Overview of concussion consensus statements since 2000

Acute and subacute clinical markers after sport-related concussion in rugby union players

OBJECTIVES

The purpose of this study was to investigate the relationship between on-field post-concussion symptoms reported by athletes, on-field neurological signs reported by a trainer or physician, and/or post-concussion symptoms 72 h after brain injury in male rugby players.

DESIGN

Cross-sectional study in a Sports Concussion Clinic setting.

METHODS

We enrolled 92 adult rugby union players, within the first 72 h after sport concussion. Four scales were measured. Immediate Concussion Sign Checklist (sideline); Immediate Concussion Symptom Checklist (24 h after concussion); Post-Concussion Symptoms Scale and Beck Depression Inventory (in-office 72 h after concussion).

RESULTS

Odds ratios revealed that overtly symptomatic athletes were over 2.6 times more likely (p = 0.047) to exhibit post-traumatic amnesia than asymptomatic athletes. There were no differences in terms of on-field loss of consciousness or confusion. Immediate symptoms reported by athletes retrospectively were associated with symptoms reported on the Beck Depression Inventory (odds ratio 2.8; 95 % confidence interval 1.14-6.88), headache (odds ratio 4.9; 95 % confidence interval 1.92-12.79), memory concerns (odds ratio 3.15; 95 % confidence interval 1.06-9.34), pressure in the head (odds ratio 2.8; 95 % confidence interval 1.03-8.08), and visual disturbances (odds ratio 3.9; 95 % confidence interval 1.05-14.50) reported 72 h after sports concussion.

CONCLUSIONS

Athletes who were overtly symptomatic after sports concussion were significantly more likely to experience post-traumatic amnesia and two or more on-field concussion signs relative to those athletes who were asymptomatic. Also, players with immediate symptoms reported higher depressive symptoms, somatic symptoms (headache and visual disturbances), and cognitive symptoms.

Transcranial Direct Current Stimulation as a Treatment Tool for Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) has been defined as a transient (<24 h) condition of confusion and/or loss of consciousness for less than 30 min after brain injury and can result in short- and long-term motor and cognitive impairments. Recent studies have documented the therapeutic potential of non-invasive neuromodulation techniques for the enhancement of cognitive and motor function in mTBI. Alongside repetitive transcranial magnetic stimulation (rTMS), the main technique used for this purpose is transcranial direct current stimulation (tDCS). The focus of this review was to provide a detailed, comprehensive (i.e., both cognitive and motor impairment) overview of the literature regarding therapeutic tDCS paradigms after mTBI. A publication search of the PubMed, Scopus, CINAHL, and PsycINFO databases was performed to identify records that applied tDCS in mTBI. The publication search yielded 14,422 records from all of the databases, however, only three met the inclusion criteria and were included in the final review. Based on the review, there is limited evidence of tDCS improving cognitive and motor performance. Surprisingly, there were only three studies that used tDCS in mTBI, which highlights an urgent need for more research to provide additional insights into ideal therapeutic brain targets and optimized stimulation parameters.

Prevalence of concussion and adherence to return-to-play guidelines amongst male secondary school rugby and hockey players

Background

Concussion injuries are common in contact sports. Young players can suffer life-threatening complications if concussion is not recognised and managed.

Objectives

To determine the prevalence of concussion amongst secondary school rugby and hockey players and describe players’ knowledge and adherence to return-to-play guidelines.

Method

A mixed-method approach included Phase A, which utilised a questionnaire completed by 221 players (n = 139 rugby; n = 82 hockey) between 13 and 18 years of age, and Phase B, which utilised three focus group discussions of 15 participants who had suffered a concussion.

Results

The prevalence of concussion (n = 221) was 31.2% (n = 69). Of those, 71% (n = 49) were rugby players. Those who had suffered a concussion were more confident in identifying symptoms of concussion in themselves and others compared with those who did not suffer a concussion (p = 0.001), were more aware of return-to-play guidelines and more confident in their knowledge of concussion (p = 0.001). There were no differences between groups when identifying concussion symptoms. Of those who had a concussion, 30.4% (n = 21) adhered to return-to-play guidelines and followed graded return-to-play after their concussion. Explanations for non-adherence to return-to-play protocols included peer pressure, intrinsic motivation and ignorance.

Conclusion

Nearly a third had suffered a concussion injury; having suffered a concussion, and awareness of return-to-play guidelines, did not guarantee adherence to return-to-play protocols. Peer pressure and intrinsic factors explained this lack of adherence.

Clinical implications

Physiotherapists are often involved with the diagnosis and management of concussion injuries among rugby and hockey players. Understanding the prevalence and the reasons why young players do not adhere to the ‘return to play’ guidelines may inform preventative strategies.

Concussion: A Global Perspective

Concussion, also referred to as mild traumatic brain injury (MTBI), is a common pediatric condition. This article reviews global perspectives on the epidemiology, treatment, and prognosis of concussion in children. A Pubmed search was conducted using Clinical Queries with the key terms "concussion" and "mild traumatic brain injury," and the search was limited to "children." The search strategy included meta-analyses, randomized controlled trials, clinical trials, and reviews. The majority of publications were from Canada and the United States. Prevalence estimates vary widely according to case definition and studied population. Due to under-reporting and to the widely varying definitions of concussion, it is difficult to estimate how common the condition is. Common causes of concussions include sports injuries, motor vehicle collisions, bicycle accidents, falls, and assaults. Diagnosis is mainly clinical. Because concussion results from a disturbance in brain function rather than structural injury, neuroimaging studies, such as computed tomography and magnetic resonance imaging, are not routinely recommended. Treatment generally involves physical and cognitive rest, with a gradual return to activities, whereas prolonged rest may actually worsen outcomes. Helmets when bicycling, skiing, snowboarding, motor biking, placing age limits on certain types of contact sports, and encouragement of fair play are recommended to decrease the impact of head injuries but they do not prevent concussions. Overall outcomes are generally favorable. The symptoms and signs of concussion usually resolve within 10 days; most patients recover in 48-72 hours. Global perspectives on management and prognosis are lacking. Concussions or MTBIs are common childhood injuries and the prognosis is good but information is predominantly from Canada and the USA. Research in other countries in particular low and middle income countries is vital to have a global perspective on MTBI.

Management of concussion in soccer

BACKGROUND

When participating in contact sports, (mild) head trauma is a common incident-observed in both professional and amateur sports. When head trauma results in transient neurological impairment, a sports-related concussion has occurred. Acute concussion, repetitive concussions, as well as cumulative "sub-concussive" head impacts may increase the risk of developing cognitive and behavioral deficits for athletes, as well as accelerated cerebral degeneration. While this concept has been well established for classic contact sports like American Football, Rugby, or Boxing, there is still an awareness gap for the role of sports-related concussion in the context of the world's most popular sport-Soccer.

METHODS

Here, we review the relevance of sport-related concussion for Soccer as well as its diagnosis and management. Finally, we provide insight into future directions for research in this field.

RESULTS

Soccer fulfills the criteria of a contact sport and is characterized by a high incidence of concussion. There is ample evidence that these events cause functional and structural cerebral disorders. Furthermore, heading, as a repeat sub-concussive impact, has been linked to structural brain changes and neurocognitive impairment. As a consequence, recommendations for the diagnosis and management of concussion in soccer have been formulated by consensus groups. In order to minimize the risk of repetitive concussion in soccer the rapid and reliable side-line diagnosis of concussion with adoption of a strict remove-from-play protocol is essential, followed by a supervised, graduated return-to-play protocol. Recent studies, however, demonstrate that adherence to these recommendations by players, coaches, clubs, and officials is insufficient, calling for stricter enforcement. In addition, future research to solidify the pathophysiological relevance of concussion for soccer athletes seems to be needed. Advanced neuroimaging and neurochemical biomarker analyses (e.g. S100β, tau and neurofilament light (NfL)) may assist in detecting concussion-related structural brain changes and selecting athletes at risk for irreversible damage.

CONCLUSION

Sports-related concussion represents a genuine neurosurgical field of interest. Given the high socioeconomic relevance, neurosurgeons should get involved in prevention and management of concussion in soccer.

Glutamate and GABA concentrations following mild traumatic brain injury: a pilot study

Animal models of mild traumatic brain injury (mTBI) suggest that metabolic changes in the brain occur immediately after a mechanical injury to the head. Proton magnetic resonance spectroscopy (¹H-MRS) can be used to determine relative concentrations of metabolites in vivo in the human brain. The purpose of this study was to determine concentrations of glutamate and GABA in the brain acutely after mTBI and throughout 2 mo of recovery. Concentrations of glutamate and GABA were obtained using ¹H-MRS in nine individuals who had suffered an mTBI and nine control individuals in two brain regions of interest: the primary motor cortex (M1), and the dorsolateral prefrontal cortex (DLPFC), and at three different time points postinjury: 72 h, 2 wk, and 2 mo postinjury. There were no differences between groups in concentrations of glutamate or GABA, or the ratio of glutamate to GABA, in M1. In the DLPFC, glutamate concentration was lower in the mTBI group compared with controls at 72 h postinjury (d = 1.02), and GABA concentration was lower in the mTBI group at 72 h and 2 wk postinjury (d = 0.81 and d = 1.21, respectively). The ratio of glutamate to GABA in the DLPFC was higher in the mTBI group at 2 wk postinjury (d = 1.63). These results suggest that changes in glutamate and GABA concentrations in the brain may be region-specific and may depend on the amount of time that has elapsed postinjury. NEW & NOTEWORTHY To our knowledge, this is the first study to examine neurotransmitter concentrations in vivo at multiple time points throughout recovery from mild traumatic brain injury in humans.

Cortical and Physical Function after Mild Traumatic Brain Injury

PURPOSE

The aim of this study was to prospectively examine the association between intracortical inhibition and functional recovery after mild traumatic brain injury (mTBI).

METHODS

Twenty individuals with mTBI and 20 matched control participants were assessed using transcranial magnetic stimulation, the Attentional Network Test, and gait analysis. Hierarchical linear modeling was used to longitudinally examine potential differences between groups and relationships in the pattern of recovery in cortical silent period (CSP) duration, cognitive reaction time, and single- and dual-task walking speeds across five testing time points. Individuals with mTBI were assessed within 72 h of injury, and again at 1 wk, 2 wk, 1 month, and 2 months postinjury. After initial testing, control participants followed a similar timeline.

RESULTS

At the 72-h time point, the group with mTBI had longer reaction time (b = -91.76, P = 0.01), similar single-task walking speed (b = 0.055, P = 0.10), and slower dual-task walking speed (b = 0.10, P = 0.012) compared with control participants. The CSP duration also tended to be longer in individuals with mTBI than controls at the 72-h time point (b = -16.34, P = 0.062). The change is CSP duration over time was not significantly associated with the change in reaction time (b = -0.19, P = 0.47), single-task walking speed (b = 0.0001, P = 0.53), or dual-task walking speed (b < 0.001, P = 0.68).

CONCLUSION

Although cognitive and motor functions were significantly impaired in the mTBI group acutely after injury, levels of intracortical inhibition were not associated with recovery in either functional domain.

Reliability and Concurrent Validity of Select C3 Logix Test Components

We sought to investigate the one-week and within-session reliability of the instrumented balance error scoring system test and the concurrent validity/one-week reliability of two neurocognitive assessments available through C3 Logix. (n = 37) Participants completed two balance error scoring system tests separated by the Trails A, Trails B, and Symbol Digit Modality test available through C3 Logix, and with paper and pencil. We found that the instrumented balance error scoring system test demonstrated strong one-week reliability and that neuropsychological tests available through C3 Logix show acceptable concurrent validity with standard (comparable) paper and pencil measures.

Management of Mild Traumatic Brain Injury Symptoms in a 31-Year-Old Woman Using Cervical Manipulation and Acupuncture: A Case Report

OBJECTIVE

The objective was to describe chiropractic and acupuncture care of a patient with acute mild traumatic brain injury (mTBI) symptoms.

CLINICAL FEATURES

A 31-year-old woman had acute neck pain, headache, dizziness, nausea, tinnitus, difficulty concentrating, and fatigue following a fall. She was diagnosed at an urgent care facility with mTBI immediately following the fall. Pharmaceutical intervention had been ineffective for her symptoms.

INTERVENTION AND OUTCOME

The patient was treated with chiropractic adjustments characterized as high velocity, low amplitude thrusts directed to the cervical spine and local acupuncture points in the cervical and cranial regions. The patient received care for a total of 8 visits over 2.5 weeks with resolution of concussive symptoms.

CONCLUSION

This patient with mTBI responded favorably to a conservative treatment protocol with the combination of chiropractic and acupuncture care.

Clinical features of repetitive traumatic brain injury and chronic traumatic encephalopathy

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease characterized by a distinct pattern of hyperphosphorylated tau (p-tau). Thought to be caused by repetitive concussive and subconcussive injuries, CTE is considered largely preventable. The majority of neuropathologically confirmed cases have occurred in professional contact sport athletes (eg, boxing, football). A recent post-mortem case series has magnified concerns for the public's health following its identification in six high school level athletes. CTE is diagnosed with certainty only following a post-mortem autopsy. Efforts to define the etiology and clinical progression during life are ongoing. The goal of this article is to characterize the clinical concepts associated with short- and long-term effects of repetitive traumatic brain injury, with a special emphasis on new clinical diagnostic criteria for CTE. Utilizing these new diagnostic criteria, two cases of neuropathologically confirmed CTE, one in a professional football player and one in a professional boxer, are reported. Differences in cerebellar pathology in CTE confirmed cases in boxing and football are discussed.

Reported Concussion Rates for Three Division I Football Programs: An Evaluation of the New NCAA Concussion Policy

Background:

There has been increased interest in the number of concussions occurring in college football over the past year. In April 2010, the National Collegiate Athletic Association (NCAA) published new guidelines for the diagnosis and treatment of concussions in student athletes.

Purpose:

To determine the number of concussions that occurred on 3 collegiate Division I military academy football teams prior to and following recent changes in the NCAA concussion management policy.

Study Design:

Descriptive epidemiology study.

Methods:

Injury reports were reviewed from 3 Division I military academy football teams. The number of concussions that occurred over the 2009-2010 and 2010-2011 seasons, including those sustained in practice and game situations, was determined for each team. Incidence rates were compared using the exact binomial method.

Results:

The combined concussion incidence rate doubled from 0.57 per 1000 athlete exposures in the 2009-2010 season to 1.16 per 1000 athlete exposures in the 2010-2011 season (incidence rate ratio, 2.04; 95% CI, 1.2-3.55; P = 0.01). The combined numbers of concussions for the 2009-2010 and 2010-2011 seasons were 23 (40,481 exposures) and 42 (36,228), respectively.

Conclusion:

The combined incidence rate of concussions for the 2010-2011 season doubled from the previous season after the implementation of new NCAA policies on concussion management. While the institution of a more formalized concussion plan on the part of medical staff is one possible factor, another may have been the increased recognition and reporting on the part of players and coaches after the rule change.

Return to play management after concussion in football: recommendations for team physicians

A concussion is a rare but potentially serious injury of football players. Thus, an immediate and valid diagnosis, estimate of severity and therapeutic management is required. To summarise the published information on management of concussion with respect to a safe return to play (RTP), a literature search was conducted. Current guidelines on concussion in sports and significant studies on concussion in football were analysed. After concussion, management and RTP decision should remain in the area of clinical judgement on an individualised basis according to the current international guidelines. If a concussion is suspected, the player should not be allowed to RTP the same day. The RTP programme should follow a gradual step-wise procedure. A concussed player should not RTP unless he/she is asymptomatic and the neurological and neuropsychological examinations are normal. Untimely RTP bears an increased risk of sustaining another more severe brain injury and repetitive brain injury of long-term sequelae. In football, the management of concussion should primarily follow the recommendations proposed by the Concussion in Sports Group. Information and education of players and their medical and coaching team help to protect the players' health. Future studies on concussion should include validated and detailed information on RTP protocols.

Do injury characteristics predict the severity of acute neuropsychological deficits following sports-related concussion? A meta-analysis

The utility of injury characteristics for predicting the severity of post-concussion outcomes remains equivocal. The purpose of this meta-analysis was to quantify the predictive relationship between these variables to inform classification of acute injury severity. Thirty-one empirical samples of concussed athletes, for which rates of loss of consciousness and/or amnesia were reported, were included in a meta-analysis evaluating acute outcomes following sports-related concussion. Outcome measures of interest were neuropsychological tests first administered 1-10 days post-injury. Loss of consciousness and anterograde amnesia significantly predicted more severe neuropsychological deficits within 10 days of concussion in studies using pre-injury baseline, but not control group, comparisons. Retrograde amnesia significantly predicted acute neuropsychological dysfunction (d = -1.03) irrespective of comparison group. Although small sample sizes require conservative interpretation and future replication, the evidence suggests that retrograde amnesia, rather than loss of consciousness, may be used to classify the acute severity of concussion.

Understanding the neuroinflammatory response following concussion to develop treatment strategies

Mild traumatic brain injuries (mTBI) have been associated with long-term cognitive deficits relating to trauma-induced neurodegeneration. These long-term deficits include impaired memory and attention, changes in executive function, emotional instability, and sensorimotor deficits. Furthermore, individuals with concussions show a high co-morbidity with a host of psychiatric illnesses (e.g., depression, anxiety, addiction) and dementia. The neurological damage seen in mTBI patients is the result of the impact forces and mechanical injury, followed by a delayed neuroimmune response that can last hours, days, and even months after the injury. As part of the neuroimmune response, a cascade of pro- and anti-inflammatory cytokines are released and can be detected at the site of injury as well as subcortical, and often contralateral, regions. It has been suggested that the delayed neuroinflammatory response to concussions is more damaging then the initial impact itself. However, evidence exists for favorable consequences of cytokine production following traumatic brain injuries as well. In some cases, treatments that reduce the inflammatory response will also hinder the brain's intrinsic repair mechanisms. At present, there is no evidence-based pharmacological treatment for concussions in humans. The ability to treat concussions with drug therapy requires an in-depth understanding of the pathophysiological and neuroinflammatory changes that accompany concussive injuries. The use of neurotrophic factors [e.g., nerve growth factor (NGF)] and anti-inflammatory agents as an adjunct for the management of post-concussion symptomology will be explored in this review.

Concussion in athletics: ongoing clinical and brain imaging research controversies

Concussion, the most common form of traumatic brain injury, proves to be increasingly complex and not mild in nature as its synonymous term mild traumatic brain injury (mTBI) would imply. Despite the increasing occurrence and prevalence of mTBI there is no universally accepted definition and conventional brain imaging techniques lack the sensitivity to detect subtle changes it causes. Moreover, clinical management of sports induced mild traumatic brain injury has not changed much over the past decade. Advances in neuroimaging that include electroencephalography (EEG), functional magnetic resonance imaging (fMRI), resting-state functional connectivity, diffusion tensor imaging (DTI) and magnetic resonance spectroscopy (MRS) offer promise in aiding research into understanding the complexities and nuances of mTBI which may ultimately influence clinical management of the condition. In this paper the authors review the major findings from these advanced neuroimaging methods along with current controversy within this field of research. As mTBI is frequently associated with youth and sports injury this review focuses on sports-related mTBI in the younger population.

High school soccer players with concussion education are more likely to notify their coach of a suspected concussion

Previously published studies have found that concussion symptoms are underreported in youth athletics. This study evaluated the likelihood high school soccer players would identify themselves as having concussion related symptoms during game situations. A questionnaire inquiring about past concussion education and the likelihood of notifying their coach of concussion symptoms was administered to 183 high school soccer players. Of the 60 (33%) who completed the survey, 18 (72%) athletes who had acknowledged receiving concussion training responded that they would always notify their coach of concussion symptoms, as compared with 12 (36%) of the players who reported having no such training (P = .01). The results of this study suggest that athletes with past concussion training are more likely to notify their coach of concussion symptoms, potentially reducing their risk for further injury. Concussion education should be considered for all high school soccer players.

Long-term cognitive and emotional consequences of mild traumatic brain injury

BACKGROUND

The objective of this study was to investigate long-term cognitive and emotional sequelae of mild traumatic brain injury (mTBI), as previous research has remained inconclusive with respect to their prevalence and extent.

METHOD

Thirty-three individuals who had sustained mTBI on average 6 years prior to the study and 33 healthy control subjects were matched according to age, gender and education. Structural brain damage at time of testing was excluded by magnetic resonance imaging (MRI). A comprehensive neuropsychological test battery was conducted to assess learning, recall, working memory, attention and executive function. Psychiatric symptoms were assessed by the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) and the Beck Depression Inventory (BDI). Possible negative response bias was ruled out by implementing the Word Memory Test (WMT).

RESULTS

The mTBI individuals had significant impairments in all cognitive domains compared to the healthy control subjects. Effect sizes of cognitive deficits were medium to large, and could not be accounted for by self-perceived deficits, depression, compensation claims or negative response bias. BDI scores were significantly higher in the patient group, and three patients fulfilled DSM-IV criteria for a mild episode of major depression.

CONCLUSIONS

Primarily, well-recovered individuals who had sustained a minor trauma more than half a decade ago continue to have long-term cognitive and emotional sequelae relevant for everyday social and professional life. mTBI may lead to a lasting disruption of neurofunctional circuits not detectable by standard structural MRI and needs to be taken seriously in clinical and forensic evaluations.

Investigation of baseline self-report concussion symptom scores

CONTEXT

Self-reported symptoms (SRS) scales comprise one aspect of a multifaceted assessment of sport-related concussion. Obtaining SRS assessments before a concussion occurs assists in determining when the injury is resolved. However, athletes may present with concussion-related symptoms at baseline. Thus, it is important to evaluate such reports to determine if the variables that are common to many athletic environments are influencing them.

OBJECTIVE

To evaluate the influence of a history of concussion, sex, acute fatigue, physical illness, and orthopaedic injury on baseline responses to 2 summative symptom scales; to investigate the psychometric properties of all responses; and to assess the factorial validity of responses to both scales in the absence of influential variables.

DESIGN

Cross-sectional study.

SETTING

Athletic training facilities of 6 National Collegiate Athletic Association institutions.

PATIENTS OR OTHER PARTICIPANTS

The sample of 1065 was predominately male (n = 805) collegiate athletes with a mean age of 19.81 +/- 1.53 years.

MAIN OUTCOME MEASURE(S)

Participants completed baseline measures for duration and severity of concussion-related SRS and a brief health questionnaire.

RESULTS

At baseline, respondents reporting a previous concussion had higher composite scores on both scales (P <or= .01), but no sex differences were found for concussion-related symptoms. Acute fatigue, physical illness, and orthopaedic injury increased composite SRS scores on both duration and severity measures (P <or= .01). Responses to both scales were stable and internally consistent. Confirmatory factor analysis provided strong evidence for the factorial validity of the responses of participants reporting no fatigue, physical illness, or orthopaedic injury on each instrument.

CONCLUSIONS

A history of concussion, acute fatigue, physical illness, and orthopaedic injury increased baseline SRS scores. These conditions need to be thoroughly investigated and controlled by clinicians before baseline SRS measures are collected.

Supporting the student-athlete's return to the classroom after a sport-related concussion

OBJECTIVE

This article provides a framework for school athletic trainers to use in advising colleagues about the health and academic needs of student-athletes presenting with concussions.

BACKGROUND

Management of sport-related concussions has been an area of growing concern for school athletic programs. Recent work in this area has highlighted significant risks for student-athletes presenting with these mild traumatic brain injuries.

DESCRIPTION

Topics covered include general teaching points for the athletic trainer to use with school colleagues. An integrated model for school management of sport concussion injuries is presented that includes involvement of the student's athletic trainer, school nurse, guidance counselor, teachers, social worker, psychologist, physicians, and parents.

CLINICAL ADVANTAGES

Academic accommodations for specific postconcussion symptoms are proposed that may help the student-athlete strike an optimum balance between rest and continued academic progress during recovery.

TEMPORAL WINDOW OF METABOLIC BRAIN VULNERABILITY TO CONCUSSION

OBJECTIVE

In the present study, the occurrence of the temporal window of brain vulnerability was evaluated in concussed athletes by measuring N-acetylaspartate (NAA) using proton magnetic resonance (1H-MR) spectroscopy.

METHODS

Thirteen nonprofessional athletes who had a sport-related concussive head injury were examined for NAA determination by means of 1H-MR spectroscopy at 3, 15, and 30 days postinjury. All athletes but three suspended their physical activity. Those who continued their training had a second concussive event and underwent further examination at 45 days from the initial injury. The single case of one professional boxer, who was studied before the match and 4, 7, 15, and 30 days after a knockout, is also presented. Before each magnetic resonance examination, patients were asked for symptoms of mild traumatic brain injury, including physical, cognitive, emotional, and sleep disturbances. Data for 1H-MR spectroscopy recorded in five normal, age-matched, control volunteers, who were previously screened to exclude previous head injuries, were used for comparison. Semiquantitative analysis of NAA relative to creatine (Cr)- and choline (Cho)-containing compounds was performed from proton spectra obtained with a 3-T magnetic resonance system.

RESULTS

Regarding the values of the NAA-to-Cr ratio (2.21 ± 0.11) recorded in control patients, singly concussed athletes, at 3 days after the concussion, showed a decrease of 18.5% (1.80 ± 0.04; P &lt; 0.001). Only a modest 3% recovery was observed at 15 days (1.88 ± 0.1; P &lt; 0.001); at 30 days postinjury, the NAA-to-Cr ratio was 2.15 ± 0.1, revealing full metabolic recovery with values not significantly different from those of control patients. These patients declared complete resolution of symptoms at the time of the 3-day study. The three patients who had a second concussive injury before the 15-day study showed an identical decrease of the NAA-to-Cr ratio at 3 days (1.78 ± 0.08); however, at 15 days after the second injury, a further diminution of the NAA-to-Cr ratio occurred (1.72 ± 0.07; P &lt; 0.05 with respect to singly concussed athletes). At 30 days, the NAA-to-Cr ratio was 1.82 ± 0.1, and at 45 days postinjury, the NAA-to-Cr ratio showed complete recovery (2.07 ± 0.1; not significant with respect to control patients). This group of patients declared a complete resolution of symptoms at the time of the 30-day study.

CONCLUSION

Results of this pilot study carried out in a cohort of singly and doubly concussed athletes, examined by 1H-MR spectroscopy for their NAA cerebral content at different time points after concussive events, demonstrate that also in humans, concussion opens a temporal window of brain metabolic imbalance, the closure of which does not coincide with resolution of clinical symptoms. The recovery of brain metabolism is not linearly related to time. A second concussive event prolonged the time of NAA normalization by 15 days. Although needing confirmation in a larger group of patients, these results show that NAA measurement by 1H-MR spectroscopy is a valid tool in assessing the full cerebral metabolic recovery after concussion, thereby suggesting its use in helping to decide when to allow athletes to return to play after a mild traumatic brain injury.

Neurologic injuries in hockey

Ice hockey is a fast contact sport played on an ice surface enclosed by rigid boards. There is an intrinsic risk for injury in hockey, with many injuries potentially affecting the nervous system. This article provides an overview of neurologic injuries occurring in hockey as reported in the scientific literature. Among all injuries, a small but real risk for catastrophic cervical spinal cord injury and a high incidence of concussion emerge as the two most important neurologic issues.

Reliable change of the sensory organization test

OBJECTIVE

To establish the sensitivity and specificity of the NeuroCom Sensory Organization Test (SOT) and provide practitioners with cut-scores for clinical decision making using estimates of reliable change.

DESIGN

Retrospective cohort study.

SETTING

Research laboratory.

PATIENTS

Healthy (n = 66) and concussed (n = 63) young adult participants.

INTERVENTIONS

Postural control assessments on the NeuroCom SOT were completed twice (baseline and follow-up) for both groups. Postconcussion assessments were administered within 24 hours of injury diagnosis.

MAIN OUTCOME MEASUREMENTS

The reliable change technique was used to calculated cut-scores for each SOT variable (composite balance; somatosensory, visual, and vestibular ratios) at the 95%, 90%, 85%, 80%, 75%, and 70% confidence interval levels.

RESULTS

When cut-scores were applied to the post-concussion evaluations, sensitivity and specificity varied with SOT variable and confidence interval. An evaluation for change on one or more SOT variable resulted in the highest combined sensitivity (57%) and specificity (80%) at the 75% confidence interval.

CONCLUSIONS

Use of reliable change scores to detect significant changes in performance on the SOT resulted in decreased sensitivity and improved specificity compared to a previous report. These findings indicate that some concussed athletes may not show large changes in postconcussion postural control and this postural control evaluation should not be used in exclusion of other assessment techniques. The postural control assessment should be combined with other evaluative measures to gain the highest sensitivity to concussive injuries.