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1.  Psychometric Properties of Self-Report Concussion Scales and Checklists 
Journal of Athletic Training  2012;47(2):221-223.
Alla S, Sullivan SJ, Hale L, McCrory P. Self-report scales/checklists for the measurement of concussion symptoms: a systematic review. Br J Sports Med. 2009;43 (suppl 1):i3–i12.
Clinical Question:
Which self-report symptom scales or checklists are psychometrically sound for clinical use to assess sport-related concussion?
Data Sources:
Articles available in full text, published from the establishment of each database through December 2008, were identified from PubMed, Medline, CINAHL, Scopus, Web of Science, SPORTDiscus, PsycINFO, and AMED. Search terms included brain concussion, signs or symptoms, and athletic injuries, in combination with the AND Boolean operator, and were limited to studies published in English. The authors also hand searched the reference lists of retrieved articles. Additional searches of books, conference proceedings, theses, and Web sites of commercial scales were done to provide additional information about the psychometric properties and development for those scales when needed in articles meeting the inclusion criteria.
Study Selection:
Articles were included if they identified all the items on the scale and the article was either an original research report describing the use of scales in the evaluation of concussion symptoms or a review article that discussed the use or development of concussion symptom scales. Only articles published in English and available in full text were included.
Data Extraction:
From each study, the following information was extracted by the primary author using a standardized protocol: study design, publication year, participant characteristics, reliability of the scale, and details of the scale or checklist, including name, number of items, time of measurement, format, mode of report, data analysis, scoring, and psychometric properties. A quality assessment of included studies was done using 16 items from the Downs and Black checklist1 and assessed reporting, internal validity, and external validity.
Main Results:
The initial database search identified 421 articles. After 131 duplicate articles were removed, 290 articles remained and were added to 17 articles found during the hand search, for a total of 307 articles; of those, 295 were available in full text. Sixty articles met the inclusion criteria and were used in the systematic review. The quality of the included studies ranged from 9 to 15 points out of a maximum quality score of 17. The included articles were published between 1995 and 2008 and included a collective total of 5864 concussed athletes and 5032 nonconcussed controls, most of whom participated in American football. The majority of the studies were descriptive studies monitoring the resolution of concussive self-report symptoms compared with either a preseason baseline or healthy control group, with a smaller number of studies (n = 8) investigating the development of a scale.
The authors initially identified 20 scales that were used among the 60 included articles. Further review revealed that 14 scales were variations of the Pittsburgh Steelers postconcussion scale (the Post-Concussion Scale, Post-Concussion Scale: Revised, Post-Concussion Scale: ImPACT, Post-Concussion Symptom Scale: Vienna, Graded Symptom Checklist [GSC], Head Injury Scale, McGill ACE Post-Concussion Symptoms Scale, and CogState Sport Symptom Checklist), narrowing down to 6 core scales, which the authors discussed further. The 6 core scales were the Pittsburgh Steelers Post-Concussion Scale (17 items), Post-Concussion Symptom Assessment Questionnaire (10 items), Concussion Resolution Index postconcussion questionnaire (15 items), Signs and Symptoms Checklist (34 items), Sport Concussion Assessment Tool (SCAT) postconcussion symptom scale (25 items), and Concussion Symptom Inventory (12 items). Each of the 6 core scales includes symptoms associated with sport-related concussion; however, the number of items on each scale varied. A 7-point Likert scale was used on most scales, with a smaller number using a dichotomous (yes/no) classification.
Only 7 of the 20 scales had published psychometric properties, and only 1 scale, the Concussion Symptom Inventory, was empirically driven (Rasch analysis), with development of the scale occurring before its clinical use. Internal consistency (Cronbach α) was reported for the Post-Concussion Scale (.87), Post-Concussion Scale: ImPACT 22-item (.88–.94), Head Injury Scale 9-item (.78), and Head Injury Scale 16-item (.84). Test-retest reliability has been reported only for the Post-Concussion Scale (Spearman r = .55) and the Post-Concussion Scale: ImPACT 21-item (Pearson r = .65). With respect to validity, the SCAT postconcussion scale has demonstrated face and content validity, the Post-Concussion Scale: ImPACT 22-item and Head Injury Scale 9-item have reported construct validity, and the Head Injury Scale 9-item and 16-item have published factorial validity.
Sensitivity and specificity have been reported only with the GSC (0.89 and 1.0, respectively) and the Post-Concussion Scale: ImPACT 21-item when combined with the neurocognitive component of ImPACT (0.819 and 0.849, respectively). Meaningful change scores were reported for the Post-Concussion Scale (14.8 points), Post-Concussion Scale: ImPACT 22-item (6.8 points), and Post-Concussion Scale: ImPACT 21-item (standard error of the difference = 7.17; 80% confidence interval = 9.18).
Numerous scales exist for measuring the number and severity of concussion-related symptoms, with most evolving from the neuropsychology literature pertaining to head-injured populations. However, very few of these were created in a systematic manner that follows scale development processes and have published psychometric properties. Clinicians need to understand these limitations when choosing and using a symptom scale for inclusion in a concussion assessment battery. Future authors should assess the underlying constructs and measurement properties of currently available scales and use the ever-increasing prospective data pools of concussed athlete information to develop scales following appropriate, systematic processes.
PMCID: PMC3418135  PMID: 22488289
mild traumatic brain injuries; evaluation; reliability; validity; sensitivity; specificity
2.  The Value of Various Assessment Techniques in Detecting the Effects of Concussion on Cognition, Symptoms, and Postural Control 
Journal of Athletic Training  2009;44(6):663-665.
Broglio SP, Puetz TW. The effect of sport concussion on neurocognitive function, self-report symptoms, and postural control: a meta-analysis. Sports Med. 2008;38(1):53–67.
Clinical Question:
How effective are various concussion assessment techniques in detecting the effects of concussion on cognition, balance, and symptoms in athletes?
Data Sources:
Studies published between January 1970 and June 2006 were identified from the PubMed and PsycINFO databases. Search terms included concussion, mild traumatic brain injury, sport, athlete, football, soccer, hockey, boxing, cognition, cognitive impairment, symptoms, balance, and postural control. The authors also handsearched the reference list of retrieved articles and sought the opinions of experts in the field for additional studies.
Study Selection:
Studies were included if they were published in English; described a sample of athletes concussed during athletic participation; reported outcome measures of neurocognitive function, postural stability, or self-report symptoms; compared the postconcussion assessments with preseason (healthy) baseline scores or a control group; completed at least 1 postinjury assessment within the first 14 days after the concussion (to reflect neurometabolic recovery); and provided enough information for the authors to calculate effect sizes (means and SDs at baseline and postinjury time points). Selected studies were grouped according to their outcome measure (neurocognitive function, symptoms, or postural control) at initial and follow-up (if applicable) time points. Excluded articles included review articles, abstracts, case studies, editorials, articles without baseline data, and articles with data extending beyond the 14-day postinjury time frame.
Data Extraction:
From each study, the following information was extracted by one author and checked by the second author: participant demographics (sport, injury severity, incidence of loss of consciousness, and postconcussion assessment times), sample sizes, and baseline and postconcussion means and SDs for all groups. All effect sizes (the Hedge g) were computed so that decreases in neurocognitive function and postural control or increases in symptom reports resulted in negative effect sizes, demonstrating deficits in these domains after concussion. The authors also extracted the following moderators: study design (with or without control group), type of neurocognitive technique (Standardized Assessment of Concussion, computerized test, or pencil-and-paper test), postconcussion assessment time, and number of postconcussion assessments.
Main Results:
The search identified 3364 possible abstracts, which were then screened by the authors, with 89 articles being further reviewed for relevancy. Fifty articles were excluded because of insufficient data to calculate effect sizes, lack of a baseline assessment or control group, or because the data had been published in more than one study. The remaining 39 studies met all of the inclusion criteria and were used in the meta-analysis; 34 reported neurocognitive outcome measures, 14 provided self-report symptom outcomes, and 6 presented postural control as the dependent variable. The analyzed studies included 4145 total participants (concussed and control) with a mean age of 19.0 ± 0.4 years. The quality of each included study was also evaluated by each of the 2 authors independently using a previously published 15-item scale; the results demonstrated excellent agreement between the raters (intraclass correlation coefficient  =  0.91, 95% confidence interval [CI]  =  0.83, 0.95). The quality appraisal addressed randomization, sample selection, outcome measures, and statistical analysis, among other methodologic considerations. Quality scores of the included studies ranged from 5.25 to 9.00 (scored from 0–15).
The initial assessment demonstrated a deficit in neurocognitive function (Z  =  7.73, P < .001, g  =  −0.81 [95% CI  =  −1.01, −0.60]), increase in self-report symptoms (Z  =  2.13, P  =  .03, g  =  −3.31 [95% CI  =  −6.35, −0.27]), and a nonsignificant decrease in postural control (Z  =  1.29, P  =  .19, g  =  −2.56 [95% CI  =  −6.44, 1.32]).
For the follow-up assessment analyses, a decrease in cognitive function (Z  =  2.59, P  =  .001, g  =  −26 [95% CI  =  −0.46, −0.06]), an increase in self-report symptoms (Z  =  2.17, P  =  .03, g  =  −1.09 [95% CI  =  −2.07, −0.11]), and a nonsignificant decrease in postural control (Z  =  1.59, P  =  0.11, g  =  −1.16 [95% CI  =  −2.59, 0.27]) were found.
Neurocognitive and symptom outcomes variables were reported in 10 studies, and the authors were able to compare changes from baseline in these measures during the initial assessment time point. A difference in effect sizes was noted (QB(1)  =  5.28, P  =  .02), with the increases in self-report symptoms being greater than the associated deficits in neurocognitive function.
Sport-related concussion had a large negative effect on cognitive function during the initial assessment and a small negative effect during the first 14 days postinjury. The largest neurocognitive effects were found with the Standardized Assessment of Concussion during the immediate assessment and with pencil-and-paper neurocognitive tests at the follow-up assessment. Large negative effects were noted at both assessment points for postural control measures. Self-report symptoms demonstrated the greatest changes of all outcomes variables, with large negative effects noted both immediately after concussion and during the follow-up assessment. These findings reiterate the recommendations made to include neurocognitive measures, postural control tests, and symptom reports into a multifaceted concussion battery to best assess these injuries.
PMCID: PMC2775369  PMID: 19911094
patient-oriented evidence; POEM; clinical outcomes; children
3.  Spectrum of acute clinical characteristics of diagnosed concussions in college athletes wearing instrumented helmets 
Journal of neurosurgery  2012;117(6):1092-1099.
Concussive head injuries have received much attention in the medical and public arenas, as concerns have been raised about the potential short- and long-term consequences of injuries sustained in sports and other activities. While many student athletes have required evaluation after concussion, the exact definition of concussion has varied among disciplines and over time. The authors used data gathered as part of a multiinstitutional longitudinal study of the biomechanics of head impacts in helmeted collegiate athletes to characterize what signs, symptoms, and clinical histories were used to designate players as having sustained concussions.
Players on 3 college football teams and 4 ice hockey teams (male and female) wore helmets instrumented with Head Impact Telemetry (HIT) technology during practices and games over 2–4 seasons of play. Preseason clinical screening batteries assessed baseline cognition and reported symptoms. If a concussion was diagnosed by the team medical staff, basic descriptive information was collected at presentation, and concussed players were reevaluated serially. The specific symptoms or findings associated with the diagnosis of acute concussion, relation to specific impact events, timing of symptom onset and diagnosis, and recorded biomechanical parameters were analyzed.
Data were collected from 450 athletes with 486,594 recorded head impacts. Forty-eight separate concussions were diagnosed in 44 individual players. Mental clouding, headache, and dizziness were the most common presenting symptoms. Thirty-one diagnosed cases were associated with an identified impact event; in 17 cases no specific impact event was identified. Onset of symptoms was immediate in 24 players, delayed in 11, and unspecified in 13. In 8 cases the diagnosis was made immediately after a head impact, but in most cases the diagnosis was delayed (median 17 hours). One diagnosed concussion involved a 30-second loss of consciousness; all other players retained alertness. Most diagnoses were based on self-reported symptoms. The mean peak angular and rotational acceleration values for those cases associated with a specific identified impact were 86.1 ± 42.6g (range 16.5–177.9g) and 3620 ± 2166 rad/sec2 (range 183–7589 rad/sec2), respectively.
Approximately two-thirds of diagnosed concussions were associated with a specific contact event. Half of all players diagnosed with concussions had delayed or unclear timing of onset of symptoms. Most had no externally observed findings. Diagnosis was usually based on a range of self-reported symptoms after a variable delay. Accelerations clustered in the higher percentiles for all impact events, but encompassed a wide range. These data highlight the heterogeneity of criteria for concussion diagnosis, and in this sports context, its heavy reliance on self-reported symptoms. More specific and standardized definitions of clinical and objective correlates of a “concussion spectrum” may be needed in future research efforts, as well as in the clinical diagnostic arena.
PMCID: PMC3716254  PMID: 23030057
concussion; traumatic brain injury; biomechanics; athletes; football; hockey
4.  Concussion History and Postconcussion Neurocognitive Performance and Symptoms in Collegiate Athletes 
Journal of Athletic Training  2008;43(2):119-124.
Athletes are at an inherent risk for sustaining concussions. Research examining the long-term consequences of sport-related concussion has been inconsistent in demonstrating lingering neurocognitive decrements that may be associated with a previous history of concussion.
To determine the relationship between concussion history and postconcussion neurocognitive performance and symptoms in collegiate athletes.
Repeated-measures design.
Multi-center analysis of collegiate athletes.
Patients or Other Participants:
Fifty-seven concussed collegiate athletes (36 without concussion history, 21 with a history of 2 or more concussions).
All subjects were administered an Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) neurocognitive test battery, which measures verbal memory, visual memory, reaction time, and visual processing speed and 22 concussion symptoms.
Main Outcome Measure(s):
Subjects who sustained a concussion were administered 2 follow-up tests at days 1 and 5 postinjury. Independent variables were history of concussion (no history of concussion, 2 or more concussions) and time (baseline, day 1 postconcussion, or day 5 postconcussion).
A within-subjects effect (time) on ImPACT performance (P < .001), a between-subjects multivariate effect of group (P < .001), and a group-by-time interaction (P  =  .034) were noted. Athletes with a concussion history performed significantly worse on verbal memory (P  =  .01) and reaction time (P  =  .023) at day 5 postconcussion compared with athletes who did not report a previous concussion. No significant group differences were seen at day 5 postinjury on visual memory (P  =  .167), processing speed (P  =  .179), or total concussion symptoms (P  =  .87).
Concussed collegiate athletes with a history of 2 or more concussions took longer to recover verbal memory and reaction time than athletes without a history of concussion.
PMCID: PMC2267331  PMID: 18345335
mild traumatic brain injury; ImPACT; memory; reaction time
A battery of tests is commonly used to measure disability with and recovery from concussion. A number of different concussion-oriented assessment tests exist and each is considered useful. To the authors' knowledge, no study has compared the scores of these tests during recovery in the middle school and high school aged population to see how each change over time.
The purposes of this study were to analyze clinical data of concussed middle school and high school aged athletes to determine the concurrent and predictive validity for post-concussion syndrome (PCS) of the Post-Concussion Symptom Scale (PCSS), Balance Error Scoring System (BESS), and the five subscales of the Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT).
The study was a retrospective chart review performed on middle school and high school aged individuals with a diagnosis of concussion from the years 2008-2010 within the Akron Children's Hospital Sports Medicine system. To be eligible for inclusion in the dataset, each subject required a baseline measurement for each of the three tests (and all five subscales of the ImPACT) and a post-test measure. The mean age of the population was 15.38 years (SD = 1.7) and ranged from 11 to 19 years. Pearson product correlation tests (correlation matrix) were used to analyze the concurrent validity of the test items during recovery following a concussion. Receiver operating characteristics (ROC) curves were used to determine the predictive validity of initial scores for developing PCS.
The correlation matrix captured five statistically significant findings; however, these suggested only weak to mild correlations. Five test items yielded an area under the curve (AUC) greater than 0.50 but only one was statistically significant. After qualitative evaluation, only one of the three tests (including the five subscales of the ImPACT) was useful in predicting post-concussion syndrome.
This study suggests that there is poor concurrent validity among three commonly used concussion tests and there is no baseline score that predicts whether post-concussion syndrome will occur.
Level of Evidence:
PMCID: PMC3163995  PMID: 21904694
Concussion; Diagnostic accuracy; Post-concussion syndrome; Validity
6.  A Brief Vestibular/Ocular Motor Screening (VOMS) Assessment to Evaluate Concussions 
Vestibular and ocular motor impairments and symptoms have been documented in patients with sport-related concussions. However, there is no current brief clinical screen to assess and monitor these issues.
To describe and provide initial data for the internal consistency and validity of a brief clinical screening tool for vestibular and ocular motor impairments and symptoms after sport-related concussions.
Study Design
Cross-sectional study; Level of evidence, 2.
Sixty-four patients, aged 13.9 ± 2.5 years and seen approximately 5.5 ± 4.0 days after a sport-related concussion, and 78 controls were administered the Vestibular/Ocular Motor Screening (VOMS) assessment, which included 5 domains: (1) smooth pursuit, (2) horizontal and vertical saccades, (3) near point of convergence (NPC) distance, (4) horizontal vestibular ocular reflex (VOR), and (5) visual motion sensitivity (VMS). Participants were also administered the Post-Concussion Symptom Scale (PCSS).
Sixty-one percent of patients reported symptom provocation after at least 1 VOMS item. All VOMS items were positively correlated to the PCSS total symptom score. The VOR (odds ratio [OR], 3.89; P <.001) and VMS (OR, 3.37; P <.01) components of the VOMS were most predictive of being in the concussed group. An NPC distance ≥5 cm and any VOMS item symptom score ≥2 resulted in an increase in the probability of correctly identifying concussed patients of 38% and 50%, respectively. Receiver operating characteristic curves supported a model including the VOR, VMS, NPC distance, and ln(age) that resulted in a high predicted probability (area under the curve = 0.89) for identifying concussed patients.
The VOMS demonstrated internal consistency as well as sensitivity in identifying patients with concussions. The current findings provide preliminary support for the utility of the VOMS as a brief vestibular/ocular motor screen after sport-related concussions. The VOMS may augment current assessment tools and may serve as a single component of a comprehensive approach to the assessment of concussions.
PMCID: PMC4209316  PMID: 25106780
concussion; vestibular; ocular motor; symptoms
7.  Contact Sport Concussion Incidence 
Journal of Athletic Training  2006;41(4):470-472.
Reference/Citation: Koh JO, Cassidy JD, Watkinson EJ. Incidence of concussion in contact sports: a systematic review of the evidence. Brain Inj.20031790191712963556.
Clinical Question: What is the incidence of concussion in various contact sports?
Data Sources: Studies for the review were found through a MEDLINE search (1985–2000) and by gathering and reviewing older articles referenced in the searched articles. The main terms that were included in the search were brain injuries, brain concussion, and incidence. Text words that were also included were mild traumatic brain injury, concussion, incidence, injury, and head injury, along with the names of 8 contact sports ( American football, boxing, ice hockey, judo, karate, tae kwon do, rugby, and soccer).
Study Selection: For this review, concussion was defined as “a mild brain injury resulting from a direct blow to the head resulting in physiological changes in brain function.” Cohort studies with documented incidence of concussion in athletes from 8 identified contact sports were the target of the search. All studies of male and female athletes in any of the 8 contact sports, including practices and games and regardless of level of competition, were included in the study search. Possible articles for review were identified through a 3-step screening process. Article titles were initially screened by one of the authors. If the title seemed to be relevant to the purpose of the review, the abstract of the article was then screened for inclusion/exclusion criteria as the second step. To be included, studies had to relate to the incidence of injury to the head and brain, report results relevant to concussion, involve 1 of the 8 identified contact sports, and be published between 1985 and 2000. All systematic reviews about mild traumatic brain injury (TBI) or concussion were also included. Studies were excluded if they discussed concussion due to whiplash injury or concussion associated with spinal cord injury, facial bone fracture, or soft tissue injuries; if they reported prevalence, rather than incidence, of concussion; if they addressed chronic TBI; if they comprised case reports or letters to the editor; or if they lacked a denominator to determine risk rates. Finally, relevant and unknown articles from the abstract screening were reviewed again for the inclusion and exclusion criteria by an independent, outside party.
Data Extraction: A general methodologic criteria design was used to critically appraise all articles that met the inclusion and exclusion criteria. This design appraised 11 study design and reporting criteria. In order for an article to be accepted into the systematic review, it had to meet at least the 5 mandatory criteria: description of the source population, appropriate description of inclusion and exclusion criteria, verifiable results from the raw data, differentiation of the incidence of injury between practice and game settings, and adequately measured denominator of population or person-time at risk. For each individual study, the 5 mandatory criteria listed above were rated with regard to whether they were included or addressed in the paper ( yes), were missing from the paper ( no), or were included but not described fully or in a way characterized by sound quality ( substandard). If any of the 5 mandatory criteria were rated no, the article was not evaluated any further. Data taken from these articles included sex, types of sessions in which concussion occurred, and numbers defining incidence of concussion within a contact sport. In some studies, rates were recalculated from the raw data in order to check accuracy, or if they were not presented in the published material, rates were calculated. These rates were recalculated with the denominator presented in the original study, athletes at risk for injury or time at risk for injury. Athlete-exposure was not defined in the review but is commonly used as the denominator in epidemiologic studies and represents one time in which an athlete takes part in a game or practice that exposes him or her to a risk for injury.
Main Results: The overall search identified 559 publications with possible relevance to the incidence of concussion in contact sports. After the titles were screened, 213 articles remained, and their abstracts were reviewed. The abstract screening for relevance yielded 127 articles to which the inclusion and exclusion criteria were applied. The investigators then critically reviewed 63 articles that fit the inclusion criteria. During this critical review, 40 articles did not meet the 5 mandatory criteria listed above and were not evaluated further. After final screening, 23 articles were included in the study. Review of these 23 articles revealed that among team sports for high school males, ice hockey athletes demonstrated the highest incidence of concussion (3.6 per 1000 athlete-exposures [AEs], 95% confidence interval [CI] = 0.99–9.29) and soccer athletes the lowest incidence of concussion (0.18 per 1000 AEs, 95% CI = 0.14–0.22). At the professional level, similar concussion incidence rates were found in both ice hockey (6.5 per 1000 player-games, 95% CI = 4.8–8.6) and rugby (9.05 per 1000 player-games, 95% CI = 4.1–17.1) players. When compared with other individual male sports (karate and tae kwon do), boxing had the highest incidence of concussion in professional (0.8 per 10 rounds, 95% CI = 0.75–0.95) and amateur (7.9 per 1000 man-minutes, 95% CI = 5.45–11.09) athletes. Only 6 included studies (5 dealing with tae kwon do and 1 with soccer) addressed concussion incidence in females. Tae kwon do had the highest incidence of concussion (8.77 per 1000 AEs, 95% CI = 0.22–47.9).
Conclusions: The information presented in the article offers helpful insight into the rate of concussion in athletes from 8 contact sports. Ice hockey seemed to have the greatest incidence of concussion for males, whereas tae kwon do had the highest incidence rate for females. Relatively few rigorous epidemiologic studies on the incidence of concussion exist. Specifically, 63% of the identified studies did not meet the methodologic criteria to be included in this systematic review. In addition, limited information exists on the risk of concussion for females in contact sports. Future authors should address the limitations in reporting incidences, including the lack of adequately measured denominators (person-time at risk), vague definitions of concussion, combining game and practice injuries, and history of concussive injury. Future researchers should also include at least the 5 mandatory methodologic criteria used in the critical appraisal of articles for this review to allow for better reporting of concussion incidence and comparison among various studies. Concussion incidence in females should also be explored.
PMCID: PMC1748409  PMID: 17273475
head injury; brain injury; epidemiology
8.  Is Neuropsychological Testing Useful in the Management of Sport-Related Concussion? 
Journal of Athletic Training  2005;40(3):139-152.
Objective: Neuropsychological (NP) testing has been used for several years as a way of detecting the effects of sport-related concussion in order to aid in return-to-play determinations. In addition to standard pencil-and-paper tests, computerized NP tests are being commercially marketed for this purpose to professional, collegiate, high school, and elementary school programs. However, a number of important questions regarding the clinical validity and utility of these tests remain unanswered, and these questions present serious challenges to the applicability of NP testing for the management of sport-related concussion. Our purpose is to outline the criteria that should be met in order to establish the utility of NP instruments as a tool in the management of sport-related concussion and to review the degree to which existing tests have met these criteria.
Data Sources: A comprehensive literature review of MEDLINE and PsychLit from 1990 to 2004, including all prospective, controlled studies of NP testing in sport-related concussion.
Data Synthesis: The effects of concussion on NP test performance are so subtle even during the acute phase of injury (1–3 days postinjury) that they often fail to reach statistical significance in group studies. Thus, this method may lack utility in individual decision making because of a lack of sensitivity. In addition, most of these tests fail to meet other psychometric criteria (eg, adequate reliability) necessary for this purpose. Finally, it is unclear that NP testing can detect impairment in players once concussion-related symptoms (eg, headache) have resolved. Because no current guideline for the management of sport-related concussion allows a symptomatic player to return to sport, the incremental utility of NP testing remains questionable.
Conclusions/Recommendations: Despite the theoretic rationale for the use of NP testing in the management of sport-related concussion, no NP tests have met the necessary criteria to support a clinical application at this time. Additional research is necessary to establish the utility of these tests before they can be considered part of a routine standard of care, and concussion recovery should be monitored via the standard clinical examination and subjective symptom checklists until NP testing or other methods are proven effective for this purpose.
PMCID: PMC1250250  PMID: 16284633
neurocognitive function; traumatic brain injury; athletic injury
9.  Self-reported concussion history: impact of providing a definition of concussion 
In recent years, the understanding of concussion has evolved in the research and medical communities to include more subtle and transient symptoms. The accepted definition of concussion in these communities has reflected this change. However, it is unclear whether this shift is also reflected in the understanding of the athletic community.
What is known about the subject
Self-reported concussion history is an inaccurate assessment of someone’s lifetime exposure to concussive brain trauma. However, unfortunately, in many cases it is the only available tool.
We hypothesize that athletes’ self-reported concussion histories will be significantly greater after reading them the current definition of concussion, relative to the reporting when no definition was provided. An increase from baseline to post-definition response will suggest that athletes are unaware of the currently accepted medical definition.
Study design
Cross-sectional study of 472 current and former athletes.
Investigators conducted structured telephone interviews with current and former athletes between January 2010 and January 2013, asking participants to report how many concussions they had received in their lives. Interviewers then read participants a current definition of concussion, and asked them to re-estimate based on that definition.
The two estimates were significantly different (Wilcoxon signed rank test: z=15.636, P<0.001). Comparison of the baseline and post-definition medians (7 and 15, respectively) indicated that the post-definition estimate was approximately twice the baseline. Follow-up analyses indicated that this effect was consistent across all levels of competition examined and across type of sport (contact versus non-contact).
Our results indicate that athletes’ current understandings of concussions are not consistent with a currently accepted medical definition. We strongly recommend that clinicians and researchers preface requests for self-reported concussion history with a definition. In addition, it is extremely important that researchers report the definition they used in published manuscripts of their work.
What this study adds to existing knowledge
Our study shows that unprompted reporting of concussion history produces results that are significantly different from those provided after a definition has been given, suggesting one possible mechanism to improve the reliability of self-reported concussion history across multiple individuals.
PMCID: PMC4019619  PMID: 24891816
concussion; self-report; sports-related concussion
10.  The Prevalence of Undiagnosed Concussions in Athletes 
Previous studies suggest athletes underreport concussions. We sought to determine whether athletes in our clinics have sustained previous concussions that went undiagnosed.
Multi-centered, cross sectional study.
Two sport concussion clinics.
Patients diagnosed with sport-related concussions or concussions with injury mechanisms and forces similar to those observed in sports were included.
Main Outcome Measures
The proportion of patients that answered “yes” to the following question were defined as having a previously undiagnosed concussion: “Have you ever sustained a blow to the head which was NOT diagnosed as a concussion but was followed by one or more of the signs and symptoms listed in the Post Concussion Symptom Scale.”
Of the 486 patients included in the final analysis, 148 (30.5%) reported a previously undiagnosed concussion. Athletes reporting previously undiagnosed concussions had a higher mean Post Concussion Symptom Scale score (33 v. 25; p < 0.004) and were more likely to have lost consciousness (31% v. 22%; p = 0.038) with their current injury than athletes without previously undiagnosed concussions.
Nearly one third of athletes have sustained previously undiagnosed concussions, defined as a blow to the head followed by the signs and symptoms included in the post concussion symptom scale. Furthermore, these previously undiagnosed concussions are associated with higher post concussion symptom scale scores and higher loss of consciousness rates when future concussions occur.
PMCID: PMC3758800  PMID: 23727697
Mild traumatic brain injury; loss of consciousness; sports injury
11.  Symptom Severity Predicts Prolonged Recovery after Sport-Related Concussion: Age and Amnesia Do Not 
The Journal of pediatrics  2013;163(3):721-725.
To identify predictors of prolonged symptoms for athletes who sustain concussions.
Study design
We conducted a multi-center, prospective, cohort study of patients in 2 sport concussion clinics. Possible predictors of prolonged symptoms from concussion were compared between two groups: those whose symptoms resolved within 28 days and those whose symptoms persisted beyond 28 days. Candidate predictor variables were entered into a logistic regression model that was used to generate adjusted odds ratios.
During the study period, 182 patients met inclusion criteria. The mean age was 15.2 years (SD 3.04 years). Over a third (N=65) of patients underwent computerized neurocognitive testing on their initial visit. In univariate analyses, Post Concussion Symptom Scale (PCSS) score and all composite scores on computerized neurocognitive testing appeared to be associated with prolonged symptom duration. Sex, age, loss of consciousness at time of injury and amnesia at time of injury were not associated with prolonged symptom duration. After adjusting for potential confounding, however, only total score on the PCSS score was associated with the odds of suffering prolonged symptoms.
After adjusting for other potential confounding variables, only total score on the PCSS was associated with the odds of suffering prolonged symptoms from sport-related concussions; age and amnesia were not. Further efforts to develop clinical tools for predicting which athletes will suffer prolonged recoveries after concussion should focus on initial symptom score.
PMCID: PMC3732501  PMID: 23628374
mild traumatic brain injury (mTBI); concussion; post-concussion syndrome; sports
12.  Neurocognitive Performance of Concussed Athletes When Symptom Free 
Journal of Athletic Training  2007;42(4):504-508.
Context: Concussed athletes may underreport concussion-related symptoms in order to expedite return to play. Whether neurocognitive impairments persist once concussion-related symptoms resolve has yet to be determined. Reliance on athlete-reported, postconcussion symptoms when making return-to-play decisions may expose athletes to subsequent injury if complete recovery has not occurred.
Objective: To evaluate the presence of neurocognitive decrements in concussed athletes no longer reporting concussion-related symptoms.
Design: Within-groups design.
Setting: University research laboratory.
Patients or Other Participants: Twenty-one National Collegiate Athletic Association Division I collegiate athletes (16 men, 5 women). Age = 19.81 ± 1.25 years, height = 180.95 ± 10.62 cm, mass = 93.66 ± 27.60 kg, and previous concussions = 1.76 ± 2.02.
Main Outcome Measure(s): The ImPACT concussion assessment test was administered to concussed athletes at baseline, when symptomatic (within 72 hours of injury), and when asymptomatic. Index scores of verbal memory, visual memory, visual-motor speed, reaction time, and concussion-related symptoms were recorded at each session. The Symptom Assessment Scale was administered daily after injury to establish when the athlete became asymptomatic.
Results: When assessed within 72 hours of concussion, 81% of the athletes showed deficits on at least 1 ImPACT variable. At the asymptomatic time point, 38% of the concussed athletes continued to demonstrate neurocognitive impairment on at least 1 ImPACT variable.
Conclusions: Neurocognitive decrements may persist when athletes no longer report concussion-related symptoms. The exclusive use of symptom reports in making a return-to-play decision is not advised. A multifaceted approach to concussion assessment that includes evaluation of a myriad of functions is warranted.
PMCID: PMC2140076  PMID: 18174938
concussion; symptoms; ImPACT; return to play
13.  A Diffusion Tensor Imaging Study on the White Matter Skeleton in Individuals with Sports-Related Concussion 
Journal of Neurotrauma  2011;28(2):189-201.
Recognizing and managing the effects of cerebral concussion is very challenging, given the discrete symptomatology. Most individuals with sports-related concussion will not score below 15 on the Glasgow Coma Scale, but will present with rapid onset of short-lived neurological impairment, demonstrating no structural changes on traditional magnetic resonance imaging (MRI) and computed tomography (CT) scans. The return-to-play decision is one of the most difficult responsibilities facing the physician, and so far this decision has been primarily based on neurological examination, symptom checklists, and neuropsychological (NP) testing. Diffusion tensor imaging (DTI) may be a more objective tool to assess the severity and recovery of function after concussion. We assessed white matter (WM) fiber tract integrity in varsity level college athletes with sports-related concussion without loss of consciousness, who experienced protracted symptoms for at least 1 month after injury. Evaluation of fractional anisotropy (FA) and mean diffusivity (MD) of the WM skeleton using tract-based spatial statistics (TBSS) revealed a large cluster of significantly increased MD for concussed subjects in several WM fiber tracts in the left hemisphere, including parts of the inferior/superior longitudinal and fronto-occipital fasciculi, the retrolenticular part of the internal capsule, and posterior thalamic and acoustic radiations. Qualitative comparison of average FA and MD suggests that with increasing level of injury severity (ranging from sports-related concussion to severe traumatic brain injury), MD might be more sensitive at detecting mild injury, whereas FA captures more severe injuries. In conclusion, the TBSS analysis used to evaluate diffuse axonal injury of the WM skeleton seems sensitive enough to detect structural changes in sports-related concussion.
PMCID: PMC3037804  PMID: 21083414
diffuse axonal injury; diffusion tensor imaging; mean diffusivity; mild traumatic brain injury; sports-related concussion
14.  Computerised cognitive assessment of concussed Australian Rules footballers 
Background—"Paper and pencil" neuropsychological tests play an important role in the management of sports related concussions. They provide objective information on the athlete's cognitive function and thus facilitate decisions on safe return to sport. It has been proposed that computerised cognitive tests have many advantages over such conventional tests, but their role in this domain is yet to be established.
Objectives—To measure cognitive impairment after concussion in a case series of concussed Australian Rules footballers, using both computerised and paper and pencil neuropsychological tests. To investigate the role of computerised cognitive tests in the assessment and follow up of sports related concussions.
Methods—Baseline measures on the Digit Symbol Substitution Test (DSST), Trail Making Test-Part B (TMT), and a simple reaction time (SRT) test from a computerised cognitive test battery (CogState) were obtained in 240 players. Tests were repeated in players who had sustained a concussive injury. A group of non-injured players were used as matched controls.
Results—Six concussions were observed over a period of nine weeks. At the follow up, DSST and TMT scores did not significantly differ from baseline scores in both control and concussed groups. However, analysis of the SRT data showed an increase in response variability and latency after concussion in the injured athletes. This was in contrast with a decrease in response variability and no change in latency on follow up of the control players (p<0.02).
Conclusion—Increased variability in response time may be an important cognitive deficit after concussion. This has implications for consistency of an athlete's performance after injury, as well as for tests used in clinical assessment and follow up of head injuries.
Key Words: concussion; football; neuropsychology; cognitive; head injury
PMCID: PMC1724390  PMID: 11579074
15.  Trends in Concussion Return-to-Play Timelines Among High School Athletes From 2007 Through 2009 
Journal of Athletic Training  2013;48(6):836-843.
Whereas guidelines about return-to-play (RTP) after concussion have been published, actual prognoses remain elusive.
To develop probability estimates for time until RTP after sport-related concussion.
Descriptive epidemiology study.
High school.
Patients or Other Participants:
Injured high school varsity, junior varsity, or freshman athletes who participated in 1 of 13 interscholastic sports at 7 area high schools during the 2007–2009 academic years.
Athletic trainers employed at each school collected concussion data. The athletic trainer or physician on site determined the presence of a concussion. Athlete-exposures for practices and games also were captured.
Main Outcome Measure(s):
Documented concussions were categorized by time missed from participation using severity outcome intervals (same-day return, 1- to 2-day return, 3- to 6-day return, 7- to 9-day return, 10- to 21-day return, >21-day return, no return [censored data]). We calculated Kaplan-Meier time-to-event probabilities that included censored data to determine the probability of RTP at each of these time intervals.
A total of 81 new concussions were documented in 478 775 athlete-exposures during the study period. After a new concussion, the probability of RTP (95% confidence interval) was 2.5% (95% confidence interval = 0.3, 6.9) for a 1- to 2-day return, 71.3% (95% confidence interval = 59.0, 82.9) for a 7- to 9-day return, and 88.8% (95% confidence interval = 72.0, 97.2) for a 10- to 21-day return.
For high school athletes, RTP within the first 2 days after concussion was unlikely. After 1 week, the probability of return rose substantially (approximately 71%). Prognostic indicators are used to educate patients about the likely course of disease. Whereas individual symptoms and recovery times vary, prognostic time-to-event probabilities allow clinicians to provide coaches, parents, and athletes with a prediction of the likelihood of RTP within certain timeframes after a concussion.
PMCID: PMC3867096  PMID: 24143901
injury incidence; time to event; survival probability
16.  Hockey Concussion Education Project, Part 2. Microstructural white matter alterations in acutely concussed ice hockey players: a longitudinal free-water MRI study 
Journal of neurosurgery  2014;120(4):873-881.
Concussion is a common injury in ice hockey and a health problem for the general population. Traumatic axonal injury has been associated with concussions (also referred to as mild traumatic brain injuries), yet the pathological course that leads from injury to recovery or to long-term sequelae is still not known. This study investigated the longitudinal course of concussion by comparing diffusion MRI (dMRI) scans of the brains of ice hockey players before and after a concussion.
The 2011–2012 Hockey Concussion Education Project followed 45 university-level ice hockey players (both male and female) during a single Canadian Interuniversity Sports season. Of these, 38 players had usable dMRI scans obtained in the preseason. During the season, 11 players suffered a concussion, and 7 of these 11 players had usable dMRI scans that were taken within 72 hours of injury. To analyze the data, the authors performed free-water imaging, which reflects an increase in specificity over other dMRI analysis methods by identifying alterations that occur in the extracellular space compared with those that occur in proximity to cellular tissue in the white matter. They used an individualized approach to identify alterations that are spatially heterogeneous, as is expected in concussions.
Paired comparison of the concussed players before and after injury revealed a statistically significant (p < 0.05) common pattern of reduced free-water volume and reduced axial and radial diffusivities following elimination of free-water. These free-water–corrected measures are less affected by partial volumes containing extracellular water and are therefore more specific to processes that occur within the brain tissue. Fractional anisotropy was significantly increased, but this change was no longer significant following the free-water elimination.
Concussion during ice hockey games results in microstructural alterations that are detectable using dMRI. The alterations that the authors found suggest decreased extracellular space and decreased diffusivities in white matter tissue. This finding might be explained by swelling and/or by increased cellularity of glia cells. Even though these findings in and of themselves cannot determine whether the observed microstructural alterations are related to long-term pathology or persistent symptoms, they are important nonetheless because they establish a clearer picture of how the brain responds to concussion.
PMCID: PMC4386884  PMID: 24490785
concussion; diffusion MRI; free-water; ice hockey; atlas; traumatic brain injury
17.  Association between Previous Concussion History and Symptom Endorsement during Preseason Baseline Testing in High School and Collegiate Athletes 
Sports Health  2009;1(1):61-65.
A graded symptom checklist is a commonly used concussion evaluation measure. Little is known about preseason baseline symptomatology of high school and college athletes with and without a previous concussion history.
The primary hypothesis investigated was that those individuals with a concussion history would report more symptoms at baseline testing. The effects of sex and age on symptoms were also examined.
Study Design:
Cross-sectional study.
Subjects included 8930 high school and collegiate athletes (height, 177.79 ± 9.97 cm; mass, 75.20 ± 19.21 kg; age, 16.60 ± 1.64 years). Subjects completed a self-report graded symptom checklist and concussion history questionnaire during a preseason clinical testing session. Symptoms reported (yes or no) on the 18-item graded symptom checklist served as the dependent variables.
A significant association was observed between symptoms on the graded symptom checklist and previous concussion history (P ≤ .001). No differences were observed between high school and college athletes regarding symptom endorsement (t8928 = 0.620; P = .535). A statistical but not clinically meaningful difference was observed between the means for males and females symptom endorsement (t8928 = −3.03; P = .002): men endorsed 1.88 ± 2.81 symptoms, and women endorsed 2.09 ± 2.90 symptoms. Headache, sleeping more than usual, difficulty concentrating, drowsiness, difficulty remembering, fatigue, difficulty sleeping, and irritability were reported by more than 10% of athletes.
High school and college athletes with a history of multiple concussions may be at risk for experiencing concussion-linked symptoms well beyond the acute stage of injury. Clinicians should be mindful of previous concussion history in athletes with increased presence of base-rate symptoms as they may be predisposed to future injury.
PMCID: PMC3445118  PMID: 23015855
preseason baseline; mild traumatic brain injury; symptomatology; concussion
18.  Current Trends in Athletic Training Practice for Concussion Assessment and Management 
Journal of Athletic Training  2005;40(4):320-325.
Context: Athletic trainers surveyed in 1999 demonstrated little consensus on the use of concussion grading scales and return-to-play criteria. Most relied on clinical examination or symptom checklists to evaluate athletes with concussion.
Objective: To investigate the current trends of certified athletic trainers in concussion assessment and management.
Design: Subjects were invited to participate in a 32-question Internet survey.
Setting: An Internet link to the survey was e-mailed to the subjects.
Patients or Other Participants: A total of 2750 certified athletic trainers and members of the National Athletic Trainers' Association were randomly e-mailed and invited to participate.
Main Outcome Measure(s): Survey questions addressed topics including years of certification, number of concussions evaluated each year, methods of assessing concussion, and guidelines used for return to play. Compliance with the recent position statement of the National Athletic Trainers' Association on sport-related concussion was also evaluated.
Results: Certified athletic trainers averaged 9.9 ± 7.3 years of certification and evaluated an average of 8.2 ± 6.5 concussions per year. To assess concussion, 95% reported using the clinical examination, 85% used symptom checklists, 48% used the Standardized Assessment of Concussion, 18% used neuropsychological testing, and 16% used the Balance Error Scoring System. The most frequently used concussion grading scale and return-to-play guideline belonged to the American Academy of Neurology (30%). When deciding whether to return an athlete to play, certified athletic trainers most often used the clinical examination (95%), return-to-play guidelines (88%), symptom checklists (80%), and player self-report (62%). The most important tools for making a return-to-play decision were the clinical examination (59%), symptom checklists (13%), and return-to-play guidelines (12%). Only 3% of certified athletic trainers surveyed complied with the recent position statement, which advocated using symptom checklists, neuropsychological testing, and balance testing for managing sport-related concussion.
Conclusions: Our findings suggest that only a small percentage of certified athletic trainers currently follow the guidelines proposed by the National Athletic Trainers' Association. Various assessment methods and tools are currently being used, but clinicians must continue to implement a combination of methods and tools in order to comply with the position statement.
PMCID: PMC1323294  PMID: 16404454
mild traumatic brain injury; mild brain injury; evaluation
19.  Premature return to play and return to learn after a sport-related concussion 
Canadian Family Physician  2014;60(6):e310-e315.
To determine what proportion of patients experience an exacerbation of their symptoms as a result of premature return to play (RTP) and return to learn (RTL) following sport-related concussions.
Retrospective study of electronic medical records from the office-based practice of one family and sport medicine physician who had systematically provided recommendations for cognitive and physical rest based on existing consensus recommendations. Two blinded authors independently reviewed each chart, which included Sport Concussion Assessment Tool (SCAT) and SCAT2 symptom self-report forms to determine whether an athlete had returned to play or learn prematurely. If there was a discrepancy between the 2 reviewers then a third author reviewed the charts.
A sport medicine and family practice in Ontario. The physician assessed sport-related concussions after self-referral or referral from other primary care physicians, teams, and schools.
A total of 170 charts of 159 patients were assessed for sport-related concussion during a 5-year period (April 2006 to March 2011). All participants were students who were participating in sports at the time of injury. There were 41 concussions in elementary students, 95 concussions in high school students, and 34 concussions in college or university students.
Main outcome measures
Premature RTP and RTL were defined as chart records documenting the recurrence or worsening of symptoms that accompanied the patients’ RTP or RTL. Measures were compared using the earliest available SCAT forms and self-reporting.
In 43.5% of concussion cases, the patient returned to sport too soon and in 44.7% of concussion cases, the patient returned to school too soon. Patients with a history of previous concussion required more days of rest before being permitted to participate in any physical activity than those patients without a previous history of concussion. Elementary school students required fewer days of rest before being permitted to return to any physical activity compared with high school students and college or university students.
Currently, physicians recommend restrictions on mental and physical activity following sport-related concussion. This is done without clear guidelines as to what cognitive rest entails for students. Further research is required to determine how to implement a management plan for student athletes to facilitate complete recovery after concussion.
PMCID: PMC4055342  PMID: 24925965
20.  Multiple Concussions and Neuropsychological Functioning in Collegiate Football Players 
Journal of Athletic Training  2001;36(3):303-306.
To document neurocognitive and neurobehavioral consequences of 1 versus 2 concussions.
Design and Setting:
Nonequivalent, pretest-posttest cohort design with multiple dependent measures. Participants were selected from a large sample of athletes who participated in a comprehensive, multiuniversity study of football-related concussion.
College football players who sustained 1 and 2 grade 1 concussive injuries were matched for age, education, and duration of competitive football.
Neuropsychological tests and symptoms checklists.
Multivariate analysis of variance did not show a statistically significant difference in test performance between players with 1 or 2 concussions. Chi square analyses revealed that concussions significantly increased the number of symptom complaints, but symptoms returned to baseline by 10 days postinjury. The effects of 2 injuries did not appear to be significantly greater than that of a single injury. Differences in response to concussion were observed.
Neurocognitive and neurobehavioral consequences of 2 concussions did not appear to be significantly different from those of 1 concussion, but methodologic issues place limitations on data interpretation. Additional studies are needed to clarify the neuropsychological consequences of multiple concussions.
PMCID: PMC155422  PMID: 12937500
sports injuries; neuropsychological tests; symptoms
21.  Multiple prior concussions are associated with symptoms in high school athletes 
The purpose of this study was to evaluate the association of prior concussion on baseline computerized neurocognitive testing in a large cohort of high school athletes.
This is a retrospective cohort study of student athletes from 49 Maine High Schools in 2010 who underwent baseline computerized neurocognitive evaluation with Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT®). As part of the ImPACT®, subjects reported a prior history of concussion as well as demographic information and a symptom questionnaire. We used linear regression to evaluate the association of prior concussion with baseline: (1) ImPACT® composite scores; and (2) symptom scores.
Six thousand seventy-five subjects were included in the study, of whom 57% were boys. The majority of student athletes (85.3%) reported no prior history of concussion while 4.6% reported having sustained two or more prior concussions. On simple linear regression, increasing number of concussions was related to worse performance in verbal memory (P = 0.039) and greater symptoms scores (P < 0.001). On multivariate modeling, only the association with baseline symptoms remained (P < 0.001). Other factors associated with baseline symptom reporting in the multivariate model included mental health history, headache/migraine history, gender, developmental and/or learning problems, and number of prior concussions.
In this large-scale, retrospective survey study, history of multiple prior concussions was associated with higher symptom burden but not baseline computerized neurocognitive testing. The association between baseline symptom reporting and clinical and demographic factors was greater than the association with a history of multiple concussions.
PMCID: PMC4184671  PMID: 25356413
22.  Possible Lingering Effects of Multiple Past Concussions 
Background. The literature on lingering or “cumulative” effects of multiple concussions is mixed. The purpose of this study was to examine whether athletes with a history of three or more concussions perform more poorly on neuropsychological testing or report more subjective symptoms during a baseline, preseason evaluation. Hypothesis. Athletes reporting three or more past concussions would perform more poorly on preseason neurocognitive testing. Study Design. Case-control study. Methods. An archival database including 786 male athletes who underwent preseason testing with a computerized battery (ImPACT) was used to select the participants. Twenty-six athletes, between the ages of 17 and 22 with a history of three or more concussions, were identified. Athletes with no history of concussion were matched, in a case-control fashion, on age, education, self-reported ADHD, school, sport, and, when possible, playing position and self-reported academic problems. Results. The two groups were compared on the four neuropsychological composite scores from ImPACT using multivariate analysis of variance followed by univariate ANOVAs. MANOVA revealed no overall significant effect. Exploratory ANOVAs were conducted using Verbal Memory, Visual Memory, Reaction Time, Processing Speed, and Postconcussion Scale composite scores as dependent variables. There was a significant effect for only the Verbal Memory composite. Conclusions. Although inconclusive, the results suggest that some athletes with multiple concussions could have lingering memory deficits.
PMCID: PMC3328154  PMID: 22550590
23.  Effect of Cognitive Activity Level on Duration of Post-Concussion Symptoms 
Pediatrics  2014;133(2):e299-e304.
To determine the effect of cognitive activity level on duration of post-concussion symptoms.
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.
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.
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.
PMCID: PMC3904277  PMID: 24394679
concussion; post-concussion syndrome; sports medicine; mild traumatic brain injury
24.  Reliability and Validity Evidence of Multiple Balance Assessments in Athletes With a Concussion 
Journal of Athletic Training  2014;49(4):540-549.
An estimated 300 000 sport-related concussion injuries occur in the United States annually. Approximately 30% of individuals with concussions experience balance disturbances. Common methods of balance assessment include the Clinical Test of Sensory Organization and Balance (CTSIB), the Sensory Organization Test (SOT), the Balance Error Scoring System (BESS), and the Romberg test; however, the National Collegiate Athletic Association recommended the Wii Fit as an alternative measure of balance in athletes with a concussion. A central concern regarding the implementation of the Wii Fit is whether it is reliable and valid for measuring balance disturbance in athletes with concussion.
To examine the reliability and validity evidence for the CTSIB, SOT, BESS, Romberg test, and Wii Fit for detecting balance disturbance in athletes with a concussion.
Data Sources:
Literature considered for review included publications with reliability and validity data for the assessments of balance (CTSIB, SOT, BESS, Romberg test, and Wii Fit) from PubMed, PsycINFO, and CINAHL.
Data Extraction:
We identified 63 relevant articles for consideration in the review. Of the 63 articles, 28 were considered appropriate for inclusion and 35 were excluded.
Data Synthesis:
No current reliability or validity information supports the use of the CTSIB, SOT, Romberg test, or Wii Fit for balance assessment in athletes with a concussion. The BESS demonstrated moderate to high reliability (interclass correlation coefficient = 0.87) and low to moderate validity (sensitivity = 34%, specificity = 87%). However, the Romberg test and Wii Fit have been shown to be reliable tools in the assessment of balance in Parkinson patients.
The BESS can evaluate balance problems after a concussion. However, it lacks the ability to detect balance problems after the third day of recovery. Further investigation is needed to establish the use of the CTSIB, SOT, Romberg test, and Wii Fit for assessing balance in athletes with concussions.
PMCID: PMC4151843  PMID: 24933431
Clinical Test of Sensory Organization and Balance; Sensory Organization Test; Balance Error Scoring System; Romberg test; Wii Fit; sensitivity; specificity
25.  Concussion Occurrence and Knowledge in Italian Football (Soccer) 
The purpose of the study was to investigate concussion history, knowledge, injury identification, and management strategies among athletes, coaches, and medical staff in Italian club level football (soccer) clubs. Surveys (N=727) were distributed among Italian football clubs. Athletes’ surveys were designed to evaluate athlete knowledge of concussive signs and symptoms and injury reporting. Coaches’ surveys explored the understanding of concussive signs and symptoms and management practices. Medical staff surveys explored the standard of care regarding concussions. A total of 342 surveys were returned, for a 47% response rate. Descriptive analyses indicated 10% of athletes sustaining a concussion in the past year and 62% of these injuries were not reported, primarily due to the athletes not thinking the injury was serious enough. Coaches consistently identified non-concussion related symptoms (98.7%), but were unable to identify symptoms associated with concussion (38.9%). Most understood that loss of consciousness is not the sole indicator of injury (82.6%). Medical staff reported a heavy reliance on the clinical exam (92%) and athlete symptom reports (92%) to make the concussion diagnosis and return to play decision, with little use of neurocognitive (16.7%) or balance (0.0%) testing. Italian football athletes appear to report concussions at a rate similar to American football players, with a slightly higher rate of unreported injuries. Most of these athletes were aware they were concussed, but did not feel the injury was serious enough to report. Although coaches served as the primary person to whom concussions were reported, the majority of coaches were unable to accurately identify concussion related symptoms. With little use for neurocognitive and postural control assessments, the medical personnel may be missing injuries or returning athletes to play too soon. Collectively, these findings suggest that athletes, coaches, and medical personnel would benefit from concussion based educational materials on the signs, symptoms, and evaluative techniques of concussion.
Key pointsItalian football (soccer) athletes report less than 40% of concussions.Injuries are most commonly reported to coaches, who may not be fully aware of concussive signs and symptoms.International educational measures on concussion awareness and management may be of use.
PMCID: PMC3761699  PMID: 24149636
Mild traumatic brain injury; symptoms

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