitudinal tracking of concussed players with persisting concussion symptoms (PCS).

METHODS

This case series comprised 87 consecutive concussed ice hockey players aged 10-18 including 66 males and 21 females referred to our Concussion Clinic from 1997 to 2017 and followed longitudinally by clinic visits and questionnaires.

RESULTS

PCS occurred in 70 (80.4%) of 87 concussed players and lasted 1-168 months in males and 3-26 months in females. Bodychecking was the most common concussion mechanism in 34 (39.1%) players and caused PCS in 24 (70.6%) with symptom duration 4.00 [2.75, 14.50] months (median [IQR]). The remaining 53 players had other concussion mechanisms with PCS in 86.8% (p = 0.113) with similar duration (p = 0.848).

CONCLUSIONS

This is the first longitudinal study of concussion with PCS in youth hockey and showed that symptoms can last for several years. Bodychecking was the commonest mechanism of prolonged disability from concussion in boys and girls' hockey with average PCS duration of 12.3 months but several years in some players. The injury prevention message is to raise the age of permitted bodychecking to 18 in boys' hockey from age 13 to 14 where it is currently. In this case series, this change could have prevented the majority of the bodycheck concussions and several years of suffering from PCS and is strong evidence for raising the permitted age for bodychecking in boys' ice hockey to age 18.

Cerebrospinal fluid levels of neuroinflammatory biomarkers are increased in athletes with persistent post-concussive symptoms following sports-related concussion

A sports-related concussion (SRC) is often caused by rapid head rotation at impact, leading to shearing and stretching of axons in the white matter and initiation of secondary inflammatory processes that may exacerbate the initial injury. We hypothesized that athletes with persistent post-concussive symptoms (PPCS) display signs of ongoing neuroinflammation, as reflected by altered profiles of cerebrospinal fluid (CSF) biomarkers, in turn relating to symptom severity. We recruited athletes with PPCS preventing sports participation as well as limiting work, school and/or social activities for ≥ 6 months for symptom rating using the Sport Concussion Assessment Tool, version 5 (SCAT-5) and for cognitive assessment using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Following a spinal tap, we analysed 27 CSF inflammatory biomarkers (pro-inflammatory chemokines and cytokine panels) by a multiplex immunoassay using antibodies as electrochemiluminescent labels to quantify concentrations in PPCS athletes, and in healthy age- and sex-matched controls exercising ≤ 2 times/week at low-to-moderate intensity. Thirty-six subjects were included, 24 athletes with PPCS and 12 controls. The SRC athletes had sustained a median of five concussions, the most recent at a median of 17 months prior to the investigation. CSF cytokines and chemokines levels were significantly increased in eight (IL-2, TNF-α, IL-15, TNF-β, VEGF, Eotaxin, IP-10, and TARC), significantly decreased in one (Eotaxin-3), and unaltered in 16 in SRC athletes when compared to controls, and two were un-detectable. The SRC athletes reported many and severe post-concussive symptoms on SCAT5, and 10 out of 24 athletes performed in the impaired range (Z < - 1.5) on cognitive testing. Individual biomarker concentrations did not strongly correlate with symptom rating or cognitive function. Limitations include evaluation at a single post-injury time point in relatively small cohorts, and no control group of concussed athletes without persisting symptoms was included. Based on CSF inflammatory marker profiling we find signs of ongoing neuroinflammation persisting months to years after the last SRC in athletes with persistent post-concussive symptoms. Since an ongoing inflammatory response may exacerbate the brain injury these results encourage studies of treatments targeting the post-injury inflammatory response in sports-related concussion.

PROTOCOL: Fear avoidance model psychological factors as predictors for persistent post-concussion clinical outcomes: An integrative review

Background

Persisting symptoms after concussion (PSaC) include physical, cognitive, and psychological symptoms which contribute to rehabilitation challenges. Previous research has not thoroughly investigated the association between PSaC and pain-related psychological factors. Therefore, there is an opportunity to use current pain models, such as the Fear Avoidance Model (FAM), as a framework to explore these relationships. The goals of this integrative review are to (1) identify and describe range of evidence that explores relationships between psychological factors and clinical outcomes in patients with PSaC, and (2) develop a comprehensive understanding of FAM-specific psychological factors that have been identified as potential predictors of clinical outcomes in patients with PSaC.

Methods

This review will be based on principles and stages of an integrative review which will allow for inclusion of diverse methodologies: (1) problem formulation, (2) literature search, (3) data evaluation, (4) data analysis, and (5) presentation. Methods for reporting this review will be informed by the 2020 PRISMA guidelines for systematic reviews.

Discussion

The findings from this integrative review will inform healthcare professionals working in post-concussion rehabilitation settings regarding relationships between FAM psychological factors and PSaC-an area that until recently has not been thoroughly explored. Additionally, this review will inform the development of other reviews and clinical studies to further investigate relationships between FAM psychological factors and PSaC.

Integrative Review Registration

OSF DOI 10.17605/OSF.IO/CNGPW.

Cortical and cerebellar structural correlates of cognitive-motor integration performance in females with and without persistent concussion symptoms

INTRODUCTION

Fifteen percent of individuals who sustain a concussion develop persistent concussion symptoms (PCS). Recent literature has demonstrated atrophy of the frontal, parietal, and cerebellar regions following acute concussive injury. The frontoparietal-cerebellar network is essential for the performance of visuomotor transformation tasks requiring cognitive-motor integration (CMI), important for daily function.

PURPOSE

We investigated cortical and subcortical structural differences and how these differences are associated with CMI performance in those with PCS versus healthy controls.

METHODS

Twenty-six age-matched  female participants (13 PCS, 13 healthy) completed four visuomotor tasks.  Additionally, MR-images were analyzed for cortical thickness and volume, and cerebellar lobule volume.

RESULTS

No statistically significant group differences were found in CMI performance. However, those with PCS demonstrated a significantly thicker and larger precuneus, and significantly smaller cerebellar lobules (VIIIa, VIIIb, X) compared to controls. When groups were combined, volumes of both the cerebellar lobules and cortical regions were associated with CMI task performance.

CONCLUSION

The lack of behavioral differences combined with the structural differences may reflect a compensatory mechanism for those with PCS. In addition, this study highlights the effectiveness of CMI tasks in estimating the structural integrity of the frontoparietal-cerebellar network and is among the first to demonstrate structural correlates of PCS.

Sensory sensitivity after acquired brain injury: A systematic review

Patients with acquired brain injury frequently report experiencing sensory stimuli as abnormally under- (sensory hyposensitivity) or overwhelming (sensory hypersensitivity). Although they can negatively impact daily functioning, these symptoms are poorly understood. To provide an overview of the current evidence on atypical sensory sensitivity after acquired brain injury, we conducted a systematic literature review. The primary aim of the review was to investigate the behavioural and neural mechanisms that are associated with self-reported sensory sensitivity. Studies were included when they studied sensory sensitivity in acquired brain injury populations, and excluded when they were not written in English, consisted of non-empirical research, did not study human subjects, studied pain, related sensory sensitivity to peripheral injury or studied patients with a neurodegenerative disorder, meningitis, encephalitis or a brain tumour. The Web of Science, PubMed and Scopus databases were searched for appropriate studies. A qualitative synthesis of the results of the 81 studies that were included suggests that abnormal sensory thresholds and a reduced information processing speed are candidate behavioural mechanisms of atypical subjective sensory sensitivity after acquired brain injury. Furthermore, there was evidence for an association between subjective sensory sensitivity and structural grey or white matter abnormalities, and to functional abnormalities in sensory cortices. However, further research is needed to explore the causation of atypical sensory sensitivity. In addition, there is a need for the development of adequate diagnostic tools. This can significantly advance the quantity and quality of research on the prevalence, aetiology, prognosis and treatment of these symptoms.

Postconcussion Symptom Catastrophizing Scale: Preliminary Reliability and Validity Analysis of Cross-sectional Data

OBJECTIVE

The aim of the study was to describe cross-sectional relationships between postconcussion symptom catastrophizing and patient-level factors in a postconcussion cohort.

DESIGN

This cross-sectional study was conducted in an outpatient rehabilitation hospital concussion clinic and consisted of adults undergoing a neuropsychological evaluation. Cronbach α assessed internal consistency for Post-Concussion Symptom Catastrophizing Scale total scores. Pearson r correlation coefficients assessed construct validity among emotional function measures and Post-Concussion Symptom Catastrophizing Scale total scores at initial evaluation. Hierarchical regression models were used to assess criterion validity.

RESULTS

Excellent internal consistency was observed for Post-Concussion Symptom Catastrophizing Scale total scores (α = 0.953). The Post-Concussion Symptom Catastrophizing Scale was significantly correlated with cause of injury ( r = -0.223, P < 0.01), litigation consideration ( r = 0.309, P < 0.05), and history of psychiatric illness ( r = 0.198, P < 0.01). The Post-Concussion Symptom Catastrophizing Scale was significantly correlated with emotional functioning (Patient Health Questionnaire [ r = 0.600, P < 0.05]; Generalized Anxiety Disorder [ r = 0.602, P < 0.05]), symptom rating (Sports Concussion Assessment Tool [Fifth Edition, r = 0.477, P < 0.05]), and cognitive functioning (Repeatable Battery for the Assessment of Neuropsychological Status [ r = -0.238, P < 0.05]) measures. The final regression model explained 64.7% variance in Post-Concussion Symptom Catastrophizing Scale total scores and included the Generalized Anxiety Disorder ( b = 1.038, β = 0.466, P = 0.001) as a unique predictor.

CONCLUSIONS

Results indicate strong, positive relationships between anxiety and catastrophizing at initial neuropsychological evaluation in a postconcussion sample.

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.

Head Trauma and Concussions in Film and Television Stunt Performers: An Exploratory Study

OBJECTIVES

The aims of the study were to assess prevalence and management of head impacts in stunt performers and to evaluate performers' quality of life and ability to work after head injury.

METHODS

Stunt performers completed an online survey about head impacts/head whips history, diagnosed concussions, reasons for not reporting injuries, health care sought after head impacts, attitudes toward on-set concussion management, perceived ability to work as a stunt performer, and health-related quality of life.

RESULTS

One hundred seventy-three performers (80%) indicated at least one head impact/head whip during their stunt career. Of these, 86% exhibited concussion-like symptoms and 38% received one or more concussion diagnoses. Sixty-five percent continued working with concussion-like symptoms. Short Form-12 mental component scores were suggestive of depression in 42%.

CONCLUSIONS

Concussion seems to be a serious occupational health issue in stunt performers. We suggest that concussion management, risk reduction, and education should be addressed in this community.

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.

Long-term postural control in elite athletes following mild traumatic brain injury

Background

Traumas to the head and neck are common in sports and often affects otherwise healthy young individuals. Sports-related concussions (SRC), defined as a mild traumatic brain injury (mTBI), may inflict persistent neck and shoulder pain, and headache, but also more complex symptoms, such as imbalance, dizziness, and visual disturbances. These more complex symptoms are difficult to identify with standard health care diagnostic procedures.

Objective

To investigate postural control in a group of former elite athletes with persistent post-concussive symptoms (PPCS) at least 6 months after the incident.

Method

Postural control was examined using posturography during quiet stance and randomized balance perturbations with eyes open and eyes closed. Randomized balance perturbations were used to examine motor learning through sensorimotor adaptation. Force platform recordings were converted to reflect the energy used to maintain balance and spectrally categorized into total energy used, energy used for smooth corrective changes of posture (i.e., <0.1 Hz), and energy used for fast corrective movements to maintain balance (i.e., >0.1 Hz).

Results

The mTBI group included 20 (13 males, mean age 26.6 years) elite athletes with PPCS and the control group included 12 athletes (9 males, mean age 26.4 years) with no history of SRC. The mTBI group used significantly more energy during balance perturbations than controls: +143% total energy, p = 0.004; +122% low frequency energy, p = 0.007; and +162% high frequency energy, p = 0.004. The mTBI subjects also adapted less to the balance perturbations than controls in total (18% mTBI vs. 37% controls, p = 0.042), low frequency (24% mTBI vs. 42% controls, p = 0.046), and high frequency (6% mTBI vs. 28% controls, p = 0.040). The mTBI subjects used significantly more energy during quiet stance than controls: +128% total energy, p = 0.034; +136% low-frequency energy, p = 0.048; and +109% high-frequency energy, p = 0.015.

Conclusion

Athletes with previous mTBI and PPCS used more energy to stand compared to controls during balance perturbations and quiet stance and had diminished sensorimotor adaptation. Sports-related concussions are able to affect postural control and motor learning.

Interdisciplinary Rehabilitation for Concussion Recovery (i-RECOveR): protocol of an investigator-blinded, randomised, case series with multiple baseline design to evaluate the feasibility and preliminary efficacy of a 12-week treatment for persistent post-concussion symptoms

BACKGROUND

Up to 25% of concussed individuals experience persistent post-concussion symptoms (PPCSs) which may interfere with the return to pre-injury activities and cause significant stress. Given that multiple etiological factors are thought to contribute to PPCSs, an interdisciplinary approach is recommended. This pilot study aims to primarily investigate the feasibility of a novel interdisciplinary treatment for PPCSs. Given this intervention is novel, uncertainty exists in terms of potential recruitment and retention rates, adverse events, and treatment adherence and fidelity. These factors will be explored to inform the feasibility of a phase-2 randomised controlled trial. Preliminary efficacy of this intervention will also be explored.

METHODS

Fifteen individuals with mild traumatic brain injury and PPCSs will receive up to 12 weeks of interdisciplinary treatments including psychology, physiotherapy, and medical interventions. Primary feasibility outcomes including data on recruitment and retention rates and treatment adherence will be explored descriptively. The cognitive therapy rating scale will be used to assess treatment fidelity. A single-case series with multiple baseline design will be used to explore preliminary efficacy. Participants will be randomly assigned to baseline phases of 2, 4, or 6 weeks. Regarding patient-centred secondary outcomes, the Rivermead Post-Concussion Symptoms Questionnaire will be assessed three times a week during baseline and treatment phases. Secondary outcomes also include measures of mood, sleep and fatigue, physical functioning, return to activity, and health-related quality of life. Patient-centred outcomes will be assessed at baseline, pretreatment, post-treatment, and one- and three-month follow-up. Thematic analysis of participant experiences will be explored through qualitative interviews.

DISCUSSION

Results from this trial will inform the feasibility and preliminary efficacy of this interdisciplinary concussion intervention and whether proceeding to a future definitive phase-2 randomised controlled trial is worthwhile. Understanding the end-user perspective of the treatment will also enable modifications to the treatment protocol for future trials to best suit the needs of individuals with PPCSs after mTBI. Outcomes from this trial can be directly translated into community rehabilitation programmes.

TRIAL REGISTRATION

ANZCTR, ACTRN12620001111965. Registered 27 October 2020, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=379118.

Sex and gender differences in mild traumatic brain injury/concussion

The high incidence of concussions/mild traumatic brain injury and the significant number of people with persisting concussion symptoms as well as the concern for delayed, neurodegenerative effects of concussions makes them a major public health concern. There is much to learn on concussions with respect to pathophysiology as well as vulnerability and resiliency factors. The heterogeneity in outcome after a concussion warrants a more personalized approach to better understand the biological and psychosocial factors that may affect outcome. In this chapter we address biological sex and gender as they impact different aspects of concussion including incidence, risk factors and outcome. As well, this chapter will provide a more fulsome overview of intimate partner violence, an often-overlooked cause of concussion in women. Applying the sex and gender lens to concussion/mild traumatic brain injury is imperative for discovery of its pathophysiology and moving closer to treatments.

Comparability of (Post-Concussion) Symptoms across Time in Individuals after Traumatic Brain Injury: Results from the CENTER-TBI Study

Post-concussion symptoms often occur after TBI, persist and cause disabilities. The Rivermead Post-Concussion Symptoms Questionnaire (RPQ) is widely used in this population, but little is known about the comparability of the symptoms over time, i.e., longitudinal measurement invariance (MI). The objectives of this study were to analyze the longitudinal MI of RPQ symptoms from three to twelve months after TBI and to find factors related to RPQ symptoms. The study involved 1023 individuals after TBI who took part in the Collaborative European NeuroTrauma Effectiveness Research in TBI (CENTER-TBI) study and completed the RPQ at three, six and twelve months post-injury. Longitudinal confirmatory factor analysis showed that the three-factor structure (somatic, emotional and cognitive) remains stable within one year after TBI. Linear mixed models revealed that sex, injury cause and prior psychiatric problems were related to the RPQ three-factor structure as well as to the RPQ total score. The study strengthens evidence for the RPQ’s factorial structure stability within one year after TBI and identifies sex, injury cause and prior psychiatric problems as important factors that may help clinicians to prevent future complications of symptomatology after TBI.

Challenging the Vestibular System Affects Gait Speed and Cognitive Workload in Chronic Mild Traumatic Brain Injury and Healthy Adults

People with persistent symptoms after mild traumatic brain injury (mTBI) report imbalance during walking with head movements. The purpose of this study was (1) to compare usual walk gait speed to walking with head turns (HT) between people with mTBI and controls, (2) to compare the cognitive workload from usual walk to HT walk between groups, and (3) to examine if gaze stability deficits and mTBI symptoms influence gait speed. Twenty-three individuals (mean age 55.7 ± 9.3 years) with persistent symptoms after mTBI (between 3 months to 2 years post-injury) were compared with 23 age and sex-matched controls. Participants walked a 12-inch wide, 60-foot walkway when looking ahead and when walking with HT to identify letters and their colors. Gait speed during usual walk and HT walk were calculated. Pupillary responses during both walks were converted to the Index of Cognitive Activity (ICA) as a measure of cognitive workload. Gaze stability was examined by the dynamic visual acuity (DVA) test in the yaw plane. The post-concussion symptom scale (PCSS) was used to collect symptom severity. Within group analysis showed that gait speed was lower during HT walk compared to usual walk in the people with mTBI (p < 0.001) as well as in controls (p < 0.001). ICA was higher with HT compared to usual walk in the mTBI group in the right eye (p = 0.01) and left eye (p = 0.001), and in controls in the right eye (p = 0.01) and left eye (p = 0.01). Participants in the mTBI group had slower usual (p < 0.001), and HT gait speed (p < 0.001) compared to controls. No differences were noted in ICA in the right or left eye during usual walk and HT walk between groups (p > 0.05). DVA loss in the yaw plane to the right and left was not different between groups (p > 0.05) and were not correlated with gait speed. PCSS scores were correlated with usual walk (r = −0.50, p < 0.001) and HT gait speed (r = −0.44, p = 0.002). Slower gait speed, poorer stability, and higher cognitive workload during walking with head turns may reduce community participation in people with mTBI and persistent symptoms.

Mobile Subthreshold Exercise Program (MSTEP) for concussion: study protocol for a randomized controlled trial

BACKGROUND

Subthreshold exercise, defined as aerobic exercise below the level that causes symptoms, has been utilized as a treatment for youth with persistent postconcussive symptoms (PPCS), but there is currently little evidence to guide use. In addition, prior studies of exercise for PPCS have all required multiple in-person visits. We developed a virtual approach for delivering subthreshold exercise to youth with PPCS called the Mobile Subthreshold Exercise Program (MSTEP), and we have now been funded to conduct a large national randomized controlled trial (RCT) to test its efficacy for reducing concussive symptoms and improving health-related quality of life.

METHODS

This investigation is an RCT comparing MSTEP to an active control. We will recruit 200 adolescents 11-18 years old with postconcussive symptoms persisting for at least 1 week but less than 1 year. Youth will be randomized to receive either 6 weeks of subthreshold exercise (MSTEP) or a stretching condition (control). Youth and parents will complete surveys of concussive symptoms at baseline, weekly during the intervention, and at 3 and 6 months. The primary outcomes will be trajectory of concussive symptoms and health-related quality of life over the 6 months of the study. Secondary outcomes will include depression, anxiety, and sleep quality. We will also assess potential mediators of treatment effects including moderate-vigorous physical activity and fear avoidance of concussive symptoms.

DISCUSSION

This multisite RCT of MSTEP will provide vital information regarding the efficacy of a virtually delivered subthreshold exercise program for youth with PPCS, and insight regarding potential mediators of treatment effects, including objectively measured physical activity and fear avoidance of concussive symptoms.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04688255. Registered on December 29, 2020.

Mental Health Outcomes Across the Lifespan in Individuals With Persistent Post-Concussion Symptoms: A Scoping Review

Objective:

Concussion is a common yet heterogenous injury. Approximately 15–30% of cases present with persistent post-concussion symptoms (PPCS), continuing 4 weeks or more post-injury in children, youth, and adolescents, and 3 months or more in adults. There are known bidirectional links between PPCS and mental health outcomes. The focus of this scoping review is to explore the literature on mental health outcomes in individuals experiencing PPCS. Research objectives were to explore: (1) the mental health outcomes of individuals with PPCS and types of assessments used to identify mental health outcomes this group, and (2) how mental health outcomes compare in terms of similarities and differences among pediatric and adult populations with PPCS.

Method

Ovid MEDLINE; EMBASE; CINAHL, and PsycInfo databases were searched. After title and abstract screening of 11,920 studies, 481 articles were reviewed. Twenty-five papers met inclusion criteria. Results were organized by mental health outcomes of pediatric and adult populations, separately.

Results

There was a significantly higher number of studies devoted to adult populations. Of the 25 studies, 19 (76%) focused on adults, while six (24%) focused on adolescents. In adult populations, studies focused on symptoms of: anxiety (n = 2), depression (n = 8), and anxiety and depression (n = 9). Two studies assessed other emotional outcomes (10.5%). Within pediatric populations, an equal number of studies explored symptoms of: anxiety (n = 2), depression (n = 2), and anxiety and depression (n = 2). No studies focused on other emotional outcomes. Studies ranged greatly in methods, design, and control group. Most studies reported higher psychiatric symptoms of anxiety and/or depression in those with PPCS compared to individuals with recovered concussion or healthy controls.

Discussion

This review contributes to the understanding of mental health outcomes in those experiencing PPCS. Mental health and PPCS requires greater attention in pediatric populations, and consider strategies for those experiencing PPCS and mental health impacts. Future studies should consider including a wider range of emotional outcomes in their design, not limited to anxiety and depression. Study results may lead to improvements and research in the identification, assessment, and management of PPCS and mental health.

Post-Concussive Vestibular Dysfunction Is Related to Injury to the Inferior Vestibular Nerve

Symptoms of vestibular dysfunction such as dizziness and vertigo are common after sports-related concussions (SRC) and associated with a worse outcome and a prolonged recovery. Vestibular dysfunction after SRC can be because of an impairment of the peripheral or central neural parts of the vestibular system. The aim of the present study was to establish the cause of vestibular impairment in athletes with SRC who have persisting post-concussive symptoms (PPCS). We recruited 42 participants-21 athletes with previous SRCs and PPCS ≥6 months and 21 healthy athletic age- and sex-matched controls-who underwent symptom rating, a detailed test battery of vestibular function and 7T magnetic resonance imaging with diffusion tensor imaging (DTI) and diffusion kurtosis imaging (DKI) of cerebellar white matter tracts, and T1-weighted imaging for cerebellar volumetrics. Vestibular dysfunction was observed in 13 SRC athletes and three controls (p = 0.001). Athletes with vestibular dysfunction reported more pronounced symptoms on the Dizziness Handicap Inventory (DHI; p < 0.001) and the Hospital Anxiety and Depression Scale (HADS; p < 0.001). No significant differences in DTI metrics were found, while in DKI two metrics were observed in the superior and/or inferior cerebellar tracts. Cerebellar gray and white matter volumes were similar in athletes with SRC and controls. Compared with controls, pathological video head impulse test results (vHIT; p < 0.001) and cervical vestibular evoked myogenic potentials (cVEMP; p = 0.002) were observed in athletes with SRC, indicating peripheral vestibular dysfunction and specifically suggesting injury to the inferior vestibular nerve. In athletes with persisting symptoms after SRC, vestibular dysfunction is associated with injury to the inferior vestibular nerve.

Association of Preinjury Medical Diagnoses With Pediatric Persistent Postconcussion Symptoms in Electronic Health Records

OBJECTIVE

To identify risk factors and generate hypotheses for pediatric persistent postconcussion symptoms (PPCS).

SETTING

A regional healthcare system in the Southeastern United States.

PARTICIPANTS

An electronic health record-based algorithm was developed and validated to identify PPCS cases and controls from an institutional database of more than 2.8 million patients. PPCS cases (n = 274) were patients aged 5 to 18 years with PPCS-related diagnostic codes or with PPCS key words identified by natural language processing of clinical notes. Age, sex, and year of index event-matched controls (n = 1096) were patients with mild traumatic brain injury codes only. Patients with moderate or severe traumatic brain injury were excluded. All patients used our healthcare system at least 3 times 180 days before their injury.

DESIGN

Case-control study.

MAIN MEASURES

The outcome was algorithmic classification of PPCS. Exposures were all preinjury medical diagnoses assigned at least 180 days before the injury.

RESULTS

Cases and controls both had a mean of more than 9 years of healthcare system use preinjury. Of 221 preinjury medical diagnoses, headache disorder was associated with PPCS after accounting for multiple testing (odds ratio [OR] = 2.9; 95% confidence interval [CI]: 1.6-5.0; P = 2.1e-4). Six diagnoses were associated with PPCS at a suggestive threshold for statistical significance (false discovery rate P < .10): gastritis/duodenitis (OR = 2.8; 95% CI: 1.6-5.1; P = 5.0e-4), sleep disorders (OR = 2.3; 95% CI: 1.4-3.7; P = 7.4e-4), abdominal pain (OR = 1.6; 95% CI: 1.2-2.2; P = 9.2e-4), chronic sinusitis (OR = 2.8; 95% CI: 1.5-5.2; P = 1.3e-3), congenital anomalies of the skin (OR = 2.9; 95% CI: 1.5-5.5; P = 1.9e-3), and chronic pharyngitis/nasopharyngitis (OR = 2.4; 95% CI: 1.4-4.3; P = 2.5e-3).

CONCLUSIONS

These results support the strong association of preinjury headache disorders with PPCS. An association of PPCS with prior gastritis/duodenitis, sinusitis, and pharyngitis/nasopharyngitis suggests a role for chronic inflammation in PPCS pathophysiology and risk, although results could equally be attributable to a higher likelihood of somatization among PPCS cases. Identified risk factors should be investigated further and potentially considered during the management of pediatric mild traumatic brain injury cases.

Specialty-Specific Diagnoses in Pediatric Patients With Postconcussion Syndrome: Experience From a Multidisciplinary Concussion Clinic

OBJECTIVE

To describe the collaborative findings across a broad array of subspecialties in children and adolescents with postconcussion syndrome (PCS) in a pediatric multidisciplinary concussion clinic (MDCC) setting.

DESIGN

Retrospective analysis.

SETTING

Multidisciplinary concussion clinic at a pediatric tertiary-level hospital.

PATIENTS

Fifty-seven patients seen in MDCC for evaluation and management of PCS between June 2014 and January 2016.

INTERVENTIONS

Clinical evaluation by neurology, sports medicine, otolaryngology, optometry, ophthalmology, physical therapy, and psychology.

MAIN OUTCOME MEASURES

Specialty-specific clinical findings and specific, treatable diagnoses relevant to PCS symptoms.

RESULTS

A wide variety of treatable, specialty-specific diagnoses were identified as potential contributing factors to patients' postconcussion symptoms. The most common treatable diagnoses included binocular vision dysfunction (76%), anxiety, (57.7%), depression (44.2%), new or change in refractive error (21.7%), myofascial pain syndrome (19.2%), and benign paroxysmal positional vertigo (17.5%).

CONCLUSIONS

Patients seen in a MDCC setting receive a high number of treatable diagnoses that are potentially related to patients' PCS symptoms. The MDCC approach may (1) increase access to interventions for PCS-related impairments, such as visual rehabilitation, physical therapy, and psychological counseling; (2) provide patients with coordinated medical care across specialties; and (3) hasten recovery from PCS.

Diagnosis, Management, and Return to Sport of a 16-Year-Old Patient With a Chiari I Malformation: A Case Report and Literature Review

This case report discusses a 16-year-old female volleyball, basketball, and track and field athlete who was diagnosed with a Chiari I malformation after a concussion. Surgical decompression was recommended and performed 3 months after her initial diagnosis. This patient presented unique challenges due to her age, desire to return to sport, and lack of access to medical care due to living in a rural area. Few evidence-based best-practice recommendations are available for the management and return to sport of patients with Chiari I malformation, particularly for those who have undergone surgical decompression. In this case study, we address the treatment and return-to-sport process for the patient and provide a comprehensive review of the published literature on patients attempting to return to sport after a diagnosis of Chiari I malformation. In addition, we explore the value of an athletic trainer in reconciling various barriers in management and return to sport evident in this case and the reviewed literature.

Brain Connectivity Changes in Post-Concussion Syndrome as the Neural Substrate of a Heterogeneous Syndrome

BACKGROUND

Post-concussion syndrome (PCS) or persistent symptoms of concussion refers to a constellation of symptoms that persist for weeks and months after a concussion. To better capture the heterogeneity of the symptoms of patients with post-concussion syndrome, we aimed to separate patients into clinical subtypes based on brain connectivity changes.

METHODS

Subject-specific structural and functional connectomes were created based on Diffusion Weighted and Resting State Functional Magnetic Resonance Imaging, respectively. Following an informed dimensionality reduction, a gaussian mixture model was used on patient specific structural and functional connectivity matrices to find potential patient clusters. For validation, the resulting patient subtypes were compared in terms of cognitive, neuropsychiatric, and post-concussive symptom differences.

RESULTS

Multimodal analyses of brain connectivity were predictive of behavioural outcomes. Our modelling revealed 2 patient subtypes; mild and severe. The severe group showed significantly higher levels of depression, anxiety, aggression, and a greater number of symptoms than the mild patient subgroup.

CONCLUSION

This study suggests that structural and functional connectivity changes together can help us better understand the symptom severity and neuropsychiatric profiles of patients with post-concussion syndrome. This work allows us to move towards precision medicine in concussions and provides a novel machine learning approach that can be applicable to other heterogeneous conditions.

Oculomotor Deficits and Symptom Severity Are Associated With Poorer Dynamic Mobility in Chronic Mild Traumatic Brain Injury

Oculomotor deficits, vestibular impairments, and persistent symptoms are common after a mild traumatic brain injury (mTBI); however, the relationship between visual-vestibular deficits, symptom severity, and dynamic mobility tasks is unclear. Twenty-three individuals (mean age 55.7 ± 9.3 years) with persistent symptoms after mTBI, who were between 3 months to 2 years post-injury were compared with 23 age and sex-matched controls. Oculomotor deficits [depth perception, near-point convergence, baseline visual acuity (BLVA), perception time], vestibular deficits (dynamic visual acuity in the pitch and yaw planes), dynamic mobility measured by the Functional Gait Assessment (FGA), and symptoms measured by the Post-Concussion Symptom Scale (PCSS) and Dizziness Handicap Inventory (DHI) were compared between groups. Participants with mTBI had poorer performance on the FGA (p < 0.001), higher symptom severity on the PCSS (p < 0.001), and higher DHI scores (p < 0.001) compared to controls. Significant differences were seen on specific items of the FGA between individuals with mTBI and controls during walking with horizontal head turns (p = 0.002), walking with vertical head tilts (p < 0.001), walking with eyes closed (p = 0.003), and stair climbing (p = 0.001). FGA performance was correlated with weeks since concussion (r = −0.67, p < 0.001), depth perception (r = −0.5348, p < 0.001), near point convergence (r = −0.4717, p = 0.001), baseline visual acuity (r = −0.4435, p = 0.002); as well as with symptoms on the PCSS (r = −0.668, p < 0.001), and DHI (r = −0.811, p < 0.001). Dynamic balance deficits persist in chronic mTBI and may be addressed using multifaceted rehabilitation strategies to address oculomotor dysfunction, post-concussion symptoms, and perception of handicap due to dizziness.

Influence of concomitant injuries on post-concussion symptoms after a mild traumatic brain injury - a prospective multicentre cohort study

Objectives: To compare post-concussion symptoms (PCS) and return to normal activities between mild Traumatic Brain Injury (mTBI) patients with or without concomitant injuries at 7-and 90 days post-mTBI.Methods: Design: Sub-analysis of a multicentre prospective cohort study.

PARTICIPANTS AND SETTING

patients with mTBI from 7 Canadian Emergency Departments.

PROCEDURE

Research assistants conducted telephone follow-ups using the Rivermead Postconcussion Symptoms Questionnaire (RPQ) at 7-, 30- and 90 days post-mTBI.

MAIN OUTCOME

Presence of PCS (RPQ: ≥3 symptoms) at 90 days.

SECONDARY OUTCOMES

RPQ score ≥21, prevalence of individual RPQ symptoms and patients' return to normal activities, at 7- and 90-days. Adjusted risk ratios (RR) were calculated.Results: 1725 mTBI patients were included and 1055 (61.1%) had concomitant injuries. Patients with concomitant injuries were at higher risk of having ≥3 symptoms on the RPQ (RR:1.26 [95% CI 1.01-1.58]) at 90 days. They were also at higher risk of experiencing specific symptoms (dizziness, fatigue, headaches and taking longer to think) and of non-return to their normal activities (RR:2.11 [95% CI 1.30-3.45]).Conclusion: Patients with concomitant injuries have slightly more PCS and seemed to be at higher risk of non-return to their normal activities 90 days, compared to patients without concomitant injuries.

Therapeutic Potential for Cannabinoids in Sports Medicine: Current Literature Review

ABSTRACT

Cannabidiol and other cannabinoids are being used more frequently for sports medicine-related conditions. This review will help sports medicine clinicians answer questions that their athletes and active patients have about the potential effectiveness of cannabinoids on common sports medicine conditions. In the article, the authors compare cannabidiol and delta-9-tetrahydrocannabinol effects, noting the difference on the endocannabinoid and nonendocannabinoid receptors. The theoretical benefits of these two compounds and the current legality in the United States surrounding cannabidiol and delta-9-tetrahydrocannabinol use also are addressed.

Sleep quality in the chronic stage of concussion is associated with poorer recovery: A systematic review

Background

Recovery from a concussion varies based on a multitude of factors. One such factor is sleep disturbances. In our prior review, it was observed that in the acute phase, sleep disturbances are predictive of poor outcomes following a concussion. The literature gap remains on how sleep in the chronic phase of recovery affects outcomes.

Objective

To examine the association between sleep quality during the chronic stage of concussion and post-concussion outcomes. Literature Survey: Literature searches were performed during 1 July to 1 August 2019 in selected databases along with searching grey literature. Out of the 733 results, 702 references were reviewed after duplicate removal.

Methods

Three reviewers independently reviewed and consented on abstracts meeting eligibility criteria ( n = 35). The full-text articles were assessed independently by two reviewers. Consensus was achieved, leaving four articles. Relevant data from each study was extracted using a standard data-extraction table. Quality appraisal was conducted to assess potential bias and the quality of articles.

Results

One study included children (18–60 months) and three studies included adolescents and/or adults (ranging 12–35 years). The association between sleep and cognition (two studies), physical activity (one study), and emotion symptoms (one study) was examined. Sleep quality was associated with decreased cognition and emotional symptoms, but not with meeting physical activity guidelines six months post-concussion injury.

Conclusions

The heterogeneity in age of participants and outcomes across studies and limited number of included studies made interpretations difficult. Future studies may consider if addressing sleep quality following concussion will improve outcomes.

Effects of CranioSacral therapy upon symptoms of post-acute concussion and Post-Concussion Syndrome: A pilot study

OBJECTIVE

The purpose of this study was to investigate the utilization of CranioSacral Therapy (CST) in patients with Post-Concussion Syndrome (PCS) and capture patient-reported perceptions of clinical outcomes of lived treatment experiences.

DESIGN

Two-part, longitudinal study conducted through a chart review of target group, followed by a Patient-reported Treatment Outcome Survey (PTOS).

PARTICIPANTS

A convenience sample of 212 patients with a historical incidence of head trauma not requiring hospitalization was obtained through medical records department dating back ten years. Inclusion criteria for further chart review (n = 67) was determined by identifying patients with a confirmed concussion directly correlated with presenting symptoms and for which CST was specifically sought as a treatment option. Demographics and patient-determined treatment duration data were analyzed by comparison groups extensively suggested in existing literature: Recovery time since injury as either Post-acute concussion (<6 months) or Post-Concussion Syndrome (PCS) (≥6 months); Athletes (A) or Non-athletes (NA); and traditional gender. Final PTOS group criteria was determined by eliminating confounding issues reporting (n = 47): (A, n = 24 and NA, n = 23).

RESULTS

Quantitative data was analyzed via Numerical Analysis, and qualitative data was analyzed via Inductive Content Analysis. Symptoms reported in all charts as well as in the PTOS were consistent with identified PCS subtypes. Utilization of CST revealed that most patients determined the treatment effect upon concussion symptoms within 1-3 sessions. Nearly twice as many sessions were attended in the PCS than post-acute groups. Referral sources, studied for a perspective on local concussion after-care discharge planning, ranged from professional to personal recommendation or self-discovery. A majority of patients met goals of reducing post-acute or PCS as reasons cited by self-determined change-in-status or discharge from service. Patients were asked to indicate on the PTOS which pre- and post-treatment symptoms were helped or not helped by this particular intervention.

CONCLUSIONS

Patient-reported changes of PCS symptoms is critical when evaluating treatment options. CST is an experiential treatment that addresses subjective levels of dysfunction, thus it is the patient deciding the value of an intervention. A sizable portion of patients in all groups reported a positive effect upon their symptoms by CST. Patients indicated personal meaning to CST through their utilization of multiple sessions. A high percentage indicated the likelihood of referring others with PCS for CST. Of the 212 patient charts first studied, the 145 not meeting inclusion criteria suggest some chronic conditions may present as long-term effects of older head injuries. CST is a low-risk, conservative treatment option for PCS sub-types worthy of further clinical study.

Early onset senescence and cognitive impairment in a murine model of repeated mTBI

Mild traumatic brain injury (mTBI) results in broad neurological symptoms and an increased risk of being diagnosed with a neurodegenerative disease later in life. While the immediate oxidative stress response and post-mortem pathology of the injured brain has been well studied, it remains unclear how early pathogenic changes may drive persistent symptoms and confer susceptibility to neurodegeneration. In this study we have used a mouse model of repeated mTBI (rmTBI) to identify early gene expression changes at 24 h or 7 days post-injury (7 dpi). At 24 h post-injury, gene expression of rmTBI mice shows activation of the DNA damage response (DDR) towards double strand DNA breaks, altered calcium and cell–cell signalling, and inhibition of cell death pathways. By 7 dpi, rmTBI mice had a gene expression signature consistent with induction of cellular senescence, activation of neurodegenerative processes, and inhibition of the DDR. At both timepoints gliosis, microgliosis, and axonal damage were evident in the absence of any gross lesion, and by 7 dpi rmTBI also mice had elevated levels of IL1β, p21, 53BP1, DNA2, and p53, supportive of DNA damage-induced cellular senescence. These gene expression changes reflect establishment of processes usually linked to brain aging and suggests that cellular senescence occurs early and most likely prior to the accumulation of toxic proteins. These molecular changes were accompanied by spatial learning and memory deficits in the Morris water maze. To conclude, we have identified DNA damage-induced cellular senescence as a repercussion of repeated mild traumatic brain injury which correlates with cognitive impairment. Pathways involved in senescence may represent viable treatment targets of post-concussive syndrome. Senescence has been proposed to promote neurodegeneration and appears as an effective target to prevent long-term complications of mTBI, such as chronic traumatic encephalopathy and other related neurodegenerative pathologies.

Coordinating Global Multi-Site Studies of Military-Relevant Traumatic Brain Injury: Opportunities, Challenges, and Harmonization Guidelines

Traumatic brain injury (TBI) is common among military personnel and the civilian population and is often followed by a heterogeneous array of clinical, cognitive, behavioral, mood, and neuroimaging changes. Unlike many neurological disorders that have a characteristic abnormal central neurologic area(s) of abnormality pathognomonic to the disorder, a sufficient head impact may cause focal, multifocal, diffuse or combination of injury to the brain. This inconsistent presentation makes it difficult to establish or validate biological and imaging markers that could help improve diagnostic and prognostic accuracy in this patient population. The purpose of this manuscript is to describe both the challenges and opportunities when conducting military-relevant TBI research and introduce the Enhancing NeuroImaging Genetics through Meta-Analysis (ENIGMA) Military Brain Injury working group. ENIGMA is a worldwide consortium focused on improving replicability and analytical power through data sharing and collaboration. In this paper, we discuss challenges affecting efforts to aggregate data in this patient group. In addition, we highlight how "big data" approaches might be used to understand better the role that each of these variables might play in the imaging and functional phenotypes of TBI in Service member and Veteran populations, and how data may be used to examine important military specific issues such as return to duty, the late effects of combat-related injury, and alteration of the natural aging processes.

The care of the concussed pediatric patient prior to presentation to primary care pediatrician versus concussion specialists: Implications for management

Objective

Absent adequate randomized control trials to inform appropriate treatment for concussion in pediatric patients, guidelines have been developed based on expert opinion and observational data that may not apply to all groups. This study examines differences in the previous clinical care between concussed patients who present in pediatric practice and specialty clinics. Differences found might influence treatment recommendations for each setting.

Study design

Prospective data collected from a pediatric practice in 2011 to 2013 were compared to chart review data from two specialty clinics between 2015 and 2017. In all three groups patients 11–19 years of age with an ICD9 billing code for concussion were included if they met the 4th International Consensus definition of concussion. Patients were excluded if hospitalized or had abnormal CNS imaging.

Results

The time between injury and presentation was substantially longer in specialty clinic patients versus those seen in the primary pediatric care office. (median 10 vs. 2 days-p < 0.001) Primary care patients presenting had higher rates of immediate rest after injury, 61.4% vs 27.9% (p < 0.001). More specialty clinic patients had been seen in the emergency departments prior to presentation (47.5% vs. 18.8% p < 0.001) regardless of rest status at presentation to the office.

Conclusion

Several differences in previous clinical care between the groups were found. These included the time of presentation from injury, rates of cognitive rest both immediate and non-immediate, and emergency department visits. These differences may have implications for management recommendations. Accordingly, the appropriate treatment for patients seen by the primary pediatric care physicians may be different from those referred to specialty care. Given these findings randomized controlled trails should be conducted independently in both groups of patients.

Post-concussion symptoms in sports-related mild traumatic brain injury compared to non-sports-related mild traumatic brain injury

OBJECTIVES

To compare post-concussion symptoms in patients who sustained a sports-related mild traumatic brain injury (TBI) to those with non-sports-related mild TBI at 7 and 90 days post-injury.

METHODS

This prospective multicentre cohort study took place in seven Canadian Emergency Departments (ED). Non-hospitalized patients aged ≥ 14 years with a documented mild TBI that occurred ≤ 24 h of ED visit and a Glasgow Coma Scale score ≥ 13 were included. Main outcome measure was the presence of ≥ 3 symptoms on the Rivermead Post-concussion Questionnaire at 90 days post-injury. Secondary outcomes were the prevalence of (1) individual Rivermead Post-concussion Questionnaire symptom, (2) total Rivermead Post-concussion Questionnaire score ≥ 21 and (3) return to normal daily activities. Adjusted risk ratios (RR) were calculated.

RESULTS

1727 patients were included, 363 (21.0%) sustained a sports-related mild TBI. Similar proportions of patients with ≥ 3 symptoms, a Rivermead Post-concussion Questionnaire score ≥ 21 and those who returned to their normal daily activities were observed at 7 and 90 days post-injury. Sports-related mild TBI patients were at higher risk of poor concentration [RR: 1.3 (95% CI 1.05-1.54)] and non-return to sports activities [RR: 2.2 (95% CI 1.69-2.94)] at 7 days post-injury. At 90 days, sports-relate -mild TBI patients reported less fatigue [RR: 0.7 (95% CI 0.51-0.98)] and feeling of dizziness [RR: 0.6 (95% CI 0.35-0.99)].

CONCLUSION

Patients who sustained sports-related mild TBI could be at lower risk of experiencing symptoms such as fatigue and dizziness 90 days post-injury. Clinicians should be mindful that non-sports-related mild TBI patients may experience more post-concussion symptoms and that the level of physical activity may influence the patient's rehabilitation.

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

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

Chronic traumatic encephalopathy-a blueprint for the bridge between neurological and psychiatric disorders

Chronic traumatic encephalopathy (CTE) is a perplexing condition characterized by a broad and diverse range of neuropathology and psychopathology. While there are no agreed upon or validated clinical criteria for CTE, case series of CTE have described a wide range of neuropsychiatric symptoms that have been attributed to repetitive traumatic brain injuries (rTBI). However, the direct links between the psychopathology of psychiatric and neurological conditions from rTBI to CTE remains poorly understood. Prior studies suggest that repetitive cerebral injuries are associated with damage to neural circuitry involved in emotional and memory processes, but these studies do not offer longitudinal assessments that prove causation. More recent studies on novel targets, such as transmission of misfolded proteins, as well as newly advanced non-invasive imaging techniques may offer more direct evidence of the pathogenesis of CTE by tracing the progression of pathology and display of related behavioral impairments. Understanding this interface in the context of rTBI can play an important role in future approaches to the definition, assessment, prevention, and treatment of CTE and mental illnesses.

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.

Anxiety, Depression, and Quality of Life: A Long-Term Follow-Up Study of Patients with Persisting Concussion Symptoms

Persisting concussion symptoms (PCS) can last for months, years, or indefinitely and affect a considerable number of concussion patients. The objectives of this study were to evaluate the prevalence of clinical symptoms of anxiety and depression and the relationship between PCS and quality of life in patients examined at the Canadian Concussion Centre. The Depression and Anxiety Stress Scale-42 (DASS-42) and the World Health Organization Quality of Life Assessment-BREF (WHOQOL-BREF) were sent to 526 adult patients diagnosed with PCS. Median with interquartile range follow-up time was 5 (4-7) years. Of the 105 respondents, 35.2% displayed mild or greater symptoms of anxiety, depression, or both. Importantly, the number of previous concussions was correlated with elevations on the DASS-42 Anxiety (p = 0.030) and Depression (p = 0.018) subscale scores, suggesting an acquired cause of symptoms. Patients with clinical elevations of depression, anxiety, or both exhibited poorer mean WHOQOL-BREF scores in each domain (p < 0.001) compared to those who scored in the normal range on the DASS-42. These findings indicate that depression and anxiety in PCS can endure for years and are associated with diminished quality of life. Consequently, depression and anxiety should be identified and treated early in PCS populations in order to optimize recovery. Although the underlying etiology of depression and anxiety cannot be ascertained with certainty in the present study, the association between depression and anxiety and the number of concussions may indicate an organic explanation. In the future, quality-of-life measures should be incorporated into treatment and research in PCS to improve intervention strategies and enhance understanding of the trajectory of recovery in this population.

Altered motor system function in post-concussion syndrome as assessed via transcranial magnetic stimulation

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Study examining corticospinal and cortical activity in post-concussion.

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Reduction in GABAB-mediated inhibition observed.

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These changes were associated with depression-related symptoms.

Objective

It is unclear why specific individuals incur chronic symptoms following a concussion. This exploratory research aims to identify and characterize any neurophysiological differences that may exist in motor cortex function in post-concussion syndrome (PCS).

Methods

Fifteen adults with PCS and 13 healthy, non-injured adults were tested. All participants completed symptom questionnaires, and transcranial magnetic stimulation (TMS) was used to measure intracortical and transcallosal excitability and inhibition in the dominant motor cortex.

Results

Cortical silent period (p = 0.02, g = 0.96) and ipsilateral silent period (p = 0.04, g = 0.78) were shorter in the PCS group compared to the control group which may reflect reduced GABA-mediated inhibition in PCS. Furthermore, increased corticomotor excitability was observed in the left hemisphere but not the right hemisphere.

Conclusions

These data suggest that persistent neurophysiological differences are present in those with PCS. The exact contributing factors to such changes remain to be investigated by future studies.

Significance

This study provides novel evidence of lasting neurophysiological changes in PCS.

Persistent Postconcussion Symptoms: An Expert Consensus-Based Definition Using the Delphi Method

OBJECTIVE

To provide an expert consensus definition of persistent postconcussion symptoms following a mild traumatic brain injury (mTBI).

PARTICIPANTS

Canadian healthcare professionals caring for patients with mTBI.

DESIGN

Online Delphi process.

MAIN MEASURES

A first Delphi round documented important dimensions or criteria to consider when defining persistent symptoms. Expert opinions were then resubmitted in 4 subsequent Delphi rounds and their relevance was rated using a 9-point Likert scale. An item with a median rating of 7 or more and a sufficient level of agreement were considered consensual.

RESULTS

After 5 rounds, consensus was reached on a set of criteria that can be summarized as follows: presence of any symptom that cannot be attributed to a preexisting condition and that appeared within hours of an mTBI, that is still present every day 3 months after the trauma, and that has an impact on at least one sphere of a person's life.

CONCLUSION

This Delphi consensus proposes a set of criteria that support a more uniform definition of persistent symptoms in mild TBI among clinicians and researchers. This definition may help clinicians better identify persistent postconcussion symptoms and improve patient management.