Is neuropsychological testing useful in the management of sport-related concussion? Acute Effects and Recovery After Sport‐Related Concussion: A Neurocognitive and Quantitative Brain Electrical Activity Study Subject-Specific Increases in Serum S-100B Distinguish Sports-Related Concussion from Sports-Related Exertion Evaluation of Neuropsychological Domain Scores and Postural Stability Following Cerebral Concussion in Sports Recovery of cerebral blood flow following sports-related concussion. Depression and neurocognitive performance after concussion among male and female high school and collegiate athletes. Blood biomarkers for brain injury in concussed professional ice hockey players. Identifying neurocognitive deficits in adolescents following concussion. The Nature and Duration of Acute Concussive Symptoms in Australian Football Effect of concussion on clinically measured reaction time in 9 NCAA division I collegiate athletes: a preliminary study. Tracking Neurocognitive Performance following Concussion in High School Athletes Return to play after an initial or recurrent concussion in a prospective study of physician-observed junior ice hockey concussions: implications for return to play after a concussion. Evaluating the cognitive consequences of mild traumatic brain injury and concussion by using electrophysiology. Cumulative effects associated with recurrent concussion in collegiate football players: the NCAA Concussion Study. Predictors of postconcussive symptoms 3 months after mild traumatic brain injury. Early Attention Impairment and Recovery Profiles After Childhood Traumatic Brain Injury MEASUREMENT OF HEAD IMPACTS IN COLLEGIATE FOOTBALL PLAYERS: RELATIONSHIP BETWEEN HEAD IMPACT BIOMECHANICS AND ACUTE CLINICAL OUTCOME AFTER CONCUSSION Predicting Slow Recovery From Sport-Related Concussion: The New Simple-Complex Distinction
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 st and ard 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 prospect i ve , 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 question able . 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 st and ard of care , and concussion recovery should be monitored via the st and ard clinical examination and subjective symptom checklists until NP testing or other methods are proven effective for this purpose Objective To investigate the clinical utility and sensitivity of a portable , automatic , frontal quantitative electroencephalographic ( QEEG ) acquisition device currently in development in detecting abnormal brain electrical activity after sport-related concussion . Design This was a prospect i ve , non-r and omized study of 396 high school and college football players , including cohorts of 28 athletes with concussion and 28 matched controls . All subjects underwent preseason baseline testing on measures of postconcussive symptoms , postural stability , and cognitive functioning , as well as QEEG . Clinical testing and QEEG were repeated on day of injury and days 8 and 45 postinjury for the concussion and control groups . Main Outcomes and Results The injured group reported more significant postconcussive symptoms during the first 3 days postinjury , which resolved by days 5 and 8 . Injured subjects also performed poorer than controls on neurocognitive testing on the day of injury , but no differences were evident on day 8 or day 45 . QEEG studies revealed significant abnormalities in electrical brain activity in the injured group on day of injury and day 8 postinjury , but not on day 45 . Conclusions Results from the current study on clinical recovery after sport-related concussion are consistent with early reports indicating a typical course of full recovery in symptoms and cognitive dysfunction within the first week of injury . QEEG results , however , suggest that the duration of physiological recovery after concussion may extend longer than observed clinical recovery . Further study is required to replicate and extend these findings in a larger clinical sample , and further demonstrate the utility of QEEG as a marker of recovery after sport-related concussion Background The on-field diagnosis of sports-related concussion ( SRC ) is complicated by the lack of an accurate and objective marker of brain injury . Purpose To compare subject-specific changes in the astroglial protein , S100B , before and after SRC among collegiate and semi-professional contact sport athletes , and compare these changes to differences in S100B before and after non-contact exertion . Study Design Longitudinal cohort study . Methods From 2009–2011 , we performed a prospect i ve study of athletes from Munich , Germany , and Rochester , New York , USA .  Serum S100B was measured in all SRC athletes at pre-season baseline , within 3 hours of injury , and at days 2 , 3 and 7 post-SRC . Among a subset of athletes , S100B was measured after non-contact exertion but before injury . All sample s were collected identically and analyzed using an automated electrochemiluminescent assay to quantify serum S100B levels . Results Forty-six athletes ( 30 Munich , 16 Rochester ) underwent baseline testing . Thirty underwent additional post-exertion S100B testing . Twenty-two athletes ( 16 Rochester , 6 Munich ) sustained a SRC , and 17 had S100B testing within 3 hours post-injury . The mean 3-hour post-SRC S100B was significantly higher than pre-season baseline ( 0.099±0.008 µg/L vs. 0.058±0.006 µg/L , p = 0.0002 ) . Mean post-exertion S100B was not significantly different than the preseason baseline . S100B levels at post-injury days 2 , 3 and 7 were significantly lower than the 3-hour level , and not different than baseline . Both the absolute change and proportional increase in S100B 3-hour post-injury were accurate discriminators of SRC from non-contact exertion without SRC ( AUC 0.772 and 0.904 , respectively ) . A 3-hour post-concussion S100B > 0.122 µg/L and a proportional S100B increase of > 45.9 % over baseline were both 96.7 % specific for SRC . Conclusions Relative and absolute increases in serum S100B can accurately distinguish SRC from sports-related exertion , and may be a useful adjunct to the diagnosis of SRC Context With increasing knowledge and research about concussion , there have been few objective studies that have used neuropsychological domain scores and postural stability to assess concussion . Objective To evaluate the recovery curve of athletes who incur sport-related concussion from repeated serial testing of neuropsychological and posturography testing . Design A prospect i ve epidemiological model was used for the course of the study . Setting Division I intercollegiate athletics . Participants Athletes participating in football , soccer , basketball , softball , and cheerleading . Main Outcome Measures  Neuropsychological scores and posturography measures  were obtained preseason and serially at day 1 , day 2 , day 3 , and day 10 postconcussion .  Control participants  were tested at the same intervals .  Neuropsychological scores were converted to st and ards score and then into domains of attention , learning , speed of information processing , concentration , memory , and verbal fluency . Analysis of covariance with the baseline test as the covariate was used to analyze the data with univariate post hoc tests performed . Results Significant group differences were found for self reported symptoms ( P = 0.001 ) , speed of information processing ( P = 0.005 ) , mean stability ( P = 0.002 ) , and vestibular function ( P = 0.003 ) between injured and control participants . A group , by day , planned comparison found that speed of information processing and composite balance measures demonstrated significant differences through day 10 postinjury , while symptoms and the vestibular ratio remained significant only through day 3 . Conclusions The concussion recovery curve demonstrated short-term neuropsychological and posturography deficits following injury . A comprehensive approach to concussion management should be used to assess the injury and make return-to-play decisions IMPORTANCE Animal models suggest that reduced cerebral blood flow ( CBF ) is one of the most enduring physiological deficits following concussion . Despite this , longitudinal studies documenting serial changes in regional CBF following human concussion have yet to be performed . OBJECTIVE To longitudinally assess the recovery of CBF in a carefully selected sample of collegiate athletes and compare time course of CBF recovery with that of cognitive and behavioral symptoms . DESIGN , SETTING , AND PARTICIPANTS A cohort of collegiate football athletes ( N = 44 ) participated in this mixed longitudinal and cross-sectional study at a private research institute specializing in neuroimaging between March 2012 and December 2013 .  Serial imaging occurred approximately 1 day , 1 week , and 1 month postconcussion for a subset of participants ( n = 17 ) . All athletes reported no premorbid mood disorders , anxiety disorders , substance abuse , or alcohol abuse . MAIN OUTCOMES AND MEASURES  Arterial spin labeling magnetic resonance imaging  was used to collect voxelwise relative CBF at each visit . Neuropsychiatric evaluations and a brief cognitive screen  were also performed at all 3 points . Clinicians trained in sports medicine provided an independent measure of real-world concussion outcome ( ie , number of days withheld from competition ) . RESULTS The results indicated both cognitive ( simple reaction time ) and neuropsychiatric symptoms at 1 day postinjury that resolved at either 1 week ( cognitive ; P < .005 ) or 1 month ( neuropsychiatric ; P < .005 ) postinjury . Imaging data suggested both cross-sectional ( ie , healthy vs concussed athletes ; P < .05 ) and longitudinal ( 1 day and 1 week vs 1 month postinjury ; P < .001 ) evidence of CBF recovery in the right insular and superior temporal cortex . Importantly , CBF in the dorsal midinsular cortex was both decreased at 1 month postconcussion in slower-to-recover athletes ( t11 = 3.45 ; P = .005 ) and was inversely related to the magnitude of initial psychiatric symptoms ( Hamilton Depression Scale : r = -0.64 , P = .02 ; Hamilton Anxiety Scale : r = -0.56 , P = .046 ) , suggesting a potential prognostic indication for CBF as a biomarker . CONCLUSIONS AND RELEVANCE To our knowledge , these results provide the first prospect i ve evidence of reduced CBF in human concussion and subsequent recovery . The resolution of CBF abnormalities closely mirrors previous reports from the animal literature and show real-world validity for predicting outcome following concussion OBJECTIVES To prospect ively examine the relationship of sport-related concussion with depression and neurocognitive performance and symptoms among male and female high school and college athletes . A secondary objective was to explore age and sex differences . DESIGN Pretest , multiple posttest , repeated- measures design . SETTING Laboratory . PARTICIPANTS High school and collegiate athletes ( N=75 ) with a diagnosed concussion . INTERVENTIONS Not applicable . MAIN OUTCOME MEASURES  Beck Depression Inventory-II and computerized neurocognitive test battery ( Immediate Post-concussion Assessment and Cognitive Test )  , which includes concussion symptoms ( Post-concussion Symptom Scale ) at baseline and at 2 , 7 , and 14 days postinjury . RESULTS Concussed athletes exhibited significantly higher levels of depression from baseline at 2 days ( P≤.001 ) , 7 days ( P=.006 ) , and 14 days postconcussion ( P=.04 ) . Collegiate athletes demonstrated a significant increase in depression at 14 days postconcussion than did high school athletes ( P=.03 ) . There were no sex differences in depression levels . Neurocognitive decrements at 14 days were supported for reaction time ( P=.001 ) and visual memory ( P=.001 ) . Somatic depression at 7 days postconcussion was related to slower reaction time at 7 days postconcussion . Somatic depression at 14 days postinjury was related to lower visual memory scores at 14 days postinjury . CONCLUSIONS Although not clinical ly significant , athletes experienced increased depression scores up to 14 days after concussion that coincided with neurocognitive decrements in reaction time and visual memory . Somatic depression appears to be most salient with regard to lower neurocognitive performance . Mood assessment s after concussion are warranted to help monitor and enhance recovery IMPORTANCE Lack of objective biomarkers for brain damage hampers acute diagnosis and clinical decision making about return to play after sports-related concussion . OBJECTIVES To determine whether sports-related concussion is associated with elevated levels of blood biochemical markers of injury to the central nervous system and to assess whether plasma levels of these biomarkers predict return to play in professional ice hockey players with sports-related concussion . DESIGN , SETTING , AND PARTICIPANTS Multicenter prospect i ve cohort study involving all 12 teams of the top professional ice hockey league in Sweden , the Swedish Hockey League . Two hundred eighty-eight professional ice hockey players from 12 teams contesting during the 2012 - 2013 season consented to participate . All players underwent clinical preseason baseline testing regarding concussion assessment measures . Forty-seven players from 2 of the 12 ice hockey teams underwent blood sampling prior to the start of the season . Thirty-five players had a concussion from September 13 , 2012 , to January 31 , 2013 ; of these players , 28 underwent repeated blood sampling at 1 , 12 , 36 , and 144 hours and when the players returned to play . MAIN OUTCOMES AND MEASURES Total tau , S-100 calcium-binding protein B , and neuron-specific enolase concentrations in plasma and serum were measured . RESULTS Concussed players had increased levels of the axonal injury biomarker total tau(median , 10.0 pg/mL ; range , 2.0 - 102 pg/mL ) compared with preseason values ( median , 4.5pg/mL ; range , 0.06 - 22.7 pg/mL ) ( P < .001 ) . The levels of the astroglial injury biomarker S-100 calcium-binding protein B were also increased in players with sports-related concussion(median , 0.075 μg/L ; range , 0.037 - 0.24 μg/L ) compared with preseason values ( median,0.045 μg/L ; range , 0.005 - 0.45 μg/L ) ( P < .001 ) . The highest biomarker concentrations of total tau and S-100 calcium-binding protein B were measured immediately after a concussion , and they decreased during rehabilitation . No significant changes were detected in the levels of neuron-specific enolase from preseason values ( median , 6.5 μg/L ; range,3.45 - 18.0 μg/L ) to postconcussion values ( median , 6.1 μg/L ; range , 3.6 - 12.8 μg/L ) ( P = .10 ) . CONCLUSIONS AND RELEVANCE Sports-related concussion in professional ice hockey players is associated with acute axonal and astroglial injury . This can be monitored using blood biomarkers , which may be developed into clinical tools to guide sport physicians in the medical counseling of athletes in return-to-play decisions OBJECTIVES This study of concussed adolescents sought to determine if a computer-based neurocognitive assessment ( Immediate Postconcussion Assessment and Cognitive Test [ ImPACT ] ) performed on patients who present to the emergency department ( ED ) immediately following head injury would correlate with assessment s performed 3 to 10 days postinjury and if ED neurocognitive testing would detect differences in concussion severity that clinical grading scales could not . METHODS A prospect i ve cohort sample of patients 11 to 17 years of age presenting to the ED within 12 hours of a head injury were evaluated using two traditional concussion grading scales and neurocognitive testing .  ED neurocognitive scores were compared to follow-up scores obtained at least 3 days postinjury . Postconcussive symptoms , outcomes , and complications were assessed via telephone follow-up for all subjects . RESULTS Sixty patients completed phone follow-up . Thirty-six patients ( 60 % ) completed follow-up testing a median of 6 days postinjury . Traditional concussion grading did not correlate with neurocognitive deficits detected in the ED or at follow-up . For the neurocognitive domains of verbal memory , processing speed , and reaction time , there was a significant correlation between ED and follow-up scores trending toward clinical improvement . By 2 weeks postinjury , 23 patients ( 41 % ) had not returned to normal activity . At 6 weeks , six patients ( 10 % ) still had not returned to normal activity . CONCLUSIONS Immediate assessment in the ED can predict neurocognitive deficits seen in follow-up and may be potentially useful to individualize management or test therapeutic interventions . Neurocognitive assessment in the ED detected deficits that clinical grading could not and correlated with deficits at follow-up Objective The purpose of this pilot study was to document the nature and temporal profile of the clinical symptoms of acute sport-related concussion . Design Prospect i ve cohort study Patient Population A total of 303 elite Australian football players participating in a national competition during a single season . Outcome Measures Number and duration of symptoms , digit symbol substitution test ( DSST ) scores , time of return to play post injury . Results A total of 23 concussions were recorded over the course of the 20-week football season . No catastrophic head injuries occurred . Headache was the most common symptom and the most persistent , with 40 % of players reporting headache symptoms lasting more than 15 minutes . Ten of the players ( 43 % ) returned to sport on the day of the injury with the remainder resuming play within 2 weeks . A low likelihood of return to play on the day of injury was found where 3 or more symptoms were present or where the symptoms lasted more than 15 minutes . These findings were significantly correlated with poor DSST performance . Conclusions This pilot study suggests that both the number of postconcussive symptoms and their duration may be used as a measure of injury severity and a guide for return to play OBJECTIVES To evaluate the effect of concussion on clinical ly measured reaction time ( RT(clin ) ) and in comparison to a computerized reaction time measure ( RT(comp ) ) . DESIGN Prospect i ve , repeated measures observational study . SETTING Athletic training clinic at a National Collegiate Athletic Association ( NCAA ) Division I university . PARTICIPANTS Data are reported for 9 collegiate athletes with acute concussion who were part of a larger cohort of 209 athletes recruited from the university 's football , women 's soccer , and wrestling teams before the start of their respective athletic seasons . METHODS  Baseline RT(clin ) and RT(comp )  were measured during preparticipation physical examinations . RT(clin ) measured the time required to catch a suspended vertical shaft by h and closure after its release by the examiner . RT(comp ) was derived from the simple RT component of the CogState-Sport computerized neurocognitive test battery . Athletes who subsequently sustained a physician-diagnosed concussion underwent repeated RT(clin ) and RT(comp ) testing within 72 hours of injury . A Wilcoxon signed rank test was used to compare baseline and after-injury RTs . MAIN OUTCOME MEASUREMENTS After-injury changes in RT(clin ) and RT(comp ) were calculated with respect to each athlete 's own preseason baseline value . RESULTS After-injury RT(clin ) was prolonged in 8 of the 9 athletes with concussions , whereas RT(comp ) was prolonged in 5 of the 9 athletes with concussions . The mean ( st and ard deviation ) RT(clin ) increased from 193 ± 21 ms to 219 ± 31 ms ( P = .050 ) , and mean RT(comp ) increased from 247 ± 75 to 462 ± 120 ms ( P = .214 ) . CONCLUSIONS We concluded that RT(clin ) appears to be sensitive to the known prolongation of RT after concussion and compares favorably with an accepted computerized RT measure . This study supports the potential utility of RT(clin ) as part of a multifaceted concussion assessment battery Abstract Objective : To extend previous research design s and examine cognitive performance up to 30 days postconcussion . Method : A prospect i ve cohort design was used to examine 2000 athletes from 8 mid-Michigan area high schools to compare baseline neurocognitive performance with postconcussion neurocognitive performance . All concussed athletes were readministered the Immediate Post Assessment and Cognitive Test ( ImPACT ) at 2 , 7 , 14 , 21 , and 30 days postconcussion . Results : A total of 72 high school athletes ( aged 15.8 ± 1.34 years ) sustained a concussion . A significant with in-subjects effect for reaction time ( F = 10.01 ; P = 0.000 ) , verbal memory ( F = 3.05 ; P = 0.012 ) , motor processing speed ( F = 18.51 ; P = 0.000 ) , and total symptoms following an injury ( F = 16.45 ; P = 0.000 ) was found . Concussed athletes demonstrated a significant decrease in reaction time up to 14 days postconcussion ( P = 0.001 ) compared with baseline reaction time . Reaction time returned to baseline levels at 21 days postinjury ( P = 0.25 ) . At 7 days postinjury , impairments in verbal memory ( P = 0.003 ) and motor processing speed ( P = 0.000 ) were documented and returned to baseline levels by 14 days postinjury . Concussed athletes self-reported significantly more symptoms at 2 days postconcussion ( P = 0.000 ) and exhibited a resolution of symptoms by 7 days postinjury ( P = 0.06 ) . Conclusion : High school athletes could take up to 21 days to return to baseline levels for reaction time . These data support current recommendations for the conservative management of concussion in the high school athlete OBJECT The authors investigated return-to-play duration for initial and recurrent concussion in the same season in 2 teams of junior ( 16 - 21-year-old ) ice hockey players during a regular season . METHODS The authors conducted a prospect i ve cohort study during 1 junior regular season ( 2009 - 2010 ) of 67 male fourth-tier ice hockey players ( mean age 18.2 ± 1.2 years [ SD ] , range 16 - 21 years ) from 2 teams . Prior to the start of the season , every player underwent baseline assessment s that were determined using the  Sideline Concussion Assessment Tool 2 ( SCAT2 ) and the Immediate Post-Concussion Assessment and Cognitive Test ( ImPACT ) . The study protocol also required players who entered the study during the season to complete a baseline SCAT2 and ImPACT . If the protocol was not followed , the postinjury test results of a player without true baseline test results were compared with previously established age- and sex-matched group normative levels . Each game was directly observed by a physician and at least 1 neutral nonphysician observer . Players suspected of suffering a concussion were evaluated by the physician during the game . If a concussion was diagnosed , the player underwent clinical evaluation at the physician 's office within 24 hours . The return-to-play decision was based on clinical evaluation guided by the Zurich return-to-play protocol ( contained in the consensus statement of international expert opinion at the 3rd International Conference on Concussion in Sport held in Zurich , November 2008 ) . This clinical evaluation and return-to-play protocol was augmented by the 2 tests ( SCAT2 and ImPACT ) also recommended by the Zurich consensus statement , for which baseline values had been obtained . RESULTS Seventeen players sustained a physician-observed or self-reported , physician-diagnosed concussion during a physician-observed ice hockey game . The mean clinical return-to-play duration ( in 15 cases ) was 12.8 ± 7.02 days ( median 10 days , range 7 - 29 days ) ; the mean number of physician office visits by players who suffered a concussion ( 15 cases ) was 2.1 ± 1.29 ( median 1.5 visits ) . Five of the 17 players who sustained a concussion also suffered a recurrent or second concussion . One of the 5 individuals who suffered a repeat concussion sustained his initial concussion in a regular season game that was not observed by a physician , and as a result this single case was not included in the total of 21 concussions . This initial concussion of the player was identified during baseline testing 2 days after the injury and was subsequently medically diagnosed and treated . The mean interval between the first and second concussions in these 5 players was 78.6 ± 39.8 days ( median 82 days ) , and the mean time between the return-to-play date of the first and second concussions was 61.8 ± 39.7 days ( median 60 days ) . CONCLUSIONS The mean rates of return to play for single and recurrent concussions were higher than rates cited in recent studies involving sport concussions . The time interval between the first and second concussions was also greater than previously cited . This difference may be the result of the methodology of direct independent physician observation , diagnosis , and adherence to the Zurich return-to-play protocol OBJECT Mild traumatic brain injury ( MTBI ) , often referred to as concussion when it occurs in sports , produces persistent cognitive problems in at least 15 % of patients . Unfortunately , conventional neuropsychological tests usually yield results within normal limits in this population . The main objective of this event-related potential ( ERP ) study was to underst and brain functioning during the performance of a working memory ( WM ) task in patients who have sustained an MTBI , mostly due to motor vehicle accident or sports concussion . This study also aim ed for a better underst and ing of the association between brain functioning as measured with ERP , behavioral performance on the WM task , postconcussion symptoms , type of injury ( that is , sports concussion vs other types ) , and time since the injury . METHODS Forty-four patients with MTBI ( 7.6 ± 8.4 months postinjury ) were tested on a visual WM task with simultaneous recording of ERP , and were compared with 40 control volunteers who were their equivalent for age and sex . Amplitude and latency of frontal ( N200 and N350 ) and parietal ( P200 and P300 ) ERP waves were measured and were compared between groups . Correlation analyses were also performed between ERP characteristics , clinical variables , and behavioral performance . RESULTS A significant group difference was found for behavioral performance on the WM task , in which the MTBI group had a lower percentage of correct answers than the control group ( p < 0.05 ) . The patients with MTBI also had smaller amplitudes of both frontal N350 and parietal P300 ERP components when compared with control volunteers ( p < 0.05 ) . No changes were found for latency of ERP components . Smaller ERP amplitudes were associated with slower reaction times and worse accuracy on the WM task among patients with MTBI ( p < 0.05 ) . Types of injury ( that is , sports concussion vs other mechanisms ) were not associated with different ERP characteristics . CONCLUSIONS Abnormal ERP results are observed in patients after MTBI or sports concussion , even for those in the nonacute stage after their injury . Current st and ard clinical evaluations most often fail to detect cerebral dysfunction after MTBI , even when patients or athletes report symptoms . Clinicians should be aware that patients with MTBI , including sports concussion , probably have underlying mild but persistent cerebral dysfunctions that require further investigation CONTEXT Approximately 300 000 sport-related concussions occur annually in the United States , and the likelihood of serious sequelae may increase with repeated head injury . OBJECTIVE To estimate the incidence of concussion and time to recovery after concussion in collegiate football players . DESIGN , SETTING , AND PARTICIPANTS Prospect i ve cohort study of 2905 football players from 25 US colleges were tested at preseason baseline in 1999 , 2000 , and 2001 on a variety of measures and followed up prospect ively to ascertain concussion occurrence . Players injured with a concussion were monitored until their concussion symptoms resolved and were followed up for repeat concussions until completion of their collegiate football career or until the end of the 2001 football season . MAIN OUTCOME MEASURES Incidence of concussion and repeat concussion ; type and duration of symptoms and course of recovery among players who were injured with a concussion during the seasons . RESULTS During follow-up of 4251 player-seasons , 184 players ( 6.3 % ) had a concussion , and 12 ( 6.5 % ) of these players had a repeat concussion within the same season . There was an association between reported number of previous concussions and likelihood of incident concussion .  Players reporting a history of 3 or more previous concussions were 3.0 ( 95 % confidence interval , 1.6 - 5.6 ) times more likely to have an incident concussion than players with no concussion history . Headache was the most commonly reported symptom at the time of injury ( 85.2 % ) , and mean overall symptom duration was 82 hours . Slowed recovery was associated with a history of multiple previous concussions ( 30.0 % of those with > or =3 previous concussions had symptoms lasting > 1 week compared with 14.6 % of those with 1 previous concussion ) . Of the 12 incident within-season repeat concussions , 11 ( 91.7 % ) occurred within 10 days of the first injury , and 9 ( 75.0 % ) occurred within 7 days of the first injury . CONCLUSIONS Our study suggests that players with a history of previous concussions are more likely to have future concussive injuries than those with no history ; 1 in 15 players with a concussion may have additional concussions in the same playing season ; and previous concussions may be associated with slower recovery of neurological function OBJECTIVE There is continuing controversy regarding predictors of poor outcome following mild traumatic brain injury ( mTBI ) . This study aim ed to prospect ively examine the influence of preinjury factors , injury-related factors , and postinjury factors on outcome following mTBI . METHOD Participants were 123 patients with mTBI and 100 trauma patient controls recruited and assessed in the emergency department and followed up 1 week and 3 months postinjury . Outcome was measured in terms of reported postconcussional symptoms . Measures included the  ImPACT Post-Concussional Symptom Scale and cognitive concussion battery , including Attention , Verbal and Visual memory , Processing Speed and Reaction Time modules , pre- and postinjury SF-36 and MINI Psychiatric status ratings , VAS Pain Inventory , Hospital Anxiety and Depression Scale , PTSD Checklist-Specific , and Revised Social Readjustment Scale . RESULTS Presence of mTBI predicted postconcussional symptoms 1 week postinjury , along with being female and premorbid psychiatric history , with elevated HADS anxiety a concurrent indicator . However , at 3 months , preinjury physical or psychiatric problems but not mTBI most strongly predicted continuing symptoms , with concurrent indicators including HADS anxiety , PTSD symptoms , other life stressors and pain . HADS anxiety and age predicted 3-month PCS in the mTBI group , whereas PTSD symptoms and other life stressors were most significant for the controls . Cognitive measures were not predictive of PCS at 1 week or 3 months . CONCLUSIONS Given the evident influence of both premorbid and concurrent psychiatric problems , especially anxiety , on postinjury symptoms , managing the anxiety response in vulnerable individuals with mTBI may be important to minimize ongoing sequelae Objectives : To examine recovery of attention from 3 to 6 months postinjury ; to identify effects of injury severity and time since injury on performance ; to explore whether complex attention skills ( eg , shifting , divided attention , attentional control ) are more vulnerable to traumatic brain injury ( TBI ) , and slower to recover than simple attention skills ( eg , attentional capacity , selective attention , sustained attention ) . Design : Prospect i ve longitudinal investigation . Participants : A total of 205 school-aged children with TBI were divided into groups according to injury severity ( mild = 63 % , moderate = 27 % , severe = 10 % ) . Setting : Emergency departments of 3 metropolitan children 's hospitals across Australia . Main Measures : St and ardized clinical measures of both simple and complex attention were administered at 3 months and 6 months postinjury . Results : Attention skills were vulnerable to the impact of TBI . More severe injury affected attention skills most negatively . Significant recovery was observed over time . There were few interaction effects , with severity groups exhibiting similar levels of recovery over the 6 months post-TBI . No differences in recovery trajectories were detected for simple and complex attention . Conclusions : These findings have important clinical and educational implication s , suggesting that children with TBI , and particularly those with more serious injuries , are most vulnerable to attention deficits in the acute stages postinjury . It is important that schools and families are aware of these limitations and structure expectations accordingly . For example , gradual return to school should be considered , and in the early stages of recovery , children should be provided with sufficient rest time , with reduced expectations for tasks such as homework OBJECTIVE To determine the relationship between recorded head accelerations and impact locations and acute clinical outcome of symptomatology , neuropsychological , and postural stability tests after cerebral concussion in Division I collegiate football players . METHODS A prospect i ve field study was used in which accelerometers were embedded in the football helmets of 88 collegiate football players .  Linear and rotational accelerations of all head impacts sustained over the course of 2004 to 2006 National Collegiate Athletic Association football seasons were collected in real-time . Change scores were calculated on clinical measures from the players ' preseason baseline to postinjury ( within 48 h ) and regressed against the recorded linear and rotational accelerations of the head at the time of the concussion . RESULTS Thirteen concussions were recorded ranging in impact magnitudes of 60.51 to 168.71 g. Linear regression showed no significant relationships between impact magnitude ( linear or rotational acceleration ) or impact location and change scores for symptom severity , postural stability , or neurocognitive function ( P > 0.05 ) . CONCLUSION Our findings suggest that football players are concussed by impacts to the head that occur at a wide range of magnitudes and that clinical measures of acute symptom severity , postural stability , and neuropsychological function all appear to be largely independent of impact magnitude and location . Because of the varying magnitudes and locations of impacts result ing in concussion as well as other factors such as the frequency of subconcussive impacts and number of previous concussions , it may be difficult to establish a threshold for concussive injury that can be applied to all football players Objective : Following the Second International Conference on Concussion in Sport in 2005 , a summary agreement statement was published that introduced new terminology for sport-related concussions . This new classification system is binary ( ie , “ simple ” versus “ complex ” concussions ) . Athletes who are slow to recover ( ie , > 10 days ) are classified as having complex concussions . The purpose of this study was to determine if high school football players , retrospectively classified as having a simple or a complex concussion , could be differentiated in the first 48 after injury on the basis of symptom reporting or neuropsychological testing . Design : Case-control study . Setting : Pennsylvania high school football programs . Participants : The total sample consisted of 114 concussed high school football players who were identified through a 3 year prospect i ve cohort study . Interventions : All completed a computerized neuropsychological screening evaluation within 72 hours of injury . They were followed clinical ly until they recovered and were cleared to return to play . They were classified retrospectively as having a simple ( n = 55 ) or complex ( n = 59 ) concussion based on their recovery times . Main Outcome Measurements : Neurocognitive test performance and symptom ratings . Results : Within 72 hours after injury , athletes with complex concussions performed more poorly on neuropsychological testing and reported more symptoms than those with simple concussions . Athletes with complex concussions who were slow to recover were 18 times more likely to have 3 unusually low neuropsychological test scores than those with simple concussions ( 95 % CI = 2.3 - 144.9 ) . Athletes with previous concussions did not recover more slowly . Conclusions : This study provides evidence that supports and refutes the clinical usefulness of the new simple-complex concussion classification system
Due to differences in modalities , time course , study design and outcomes , it is not possible to define a single ‘ physiological time window ’ for SRC recovery .
Multiple studies suggest physiological dysfunction may outlast current clinical measures of recovery , supporting a buffer zone of gradually increasing activity before full contact risk .
Aim or objective The aim of this study is to consoli date studies of physiological measures following sport-related concussion ( SRC ) to determine if a time course of postinjury altered neurobiology can be outlined .
This biological time course was considered with respect to clinical ly relevant outcomes such as vulnerability to repeat injury and safe timing of return to physical contact risk .