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: Purpose : The main objectives of this study were to describe long-term self-reported balance problems  and to explore their associations with post-concussion symptoms and performance-based tests . Method : Prospect i ve study of patients with mild traumatic brain injury ( MTBI ) .  Self-reported balance problems and post-concussion symptoms were measured with the Rivermead Post-concussion Symptoms Question naire at 1 and 4 years after injury . Performance-based tests were performed 4 years after injury and included  posturography , the Dynamic Gait Index ( DGI ) , walking speed tests , and the six-minute walk test . Results : Self-reported balance problems were reported in 31 % of patients 4 years after injury and correlated significantly with post-concussion symptoms . The correlations with performance-based tests varied from ρ = 0.18 to ρ = 0.70 and were strongest for the maximum walking speed test ( ρ = 0.70 ) and a dual-task test ( ρ = 0.43 ) . The DGI had a considerable ceiling effect . Conclusions : Balance problems were long-term consequences of MTBI in one third of this study sample . Self-reported balance problems correlated with post-concussion symptoms and some of the performance-based tests . Future research needs to develop and evaluate appropriate rehabilitation strategies that also address the balance problems . Implication s for Rehabilitation Balance problems may persist several years after a mild traumatic brain injury . We need to develop and evaluate appropriate rehabilitation strategies that also address the balance problems Background Biomechanical measures of postural stability , while generally useful in neuroscience and physical rehabilitation research , may be limited in their ability to detect more subtle influences of attention on postural control . Approximate entropy ( ApEn ) , a regularity statistic from nonlinear dynamics , recently has demonstrated relatively good measurement precision and shown promise for detecting subtle change in postural control after cerebral concussion . Our purpose was to further explore the responsiveness of ApEn by using it to evaluate the immediate , short-term effect of secondary cognitive task performance on postural control in healthy , young adults . Methods Thirty healthy , young adults performed a modified version of the Sensory Organization Test  featuring single ( posture only ) and dual ( posture plus cognitive ) task trials .  ApEn values , root mean square ( RMS ) displacement , and equilibrium scores ( ES ) were calculated from anterior-posterior ( AP ) and medial-lateral ( ML ) center of pressure ( COP ) component time series . For each sensory condition , we compared the ability of the postural control parameters to detect an effect of cognitive task performance . Results COP AP time series generally became more r and om ( higher ApEn value ) during dual task performance , result ing in a main effect of cognitive task ( p = 0.004 ) . In contrast , there was no significant effect of cognitive task for ApEn values of COP ML time series , RMS displacement ( AP or ML ) or ES . Conclusion During dual task performance , ApEn revealed a change in the r and omness of COP oscillations that occurred in a variety of sensory conditions , independent of changes in the amplitude of COP oscillations . The finding exp and s current support for the potential of ApEn to detect subtle changes in postural control . Implication s for future studies of attention in neuroscience and physical rehabilitation are discussed PURPOSE Athletic performance dem and s simultaneous use of cognitive and postural control capabilities . Decrements to both systems have been observed following concussion . This study evaluated a dual-task methodology to establish the tenability of using this testing model in concussed athletes . METHODS Nonconcussed subjects were assessed over 2 d. Subjects were introduced to the task-switching cognitive assessment test and a NeuroCom Smart Balance Master postural control assessment protocol on day 1 . In the following session , subjects were evaluated on  postural control and cognitive function tests independently ( single task ) , and then concurrently ( dual task ) . RESULTS Significant improvements were seen in three of the four balance conditions and in three of the four reaction times when the cognitive and balance task were performed simultaneously ( P<0.05 ) . No significant balance by cognitive task interaction was revealed ( P>0.05 ) ; however , significant differences existed in reaction time based on stimulus position and increasing balance dem and s ( P<0.05 ) . CONCLUSION Combining the cognitive and balance assessment s result ed in healthy subjects showing improved performance when compared with individual task performance . The dual-task methodology brought about systematic changes to reaction time in relation to increasing balance dem and s. The ability of this protocol to detect changes in postural control or cognitive function following concussive injury requires further study Objective : To determine if serial administration of the St and ardized Assessment of Concussion ( SAC ) and Balance Error Scoring System ( BESS ) would elicit a learning effect in young athletes and to determine the intratester reliability of scoring the BESS . Design : A prospect i ve study of 50 healthy young athletes who were assigned to either the control or practice group . All subjects were administered the assessment s on 2 occasions , 60 days apart . In addition , subjects in the practice group received serial administration of the assessment s on 3 occasions in the week following the initial assessment . Setting : University Sports Medicine/Athletic Training Research Laboratory . Subjects : Fifty uninjured young athletes between 9 and 14 years of age . Main Outcome Measured : Scores on 2 clinical concussion assessment s , the SAC and the BESS . Results : We found a significant learning effect upon serial BESS testing in the practice group . BESS error scores were significantly lower than baseline ( 15.0 ± 4.6 ) on days 5 ( 11.3 ± 5.33 ) , 7 ( 12.4 ± 6.2 ) , and 60 ( 12.6 ± 6.2 ) . We also found a significant learning effect upon the day 60 BESS administration across all subjects . We did not find a practice or learning effect with serial SAC test administration . The intratester reliability of the investigator ’s ability to score repeated observations of the same BESS test ranged from 0.87 to 0.98 . Conclusions : Our results demonstrated that serial administration of the BESS elicited a learning effect , which was more prominent during the t and em conditions . Clinicians utilizing the BESS as a measure of postural stability should be aware of the potential for improvement with repeated testing . Clinicians should not expect improvement with the SAC , as scores remained relatively stable across all trials PURPOSE The objective of this study is to determine the stability and sensitivity of a dual-task ( DT ) methodology that can be used to assess the effects of concussion in athletes . METHODS Fifty-nine healthy young adults ( Mage = 20.32 ± 1.84 yr , 19 males ) who volunteered to participate completed auditory switch tasks that varied in length ( 30 , 40 , and 60 items ) at baseline , 1 wk later , and approximately 7 months later . During sessions 2 and 3 , the participants completed one of three switch tasks while concurrently performing a modified Harvard Step Test .  Global switch cost indices and percentage error were calculated for each switch task . The stability reliability of the global switch cost indices was assessed under single-task conditions , and the sensitivity of the global switch costs to interference effects was assessed under DT conditions . RESULTS The stability reliability was 0.64 , 0.84 , and 0.83 for the 30- , 40- , and 60-item tests , respectively . ANOVA revealed a main effect for condition ( single task vs DT ) for both global switch costs ( F(1,55 ) = 44.53 , P < 0.0001 ) and percentage error ( F(1,56 ) = 64.69 , P < 0.001 ) . The magnitude of the global switch cost interference effects was nearly identical across the three DT conditions . CONCLUSIONS The current concussion testing models test athletes ' cognitive and physical function in isolation . The stability reliability of the global switch cost index obtained under DT conditions suggests that it may be a useful measure for clinicians . The DT paradigm presents another test methodology that may be useful for making return-to-play decisions as part of a comprehensive concussion management plan OBJECTIVE The purpose of this study was to determine the intrarater and interrater reliability of the Balance Error Scoring System ( BESS ) . DESIGN A prospect i ve observational study . SETTING Academic sports medicine center . PARTICIPANTS Three scorers participated in this study . METHODS Three scorers experienced in using the  BESS viewed a videotape depicting 30 consecutive individuals performing the BESS stance positions . The 3 scorers independently scored each of the 30 videotaped individuals using the BESS scoring criteria . A week later , the same 3 subjects viewed and scored the videotape again . MAIN OUTCOME MEASUREMENTS The interrater and intrarater reliability of the BESS  was determined using intraclass correlation coefficients ( ICC ) , reported with 95 % confidence intervals . The minimum detectible change was also determined . RESULTS The interrater and intrarater reliability ICCs for the total BESS scores were 0.57 and 0.74 , respectively . The interrater reliability ICCs for the 6 different stance positions were between 0.44 and 0.83 , while the intrarater reliability ICCs were between 0.50 and 0.88 . The interrater and intrarater minimum detectible change for the total BESS score were 9.4 and 7.3 points , respectively . CONCLUSION This study suggests that certain subcategories of the BESS have sufficient reliability to be used in the evaluation of postural stability but that the total BESS score is not reliable . In addition , a change in score of greater than 9.4 ( interrater ) or 7.3 ( intrarater ) points is required before the change in postural stability can be attributed to the balancer rather than to the scorer OBJECTIVES To determine the reliability and effects of a dual-task paradigm on  balance and cognitive function  compared to a single-task paradigm . DESIGN Repeated measures . METHODS Healthy participants ( n=23 ) completed a variation of the Sensory Organization Test and the incongruent Stroop test individually ( single-task ) and concurrently ( dual-task ) during two testing sessions . RESULTS The Sensory Organization Test and incongruent Stroop test had moderate to high reliability ( 1.00>ICC2,k>0.60 ) under the dual-task conditions . Reaction time was significantly longer ( t21=-2.54 , p=0.019 ) under the dual-task conditions , while balance scores under one of the four conditions of the Sensory Organization Test ( sway floor/fixed wall ) were statistically better ( t22=-3.03 , p=0.006 ) under the dual-task conditions . However , this difference in balance scores may not be clinical ly meaningful . CONCLUSIONS These findings illustrate that the Sensory Organization Test and incongruent Stroop task can be reliably incorporated into a dual-task assessment paradigm . The slowed reaction time under the dual-task paradigm indicates that the dual-task provided an additional cost to cognitive function . Dual-task concussion assessment paradigms involving these two tasks are psychometrically appropriate as well as more representative of actual sporting situations . However , more research should be conducted in a concussed population to further vali date this cl aim BACKGROUND The need to identify functional impairment following a brain injury is critical to prevent re-injury during the period of recovery . While many neuropsychological tests have been developed to assess cognitive performance , relatively little information on gait and dynamic stability is available on motor task performance for young adults following concussion . This study was performed to investigate the effect of divided attention following concussion on various gait variables . It was hypothesized that , when compared to uninjured controls , concussed subjects would demonstrate deficits in maintenance of dynamic stability . METHODS Ten subjects with Grade 2 concussion completed testing within 48 h of injury as well as 10 age- , height- , weight- , and activity-matched controls . The gait protocol consisted of level walking under two conditions : ( 1 ) undivided attention ( single-task ) and ( 2 ) while simultaneously completing simple mental tasks ( dual-task ) . Whole-body motion data were collected using a six-camera motion analysis system . A 13-segment biomechanical model was used to compute whole body center of mass motion and velocity . FINDINGS Walking with a concurrent cognitive task result ed in significant changes in gait and center of mass measurements for both groups . Concussed subjects were found to be able to conservatively adjust their whole body center of mass motion to maintain dynamic stability while walking without divided attention . However , while walking with divided attention , subjects with concussion demonstrated a significantly greater medio-lateral center of mass sway . INTERPRETATION These data suggest that the ability to control and maintain stability in the frontal plane during walking is diminished under divided attention in individuals following a concussion 
    Output:
    
agent
Response times are greater , gait strategies are less efficient , and postural control deficits are greater in concussed participants compared with healthy controls both immediately and for some period following concussive injury , specifically under divided attention conditions .
Dual task assessment s in some cases were more reliable than single task assessment s and may be better able to detect lingering effects following concussion .
***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: Purpose : The main objectives of this study were to describe long-term self-reported balance problems  and to explore their associations with post-concussion symptoms and performance-based tests . Method : Prospect i ve study of patients with mild traumatic brain injury ( MTBI ) .  Self-reported balance problems and post-concussion symptoms were measured with the Rivermead Post-concussion Symptoms Question naire at 1 and 4 years after injury . Performance-based tests were performed 4 years after injury and included  posturography , the Dynamic Gait Index ( DGI ) , walking speed tests , and the six-minute walk test . Results : Self-reported balance problems were reported in 31 % of patients 4 years after injury and correlated significantly with post-concussion symptoms . The correlations with performance-based tests varied from ρ = 0.18 to ρ = 0.70 and were strongest for the maximum walking speed test ( ρ = 0.70 ) and a dual-task test ( ρ = 0.43 ) . The DGI had a considerable ceiling effect . Conclusions : Balance problems were long-term consequences of MTBI in one third of this study sample . Self-reported balance problems correlated with post-concussion symptoms and some of the performance-based tests . Future research needs to develop and evaluate appropriate rehabilitation strategies that also address the balance problems . Implication s for Rehabilitation Balance problems may persist several years after a mild traumatic brain injury . We need to develop and evaluate appropriate rehabilitation strategies that also address the balance problems Background Biomechanical measures of postural stability , while generally useful in neuroscience and physical rehabilitation research , may be limited in their ability to detect more subtle influences of attention on postural control . Approximate entropy ( ApEn ) , a regularity statistic from nonlinear dynamics , recently has demonstrated relatively good measurement precision and shown promise for detecting subtle change in postural control after cerebral concussion . Our purpose was to further explore the responsiveness of ApEn by using it to evaluate the immediate , short-term effect of secondary cognitive task performance on postural control in healthy , young adults . Methods Thirty healthy , young adults performed a modified version of the Sensory Organization Test  featuring single ( posture only ) and dual ( posture plus cognitive ) task trials .  ApEn values , root mean square ( RMS ) displacement , and equilibrium scores ( ES ) were calculated from anterior-posterior ( AP ) and medial-lateral ( ML ) center of pressure ( COP ) component time series . For each sensory condition , we compared the ability of the postural control parameters to detect an effect of cognitive task performance . Results COP AP time series generally became more r and om ( higher ApEn value ) during dual task performance , result ing in a main effect of cognitive task ( p = 0.004 ) . In contrast , there was no significant effect of cognitive task for ApEn values of COP ML time series , RMS displacement ( AP or ML ) or ES . Conclusion During dual task performance , ApEn revealed a change in the r and omness of COP oscillations that occurred in a variety of sensory conditions , independent of changes in the amplitude of COP oscillations . The finding exp and s current support for the potential of ApEn to detect subtle changes in postural control . Implication s for future studies of attention in neuroscience and physical rehabilitation are discussed PURPOSE Athletic performance dem and s simultaneous use of cognitive and postural control capabilities . Decrements to both systems have been observed following concussion . This study evaluated a dual-task methodology to establish the tenability of using this testing model in concussed athletes . METHODS Nonconcussed subjects were assessed over 2 d. Subjects were introduced to the task-switching cognitive assessment test and a NeuroCom Smart Balance Master postural control assessment protocol on day 1 . In the following session , subjects were evaluated on  postural control and cognitive function tests independently ( single task ) , and then concurrently ( dual task ) . RESULTS Significant improvements were seen in three of the four balance conditions and in three of the four reaction times when the cognitive and balance task were performed simultaneously ( P<0.05 ) . No significant balance by cognitive task interaction was revealed ( P>0.05 ) ; however , significant differences existed in reaction time based on stimulus position and increasing balance dem and s ( P<0.05 ) . CONCLUSION Combining the cognitive and balance assessment s result ed in healthy subjects showing improved performance when compared with individual task performance . The dual-task methodology brought about systematic changes to reaction time in relation to increasing balance dem and s. The ability of this protocol to detect changes in postural control or cognitive function following concussive injury requires further study Objective : To determine if serial administration of the St and ardized Assessment of Concussion ( SAC ) and Balance Error Scoring System ( BESS ) would elicit a learning effect in young athletes and to determine the intratester reliability of scoring the BESS . Design : A prospect i ve study of 50 healthy young athletes who were assigned to either the control or practice group . All subjects were administered the assessment s on 2 occasions , 60 days apart . In addition , subjects in the practice group received serial administration of the assessment s on 3 occasions in the week following the initial assessment . Setting : University Sports Medicine/Athletic Training Research Laboratory . Subjects : Fifty uninjured young athletes between 9 and 14 years of age . Main Outcome Measured : Scores on 2 clinical concussion assessment s , the SAC and the BESS . Results : We found a significant learning effect upon serial BESS testing in the practice group . BESS error scores were significantly lower than baseline ( 15.0 ± 4.6 ) on days 5 ( 11.3 ± 5.33 ) , 7 ( 12.4 ± 6.2 ) , and 60 ( 12.6 ± 6.2 ) . We also found a significant learning effect upon the day 60 BESS administration across all subjects . We did not find a practice or learning effect with serial SAC test administration . The intratester reliability of the investigator ’s ability to score repeated observations of the same BESS test ranged from 0.87 to 0.98 . Conclusions : Our results demonstrated that serial administration of the BESS elicited a learning effect , which was more prominent during the t and em conditions . Clinicians utilizing the BESS as a measure of postural stability should be aware of the potential for improvement with repeated testing . Clinicians should not expect improvement with the SAC , as scores remained relatively stable across all trials PURPOSE The objective of this study is to determine the stability and sensitivity of a dual-task ( DT ) methodology that can be used to assess the effects of concussion in athletes . METHODS Fifty-nine healthy young adults ( Mage = 20.32 ± 1.84 yr , 19 males ) who volunteered to participate completed auditory switch tasks that varied in length ( 30 , 40 , and 60 items ) at baseline , 1 wk later , and approximately 7 months later . During sessions 2 and 3 , the participants completed one of three switch tasks while concurrently performing a modified Harvard Step Test .  Global switch cost indices and percentage error were calculated for each switch task . The stability reliability of the global switch cost indices was assessed under single-task conditions , and the sensitivity of the global switch costs to interference effects was assessed under DT conditions . RESULTS The stability reliability was 0.64 , 0.84 , and 0.83 for the 30- , 40- , and 60-item tests , respectively . ANOVA revealed a main effect for condition ( single task vs DT ) for both global switch costs ( F(1,55 ) = 44.53 , P < 0.0001 ) and percentage error ( F(1,56 ) = 64.69 , P < 0.001 ) . The magnitude of the global switch cost interference effects was nearly identical across the three DT conditions . CONCLUSIONS The current concussion testing models test athletes ' cognitive and physical function in isolation . The stability reliability of the global switch cost index obtained under DT conditions suggests that it may be a useful measure for clinicians . The DT paradigm presents another test methodology that may be useful for making return-to-play decisions as part of a comprehensive concussion management plan OBJECTIVE The purpose of this study was to determine the intrarater and interrater reliability of the Balance Error Scoring System ( BESS ) . DESIGN A prospect i ve observational study . SETTING Academic sports medicine center . PARTICIPANTS Three scorers participated in this study . METHODS Three scorers experienced in using the  BESS viewed a videotape depicting 30 consecutive individuals performing the BESS stance positions . The 3 scorers independently scored each of the 30 videotaped individuals using the BESS scoring criteria . A week later , the same 3 subjects viewed and scored the videotape again . MAIN OUTCOME MEASUREMENTS The interrater and intrarater reliability of the BESS  was determined using intraclass correlation coefficients ( ICC ) , reported with 95 % confidence intervals . The minimum detectible change was also determined . RESULTS The interrater and intrarater reliability ICCs for the total BESS scores were 0.57 and 0.74 , respectively . The interrater reliability ICCs for the 6 different stance positions were between 0.44 and 0.83 , while the intrarater reliability ICCs were between 0.50 and 0.88 . The interrater and intrarater minimum detectible change for the total BESS score were 9.4 and 7.3 points , respectively . CONCLUSION This study suggests that certain subcategories of the BESS have sufficient reliability to be used in the evaluation of postural stability but that the total BESS score is not reliable . In addition , a change in score of greater than 9.4 ( interrater ) or 7.3 ( intrarater ) points is required before the change in postural stability can be attributed to the balancer rather than to the scorer OBJECTIVES To determine the reliability and effects of a dual-task paradigm on  balance and cognitive function  compared to a single-task paradigm . DESIGN Repeated measures . METHODS Healthy participants ( n=23 ) completed a variation of the Sensory Organization Test and the incongruent Stroop test individually ( single-task ) and concurrently ( dual-task ) during two testing sessions . RESULTS The Sensory Organization Test and incongruent Stroop test had moderate to high reliability ( 1.00>ICC2,k>0.60 ) under the dual-task conditions . Reaction time was significantly longer ( t21=-2.54 , p=0.019 ) under the dual-task conditions , while balance scores under one of the four conditions of the Sensory Organization Test ( sway floor/fixed wall ) were statistically better ( t22=-3.03 , p=0.006 ) under the dual-task conditions . However , this difference in balance scores may not be clinical ly meaningful . CONCLUSIONS These findings illustrate that the Sensory Organization Test and incongruent Stroop task can be reliably incorporated into a dual-task assessment paradigm . The slowed reaction time under the dual-task paradigm indicates that the dual-task provided an additional cost to cognitive function . Dual-task concussion assessment paradigms involving these two tasks are psychometrically appropriate as well as more representative of actual sporting situations . However , more research should be conducted in a concussed population to further vali date this cl aim BACKGROUND The need to identify functional impairment following a brain injury is critical to prevent re-injury during the period of recovery . While many neuropsychological tests have been developed to assess cognitive performance , relatively little information on gait and dynamic stability is available on motor task performance for young adults following concussion . This study was performed to investigate the effect of divided attention following concussion on various gait variables . It was hypothesized that , when compared to uninjured controls , concussed subjects would demonstrate deficits in maintenance of dynamic stability . METHODS Ten subjects with Grade 2 concussion completed testing within 48 h of injury as well as 10 age- , height- , weight- , and activity-matched controls . The gait protocol consisted of level walking under two conditions : ( 1 ) undivided attention ( single-task ) and ( 2 ) while simultaneously completing simple mental tasks ( dual-task ) . Whole-body motion data were collected using a six-camera motion analysis system . A 13-segment biomechanical model was used to compute whole body center of mass motion and velocity . FINDINGS Walking with a concurrent cognitive task result ed in significant changes in gait and center of mass measurements for both groups . Concussed subjects were found to be able to conservatively adjust their whole body center of mass motion to maintain dynamic stability while walking without divided attention . However , while walking with divided attention , subjects with concussion demonstrated a significantly greater medio-lateral center of mass sway . INTERPRETATION These data suggest that the ability to control and maintain stability in the frontal plane during walking is diminished under divided attention in individuals following a concussion 
    Output:
    