human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background Neurocognitive testing has been endorsed as a “ cornerstone ’ of concussion management by recent Vienna and Prague meetings of the Concussion in Sport Group . Neurocognitive testing is important given the potential unreliability of athlete self-report after injury . Relying only on athletes'ormalities after injury . Study Design Case control study ; Level of evidence , 3 . Methods High school and college athletes with a diagnosed concussion were tested 2 days after injury . Postinjury neurocognitive performance ( Immediate Postconcussion Assessment and Cognitive Testing ) and symptom ( postconcussion symptom ) scores were compared with preinjury ( baseline ) scores and with those of an agex and education-matched noninjured athlete control group . “ Abnormal ” test performance was determined statistically with Reliable Change Index scores . Results Sixty-four percent of concussed athletes reported a significant increase in symptoms , as judged by postconcussion symptom scores , compared with preinjury baseline at 2 days after injury . Eighty-three percent of the concussed sample demonstrated significantly poorer neurocognitive test results relative to their own baseline performance . The addition of neurocognitive testing result ed in a net increase in sensitivity of 19 % . Ninety-three percent of the sample had either abnormal neurocognitive test results or a significant increase in symptoms , relative to their own baseline ; 30 % of a control group demonstrated either abnormalities in neurocognitive testing or elevated symptoms , as judged by postconcussion symptom scores . For the concussed group , use of symptom and neurocognitive test results result ed in an increased yield of 29 % overreliance on symptoms alone . In contrast , 0 % of the control group had both symptoms and abnormal neurocognitive testing . Conclusion Reliance on patients ’ self-reported symptoms after concussion is likely to result in underdiagnosis of concussion and may result in premature return to play . Neurocognitive testing increases diagnostic accuracy when used in conjunction with self-reported symptoms CONTEXT The return-to-play decision after sport-related cerebral concussion depends in part on knowing when an athlete has fully recovered postural control after injury . OBJECTIVE To describe the postconcussion recovery of postural control using approximate entropy ( ApEn ) , a regularity statistic from nonlinear dynamics . DESIGN Retrospective case series analysis . SETTING Sports medicine research laboratory . PATIENTS OR OTHER PARTICIPANTS Collegiate athletes from whom center-of-pressure and symptom data were collected at preseason , less than 48 hours after injury , and 48 to 96 hours after injury . MAIN OUTCOME MEASURE(S ) Approximate entropy values reflecting the amount of r and omness contained in center-of-pressure oscillations were calculated for anterior-posterior ( AP ) and medial-lateral ( ML ) time series . Equilibrium scores reflecting the amplitude of center-of-pressure AP oscillations were used to indicate postural stability . The number and severity of symptoms were described . RESULTS Compared with the healthy preseason state , ApEn values for the AP and ML time series generally declined immediately after injury in both steady and unsteady injured athletes . At 48 to 96 hours after injury , ApEn values for the ML time series remained significantly depressed ( mean difference compared with preseason = -0.268 , st and ard error = 0.072 ) , even among athletes whose initial postural instability had resolved . We found few significant relationships between changes in ApEn values and changes in symptoms before and after injury . CONCLUSIONS The effects of cerebral concussion on postural control appear to persist for longer than 3 to 4 days , even among athletes with no signs of unsteadiness . Our results may reflect changes in neurophysiologic or mechanical constraints on postural control . Approximate entropy provides a theoretically distinct , valuable measurement alternative that may prove useful for reducing uncertainty in the return-to-play decision 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 This study explored the diagnostic utility of the composite scores of Immediate Post-Concussion Assessment and Cognitive Testing ( ImPACT ) and Post Concussion Symptom Scale scores ( PCSS ) . Recently concussed high school athletes ( N=72 ) were tested within 72 h of sustaining a concussion , and data were compared to non-concussed high school athletes with no history of concussion ( N=66 ) . Between-groups MANOVA revealed a significant multivariate effect of concussion on test performance ( p<.001 ) ; univariate ANOVAS revealed all six measures contributed to the between-groups differences . A discriminant function analyses was conducted to measure the ability of the five ImPACT composite scores , as well as the PCSS to classify concussion status . One discriminant function was identified that consisted of the Visual Memory , Processing Speed , and Impulse Control composite scores PCSS , which correctly classified 85.5 % of the cases . Approximately 82 % of participants in the concussion group and 89 % of participants in the control group were correctly classified . Using these data , the sensitivity of ImPACT was 81.9 % , and the specificity was 89.4 % . As part of a formal concussion management program , ImPACT is a useful tool for the assessment of the neurocognitive and neurobehavioral sequelae of concussion , and can also provide post-injury cognitive and symptom data that can assist a practitioner in making safer return to play decisions 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 Primary objective : To examine the relationship between the occurrence of  whiplash-associated disorders and concussion symptoms in hockey players . Research design : Prospect i ve cohort observational study to examine the relationship between whiplash associated disorders and concussion in actual hockey play . Methods and procedures : Twenty hockey teams were followed prospect ively for one season . Team therapists completed acute and 7–10 day follow-up evaluation question naires for all of the players who received either a whiplash mechanism or a concussion . Main outcomes and results : 183 players were registered for this study ; 13 received either a whiplash mechanistic injury or a concussion injury . Initial injuries ranged from WAD I to WAD III and all subjects reported concussion symptoms . Only three subjects reported full resolution of bothWAD and concussion symptoms at the 7–10 day follow-up evaluation . Conclusions : There is a strong association between whiplash induced neck injuries and the symptoms of concussion in hockey injuries . Both should be evaluated when dealing with athletes/ patients suffering from either injury OBJECTIVE : The purpose of this study was to compare concussion rates and recovery times for athletes wearing newer helmet technology compared to traditional helmet design . METHODS : This was a three-year , prospect i ve , naturalistic , cohort study . Participants were 2,141 high school athletes from Western Pennsylvania . Approximately half of the sample wore the Revolution helmet manufactured by Riddell , Inc.  ( n = 1,173 ) and the remainder of the sample used  st and ard helmets ( n = 968 ) . Athletes underwent computerized neurocognitive testing through the use of ImPACT at the beginning of the study . Following a concussion , players were reevaluated at various time intervals until recovery was complete . RESULTS : In the total sample , the concussion rate in athletes wearing the Revolution was 5.3 % and in athletes wearing st and ard helmets was 7.6 % [ & khgr;2 ( 1 , 2 , 141 ) = 4.96 , P < 0.027 ] . The relative risk estimate was 0.69 ( 95 % confidence interval = 0.499– 0.958 ) . Wearing the Revolution helmet was associated with approximately a 31 % decreased relative risk and 2.3 % decreased absolute risk for sustaining a concussion in this cohort study . The athletes wearing the Revolution did not differ from athletes wearing st and ard helmets on the mechanism of injury ( e.g. , head-to-head strike ) , on-field concussion markers ( e.g. , amnesia or loss of consciousness ) , or on-field presentation of symptoms ( e.g. , headaches , dizziness , or balance problems ) . CONCLUSION : Recent sophisticated laboratory research has better eluci date d injury biomechanics associated with concussion in professional football players . This data has led to changes in helmet design and new helmet technology , which appears to have beneficial effects in reducing the incidence of cerebral concussion in high school football players 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 OBJECTIVE Our purpose was to determine whether sex differences exist with respect to post-concussion symptoms and neurocognitive function in concussed collegiate athletes . METHODS A prospect i ve dependent- sample cohort design was used to compare baseline and post-concussion neuropsychological test scores and endorsed 
    Output:
    
agent
Six core scales were identified with a broad range of symptom items but with limited information on their psychometric properties .
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background Neurocognitive testing has been endorsed as a “ cornerstone ’ of concussion management by recent Vienna and Prague meetings of the Concussion in Sport Group . Neurocognitive testing is important given the potential unreliability of athlete self-report after injury . Relying only on athletes'ormalities after injury . Study Design Case control study ; Level of evidence , 3 . Methods High school and college athletes with a diagnosed concussion were tested 2 days after injury . Postinjury neurocognitive performance ( Immediate Postconcussion Assessment and Cognitive Testing ) and symptom ( postconcussion symptom ) scores were compared with preinjury ( baseline ) scores and with those of an agex and education-matched noninjured athlete control group . “ Abnormal ” test performance was determined statistically with Reliable Change Index scores . Results Sixty-four percent of concussed athletes reported a significant increase in symptoms , as judged by postconcussion symptom scores , compared with preinjury baseline at 2 days after injury . Eighty-three percent of the concussed sample demonstrated significantly poorer neurocognitive test results relative to their own baseline performance . The addition of neurocognitive testing result ed in a net increase in sensitivity of 19 % . Ninety-three percent of the sample had either abnormal neurocognitive test results or a significant increase in symptoms , relative to their own baseline ; 30 % of a control group demonstrated either abnormalities in neurocognitive testing or elevated symptoms , as judged by postconcussion symptom scores . For the concussed group , use of symptom and neurocognitive test results result ed in an increased yield of 29 % overreliance on symptoms alone . In contrast , 0 % of the control group had both symptoms and abnormal neurocognitive testing . Conclusion Reliance on patients ’ self-reported symptoms after concussion is likely to result in underdiagnosis of concussion and may result in premature return to play . Neurocognitive testing increases diagnostic accuracy when used in conjunction with self-reported symptoms CONTEXT The return-to-play decision after sport-related cerebral concussion depends in part on knowing when an athlete has fully recovered postural control after injury . OBJECTIVE To describe the postconcussion recovery of postural control using approximate entropy ( ApEn ) , a regularity statistic from nonlinear dynamics . DESIGN Retrospective case series analysis . SETTING Sports medicine research laboratory . PATIENTS OR OTHER PARTICIPANTS Collegiate athletes from whom center-of-pressure and symptom data were collected at preseason , less than 48 hours after injury , and 48 to 96 hours after injury . MAIN OUTCOME MEASURE(S ) Approximate entropy values reflecting the amount of r and omness contained in center-of-pressure oscillations were calculated for anterior-posterior ( AP ) and medial-lateral ( ML ) time series . Equilibrium scores reflecting the amplitude of center-of-pressure AP oscillations were used to indicate postural stability . The number and severity of symptoms were described . RESULTS Compared with the healthy preseason state , ApEn values for the AP and ML time series generally declined immediately after injury in both steady and unsteady injured athletes . At 48 to 96 hours after injury , ApEn values for the ML time series remained significantly depressed ( mean difference compared with preseason = -0.268 , st and ard error = 0.072 ) , even among athletes whose initial postural instability had resolved . We found few significant relationships between changes in ApEn values and changes in symptoms before and after injury . CONCLUSIONS The effects of cerebral concussion on postural control appear to persist for longer than 3 to 4 days , even among athletes with no signs of unsteadiness . Our results may reflect changes in neurophysiologic or mechanical constraints on postural control . Approximate entropy provides a theoretically distinct , valuable measurement alternative that may prove useful for reducing uncertainty in the return-to-play decision 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 This study explored the diagnostic utility of the composite scores of Immediate Post-Concussion Assessment and Cognitive Testing ( ImPACT ) and Post Concussion Symptom Scale scores ( PCSS ) . Recently concussed high school athletes ( N=72 ) were tested within 72 h of sustaining a concussion , and data were compared to non-concussed high school athletes with no history of concussion ( N=66 ) . Between-groups MANOVA revealed a significant multivariate effect of concussion on test performance ( p<.001 ) ; univariate ANOVAS revealed all six measures contributed to the between-groups differences . A discriminant function analyses was conducted to measure the ability of the five ImPACT composite scores , as well as the PCSS to classify concussion status . One discriminant function was identified that consisted of the Visual Memory , Processing Speed , and Impulse Control composite scores PCSS , which correctly classified 85.5 % of the cases . Approximately 82 % of participants in the concussion group and 89 % of participants in the control group were correctly classified . Using these data , the sensitivity of ImPACT was 81.9 % , and the specificity was 89.4 % . As part of a formal concussion management program , ImPACT is a useful tool for the assessment of the neurocognitive and neurobehavioral sequelae of concussion , and can also provide post-injury cognitive and symptom data that can assist a practitioner in making safer return to play decisions 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 Primary objective : To examine the relationship between the occurrence of  whiplash-associated disorders and concussion symptoms in hockey players . Research design : Prospect i ve cohort observational study to examine the relationship between whiplash associated disorders and concussion in actual hockey play . Methods and procedures : Twenty hockey teams were followed prospect ively for one season . Team therapists completed acute and 7–10 day follow-up evaluation question naires for all of the players who received either a whiplash mechanism or a concussion . Main outcomes and results : 183 players were registered for this study ; 13 received either a whiplash mechanistic injury or a concussion injury . Initial injuries ranged from WAD I to WAD III and all subjects reported concussion symptoms . Only three subjects reported full resolution of bothWAD and concussion symptoms at the 7–10 day follow-up evaluation . Conclusions : There is a strong association between whiplash induced neck injuries and the symptoms of concussion in hockey injuries . Both should be evaluated when dealing with athletes/ patients suffering from either injury OBJECTIVE : The purpose of this study was to compare concussion rates and recovery times for athletes wearing newer helmet technology compared to traditional helmet design . METHODS : This was a three-year , prospect i ve , naturalistic , cohort study . Participants were 2,141 high school athletes from Western Pennsylvania . Approximately half of the sample wore the Revolution helmet manufactured by Riddell , Inc.  ( n = 1,173 ) and the remainder of the sample used  st and ard helmets ( n = 968 ) . Athletes underwent computerized neurocognitive testing through the use of ImPACT at the beginning of the study . Following a concussion , players were reevaluated at various time intervals until recovery was complete . RESULTS : In the total sample , the concussion rate in athletes wearing the Revolution was 5.3 % and in athletes wearing st and ard helmets was 7.6 % [ & khgr;2 ( 1 , 2 , 141 ) = 4.96 , P < 0.027 ] . The relative risk estimate was 0.69 ( 95 % confidence interval = 0.499– 0.958 ) . Wearing the Revolution helmet was associated with approximately a 31 % decreased relative risk and 2.3 % decreased absolute risk for sustaining a concussion in this cohort study . The athletes wearing the Revolution did not differ from athletes wearing st and ard helmets on the mechanism of injury ( e.g. , head-to-head strike ) , on-field concussion markers ( e.g. , amnesia or loss of consciousness ) , or on-field presentation of symptoms ( e.g. , headaches , dizziness , or balance problems ) . CONCLUSION : Recent sophisticated laboratory research has better eluci date d injury biomechanics associated with concussion in professional football players . This data has led to changes in helmet design and new helmet technology , which appears to have beneficial effects in reducing the incidence of cerebral concussion in high school football players 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 OBJECTIVE Our purpose was to determine whether sex differences exist with respect to post-concussion symptoms and neurocognitive function in concussed collegiate athletes . METHODS A prospect i ve dependent- sample cohort design was used to compare baseline and post-concussion neuropsychological test scores and endorsed 
    Output:
    