Prognostic value of neuron-specific enolase (NSE) for prediction of post-concussion symptoms following a mild traumatic brain injury: a systematic review

BACKGROUND

This systematic review aimed to determine the prognostic value of neuron-specific enolase (NSE) to predict post-concussion symptoms following mild traumatic brain injury (TBI).

METHODS

Seven databases were searched for studies evaluating the association between NSE levels and post-concussion symptoms assessed ≥ 3 months (persistent) or ≥ 7 days < 3 months (early) after mild TBI. Two researchers independently screened studies for inclusion, extracted data and appraised quality using the Quality in Prognostic Studies (QUIPS) tool.

RESULTS

The search strategy yielded a total of 23,298 citations from which 8 cohorts presented in 10 studies were included. Studies included between 45 and 141 patients (total 608 patients). The outcomes most frequently assessed were post-concussion syndrome (PCS, 12 assessments) and neuropsychological performance deficits (10 assessments). No association was found between an elevated NSE serum level and PCS. Only one study reported a statistically significant association between a higher NSE serum level and alteration of at least three cognitive domains at 2 weeks but this association was no longer significant at 6 weeks. Overall, risk of bias of the included studies was considered moderate.

CONCLUSIONS

Early NSE serum level is not a strong independent predictor of post-concussion symptoms following mild TBI.

Characteristics of patients included and enrolled in studies on the prognostic value of serum biomarkers for prediction of postconcussion symptoms following a mild traumatic brain injury: a systematic review

OBJECTIVE

Mild traumatic brain injury (mTBI) has been insufficiently researched, and its definition remains elusive. Investigators are confronted by heterogeneity in patients, mechanism of injury and outcomes. Findings are thus often limited in generalisability and clinical application. Serum protein biomarkers are increasingly assessed to enhance prognostication of outcomes, but their translation into clinical practice has yet to be achieved. A systematic review was performed to describe the adult populations included and enrolled in studies that evaluated the prognostic value of protein biomarkers to predict postconcussion symptoms following an mTBI.

DATA SOURCES

Searches of MEDLINE, Embase, CENTRAL, CINAHL, Web of Science, PsycBITE and PsycINFO up to October 2016.

DATA SELECTION AND EXTRACTION

Two reviewers independently screened for potentially eligible studies, extracted data and assessed the overall quality of evidence by outcome using the Grading of Recommendations Assessment, Development and Evaluation approach.

RESULTS

A total of 23 298 citations were obtained from which 166 manuscripts were reviewed. Thirty-six cohort studies (2812 patients) having enrolled between 7 and 311 patients (median 89) fulfilled our inclusion criteria. Most studies excluded patients based on advanced age (n=10 (28%)), neurological disorders (n=20 (56%)), psychiatric disorders (n=17 (47%)), substance abuse disorders (n=13 (36%)) or previous traumatic brain injury (n=10 (28%)). Twenty-one studies (58%) used at least two of these exclusion criteria. The pooled mean age of included patients was 39.3 (SD 4.6) years old (34 studies). The criteria used to define a mTBI were inconsistent. The most frequently reported outcome was postconcussion syndrome using the Rivermead Post-Concussion Symptoms Questionnaire (n=18 (50%)) with follow-ups ranging from 7 days to 5 years after the mTBI.

CONCLUSIONS

Most studies have recruited samples that are not representative and generalisable to the mTBI population. These exclusion criteria limit the potential use and translation of promising serum protein biomarkers to predict postconcussion symptoms.

The effects of exercise on a choice reaction time task in individuals with post-concussion syndrome

PURPOSE

To assess cognitive performance differences pre- and post-exercise in individuals without concussion (non-concussed, NC) and individuals with post-concussion syndrome (PCS).

METHODS

A total of 30 participants completed a choice reaction time (CRT) task in the form of an iPad application, measuring each individual's decision-making capabilities, while wearing a head-mounted eye tracker system. Participants completed four blocks of testing; the time interval between the first two blocks of trials and the last two blocks of trials was 10 minutes. Between the completion of block 2 and the start of block 3, the participants completed a 15-minute bout of exercise.

RESULTS

Individuals with PCS at rest and following exercise displayed greater average reaction time (RT) (p<.01), lower overall accuracy (p<.01) and shorter final fixation durations (p<.05) than NC. Combined influence of learning and exercise resulted in a significant difference (p<.05) in RT from block 1 to block 3 and block 1 to block 4.

CONCLUSION

Persistent concussion-based symptoms may be indicative of deficits in higher-level cognitive processing, as indicated by both decreased CRT performance and differences in gaze behaviours between groups. Therefore, individuals with PCS may not elicit appropriate decisions when navigating through an environment, potentially leading to further risk of injury.

Prevalence of Abnormal Magnetic Resonance Imaging Findings in Children with Persistent Symptoms after Pediatric Sports-Related Concussion

A subset of patients experience persistent symptoms after pediatric concussion, and magnetic resonance imaging (MRI) is commonly used to evaluate for pathology. The utility of this practice is unclear. We conducted a retrospective cohort study to describe the MRI findings in children with concussion. A registry of all patients seen at our institution from January 2010 through March 2016 with pediatric sports-related concussion was cross-referenced with a database of radiographical studies. Radiology reports were reviewed for abnormal findings. Patients with abnormal computed tomographies or MRI scans ordered for reasons other than concussion were excluded. Among 3338 children identified with concussion, 427 underwent MRI. Only 2 (0.5%) had findings compatible with traumatic injury, consisting in both of microhemorrhage. Sixty-one patients (14.3%) had abnormal findings unrelated to trauma, including 24 nonspecific T₂ changes, 15 pineal cysts, eight Chiari I malformations, and five arachnoid cysts. One child underwent craniotomy for a cerebellar hemangioblastoma after presenting with ataxia; another had cortical dysplasia resected after seizure. The 2 patients with microhemorrhage each had three previous concussions, significantly more than patients whose scans were normal (median, 1) or abnormal without injury (median, 1.5; p = 0.048). MRI rarely revealed intracranial injuries in children post-concussion, and the clinical relevance of these uncommon findings remains unclear. Abnormalities unrelated to trauma are usually benign. However, MRI should be thoughtfully considered in children who present with concerning or atypical symptoms.

Transcranial Direct Current Stimulation for Post-Concussion Syndrome: Study Protocol for a Randomized Crossover Trial

Background

Mild traumatic brain injury (MTBI) represents 70–80% of all treated brain injuries. A considerable proportion of MTBI patients experience post-concussion symptoms for a prolonged period after MTBI, and these symptoms are diagnosed as persistent post-concussion syndrome (PPCS). PPCS is defined as a range of physical, cognitive, and emotional symptoms. However, memory and executive dysfunction seems to be one of the most debilitating symptoms. Recently, non-invasive brain stimulation has been studied as a potential treatment method for traumatic brain injury (TBI) patients. Therefore, our primary goal is to verify the effects of transcranial direct current stimulation (tDCS) in patients with PPCS who demonstrate cognitive deficits in long-term episodic memory, working memory, and executive function following MTBI.

Methods/design

This is a randomized crossover trial of patients with a history of MTBI with cognitive deficits in memory and executive function. Thirty adult patients will be randomized in a crossover manner to receive three weekly sessions of anodal tDCS (2 mA) at left dorsolateral prefrontal cortex, left temporal cortex, and sham stimulation that will be performed at 7-day intervals (washout period). The clinical diagnosis of PPCS will be determined using the Rivermead Post-Concussion Symptoms Questionnaire. Patients who meet the inclusion criteria will be assessed with a neuropsychological evaluation. A new battery of computerized neuropsychological tests will be performed before and immediately after each stimulation. Statistical analysis will be performed to determine trends of cognitive improvement.

Discussion

There is paucity of studies regarding the use of tDCS in TBI patients, and although recent results showed controversial data regarding the effects of tDCS in such patients, we will address specifically patients with PPCS and MTBI and no brain abnormalities on CT scan other than subarachnoid hemorrhage. Moreover, due to the missing information on literature regarding the best brain region to be studied, we will evaluate two different regions to find immediate effects of tDCS on memory and executive dysfunction.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier NCT02292589 (https://register.clinicaltrials.gov).

Factors that predict discharge recommendations following paediatric mild traumatic brain injury

PRIMARY OBJECTIVE

To investigate factors that predict discharge recommendations for children and adolescents who present to an Australian paediatric Emergency Department (ED) following a mild traumatic brain injury (mTBI).

RESEARCH DESIGN

Retrospective data base analysis.

METHODS

The study retrospectively analysed an ED database to test the relationship between injury risk factors (symptoms, Glasgow Coma Scale, prior TBI, mechanism of injury and Computed Tomography scan), non-injury risk factors (sex, age, socio-economic status (SES)) and discharge recommendations of 2807 children and adolescents (0-18 years) who presented to a children's hospital ED over a three year period with mTBI.

RESULTS

Univariate analyses indicated a statistically significant association of discharge recommendations with age, SES, mechanism of injury and vomiting. However, multivariate analyses indicated vomiting and mechanism of injury were the only statistically significant risk factor associated with discharge recommendations, when controlling for other risk factors.

CONCLUSIONS

The current study suggests vomiting and mechanism of injury are the only risk factors predicting discharge recommendations for children and adolescents with mTBI.

Depression in youth recovering from concussion: Correlates and predictors

OBJECTIVES

Although depression can be a serious consequence of concussion, little is known about the factors that predict depression and concussion recovery outcomes in children. The purpose of this study was to explore the risk and possible predictors of developing significant depressive symptoms in children recovering from concussion.

METHODS

A prospective cohort study was conducted in a paediatric tertiary care clinic. Depression data were collected from 92 children using the Children's Depression Inventory-2 (CDI-2) screening tool. Correlations, t-tests and logistic regression were used to examine the associations between depression scores and demographic as well as injury-related factors.

RESULTS

Depressive symptoms were found in 22% of the children (T score on CDI-2 >65). Children with evidence of depressive symptomatology had significantly higher mean post-concussive symptom inventory (PCSI) scores in recovery (p = 0.004) than children who were not depressed. Variables of i) Sex; ii) hospital admission; iii) number of head injuries; iv) post-concussion symptom score and v) experience of prolonged symptoms were predictive of clinically significant CDI T scores, explaining 36% of the variation in the binary logistic model.

CONCLUSION

Depression is commonly reported in this subset of children. High post-concussive symptom scores and hospital admission were strong predictors of depression. Screening for depression should be standard practice in concussion management in children and youth.

Longitudinal Assessment of Health-Related Quality of Life following Adolescent Sports-Related Concussion

To examine initial and longitudinal health-related quality of life (HRQOL) in adolescent sports-related concussion (SRC) patients, a prospective observational case-series study was conducted among adolescent SRC patients who were evaluated at a multi-disciplinary pediatric concussion program. Health-related quality of life was measured using the child self-report Pediatric Quality of Life Inventory (PedsQL) generic score scale (age 13-18 version) and the PedsQL Cognitive Functioning scale. Initial and longitudinal HRQOL outcomes were compared between patients who did and did not develop post-concussion syndrome (PCS). A total of 63 patients met the inclusion criteria during the study period. The mean age of the cohort was 14.57 years (standard deviation, 1.17) and 61.9% were male. The median time from injury to initial consultation was 6.5 days (interquartile range, 5, 11). At initial consultation, impairments in physical and cognitive HRQOL but not social or emotional HRQOL were observed. Initial symptom burden and length of recovery were associated with greater impairment in physical and cognitive HRQOL. Patients who went on to develop PCS had significantly worse physical and cognitive HRQOL at initial consultation and demonstrated a slower rate of recovery in these domains, compared with those who recovered in less than 30 days. Adolescent SRC was associated with HRQOL impairments that correlated with clinical outcomes. No persistent impairments in HRQOL were detected among patients who achieved physician-documented clinical recovery. Future studies are needed to evaluate the clinical utility of HRQOL measurement in the longitudinal management of adolescent SRC and PCS patients.

Three versus seven days to return-to-work after mild traumatic brain injury: a randomized parallel-group trial with neuropsychological assessment

Although most patients with a mild traumatic brain injury (mTBI) recover within days to weeks, some experience persistent physical, cognitive and emotional symptoms, often described as post-concussion syndrome (PCS). The optimal recovery time including return-to-work (RTW) after mTBI is unclear. In this single-centre parallel-group trial, patients assigned three days (3D-group) or seven days (7D-group) sick leave were compared with a comprehensive neuropsychological test battery including the Post-Concussion Symptom Scale (PCSS) within one week, after three and 12 months post-injury. The influence of the effective time until RTW on post-concussional symptoms and cognitive performance was analysed. The 3D-group rated significantly higher mean scores in some PCSS symptoms, tended to fulfil diagnosis criteria of PCS more often and showed better cognitive performance in several neuropsychological test scores than the 7D-group at all three time-points of follow-up. Overall, patients returned to work 11.35 d post-injury, thus distinctly above both recommended sick leaves. There was a trend for longer sick leave in patients randomized into the 3D-group. Further analyses revealed that the group with an absolute RTW within one week showed lower symptom severity in fatigue at 3 and 12 months, less PCS and faster performance in fine motor speed at 12 months than the group with an absolute RTW after one week. Our data underline the heterogeneity of mTBI and show that acute and sub-acute symptoms are not prognostic factors for neuropsychological outcome at one year. Later, ability to work seems to be prognostic for long-term occurrence of PCS.

Return to Meaningful Activities After a Multi-Modal Rehabilitation Programme among Individuals Who Experience Persistent Dizziness and Debility Longer Than 9 Months after Sustaining a Concussion: A Case Series

Purpose: The authors explored changes in outcome measures and return to meaningful life activities in six individuals who participated in a home-based multi-modal rehabilitation programme to address persistent dizziness and debility that had continued for more than 9 months since a documented concussion. Methods: In a case series using a repeated-measures design, changes from pre- to post-treatment assessments were assessed after a 6-month intervention. The outcome measures used were the Rivermead Post-Concussion Symptoms Questionnaire's subsidiary scales (RPQ-3, RPQ-13), Dizziness Handicap Inventory (DHI), Activities-specific Balance Confidence Scale, Functional Gait Assessment, return to work or study, and return to activity. Results: Six months after the multi-modal rehabilitation programme, statistically significant differences were found on the RPQ-3 (p=0.026), RPQ-13 (p=0.037), and DHI (p=0.033). In addition, four participants had returned to their previous work, and all six participants had been able to return to physical activity. Conclusion: A supervised home programme, provided in the context of a multi-modal rehabilitation programme, has the potential to improve outcomes even when rehabilitative services are delayed and persistent concussion-related symptoms continue for a significant amount of time after the onset of a concussion.

Graded aerobic treadmill testing in pediatric sports-related concussion: safety, clinical use, and patient outcomes

OBJECTIVE The objectives of this study were 2-fold: 1) to evaluate the safety, tolerability, and clinical use of graded aerobic treadmill testing in pediatric patients with sports-related concussion (SRC), and 2) to evaluate the clinical outcomes of treatment with a submaximal aerobic exercise program in patients with physiological post-concussion disorder (PCD). METHODS The authors conducted a retrospective chart review of pediatric patients (age < 20 years) with SRC who were referred to a multidisciplinary pediatric concussion program and underwent graded aerobic treadmill testing between October 9, 2014, and February 11, 2016. Clinical assessments were carried out by a single neurosurgeon and included clinical history taking, physical examination, and recording specific patient-reported concussion-related symptoms using the Post-Concussion Symptom Scale (PCSS). Graded aerobic treadmill testing using a modified Balke protocol for incremental increases in intensity was used as a diagnostic tool to assess physiological recovery, classify post-concussion syndrome (PCS) subtype, and reassess patients following treatment. Patients with a symptom-limited threshold on treadmill testing (physiological PCD) were treated with an individually tailored submaximal exercise prescription and multidisciplinary targeted therapies. RESULTS One hundred six patients (mean age 15.1 years, range 11-19 years) with SRC underwent a total of 141 treadmill tests. There were no serious complications related to treadmill testing in this study. Overall, 138 (97.9%) of 141 tests were well tolerated and contributed valuable clinical information. Treadmill testing confirmed physiological recovery in 63 (96.9%) of 65 patients tested, allowing successful return to play in 61 (93.8%). Treadmill testing was used to diagnose physiological PCD in 58 patients and cervicogenic PCD in 1 patient. Of the 41 patients with physiological PCD who had complete follow-up and were treated with tailored submaximal exercise prescription, 37 (90.2%) were classified as clinically improved and 33 (80.5%) successfully returned to sporting activities. Patients who did not respond or experienced an incomplete response to submaximal aerobic exercise treatment included 7 patients with migraine headaches and 1 patient with a postinjury psychiatric disorder. CONCLUSIONS Graded aerobic treadmill testing is a safe, tolerable, and clinically valuable tool that can assist in the evaluation and management of pediatric SRC. Future research is needed to confirm the clinical value of this tool in return-to-play decision making. Studies are also needed to understand the pathophysiology of physiological PCD and the effects of targeted treatment.

Diffusion Tensor Imaging Findings in Post-Concussion Syndrome Patients after Mild Traumatic Brain Injury: A Systematic Review

Objectives

To review the evidence for the use of diffusion tensor imaging (DTI) parameters in the human brain as a diagnostic tool for and predictor of post-concussion syndrome (PCS) after a mild traumatic brain injury (mTBI).

Design

Systematic review.

Data sources

All relevant studies in AMED, Embase, MEDLINE, Ovid, PubMed, Scopus, and Web of Science through 20 May, 2016.

Study selection

Studies that analyze traditional DTI measures [fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD)] and the severity of PCS symptoms or the development of PCS in humans after an mTBI.

Data extraction

Population studied, patient source, mTBI diagnosis method, PCS diagnosis method, DTI values measured, significant findings, and correlation between DTI findings and PCS.

Data synthesis

Ten studies investigated correlations between DTI values and PCS symptom severity or between DTI values and the development of PCS in mTBI patients. Decreased FA and increased MD and RD were associated with the development and severity of PCS. AD was not found to change significantly. Brain regions found to have significant changes in DTI parameters varied from study to study, although the corpus callosum was most frequently cited as having abnormal DTI parameters in PCS patients.

Conclusion

DTI abnormalities correlate with PCS incidence and symptom severity, as well as indicate an increased risk of developing PCS after mTBI. Abnormal DTI findings should prompt investigation of the syndrome to ensure optimal symptom management at the earliest stages. Currently, there is no consensus in the literature about the use of one DTI parameter in a specific region of the brain as a biomarker for PCS because no definite trends for DTI parameters in PCS subjects have been identified. Further research is required to establish a standard biomarker for PCS.

Multi-Disciplinary Management of Athletes with Post-Concussion Syndrome: An Evolving Pathophysiological Approach

Historically, patients with sports-related concussion (SRC) have been managed in a uniform fashion consisting mostly of prescribed physical and cognitive rest with the expectation that all symptoms will spontaneously resolve with time. Although this approach will result in successful return to school and sports activities in the majority of athletes, an important proportion will develop persistent concussion symptoms characteristic of post-concussion syndrome (PCS). Recent advances in exercise science, neuroimaging, and clinical research suggest that the clinical manifestations of PCS are mediated by unique pathophysiological processes that can be identified by features of the clinical history and physical examination as well as the use of graded aerobic treadmill testing. Athletes who develop PCS represent a unique population whose care must be individualized and must incorporate a rehabilitative strategy that promotes enhanced recovery of concussion-related symptoms while preventing physical deconditioning. In this review, we present our evolving evidence-based approach to evaluation and management of athletes with PCS that aims to identify the pathophysiological mechanisms mediating persistent concussion symptoms and guides the initiation of individually tailored rehabilitation programs that target these processes. In addition, we outline the important qualified roles that multi-disciplinary healthcare professionals can play in the management of this patient population, and discuss where future research efforts must be focused to further evaluate this evolving pathophysiological approach.

Somatization in Post-Concussion Syndrome: A Retrospective Study

This is a retrospective study of concussion patient data conducted to analyze the prevalence of somatization in patients presenting with post-concussion symptoms. Patient records from June 2010 to December 2015 were examined for concussion history, psychosocial history, neuropsychological test results, validity scores, and a symptom severity scale. Records meeting inclusion criteria from 33 males and 27 females were located. The sample had an age range of 11–78 years with a mean age of 33.40 (SD +/- 7.5 years). A clinically significant number of patients (55%) were found to be somaticizing their symptoms and a significant majority (78%) of somaticizing patients reported no loss of consciousness, retrograde amnesia, or post-traumatic amnesia but their symptom validity scales were significantly exaggerated. Caution should be exercised by clinicians to ensure that the obtained results of neuropsychological testing are reliable and valid. It is very important for the clinician to take into account the entire patient history, including psychosocial factors (such as pre-existing psychological traits or conditions) and social influences (such as stressors in family dynamics or work/school activities that may be affecting the patient's complaints).

Neuropsychological assessments in a hyperbaric trial of post-concussive symptoms

Results of studies addressing the effect of mild traumatic brain injury (mTBI) and post-traumatic stress disorder (PTSD) on symptoms and neuropsychological assessments are mixed regarding cognitive deficits in these populations. Neuropsychological assessments were compared between U.S. military service members with mTBI only (n=36) vs. those with mTBI÷ PTSD (n=35) from a randomized interventional study of mTBI participants with persistent post-concussive symptoms (PCS). The mTBI group endorsed worse symptoms than published norms on PCS, PTSD and pain scales (⟩50% abnormal on Neurobehavioral Symptom Inventory (NSI), PTSD Checklist-Civilian, McGill Pain Questionnaire-Short Form) and some quality of life domains. Worse symptom reporting was found in the mTBI÷ PTSD group compared to mTBI (e.g., mean NSI total score in mTBI 27.5 (SD=12.7), mTBI÷ PTSD 39.9 (SD=13.6), p⟨0.001). The mTBI÷PTSD group performed worse than mTBI on the Weschler Adult Intelligence Scale digit span (mean difference -1.5, 95% CI[-2.9,-0.1], p=0.04) and symbol search (mean difference -1.5, 95% CI[-2.7,-0.2], p=0.03) and Grooved Pegboard (dominant hand mean difference -7.0, 95% CI[-11.5,-2.4], p=0.003; non-dominant mean difference -9.8, 95% CI[-14.9,-4.7], p⟨0.001). Differences were detected in ANAM simple reaction time (p=0.04) and mathematical processing (p=0.03) but not verbal fluency or visuospatial memory assessments. Results indicate increased symptom severity and some cognitive deficits in mTBI÷ PTSD compared to mTBI alone.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01611194; https://clinicaltrials.gov/show/NCT01611194.

Longitudinal Brain Magnetic Resonance Imaging CO2 Stress Testing in Individual Adolescent Sports-Related Concussion Patients: A Pilot Study

Background

Advanced neuroimaging studies in concussion have been limited to detecting group differences between concussion patients and healthy controls. In this small pilot study, we used brain magnetic resonance imaging (MRI) CO₂ stress testing to longitudinally assess cerebrovascular responsiveness (CVR) in individual sports-related concussion (SRC) patients.

Methods

Six SRC patients (three males and three females; mean age = 15.7, range = 15–17 years) underwent longitudinal brain MRI CO₂ stress testing using blood oxygen level-dependent (BOLD) MRI and model-based prospective end-tidal CO₂ targeting under isoxic conditions. First-level and second-level comparisons were undertaken using statistical parametric mapping (SPM) to score the scans and compare them to an atlas of 24 healthy control subjects.

Results

All tests were well tolerated and without any serious adverse events. Anatomical MRI was normal in all study participants. The CO₂ stimulus was consistent between the SRC patients and control subjects and within SRC patients across the longitudinal study. Individual SRC patients demonstrated both quantitative and qualitative patient-specific alterations in CVR (p < 0.005) that correlated strongly with clinical findings, and that persisted beyond clinical recovery.

Conclusion

Standardized brain MRI CO₂ stress testing is capable of providing a longitudinal assessment of CVR in individual SRC patients. Consequently, larger prospective studies are needed to examine the utility of brain MRI CO₂ stress testing as a clinical tool to help guide the evaluation, classification, and longitudinal management of SRC patients.

Chronic Post-Concussion Neurocognitive Deficits. II. Relationship with Persistent Symptoms

Individuals who sustain a concussion may continue to experience problems long after their injury. However, it has been postulated in the literature that the relationship between a concussive injury and persistent complaints attributed to it is mediated largely by the development of symptoms associated with posttraumatic stress disorder (PTSD) and depression. We sought to characterize cognitive deficits of adult patients who had persistent symptoms after a concussion and determine whether the original injury retains associations with these deficits after accounting for the developed symptoms that overlap with PTSD and depression. We compared the results of neurocognitive testing from 33 patients of both genders aged 18-55 at 3 months to 5 years post-injury with those from 140 control subjects. Statistical comparisons revealed that patients generally produced accurate responses on reaction time-based tests, but with reduced efficiency. On visual tracking, patients increased gaze position error variability following an attention demanding task, an effect that may reflect greater fatigability. When neurocognitive performance was examined in the context of demographic- and symptom-related variables, the original injury retained associations with reduced performance at a statistically significant level. For some patients, reduced cognitive efficiency and fatigability may represent key elements of interference when interacting with the environment, leading to varied paths of recovery after a concussion. Poor recovery may be better understood when these deficits are taken into consideration.

Chronic Post-Concussion Neurocognitive Deficits. I. Relationship with White Matter Integrity

We previously identified visual tracking deficits and associated degradation of integrity in specific white matter tracts as characteristics of concussion. We re-explored these characteristics in adult patients with persistent post-concussive symptoms using independent new data acquired during 2009–2012. Thirty-two patients and 126 normal controls underwent cognitive assessments and MR-DTI. After data collection, a subset of control subjects was selected to be individually paired with patients based on gender and age. We identified patients’ cognitive deficits through pairwise comparisons between patients and matched control subjects. Within the remaining 94 normal subjects, we identified white matter tracts whose integrity correlated with metrics that indicated performance degradation in patients. We then tested for reduced integrity in these white matter tracts in patients relative to matched controls. Most patients showed no abnormality in MR images unlike the previous study. Patients’ visual tracking was generally normal. Patients’ response times in an attention task were slowed, but could not be explained as reduced integrity of white matter tracts relating to normal response timing. In the present patient cohort, we did not observe behavioral or anatomical deficits that we previously identified as characteristic of concussion. The recent cohort likely represented those with milder injury compared to the earlier cohort. The discrepancy may be explained by a change in the patient recruitment pool circa 2007 associated with an increase in public awareness of concussion.

Recovery from Mild Traumatic Brain Injury in Previously Healthy Adults

This prospective longitudinal study reports recovery from mild traumatic brain injury (MTBI) across multiple domains in a carefully selected consecutive sample of 74 previously healthy adults. The patients with MTBI and 40 orthopedic controls (i.e., ankle injuries) completed assessments at 1, 6, and 12 months after injury. Outcome measures included cognition, post-concussion symptoms, depression, traumatic stress, quality of life, satisfaction with life, resilience, and return to work. Patients with MTBI reported more post-concussion symptoms and fatigue than the controls at the beginning of recovery, but by 6 months after injury, did not differ as a group from nonhead injury trauma controls on cognition, fatigue, or mental health, and by 12 months, their level of post-concussion symptoms and quality of life was similar to that of controls. Almost all (96%) patients with MTBI returned to work/normal activities (RTW) within the follow-up of 1 year. A subgroup of those with MTBIs and controls reported mild post-concussion-like symptoms at 1 year. A large percentage of the subgroup who had persistent symptoms had a modifiable psychological risk factor at 1 month (i.e., depression, traumatic stress, and/or low resilience), and at 6 months, they had greater post-concussion symptoms, fatigue, insomnia, traumatic stress, and depression, and worse quality of life. All of the control subjects who had mild post-concussion-like symptoms at 12 months also had a mental health problem (i.e., depression, traumatic stress, or both). This illustrates the importance of providing evidence-supported treatment and rehabilitation services early in the recovery period.

Dementia resulting from traumatic brain injury

Traumatic brain injury (TBI) represents a significant public health problem in modern societies. It is primarily a consequence of traffic-related accidents and falls. Other recently recognized causes include sports injuries and indirect forces such as shock waves from battlefield explosions. TBI is an important cause of death and lifelong disability and represents the most well-established environmental risk factor for dementia. With the growing recognition that even mild head injury can lead to neurocognitive deficits, imaging of brain injury has assumed greater importance. However, there is no single imaging modality capable of characterizing TBI. Current advances, particularly in MR imaging, enable visualization and quantification of structural and functional brain changes not hitherto possible. In this review, we summarize data linking TBI with dementia, emphasizing the imaging techniques currently available in clinical practice along with some advances in medical knowledge.

Strategies to avoid a missed diagnosis of co-occurring concussion in post-acute patients having a spinal cord injury

Research scientists and clinicians should be aware that missed diagnoses of mild-moderate traumatic brain injuries in post-acute patients having spinal cord injuries may approach 60-74% with certain risk factors, potentially causing clinical consequences for patients, and confounding the results of clinical research studies. Factors leading to a missed diagnosis may include acute trauma-related life-threatening issues, sedation/intubation, subtle neuropathology on neuroimaging, failure to collect Glasgow Coma Scale scores or duration of posttraumatic amnesia, or lack of validity of this information, and overlap in neuro-cognitive symptoms with emotional responses to spinal cord injuries. Strategies for avoiding a missed diagnosis of mild-moderate traumatic brain injuries in patients having a spinal cord injuries are highlighted in this perspective.

The role of the cervical spine in post-concussion syndrome

While much is known regarding the pathophysiology surrounding concussion injuries in the acute phase, there is little evidence to support many of the theorized etiologies to post-concussion syndrome (PCS); the chronic phase of concussion occurring in ∼ 10-15% of concussed patients. This paper reviews the existing literature surrounding the numerous proposed theories of PCS and introduces another potential, and very treatable, cause of this chronic condition; cervical spine dysfunction due to concomitant whiplash-type injury. We also discuss a short case-series of five patients with diagnosed PCS having very favorable outcomes following various treatment and rehabilitative techniques aimed at restoring cervical spine function.

Outpatient follow-up and return to school after emergency department evaluation among children with persistent post-concussion symptoms

OBJECTIVE

To describe differences in outpatient follow-up and academic accommodations received by children with and without persistent post-concussion symptoms (PPCS) after emergency department (ED) evaluation. It was hypothesized that children with PPCS would have more outpatient visits and receive academic accommodations more often than children without PPCS and that follow-up would be positively associated with receiving accommodations.

METHODS

Children aged 8-18 years with acute (≤6hours) concussion at time of presentation to a paediatric ED were enrolled in an observational study. Outcomes were assessed through a telephone survey 30 days after injury.

RESULTS

Of 234 enrolled participants, 179 (76%) completed follow-up. PPCS occurred in 21%. Only 45% of subjects had follow-up visits after ED discharge. Follow-up visit rates were similar for those with and without PPCS (58% vs. 41%, respectively; p = 0.07). Children with PPCS missed twice as many school days as those without (3 vs. 1.5; p < 0.001), but did not differ in receiving academic accommodations (36% vs. 53%; p = 0.082). Outpatient follow-up was associated with receiving academic accommodations (RR = 2.2; 95% CI = 1.4-3.5).

CONCLUSIONS

Outpatient follow-up is not routine for concussed children. Despite missing more school days, children with PPCS do not receive academic accommodations more often. Outpatient follow-up may facilitate academic accommodations.

Characterizing self-reported sleep disturbance after mild traumatic brain injury

Sleep disturbance after mild traumatic brain injury (mTBI) is commonly reported as debilitating and persistent. However, the nature of this disturbance is poorly understood. This study sought to characterize sleep after mTBI compared with a control group. A cross-sectional matched case control design was used. Thirty-three persons with recent mTBI (1-6 months ago) and 33 age, sex, and ethnicity matched controls completed established questionnaires of sleep quality, quantity, timing, and sleep-related daytime impairment. The mTBI participants were compared with an independent sample of close-matched controls (CMCs; n = 33) to allow partial internal replication. Compared with controls, persons with mTBI reported significantly greater sleep disturbance, more severe insomnia symptoms, a longer duration of wake after sleep onset, and greater sleep-related impairment (all medium to large effects, Cohen's d > 0.5). No differences were found in sleep quantity, timing, sleep onset latency, sleep efficiency, or daytime sleepiness. All findings except a measure of sleep timing (i.e., sleep midpoint) were replicated for CMCs. These results indicate a difference in the magnitude and nature of perceived sleep disturbance after mTBI compared with controls, where persons with mTBI report poorer sleep quality and greater sleep-related impairment. Sleep quantity and timing did not differ between the groups. These preliminary findings should guide the provision of clearer advice to patients about the aspects of their sleep that may change after mTBI and could inform treatment selection.

In search of evidence-based treatment for concussion: characteristics of current clinical trials

Abstract Objective: To assess the characteristics of current clinical trials investigating the treatment of concussion.

BACKGROUND

Recent systematic literature reviews have concluded that there is minimal evidence to support any specific treatment for concussion, including the principles of return-to-activity protocols such as type or duration of rest.

DESIGN/METHODS

Clinical trial data was extracted from Clinicaltrials.gov and seven additional World Health Organization primary registries. The trial databases were accessed up until 3 October 2013. This study used search terms of 'concussion' or 'mild traumatic brain injury' (mTBI) and filtered for interventional trials. Trials that were terminated, already published or not interventional trials of concussion/mTBI were excluded.

RESULTS

Of the 142 concussion/mTBI interventional clinical trials identified, 71 met inclusion criteria. Trials had a median estimated enrolment of 60 participants. There was a wide-range of treatments studied, including cognitive/behavioural therapies (28.2%), medications (28.2%), devices (11.3%), dietary supplements (8.5%), return-to-activity/rest (1.4%) and others (22.4%). Heterogeneity among trials for concussion identification/diagnosis and primary outcomes utilized was evident. Symptom-based questionnaires (39.4%) and neuropsychological tests (28.2%) were the most common outcome measures.

CONCLUSIONS

Diverse, potentially promising therapeutics are currently being studied for the treatment of concussion. However, several deficiencies were identified including a paucity of trials addressing return-to-activity principles. Also, small sample size and trial heterogeneity may threaten scientific evaluation and subsequent clinical application.

Chronic neck pain: making the connection between capsular ligament laxity and cervical instability

The use of conventional modalities for chronic neck pain remains debatable, primarily because most treatments have had limited success. We conducted a review of the literature published up to December 2013 on the diagnostic and treatment modalities of disorders related to chronic neck pain and concluded that, despite providing temporary relief of symptoms, these treatments do not address the specific problems of healing and are not likely to offer long-term cures. The objectives of this narrative review are to provide an overview of chronic neck pain as it relates to cervical instability, to describe the anatomical features of the cervical spine and the impact of capsular ligament laxity, to discuss the disorders causing chronic neck pain and their current treatments, and lastly, to present prolotherapy as a viable treatment option that heals injured ligaments, restores stability to the spine, and resolves chronic neck pain. The capsular ligaments are the main stabilizing structures of the facet joints in the cervical spine and have been implicated as a major source of chronic neck pain. Chronic neck pain often reflects a state of instability in the cervical spine and is a symptom common to a number of conditions described herein, including disc herniation, cervical spondylosis, whiplash injury and whiplash associated disorder, postconcussion syndrome, vertebrobasilar insufficiency, and Barré-Liéou syndrome. When the capsular ligaments are injured, they become elongated and exhibit laxity, which causes excessive movement of the cervical vertebrae. In the upper cervical spine (C0-C2), this can cause a number of other symptoms including, but not limited to, nerve irritation and vertebrobasilar insufficiency with associated vertigo, tinnitus, dizziness, facial pain, arm pain, and migraine headaches. In the lower cervical spine (C3-C7), this can cause muscle spasms, crepitation, and/or paresthesia in addition to chronic neck pain. In either case, the presence of excessive motion between two adjacent cervical vertebrae and these associated symptoms is described as cervical instability. Therefore, we propose that in many cases of chronic neck pain, the cause may be underlying joint instability due to capsular ligament laxity. Currently, curative treatment options for this type of cervical instability are inconclusive and inadequate. Based on clinical studies and experience with patients who have visited our chronic pain clinic with complaints of chronic neck pain, we contend that prolotherapy offers a potentially curative treatment option for chronic neck pain related to capsular ligament laxity and underlying cervical instability.

Acute concussion symptom severity and delayed symptom resolution

BACKGROUND AND OBJECTIVES

Up to 30% of children who have concussion initially evaluated in the emergency department (ED) display delayed symptom resolution (DSR). Greater initial symptom severity may be an easily quantifiable predictor of DSR. We hypothesized that greater symptom severity immediately after injury increases the risk for DSR.

METHODS

We conducted a prospective longitudinal cohort study of children 8 to 18 years old presenting to the ED with concussion. Acute symptom severity was assessed using a graded symptom inventory. Presence of DSR was assessed 1 month later. Graded symptom inventory scores were tested for association with DSR by sensitivity analysis. We conducted a similar analysis for post-concussion syndrome (PCS) as defined by the International Statistical Classification of Diseases and Related Health Problems, 10th revision. Potential symptoms characteristic of DSR were explored by using hierarchical cluster analysis.

RESULTS

We enrolled 234 subjects; 179 (76%) completed follow-up. Thirty-eight subjects (21%) experienced DSR. Initial symptom severity was not significantly associated with DSR 1 month after concussion. A total of 22 subjects (12%) had PCS. Scores >10 (possible range, 0-28) were associated with an increased risk for PCS (RR, 3.1; 95% confidence interval 1.2-8.0). Three of 6 of the most characteristic symptoms of DSR were also most characteristic of early symptom resolution. However, cognitive symptoms were more characteristic of subjects reporting DSR.

CONCLUSIONS

Greater symptom severity measured at ED presentation does not predict DSR but is associated with PCS. Risk stratification therefore depends on how the persistent symptoms are defined. Cognitive symptoms may warrant particular attention in future study. Follow-up is recommended for all patients after ED evaluation of concussion to monitor for DSR.

Duration and course of post-concussive symptoms

OBJECTIVES

To examine the incidence, duration, and clinical course of individual post-concussive symptoms in patients presenting to a pediatric emergency department (ED) with a concussion.

METHODS

We conducted secondary analysis of a prospective cohort study of patients 11 to 22 years old presenting to the ED of a children's hospital with an acute concussion. The main outcome measure was duration of symptoms, assessed by the Rivermead Post-Concussion Symptoms Questionnaire (RPSQ). Patients initially completed a questionnaire describing mechanism of injury, associated symptoms, past medical history, and the RPSQ, then were serially administered the RPSQ for 3 months after the concussion or until all symptoms resolved.

RESULTS

Headache, fatigue, dizziness, and taking longer to think were the most common symptoms encountered at presentation, whereas sleep disturbance, frustration, forgetfulness, and fatigue were the symptoms most likely to develop during the follow-up period that had not initially been present. Median duration of symptoms was the longest for irritability (16 days), sleep disturbance (16 days), frustration (14 days), and poor concentration (14 days), whereas nausea, depression, dizziness, and double-vision abated most quickly. One month after injury, nearly a quarter of children still complained of headache, >20% suffered from fatigue, and nearly 20% reported taking longer to think.

CONCLUSIONS

Among patients presenting to a pediatric ED after a concussion, physical symptoms such as headache predominate immediately after the injury, emotional symptoms tend to develop later in the recovery period, and cognitive symptoms may be present throughout.

Effect of cognitive activity level on duration of post-concussion symptoms

OBJECTIVE

To determine the effect of cognitive activity level on duration of post-concussion symptoms.

METHODS

We conducted a prospective cohort study of patients who presented to a Sports Concussion Clinic within 3 weeks of injury between October 2009 and July 2011. At each visit, patients completed a scale that recorded their average level of cognitive activity since the previous visit. The product of cognitive activity level and days between visits (cognitive activity-days) was calculated and divided into quartiles. Kaplan-Meier Product Limit method was used to generate curves of symptom duration based on cognitive activity level. To adjust for other possible predictors of concussion recovery, we constructed a Cox proportional hazard model with cognitive activity-days as the main predictor.

RESULTS

Of the 335 patients included in the study, 62% were male, 19% reported a loss of consciousness, and 37% reported experiencing amnesia at the time of injury. The mean age of participants was 15 years (range, 8-23) and the mean number of previous concussions was 0.76; 39% of athletes had sustained a previous concussion. The mean Post-Concussion Symptom Scale score at the initial visit was 30 (SD, 26). The overall mean duration of symptoms was 43 days (SD, 53). Of all variables assessed, only total symptom burden at initial visit and cognitive activity level were independently associated with duration of symptoms.

CONCLUSIONS

Increased cognitive activity is associated with longer recovery from concussion. This study supports the use of cognitive rest and adds to the current consensus opinion.

Application of blood-based biomarkers in human mild traumatic brain injury

Traumatic Brain Injury (TBI) is a global health concern. The majority of TBI's are mild, yet our ability to diagnose and treat mild traumatic brain injury (mTBI) is lacking. This deficiency results from a variety of issues including the difficulty in interpreting ambiguous clinically presented symptoms, and ineffective imaging techniques. Thus, researchers have begun to explore cellular and molecular based approaches to improve both diagnosis and prognosis. This has been met with a variety of challenges, including difficulty in relating biological markers to current clinical symptoms, and overcoming our lack of fundamental understanding of the pathophysiology of mTBI. However, recent adoption of high throughput technologies and a change in focus from the identification of single to multiple markers has given just optimism to mTBI research. The purpose of this review is to highlight a number of current experimental peripheral blood biomarkers of mTBI, as well as comment on the issues surrounding their clinical application and utility.

Long-term effects of mild traumatic brain injury on cognitive performance

Although a proportion of individuals report chronic cognitive difficulties after mild traumatic brain injury (mTBI), results from behavioral testing have been inconsistent. In fact, the variability inherent to the mTBI population may be masking subtle cognitive deficits. We hypothesized that this variability could be reduced by accounting for post-concussion syndrome (PCS) in the sample. Thirty-six participants with mTBI (>1 year post-injury) and 36 non-head injured controls performed information processing speed (Paced Visual Serial Addition Task, PVSAT) and working memory (n-Back) tasks. Both groups were split by PCS diagnosis (4 groups, all n = 18), with categorization of controls based on symptom report. Participants with mTBI and persistent PCS had significantly greater error rates on both the n-Back and PVSAT, at every difficulty level except 0-Back (used as a test of performance validity). There was no difference between any of the other groups. Therefore, a cognitive deficit can be observed in mTBI participants, even 1 year after injury. Correlations between cognitive performance and symptoms were only observed for mTBI participants, with worse performance correlating with lower sleep quality, in addition to a medium effect size association (falling short of statistical significance) with higher PCS symptoms, post-traumatic stress disorder (PTSD), and anxiety. These results suggest that the reduction in cognitive performance is not due to greater symptom report itself, but is associated to some extent with the initial injury. Furthermore, the results validate the utility of our participant grouping, and demonstrate its potential to reduce the variability observed in previous studies.

Rehabilitation of Concussion and Post-concussion Syndrome

CONTEXT

Prolonged symptoms after concussion are called post-concussion syndrome (PCS), which is a controversial disorder with a wide differential diagnosis.

EVIDENCE ACQUISITION

MEDLINE and PubMed searches were conducted for the years 1966 to 2011 using the search terms brain concussion/complications OR brain concussion/diagnosis OR brain concussion/therapy AND sports OR athletic injuries. Secondary search terms included post-concussion syndrome, trauma, symptoms, metabolic, sports medicine, cognitive behavioral therapy, treatment and rehabilitation. Additional articles were identified from the bibliographies of recent reviews.

RESULTS

Of 564 studies that fulfilled preliminary search criteria, 119 focused on the diagnosis, pathophysiology, and treatment/rehabilitation of concussion and PCS and formed the basis of this review. Rest is the primary treatment for the acute symptoms of concussion. Ongoing symptoms are either a prolonged version of the concussion pathophysiology or a manifestation of other processes, such as cervical injury, migraine headaches, depression, chronic pain, vestibular dysfunction, visual dysfunction, or some combination of conditions. The pathophysiology of ongoing symptoms from the original concussion injury may reflect multiple causes: anatomic, neurometabolic, and physiologic.

CONCLUSIONS

Treatment approaches depend on the clinician's ability to differentiate among the various conditions associated with PCS. Early education, cognitive behavioral therapy, and aerobic exercise therapy have shown efficacy in certain patients but have limitations of study design. An algorithm is presented to aid clinicians in the evaluation and treatment of concussion and PCS and in the return-to-activity decision.