Altered Integrated Locomotor and Cognitive Function in Elite Athletes 30 Days Postconcussion: A Preliminary Study

Relation Between Cognitive Assessment and Clinical Physical Performance Measures After Mild Traumatic Brain Injury

OBJECTIVES

To investigate the relation between cognitive and motor performance in individuals with mild traumatic brain injury (mTBI) and examine differences in both cognitive and motor performance between adults after mTBI and healthy controls.

DESIGN

Multi-center, cross-sectional study.

SETTING

Three institutional sites (Courage Kenny Research Center, Minneapolis, MN, Oregon Health & Science University, Portland, OR, and University of Utah, Salt Lake City, UT).

PARTICIPANTS

Data were collected from 110 participants (N=110), including those with mTBI and healthy controls, who completed cognitive and physical performance assessments.

INTERVENTIONS

Not applicable.

OUTCOME MEASURES

Cognitive assessments involved the Automated Neuropsychological Assessment Metrics to evaluate domains of attention, memory, reaction time, processing speed, and executive function. Physical performance was evaluated through clinical performance assessments, such as the 1-min walk test, the modified Illinois Agility Test, the Functional Gait Assessment Tool, the High-Level Mobility Assessment Tool, a complex turning course, and a 4-Item Hybrid Assessment of Mobility for mTBI. Participants also completed additional trials of the 1-min walk test, modified Illinois Agility Test, and complex turning course with a simultaneous cognitive task.

RESULTS

Individuals with mTBI performed worse on cognitive assessments, as well as several of the physical performance assessments compared with healthy controls. Complex tasks were more strongly related to cognitive assessments compared with simple walking tasks.

CONCLUSIONS

Combining complex motor tasks with cognitive demands may better demonstrate functional performance in individuals recovering from mTBI. By understanding the relation between cognitive and physical performance in individuals recovering from mTBI, clinicians may be able to improve clinical care and assist in return to activity decision-making.

Mechanical and Contractile Properties of Knee Joint Muscles after Sports-Related Concussions in Women Footballers

The purpose of this study was to determine if women footballers have an increased lack of neuromuscular control of the knee joint after a concussion compared to a healthy cohort tested with tensiomyography (TMG). Forty-one female collegiate footballers were enrolled in this study from which there were 20 with a history of sports-related concussions (SRCs) and 21 control subjects. Results from the SRC group had significantly higher Tc (ms) (z = -5.478, p = 0.000) and significantly lower Dm (mm) (z = -3.835, p = 0.000) than the control group in the case of the rectus femoris muscle. The SRC group had significantly higher Tc (ms) (z = -2.348, p = 0.016) and significantly lower Dm (mm) (z = -4.776, p = 0.000) than the control group in the case of the vastus medialis muscle. The SRC group had significantly higher Tc (ms) (z = -5.400, p = 0.000) and significantly lower Dm (mm) (z = -4.971, p = 0.000) than the control group in the case of the vastus lateralis muscle. The SRC group had significantly higher Tc (ms) (z = -5.349, p = 0.000) than the control group in the case of the biceps femoris muscle response, whereas no significant difference was found in Dm (mm) (z = -0.198, p = 0.853) between the groups. The results of the current study may have implications for current practice standards regarding the evaluation and management of concussions and can add valuable information for knee prevention programs as well.

The variability of dual-task walking parameters using in-shoe inertial sensors in nonconcussed individuals: A randomized within-subject repeated measures design

Background and Aims

There is a need for high utility and portability, and cost-effective technologies that are suitable for assessing dual-task gait after experiencing a concussion. Current technologies utilized such as 3D motion capture and force plates are too complex and expensive for most practitioners. The aim of this study was to quantify the variability of dual-task walking gait parameters using in-shoe inertial sensors in nonconcussed individuals.

Methods

This was a randomized within-subject repeated measures design conducted within a sports laboratory. Twenty healthy, uninjured, nonconcussed participants were recruited for this study. Gait variables of interest were measured across three 2-min continuous walking protocols (12 m, 30 m, 1 min out and back) while performing a cognitive task of counting backward in sevens from a randomly generated number between 300 and 500. Testing was completed over three occasions separated by 7 days, for a total of nine walking trials. Participants completed the testing protocols in a randomized, individual order. The primary outcome was to determine the variability of dual-task walking gait parameters using in-shoe inertial sensors in nonconcussed individuals across three protocols.

Results

Three to four participants were allocated to each randomized protocol order. Regarding the absolute consistency (coefficient of variation [CV]) between testing occasions, no gait measure was found to have variability above 6.5%. Relative consistency (intraclass correlation coefficient [ICC]) was acceptable (>0.70) in 95% of the variables of interest, with only three variables < 0.70. Similar variability was found across the three testing protocols.

Conclusion

In-shoe inertial sensors provide a viable option for monitoring gait parameters. This technology is also reliable across different testing distances, thus offering various testing options for practitioners. Further research needs to be conducted to examine the variability with concussed subjects.

Methodological Critique of Concussive and Non-Concussive Dual Task Walking Assessments: A Scoping Review

OBJECTIVE

To understand the methodological approaches taken by various research groups and determine the kinematic variables that could consistently and reliably differentiate between concussed and non-concussed individuals.

METHODS

MEDLINE via PubMed, CINAHL Complete via EBSCO, EBSCOhost, SPORTDiscus, and Scopus were searched from inception until 31 December 2021, using key terms related to concussion, mild traumatic brain injury, gait, cognition and dual task. Studies that reported spatiotemporal kinematic outcomes were included. Data were extracted using a customised spreadsheet, including detailed information on participant characteristics, assessment protocols, equipment used, and outcomes.

RESULTS

Twenty-three studies involving 1030 participants met the inclusion criteria. Ten outcome measures were reported across these articles. Some metrics such as gait velocity and stride length may be promising but are limited by the status of the current research; the majority of the reported variables were not sensitive enough across technologies to consistently differentiate between concussed and non-concussed individuals. Understanding variable sensitivity was made more difficult given the absence of any reporting of reliability of the protocols and variables in the respective studies.

CONCLUSION

Given the current status of the literature and the methodologies reviewed, there would seem little consensus on which gait parameters are best to determine return to play readiness after concussion. There is potential in this area for such technologies and protocols to be utilised as a tool for identifying and monitoring concussion; however, improving understanding of the variability and validity of technologies and protocols underpins the suggested directions of future research. Inertial measurement units appear to be the most promising technology in this aspect and should guide the focus of future research.

IMPACT

Results of this study may have an impact on what technology is chosen and may be utilised to assist with concussion diagnosis and return to play protocols.

The Use of Electroencephalography as an Informative Tool in Assisting Early Clinical Management after Sport-Related Concussion: a Systematic Review

Sport-related concussion (SRC) is managed primarily through serial clinical evaluations throughout recovery. However, studies suggest that clinical measures may not be suitable to detect subtle alterations in functioning and are limited by numerous internal and external factors. Electroencephalography (EEG) has been used for over eight decades to discern altered function following illnesses and injuries, including traumatic brain injury. This study evaluated the associations between EEG measures and clinical presentation within three-months following SRC. A systematic review of the literature was performed in Medline, Embase, PsycINFO, CINAHL and Web of Science databases following Preferred Reporting Items for Systematic Reviews and Meta Analyses guidelines, yielding a total of 13 peer-reviewed articles. Most studies showed low to moderate bias and moderate to high quality. The majority of the existing literature on the impact of concussion within the first 3 months post-injury suggests that individuals with concussion show altered brain function, with EEG abnormalities outlasting clinical dysfunction. Of all EEG biomarkers evaluated, P300 shows the most promise and should be explored further. Despite the relatively high quality of included articles, significant limitations are still present within this body of literature, including potential conflicts of interest and proprietary algorithms, making it difficult to draw strong and meaningful conclusions on the use of EEG in the early stages of SRC. Therefore, further exploration of the relationship between EEG measures and acute clinical presentation is warranted to determine if EEG provides additional benefits over current clinical assessments and is a feasible tool in clinical settings.

Multi-domain assessment of sports-related and military concussion recovery: A scoping review

OBJECTIVE

This review explores the literature on multi-domain assessments used in concussion recovery, to inform evidence-based and ecologically valid return-to-play. It asks: What simultaneous, dynamic multi-domain paradigms are used to assess recovery of youth and adults following concussion?

METHODS

Five databases were searched (CINAHL, EMBASE, MEDLINE, PsycInfo, SPORTDiscus) until September 30, 2021. Records were limited to those published in peer-reviewed journals, in English, between 2002 and 2021. Included studies were required to describe the assessment of concussion recovery using dynamic paradigms (i.e., requiring sport-like coordination) spanning multiple domains (i.e., physical, cognitive, socio-emotional functioning) simultaneously.

RESULTS

7098 unique articles were identified. 64 were included for analysis, describing 36 unique assessments of 1938 concussed participants. These assessments were deconstructed into their constituent tasks: 13 physical, 17 cognitive, and one socio-emotional. Combinations of these "building blocks" formed the multi-domain assessments. Forty-six studies implemented level walking with a concurrent cognitive task. The most frequently implemented cognitive tasks were 'Q&A' paradigms requiring participants to answer questions aloud during a physical task.

CONCLUSIONS

A preference emerged for dual-task assessments, specifically combinations of level walking and Q&A tasks. Future research should balance ecological validity and clinical feasibility in multi-domain assessments, and work to validate these assessments for practice.

R2Play development: Fostering user-driven technology that supports return-to-play decision-making following pediatric concussion

Objective

To design a multi-domain return-to-play assessment system (R2Play) for youth athletes with concussion.

Methods

The R2Play system was developed using an overarching user-centered approach, the Design Thinking Framework, and research activities included: 1) structured brainstorming within our research team, 2) interviews with clinician and youth sports coaches, 3) building a testable prototype, and 4) interface testing through cognitive walkthroughs with clinician partners.

Results

Clinician and coach participants provided feedback on the R2Play concept, which was integrated into the design process and provided future directions for research. Examples of feedback-driven design choices included reducing assessment time, increasing ecological validity by adding in background noise, and developing youth-friendly graphical results screens. Following refinement based on stakeholder feedback, the R2Play system was outlined in detail and a testable prototype was developed. It is made up of two parts: a clinician tablet, and a series of tablet "buttons" that display numbers and letters. Youth athletes run between the buttons to connect a "trail" in ascending alphanumeric order, 1-A-2-B, etc. Their performance across a series of levels of increasing difficulty is logged on the clinician tablet. Initial testing with five clinicians showed the system's interface to have excellent usability with a score of 81% (SD = 8.02) on the System Usability Scale.

Conclusion

Through this research, a prototype of the R2Play system was innovated and evaluated by clinician and coach stakeholders. Initial usability was excellent and directions for future iterations were highlighted. Outcomes suggest the potential benefits of using technologies to assist in complex clinical assessment, as well as utilizing a user-centered approach to design.

Dual-Task Gait Performance Following Head Impact Exposure in Male and Female Collegiate Rugby Players

Background

Gait impairments have been well-studied in concussed athletes. However, the sex-specific effect of cumulative head impacts on gait is not well understood. When a cognitive task is added to a walking task, dual-task gait assessments can help amplify deficits in gait and are representative of tasks in everyday life. Dual-task cost is the difference in performance from walking (single-task) to walking with a cognitive load (dual-task).

Purpose

The objectives of this study were to explore the differences between sexes in 1) dual-task gait metrics, 2) gait metric changes from pre-season to post-concussion and post-season, and 3) the dual-task costs associated with gait metrics.

Study Design

Cross-sectional study.

Methods

Over two seasons, 77 female athlete-seasons and 64 male athlete-seasons from collegiate club rugby teams participated in this study. Subjects wore inertial sensors and completed walking trials with and without a cognitive test at pre-season, post-season, and post-concussion (if applicable).

Results

Females athletes showed improvement in cadence (mean = 2.7 step/min increase), double support time (mean = -0.8% gait cycle time decrease), gait speed (mean = 0.1 m/s increase), and stride length (mean = 0.2 m increase) in both task conditions over the course of the season (p < 0.030). Male athletes showed no differences in gait metrics over the course of the season, except for faster gait speeds and longer stride lengths in the dual-task condition (p < 0.034). In all four gait characteristics, at baseline and post-season, females had higher dual-task costs (mean difference = 4.4, p < 0.003) than the males.

Conclusions

This results of this study showed little evidence suggesting a relationship between repetitive head impact exposure and gait deficits. However, there are sex-specific differences that should be considered during the diagnosis and management of sports-related concussion.

Level of Evidence

Level 2b.

Collision avoidance strategies between two athlete walkers: Understanding impaired avoidance behaviours in athletes with a previous concussion

BACKGROUND

Individuals who have sustained a concussion often display associated balance control deficits and visuomotor impairments despite being cleared by a physician to return to sport. Such visuomotor impairments can be highlighted in collision avoidance tasks that involves a mutual adaptation between two walkers. However, studies have yet to challenged athletes with a previous concussion during an everyday collision avoidance task, following return to sport.

RESEARCH QUESTION

Do athletes with a previous concussion display associated behavioural changes during a 90°-collision avoidance task with an approaching pedestrian?

METHODS

Thirteen athletes (ATH; 9 females, 23 ± 4years) and 13 athletes with a previous concussion (CONC; 9 females, 22 ± 3 years, concussion <6 months) walked at a comfortable walking speed along a 12.6 m pathway while avoiding another athlete on a 90º-collision course. Each participant randomly interacted with individuals from the same group 20 times and interacted with individuals from the opposite group 21 times. Minimum predicted distance (mpd) was used to examine collision avoidance behaviours between ATH and CONC groups.

RESULTS

The overall progression of mpd(t) did not differ between groups (p > .05). During the collision avoidance task, previously concussed athletes contributed less when passing second compared to their peers(p < .001). When two previously concussed athletes were on a collision course, there was a greater amount of variability resulting in inappropriate adaptive behaviours.

SIGNIFICANCE

Although successful at avoiding a collision with an approaching athlete, previously concussed athletes exhibit behavioural changes manifesting in riskier behaviours. The current findings suggest that previously concussed athletes possess behavioural changes even after being cleared to returned to sport, which may increase their risk of a subsequent injury when playing.

What Is the Evidence on Natural Recovery Over the Year Following Sports-Related and Non-sports-Related Mild Traumatic Brain Injury: A Scoping Review

Background: Treatment approaches often differ dependent upon whether a person experiences a sports-related or a non-sports-related mild traumatic brain injury. It remains unclear if recovery from these injuries is comparable or unique to context of the injury.

Objective: To identify knowledge gaps on self-reported outcomes and trajectories between sports- and non-sports-related mild traumatic brain injuries and how they are assessed in adults.

Methods: This scoping review used a systematic search of key electronic databases, including PubMed, SPORTDiscus, Embase, MEDLINE, and CINAHL for articles published in 1937 until March 10, 2021. Articles were included if they were available in English; full text published in a peer-reviewed journal; had a prospective or retrospective study design; reported data on mild TBI cases >16 years of age, and included data from at least two time points on self-reported outcomes within 12 months post-injury. A standardized data extraction spreadsheet was used to determine the participant characteristics, definitions, assessment methods, outcomes, and recovery time frames.

Results: Following removal of duplicates, the search strategy elicited 6,974 abstracts. Following abstract review, 174 were retained for full text review. Of the 42 articles that met inclusion criteria, 18 were sports related (15 in the USA and three in Canada) and 24 were general population studies (six in USA, three in Canada, three in Australasia, nine in Europe, two in Taiwan, and one in Morocco). Direct comparison in recovery trajectories between the sport and general population studies was difficult, given notable differences in methodology, definitions, types of outcome measures, and timing of follow-up assessments. Only one article reported on both sports-related and non-sports-related traumatic brain injuries separately at comparable timepoints. This study revealed no differences in recovery time frames or overall symptom burden.

Discussion: Whilst there is a clear benefit in researching specific subpopulations in detail, standardized outcome measures and follow-up time frames are needed across contexts to facilitate understanding of similarities and differences between sports- and non-sports-related mild traumatic brain injuries to inform clinical treatment.

Dynamic Visual Stimulations Produced in a Controlled Virtual Reality Environment Reveals Long-Lasting Postural Deficits in Children With Mild Traumatic Brain Injury

Motor control deficits outlasting self-reported symptoms are often reported following mild traumatic brain injury (mTBI). The exact duration and nature of these deficits remains unknown. The current study aimed to compare postural responses to static or dynamic virtual visual inputs and during standard clinical tests of balance in 38 children between 9 and 18 years-of-age, at 2 weeks, 3 and 12 months post-concussion. Body sway amplitude (BSA) and postural instability (vRMS) were measured in a 3D virtual reality (VR) tunnel (i.e., optic flow) moving in the antero-posterior direction in different conditions. Measures derived from standard clinical balance evaluations (BOT-2, Timed tasks) and post-concussion symptoms (PCSS-R) were also assessed. Results were compared to those of 38 healthy non-injured children following a similar testing schedule and matched according to age, gender, and premorbid level of physical activity. Results highlighted greater postural response with BSA and vRMS measures at 3 months post-mTBI, but not at 12 months when compared to controls, whereas no differences were observed in post-concussion symptoms between mTBI and controls at 3 and 12 months. These deficits were specifically identified using measures of postural response in reaction to 3D dynamic visual inputs in the VR paradigm, while items from the BOT-2 and the 3 timed tasks did not reveal deficits at any of the test sessions. PCSS-R scores correlated between sessions and with the most challenging condition of the BOT-2 and as well as with the timed tasks, but not with BSA and vRMS. Scores obtained in the most challenging conditions of clinical balance tests also correlated weakly with BSA and vRMS measures in the dynamic conditions. These preliminary findings suggest that using 3D dynamic visual inputs such as optic flow in a controlled VR environment could help detect subtle postural impairments and inspire the development of clinical tools to guide rehabilitation and return to play recommendations.

Static and Dynamic Cognitive Performance in Youth and Collegiate Athletes With Concussion

OBJECTIVE

To determine if individuals with a concussion demonstrate altered cognitive performance while standing still or while walking relative to uninjured controls.

DESIGN

Cross-sectional.

SETTING

Sports-medicine clinic.

PARTICIPANTS

Youth and collegiate athletes diagnosed with a concussion, assessed within 10 days of injury, and a group of uninjured control subjects.

INDEPENDENT VARIABLES

Concussion and control groups.

MAIN OUTCOME MEASURES

Participants stood still for 30 seconds while completing a cognitive task (spelling words backward, serial subtraction, or reverse month recitation) and completed a similar set of cognitive tasks while walking. Our primary outcome variables were (1) overall cognitive task performance (accuracy) and (2) the total number of task items completed during testing (completion rate) during standing and walking conditions.

RESULTS

One hundred ninety-one participants completed the study: 94 with concussion (tested mean = 5.1 ± 2.9 days postconcussion; 51% female; mean age = 17.1 ± 3.3 years) and 97 control subjects (40% female; mean age = 17.5 ± 2.1 years). The concussion group completed significantly fewer responses than the control group while standing still (37.3 ± 14.5 vs 45.1 ± 17.6 responses; P = 0.03) and while walking (22.7 ± 7.5 vs 33.6 ± 13.4 responses; P < 0.001). They were also significantly less accurate at spelling words backward (81.2 ± 28.6% correct vs 89.8 ± 15.0% correct; P = 0.049) and reciting months in reverse order (95.8 ± 10.4% correct vs 98.2 ± 4.2% correct; P = 0.034) while walking.

CONCLUSIONS

Athletes displayed lower cognitive task accuracy rates after concussion compared with control subjects during backward spelling and reverse month recitation tasks while walking but similar levels of accuracy while standing. Assessment of cognitive performance during dynamic tasks may be a clinically viable method to evaluate post-concussion deficits.

Does Concussion Affect Perception-Action Coupling Behavior? Action Boundary Perception as a Biomarker for Concussion

BACKGROUND

After a concussion, athletes may be at increased risk of musculoskeletal injuries. Altered perception of action boundaries (ABP), or the limits of one's action capabilities, is one possible mechanism for this increase in injury risk after concussion.

OBJECTIVE

To evaluate differences in symptoms, neurocognitive, vestibular/oculomotor, and action boundary function between subjects with no concussion history (NoHx) and concussion history (ConcHX).

DESIGN

Cross-sectional study.

SETTING

Laboratory at the University of Pittsburgh.

PARTICIPANTS

ConcHx (n = 22; age: 21.8 ± 3.0 years, height: 174.0 ± 8.3 cm, and mass: 77.8 ± 14.8 kg) and NoHx athletes (n = 24; age: 21.6 ± 2.0 years, height: 176.0 ± 10.0 cm, and mass: 72.0 ± 15.3 kg).

INTERVENTION

Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) and Post-Concussion Symptom Scale (PCSS), Vestibular-Ocular Motor Screening (VOMS) tool, and the Perception-Action Coupling Task (PACT). The PACT measures the accuracy of ABP.

MAIN OUTCOME MEASURES

Neurocognitive domain scores, PCSS, VOMS subdomain symptom gain, ABP accuracy, and actualization.

RESULTS

ConcHx reported 2.7 ± 1.5 previous concussions occurring on average 263.8 ± 228.9 days prior. ConcHx was higher on several VOMS items including vertical/horizontal saccades (P = 0.001; P = 0.05), vertical/horizontal vestibular-ocular reflex (P < 0.001; P = 0.04), and visual motion sensitivity (P < 0.001). Average PACT movement time (P = 0.01) and reaction time (P = 0.01) were longer in ConcHx.

CONCLUSIONS

These findings provide preliminary support for impaired vestibular/oculomotor function and ABP in ConcHx compared with NoHx. The current results may enhance our understanding of the mechanisms for increased musculoskeletal injury risk after concussion.

Objective Dual-Task Turning Measures for Return-to-Duty Assessment After Mild Traumatic Brain Injury: The ReTURN Study Protocol

Determining readiness for duty after mild traumatic brain injury (mTBI) is essential for the safety of service members and their unit. Currently, these decisions are primarily based on self-reported symptoms, objective measures that assess a single system, or standardized physical or cognitive tests that may be insensitive or lack ecological validity for warrior tasks. While significant technological advancements have been made in a variety of assessments of these individual systems, assessments of isolated tasks are neither diagnostically accurate nor representative of the demands imposed by daily life and military activities. Emerging evidence suggests that complex tasks, such as dual-task paradigms or turning, have utility in probing functional deficits after mTBI. Objective measures from turning tasks in single- or dual-task conditions, therefore, may be highly valuable for clinical assessments and return-to-duty decisions after mTBI. The goals of this study are to assess the diagnostic accuracy, predictive capacity, and responsiveness to rehabilitation of objective, dual-task turning measures within an mTBI population. These goals will be accomplished over two phases. Phase 1 will enroll civilians at three sites and active-duty service members at one site to examine the diagnostic accuracy and predictive capacity of dual-task turning outcomes. Phase 1 participants will complete a series of turning tasks while wearing inertial sensors and a battery of clinical questionnaires, neurocognitive testing, and standard clinical assessments of function. Phase 2 will enroll active-duty service members referred for rehabilitation from two military medical treatment facilities to investigate the responsiveness to rehabilitation of objective dual-task turning measures. Phase 2 participants will complete two assessments of turning while wearing inertial sensors: a baseline assessment prior to the first rehabilitation session and a post-rehabilitation assessment after the physical therapist determines the participant has completed his/her rehabilitation course. A variable selection procedure will then be implemented to determine the best task and outcome measure for return-to-duty decisions based on diagnostic accuracy, predictive capacity, and responsiveness to rehabilitation. Overall, the results of this study will provide guidance and potential new tools for clinical decisions in individuals with mTBI.

Clinical Trial Registration: clinicaltrials.gov, Identifier NCT03892291.

Using functional movement tests to investigate the presence of sensorimotor impairment in amateur athletes following sport-related concussion: A prospective, longitudinal study

OBJECTIVE

To longitudinally investigate the presence of sensorimotor impairments in amateur athletes following sport-related concussion using two functional movement tests.

DESIGN

Prospective, longitudinal study.

SETTING

Human movement analysis laboratory.

PARTICIPANTS

Athletes who presented to a hospital emergency department and were diagnosed with sport-related concussion, and sex-, age-, and activity-matched non-concussed, control athletes. Concussed participants were assessed within one-week following sport-related concussion, upon clearance to return-to-sporting activity (RTA), and two weeks after RTA. Control participants were assessed at an initial time-point and approximately two and four weeks following their initial study assessment.

MAIN OUTCOMES MEASURES

At each laboratory assessment, participants completed two functional movement tests: the Star Excursion Balance Test to evaluate anterior reach distance (normalised for leg length) and fractal dimension (centre of pressure path complexity), and the Multiple Hop Test to evaluate corrective postural strategies and time-to-stabilisation.

RESULTS

Fifty concussed athletes and 50 control athletes completed the study. There were no significant differences at any study assessment between the concussion and control group on the Star Excursion Balance Test anterior reach distance or fractal dimension (centre of pressure path complexity). During the Multiple Hop Test, the concussion group used a significantly greater number of corrective postural strategies than the control group one-week following sport-related concussion and upon clearance to RTA, but not two weeks following RTA.

CONCLUSION

Recently concussed athletes made a greater number of corrective postural strategies than control participants during the Multiple Hop Test upon clearance to RTA but not two weeks after RTA. The Multiple Hop Test may offer a clinically useful tool for practitioners to examine the recovery of subtle sensorimotor impairments and related RTA readiness.

Turn Characteristics During Gait Differ With and Without a Cognitive Demand Among College Athletes

CONTEXT

Sports often involve complex movement patterns, such as turning. Although cognitive load effects on gait patterns are well known, little is known on how it affects biomechanics of turning gait among athletes. Such information could help evaluate how concussion affects turning gait required for daily living and sports.

OBJECTIVE

To determine the effect of a dual task on biomechanics of turning while walking among college athletes.

DESIGN

Cross-sectional study.

SETTING

University laboratory.

PARTICIPANTS

Fifty-three participants performed 5 trials of a 20-m walk under single- and dual-task conditions at self-selected speed with a 180° turn at 10-m mark. The cognitive load included subtraction, spelling words backward, or reciting the months backward.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Turn duration, turning velocity, number of steps, SD of turn duration and velocity, and coefficient of variation of turn duration and velocity.

RESULTS

Participants turned significantly slower (155.99 [3.71] cm/s vs 183.52 [4.17] cm/s; P < .001) and took longer time to complete the turn (2.63 [0.05] s vs 2.33 [0.04] s; P < .001) while dual tasking, albeit taking similar number of steps to complete the turn. Participants also showed more variability in turning time under the dual-task condition (SD of turn duration = 0.39 vs 0.31 s; P = .004).

CONCLUSIONS

Overall, college athletes turned slower and showed more variability during turning gait while performing a concurrent cognitive dual-task turning compared with single-task turning. The slower velocity increased variability may be representative of specific strategy of turning gait while dual tasking, which may be a result of the split attention to perform the cognitive task. The current study provides descriptive values of absolute and variability turning gait parameters for sports medicine personnel to use while they perform their concussion assessments on their college athletes.

Considerations for Diagnosis and Management of Concussion

Concussion is an ongoing concern for health care providers. The incidence rates continue to be high and the rate of recovery is variable due to potential risk factors. With no valid biomarkers, diagnosis and assessment of concussion remain a clinical challenge. The heterogeneity in presentation following injury provides an additional level of complexity, requiring the screening and evaluation of diverse body systems, including oculomotor, vestibular, autonomic, psychiatric, cervical, and cognitive symptoms. While a few tools, such as the Vestibular/Ocular Motor Screening and Balance Error Scoring System, have been developed specifically for concussion, the vast majority of tests are adapted from other conditions. Further complicating the process is the overlapping and interactive nature of the multiple domains of postconcussion presentation. This commentary illustrates how clinicians can conceptualize the multiple profiles that present following concussion and describes tools that are available to assist with screening and evaluation of each area. The multifaceted nature of concussion warrants broad clinical screening skills and an interdisciplinary approach to management. J Orthop Sports Phys Ther 2019;49(11):787-798. doi:10.2519/jospt.2019.8855.

Oculomotor Executive Dysfunction during the Early and Later Stages of Sport-Related Concussion Recovery

Executive dysfunction represents the most persistent sequela of mild traumatic brain injury. It is, however, largely unclear whether a sport-related concussion similarly contributes to a persistent executive dysfunction even when an athlete has been cleared medically for return to play. Here, individuals with a diagnosis of a sport-related concussion-and their age- and sex-matched controls-completed an oculomotor assessment during the acute and later stages of injury recovery. Prosaccades (i.e., saccade to a target) and executive-related antisaccades (i.e., saccade mirror-symmetrical to a target) were completed: (1) 2-6 days after a concussive event (initial assessment), and (2) 14-20 days after the initial oculomotor assessment when individuals were cleared for return to play (follow-up assessment). At the initial assessment, the concussed group produced antisaccade reaction times (RT) that were 93 ms longer than the control group (p < 0.001), whereas prosaccade RTs did not differ between groups (p = 0.25). At the follow-up assessment, concussed and control groups produced comparable pro- and antisaccade RTs (ps >0.31); however, the former group exhibited a continued increase in directional errors (p < 0.05). That initial assessment antisaccades-but not prosaccades-differed between groups indicates that the acute recovery of a concussion is associated with a selective executive-related oculomotor deficit, and the continued increase in directional errors at the follow-up assessment suggests that such a deficit persists even when an athlete has been cleared medically for return to play. The antisaccade task may therefore serve to assess subtle executive deficits and determine when an athlete may return to play safely.

Is There an Optimal Time to Initiate an Active Rehabilitation Protocol for Concussion Management in Children? A Case Series

OBJECTIVE

To estimate the time frame during which initiating an active rehabilitation intervention (aerobic exercise, balance, and sport specific skills) after concussion contributed to improvement in symptoms at follow-up in children and adolescents who are slow to recover (symptoms persisting beyond 2 weeks) from concussion.

SETTING

Concussion clinic at a tertiary care pediatric teaching hospital.

PARTICIPANTS

A total of 677 children and adolescents with concussion aged 7 to 18 years.

DESIGN

Case series of participants starting active rehabilitation less than 2, 2, 3, 4, 5, or 6 or more weeks postconcussion.

MAIN MEASURE

Symptom severity measured by the 22-item Post-Concussion Scale (PCS)-revised.

RESULTS

All patients experienced significant improvement of symptoms while participating in active rehabilitation, irrespective of the start time postonset. Patients initiating active rehabilitation at 2 (P < .001) or 3 (P = .039) weeks postinjury demonstrated lower symptom severity at follow-up than those starting at 6 weeks or later. Patients starting at 2 weeks had lower symptom severity than patients starting less than 2 (P = .02), 4 (P = .20), or 5 weeks postinjury (P = .04). Lastly, patients starting less than 2 and 6 weeks or more postinjury yielded equivalent outcomes.

CONCLUSIONS

The findings support the use of active rehabilitation in children and adolescents who are slow to recover from concussion. Participants starting active rehabilitation less than 2 weeks and up to 6 or more weeks postconcussion demonstrated significant symptom improvements, but improvement was observed in all groups, regardless of the time to start active rehabilitation.

Concussed athletes walk slower than non-concussed athletes during cognitive-motor dual-task assessments but not during single-task assessments 2 months after sports concussion: a systematic review and meta-analysis using individual participant data

Objectives

To determine whether individuals who sustained a sports concussion would exhibit persistent impairments in gait and quiet standing compared to non-injured controls during a dual-task assessment .

Design

Systematic review and meta-analysis using individual participant data (IPD).

Data sources

The search strategy was applied across seven electronic bibliographic and grey literature databases: MEDLINE, EMBASE, CINAHL, SportDISCUS, PsycINFO, PsycARTICLES and Web of Science, from database inception until June 2017.

Eligibility criteria for study selection

Studies were included if; individuals with a sports concussion and non-injured controls were included as participants; a steady-state walking or static postural balance task was used as the primary motor task; dual-task performance was assessed with the addition of a secondary cognitive task; spatiotemporal, kinematic or kinetic outcome variables were reported, and; included studies comprised an observational study design with case–control matching.

Data extraction and synthesis

Our review is reported in line with the Preferred Reporting Items for Systematic review and Meta-Analyses-IPD Statement. We implemented the Risk of Bias Assessment tool for Non-randomised Studies to undertake an outcome-level risk of bias assessment using a domain-based tool. Study-level data were synthesised in one of three tiers depending on the availability and quality of data: (1) homogeneous IPD; (2) heterogeneous IPD and (3) aggregate data for inclusion in a descriptive synthesis. IPD were aggregated using a ‘one-stage’, random-effects model.

Results

26 studies were included. IPD were available for 20 included studies. Consistently high and unclear risk of bias was identified for selection, detection, attrition, and reporting biases across studies. Individuals with a recent sports concussion walked with slower average walking speed (χ2=51.7; df=4; p<0.001; mean difference=0.06 m/s; 95% CI: 0.004 to 0.11) and greater frontal plane centre of mass displacement (χ2=10.3; df=4; p=0.036; mean difference −0.0039 m; 95% CI: −0.0075 to −0.0004) than controls when evaluated using a dual-task assessment up to 2 months following concussion.

Summary/conclusions

Our IPD evidence synthesis identifies that, when evaluated using a dual-task assessment, individuals who had incurred a sports concussion exhibited impairments in gait that persisted beyond reported standard clinical recovery timelines of 7–10 days. Dual-task assessment (with motion capture) may be a useful clinical assessment to evaluate recovery after sports concussion.

Protocol pre-registration

This systematic review was prospectively registered in PROSPERO CRD42017064861.

Balance and Gait Alterations Observed More Than 2 Weeks After Concussion: A Systematic Review and Meta-Analysis

OBJECTIVE

The aim of the study was to systematically review and quantitatively synthesize the existing evidence of balance and gait alterations lasting more than 2 wks after concussion in adults.

DESIGN

A systematic review was conducted through PubMed, CINAHL, SPORTDiscus, and Web of Science. Investigations must include adult participants with at least one concussion, were measured for 14 days after injury, and reported balance or gait measures. Balance error scoring system scores, center of pressure sway area and displacement, and gait velocity were extracted for the meta-analysis.

RESULTS

Twenty-two studies were included. Balance alterations were observed for 2 wks after concussion when participants were tested with eyes closed, for longer durations of time, and with nonlinear regulatory statistics. The meta-analysis of center of pressure sway area with no visual feedback indicated that concussed individuals had greater sway area (P < 0.001). Various gait alterations were also observed, which may indicate that concussed individuals adopt a conservative gait strategy. The meta-analysis revealed that concussed participants walked 0.12 m/sec (P < 0.001) and 0.06 m/sec (P = 0.023) slower in single and dual-task conditions, respectively.

CONCLUSIONS

Subtle balance and gait alterations were observed after 2 wks after a concussion. Understanding these alterations may allow clinicians to improve concussion diagnosis and prevent subsequent injury.

Single and dual tandem gait assessment post concussion: What performance time is clinically relevant across adult ages and what can influence results?

AIM

The three-metre tandem gait test (TG) is used to assess postural control during locomotion following sports concussion. However, values used to determine a pass/fail result are currently based on young athletic populations. Times for test completion may be influenced by several intrinsic or extrinsic factors. The aim of this study was to collate healthy individual single, dual task as well as dual task cost - motor TG times for a non-elite athlete population, across several age groups, and to investigate several potential influencing factors.

METHODS

Healthy individuals aged 18-55+, who had never experienced a concussion completed single and dual task TG following the SCAT5 protocol. A separate group (n = 20, age, foot length and body mass index matched) performed the tests with alternate instructions.

RESULTS

Mean best TG time for all participants were: single task 21.03 (±5.26s), dual task 29.59 (±9.84s) and DTC-motor 8.57 (±7.5s:41.7%). Age and foot length but not specificity of verbal instructions were related to TG times. Significantly slower single and dual task times were identified for the 55 + age group when compared to the three youngest groups (p < 0.01). No difference was seen for DTC-motor time or % between age groups (p > 0.05).

CONCLUSION

Healthy individual data collected exceeded previously reported average times. Faster times were evident in younger participants and those with longer foot length. Results from this study can be used as a reliable guideline to inform clinical decisions around the pass/fail result of TGT across age ranges in non-elite athlete populations post-concussion.

Effects of Recent Concussion and Injury History on Instantaneous Relative Risk of Lower Extremity Injury in Division I Collegiate Athletes

BACKGROUND

Growing evidence suggests that concussion increases the risk of lower extremity (LE) musculoskeletal injury. However, it is unclear to how the effect of concussion on LE injury risk may be influenced by previous injuries. This study sought to examine the association between concussion, previous LE injuries, and the risk LE injury to the same previously injured limb (ipsilateral) or the opposite limb (contralateral).

METHODS

This retrospective study examined medical records from 110 concussed athletes and 110 matched controls for LE injuries in the 365 days before and after the concussion event. The effect of concussion on time to injury was assessed with a Cox proportional hazard model after adjusting for injury history. Fine and Gray subdistribution models assessed the cumulative risk of ipsilateral and contralateral injury by group.

RESULTS

Concussion was associated with an increased instantaneous relative risk of LE injury when adjusting for LE injury history [hazard ratio (HR) = 1.67, 95% confidence interval (CI) = 1.11-2.53], agreeing with previous results. Among individuals who had a history of LE injuries before the concussion event, a nonsignificant yet moderate effect of concussion on the instantaneous relative risk of ipsilateral injuries was found after adjusting for the competing risk of contralateral injuries and censored values (HR = 1.85, 95% CI = 0.76-4.46).

CONCLUSIONS

This study provides independent confirmation of previous studies, reporting an association between concussion and LE injury risk. Furthermore, this study suggests that future large-scale studies should consider the competing risk of ipsilateral, contralateral, and new injuries in populations with an injury history.

Three-dimensional multiple object tracking in the pediatric population: the NeuroTracker and its promising role in the management of mild traumatic brain injury

As mild traumatic brain injury (mTBI) affects hundreds of thousands of children and their families each year, investigation of potential mTBI assessments and treatments is an important research target. Three-dimensional multiple object tracking (3D-MOT), where an individual must allocate attention to moving objects within 3D space, is one potentially promising assessment and treatment tool. To date, no research has looked at 3D-MOT in a pediatric mTBI population. Thus, the aim of this study was to examine 3D-MOT learning in children and youth with and without mTBI. Thirty-four participants (mean age=14.69±2.46 years), with and without mTBI, underwent six visits of 3D-MOT. A two-way repeated-measures analysis of variance (ANOVA) showed a significant time effect, a nonsignificant group effect, and a nonsignificant group-by-time interaction on absolute speed thresholds. In contrast, significant group and time effects and a significant group-by-time interaction on normalized speed thresholds were found. Individuals with mTBI showed smaller training gains at visit 2 than healthy controls, but the groups did not differ on the remaining visits. Although youth can significantly improve their 3D-MOT performance following mTBI, similar to noninjured individuals, they show slower speed of processing in the first few training sessions. This preliminary work suggests that using a 3D-MOT paradigm to train visual perception after mTBI may be beneficial for both stimulating recovery and informing return to activity decisions.

Shared Neuromuscular Performance Traits in Military Personnel with Prior Concussion

Concussions are common in military personnel and may result in increased risk of musculoskeletal injury. One plausible explanation for this risk could be that neuromotor deficiencies enhance injury risk after a concussion through altered muscular activation/contraction timing.

PURPOSE

To compare military personnel with at least one concussion during the past 1 month to 2 yr (CONCUSSED) to military branch-matched, age-matched, and Special Operations Forces group-matched controls (CONTROL) on physiological, musculoskeletal, and biomechanical performance.

METHODS

A total of 48 (24 CONCUSSED, 24 CONTROL) male Air Force and Naval Special Warfare Operators age 19 to 34 yr participated in the study. Participants self-reported demographics/injury history and completed the following assessments: 1) physiological-body composition, anaerobic power and capacity, aerobic capacity and lactate threshold; 2) musculoskeletal-lower extremity isokinetic strength testing, including time to peak torque; and 3) biomechanical-single-leg jump and landing task, including landing kinematics of the hip, knee and ankle. A machine learning decision tree algorithm (C5.0) and one-way ANOVA were used to compare the two groups on these outcomes.

RESULTS

Despite nonsignificant differences using ANOVA, the C5.0 algorithm revealed CONCUSSED demonstrated quicker time to peak knee flexion angle during the single-leg landing task (≤0.170 s; CONCUSSED: n = 22 vs CONTROL: n = 14), longer time to peak torque in knee extension isokinetic strength testing (>500 ms; CONCUSSED: n = 18 vs CONTROL: n = 4) and larger knee flexion angle at initial contact (>7.7°; CONCUSSED: n = 18 vs CONTROL: n = 2).

CONCLUSION

The findings supported the hypothesis that CONCUSSED military personnel would demonstrate altered neuromuscular control in landing strategies and muscular activation. Future research should assess prospectively neuromuscular changes after a concussion and determine if these changes increase risk of subsequent musculoskeletal injuries.

Alterations in dual-task walking persist two months after mild traumatic brain injury in young adults

Objectives

To compare dual-task performance involving different cognitive-locomotor combinations between healthy controls and participants with sub-acute mild traumatic brain injury (mTBI) and to correlate dual-task performances to history of prior head injuries.

Methods

Eighteen participants having recently sustained mTBI and 15 controls performed nine dual-tasks combining locomotor (level-walking, narrow obstacle, deep obstacle) and cognitive (Stroop task, Verbal fluency, Counting backwards) tasks. Previous history of concussion was also investigated.

Results

Slower gait speeds were observed in the mTBI group compared to controls during both single and dual-tasks. Longer response times to cognitive tasks in the mTBI group further suggested the presence of residual impairments two months following injury. No combination of dual-task was more sensitive. Correlations were observed between history of mTBI and several measures of dual-task performance, underlying the need to further consider the effects of multiple injuries in relation to dual-task walking.

Conclusion

Dual-tasks using simultaneously locomotor and cognitive functions represent an ecological way for clinicians to detect residual, but subtle, alterations post-mTBI. History of previous mTBI needs to be considered as a personal characteristic which may influence dual-task walking performance.

Neuromuscular Control Deficits and the Risk of Subsequent Injury after a Concussion: A Scoping Review

An emerging area of research has identified that an increased risk of musculoskeletal injury may exist upon returning to sports after a sport-related concussion. The mechanisms underlying this recently discovered phenomenon, however, remain unknown. One theorized reason for this increased injury risk includes residual neuromuscular control deficits that remain impaired despite clinical recovery. Thus, the objectives of this review were: (1) to summarize the literature examining the relationship between concussion and risk of subsequent injury and (2) to summarize the literature for one mechanism with a theorized association with this increased injury risk, i.e., neuromuscular control deficits observed during gait after concussion under dual-task conditions. Two separate reviews were conducted consistent with both specified objectives. Studies published before 9 December, 2016 were identified using PubMed, Web of Science, and Academic Search Premier (EBSCOhost). Inclusion for the objective 1 search included dependent variables of quantitative measurements of musculoskeletal injury after concussion. Inclusion criteria for the objective 2 search included dependent variables pertaining to gait, dynamic balance control, and dual-task function. A total of 32 studies were included in the two reviews (objective 1 n = 10, objective 2 n = 22). According to a variety of study designs, athletes appear to have an increased risk of sustaining a musculoskeletal injury following a concussion. Furthermore, dual-task neuromuscular control deficits may continue to exist after patients report resolution of concussion symptoms, or perform normally on other clinical concussion tests. Therefore, musculoskeletal injury risk appears to increase following a concussion and persistent motor system and attentional deficits also seem to exist after a concussion. While not yet experimentally tested, these motor system and attentional deficits may contribute to the risk of sustaining a musculoskeletal injury upon returning to full athletic participation.

Driving after brain injury: Does dual-task modality matter?

BACKGROUND

Virtual reality technology allows neuropsychologists to examine complex, real-world behaviors with high ecological validity and can provide an understanding of the impact of demanding dual-tasks on driving performance.

OBJECTIVE

We hypothesized that a task imposing high cognitive and physical demands (coin-sorting) would result in the greatest reduction in driving maintenance performance.

METHODS

Twenty participants with acquired brain injury and 28 healthy controls were included in the current study. All participants were licensed and drove regularly. Participants completed two standardized VRDS drives: (1) a baseline drive with no distractions, and (2) the same route with three, counterbalanced dual-tasks representing differing demands.

RESULTS

A series of 3 (Task)×2 (Group) ANOVAs revealed that the ABI group tended to go slower than the HC group in the presence of a dual-task, F (1, 111) = 6.24, p = 0.01. Importantly, the ABI group also showed greater variability in speed, F (1, 110) = 10.97, p < 0.01, and lane position, F (1, 108) = 7.81, p < 0.01, an effect driven by dual-tasks with both a cognitive and motor demand.

CONCLUSIONS

These results indicate that long-term driving difficulties following ABI are subtle and likely due to reduced cognitive resources.

Concussion May Increase the Risk of Subsequent Lower Extremity Musculoskeletal Injury in Collegiate Athletes

BACKGROUND

Laboratory-based studies on neuromuscular control after concussion and epidemiological studies suggest that concussion may increase the risk of subsequent musculoskeletal injury.

OBJECTIVE

The purpose of this study was to determine if athletes have an increased risk of lower extremity musculoskeletal injury after return to play from a concussion.

METHODS

Injury data were collected from 2006 to 2013 for men's football and for women's basketball, soccer and lacrosse at a National Collegiate Athletic Association Division I university. Ninety cases of in-season concussion in 73 athletes (52 male, 21 female) with return to play at least 30 days prior to the end of the season were identified. A period of up to 90 days of in-season competition following return to play was reviewed for time-loss injury. The same period was studied in up to two control athletes who had no concussion within the prior year and were matched for sport, starting status and position.

RESULTS

Lower extremity musculoskeletal injuries occurred at a higher rate in the concussed athletes (45/90 or 50 %) than in the non-concussed athletes (30/148 or 20 %; P < 0.01). The odds of sustaining a musculoskeletal injury were 3.39 times higher in the concussed athletes (95 % confidence interval 1.90-6.05; P < 0.01). Overall, the number of days lost because of injury was similar between concussed and non-concussed athletes (median 9 versus 15; P = 0.41).

CONCLUSIONS

The results of this study demonstrate a relationship between concussion and an increased risk of lower extremity musculoskeletal injury after return to play, and may have implications for current medical practice standards regarding evaluation and management of concussion injuries.

Detecting gait abnormalities after concussion or mild traumatic brain injury: A systematic review of single-task, dual-task, and complex gait

BACKGROUND

While a growing number of studies have investigated the effects of concussion or mild traumatic brain injury (mTBI) on gait, many studies use different experimental paradigms and outcome measures. The path for translating experimental studies for objective clinical assessments of gait is unclear.

RESEARCH QUESTION

This review asked 2 questions: 1) is gait abnormal after concussion/mTBI, and 2) what gait paradigms (single-task, dual-task, complex gait) detect abnormalities after concussion.

METHODS

Data sources included MEDLINE/PubMed, Scopus, Web of Science, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) accessed on March 14, 2017. Original research articles reporting gait outcomes in people with concussion or mTBI were included. Studies of moderate, severe, or unspecified TBI, and studies without a comparator were excluded.

RESULTS

After screening 233 articles, 38 studies were included and assigned to one or more sections based on the protocol and reported outcomes. Twenty-six articles reported single-task simple gait outcomes, 24 reported dual-task simple gait outcomes, 21 reported single-task complex gait outcomes, and 10 reported dual-task complex gait outcomes.

SIGNIFICANCE

Overall, this review provides evidence for two conclusions: 1) gait is abnormal acutely after concussion/mTBI but generally resolves over time; and 2) the inconsistency of findings, small sample sizes, and small number of studies examining homogenous measures at the same time-period post-concussion highlight the need for replication across independent populations and investigators. Future research should concentrate on dual-task and complex gait tasks, as they showed promise for detecting abnormal locomotor function outside of the acute timeframe. Additionally, studies should provide detailed demographic and clinical characteristics to enable more refined comparisons across studies.

Return to Physical Activity Timing and Dual-Task Gait Stability Are Associated 2 Months Following Concussion

OBJECTIVE

The effect of physical activity resumption on functional recovery following concussion is poorly understood. We sought to examine the relationship between physical activity resumption timing and gait stability 2 months following concussion.

SETTING

Motion analysis laboratory.

PARTICIPANTS

Twenty-nine individuals who sustained a concussion and were subsequently allowed to return to preinjury levels of physical activity within 2 months postinjury.

DESIGN

Prospective cohort study.

MAIN MEASURES

The return-to-activity day (RTA-day) was identified as the first day postinjury that each participant was medically cleared to resume regular physical activity. Whole-body center-of-mass (COM) motion during single-task and dual-task walking was assessed 2 months postinjury. Correlation coefficients were calculated between the RTA-day and single/dual-task gait stability as well as symptom severity measurements 2 months postinjury.

RESULTS

Dual-task medial-lateral COM displacement (r = -0.52, P = .004) and peak medial-lateral COM velocity (r = -0.37, P = .048) were significantly correlated with RTA-day. Dual-task peak forward velocity and single-task gait stability measures were not significantly correlated with RTA-day.

CONCLUSIONS

The time of RTA-day clearance, within a 2 months postinjury period, is significantly correlated with dual-task medial-lateral gait stability measured at the end of that period, suggesting that frontal plane gait stability recovery is sensitive to the timing of RTA-day.

Using concurrent gait and cognitive assessments to identify impairments after concussion: a narrative review

Understanding how a concussion affects an individual is oftentimes difficult for clinicians due to the varying symptom profiles reported by the patient and the multifaceted and heterogeneous nature of the injury. Accordingly, the interpretation of postconcussion performance can be challenging, because many different testing paradigms have been reported as potentially useful in the literature. Among the types of tests clinicians use to understand how concussion affects an individual, both gait and neurocognitive evaluations have demonstrated utility. Our purpose is to describe how combined gait and cognitive (i.e., dual task), as well as single-task gait and computerized neurocognitive examinations can assist clinical decision-making.

Detection of Acute and Long-Term Effects of Concussion: Dual-Task Gait Balance Control Versus Computerized Neurocognitive Test

OBJECTIVE

To examine the acute (within 72h of injury) and long-term (2mo postinjury) independent associations between objective dual-task gait balance and neurocognitive measurements among adolescents and young adults with a concussion and matched controls.

DESIGN

Longitudinal case-control.

SETTING

Motion analysis laboratory.

PARTICIPANTS

A total of 95 participants completed the study: 51 who sustained a concussion (mean age, 17.5±3.3y; 71% men) and 44 controls (mean age, 17.7±2.9y; 72% men). Participants who sustained a concussion underwent a dual-task gait analysis and computerized neurocognitive testing within 72 hours of injury and again 2 months later. Uninjured controls also completed the same test protocol in similar time increments.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

We compared dual-task gait balance control and computerized neurocognitive test performance between groups using independent samples t tests. Multivariable binary logistic regression models were then constructed for each testing time to determine the association between group membership (concussion vs control), dual-task gait balance control, and neurocognitive function.

RESULTS

Medial-lateral center-of-mass displacement during dual-task gait was independently associated with group membership at the initial test (adjusted odds ratio [aOR], 2.432; 95% confidence interval [CI], 1.269-4.661) and 2-month follow-up test (aOR, 1.817; 95% CI, 1.014-3.256) tests. Visual memory composite scores were significantly associated with group membership at the initial hour postinjury time point (aOR, .953; 95% CI, .833-.998). However, the combination of computerized neurocognitive test variables did not predict dual-task gait balance control for participants with concussion, and no single neurocognitive variable was associated with dual-task gait balance control at either testing time.

CONCLUSIONS

Dual-task assessments concurrently evaluating gait and cognitive performance may allow for the detection of persistent deficits beyond those detected by computerized neurocognitive deficits alone.

Osteoarthritis Prevalence in Retired National Football League Players With a History of Concussion and Lower Extremity Injury

CONTEXT

  Dynamic balance deficits have been described postconcussion, even after athletes return to play. Lower extremity (LE) musculoskeletal injury rates increase for up to 1 year after concussion, but the long-term musculoskeletal implications of concussion are unclear.

OBJECTIVE

  To (1) examine the association of concussion and LE injury histories with osteoarthritis (OA) prevalence in retired National Football League players and (2) examine the association of concussion and LE injury histories with OA prevalence in those ≤55 years of age.

DESIGN

  Case-control study.

SETTING

  Survey.

PATIENTS OR OTHER PARTICIPANTS

  We administered the Health Survey of Retired National Football League Players, which collects information about demographics, OA, LE injury, and concussion history.

MAIN OUTCOME MEASURE(S)

  Twelve discrete categories were created based on concussion and LE injury history, ranging from 0 concussions and 0 LE injuries (referent group) to 3+ concussions and 2+ LE injuries. Binomial regression analysis modeled lifetime OA prevalence. Covariates were body mass index, age at the time of the survey, and total years playing professional football.

RESULTS

  Complete data were available for 2696 participants. Lifetime OA prevalence was smallest in the referent group (21.1%) and largest in the 3+ concussion and 2+ LE group (50.6%; 2.5 times the referent; 95% confidence interval [CI] = 2.1, 3.1). Participants in all concussion groups (1, 2, 3+) who reported a history of 0 LE injuries had a greater OA prevalence than the referent group. When participants were stratified by age, the ≤55 years of age, 3+ concussions, and 2+ LE injuries group prevalence ratio (3.6; 95% CI = 2.7, 5.2) was larger than that of the >55 years of age, 3+ concussions, and 2+ LE injuries group (1.8; 95% CI = 1.3, 2.4) compared with the respective referent groups.

CONCLUSIONS

  Concussion with or without a history of LE injury may be an important moderator of OA. Future researchers should seek to better understand the mechanisms that influence the association among concussion, LE injury, and OA.

Dual-Task Assessment Protocols in Concussion Assessment: A Systematic Literature Review

Study Design Systematic review. Background When assessed in isolation, balance and neurocognitive testing may not be sufficiently responsive to capture changes that occur with concussion. Normal daily activities require simultaneous cognitive and physical demands. Therefore, a dual-task assessment paradigm should be considered to identify performance deficits. Objectives To evaluate the literature and to identify dual-task testing protocols associated with changes in gait after concussion. Methods A systematic review of articles of individuals with concussion who underwent dual-task testing with a combination of motor and cognitive tasks was conducted. The AMED, CINAHL, Embase, PsycINFO, PubMed, Scopus, SPORTDiscus, and Web of Science databases and gray literature were searched from inception to January 29, 2017. Title and abstract, full-text, and quality review and data abstraction were performed by 2 independent reviewers. Results Twenty-four articles met the inclusion criteria. Eleven articles reported decreased gait velocity and increased medial-lateral displacement for individuals with concussion during dual-task conditions. Overall, included articles were of poor to moderate methodological quality. Fifteen articles used the same participants and data sets, creating a threat to validity and limiting the ability to make conclusions. Conclusion A deterioration in gait performance during dual-task testing is present among people with concussion. Specific recommendations for the use of a dual-task protocol to assess individuals with suspected concussion injury in a clinical setting have yet to be determined. J Orthop Sports Phys Ther 2018;48(2):87-103. Epub 7 Nov 2017. doi:10.2519/jospt.2018.7432.

GAIT DEFICITS UNDER DUAL - TASK CONDITIONS IN THE CONCUSSED ADOLESCENT AND YOUNG ATHLETE POPULATION: A SYSTEMATIC REVIEW

BACKGROUND

There are no current sport concussion assessments that capture the effects of dual-task conditions on gait. Multiple studies have evaluated changes, but none have comprehensively examined literature related to the adolescent and young adult population.Purpose: The purpose of this systematic review is to synthesize documented changes in gait under dual-task conditions in adolescents and young adults after sustaining a concussion.Study Design: Systematic Review.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was consulted to guide this systematic review. Six databases were searched: Cinahl, ProQuest, PubMed, Scopus, SPORTdiscus, and Web of Science. Concussion, gait, and dual-task, along with their synonymous terms were the search terms used. Inclusion criteria consisted of adolescent and young adult age groups, acute concussion, dual-tasking, and matched controls. Quality assessment was performed using The Joanna Briggs Institute Critical Appraisal Checklist for Case Control Studies.

RESULTS

Ten full-text articles were selected for inclusion. Concussed individuals demonstrated longer stride times with shorter stride lengths, increased mediolateral displacement with corresponding increases in sagittal and frontal plane peak velocity, and decreased sagittal plane Center of Mass (COM) and Center of Pressure (COP) displacement. The majority of included studies demonstrated moderate to large effect sizes in these gait characteristics.

CONCLUSION

Concussed individuals demonstrated decreased gait stability while ambulating with a dual-task condition. Though statistically significant differences between concussed individuals and matched controls lasted only 72 hours, concussed individuals demonstrated continued improvements in gait for up to two months post-injury, which has the potential to affect an athlete's ability to perform. Further research is needed to determine if a gait examination with a dual-task condition is a realistic, reliable, and valid measure to be included in return to sport testing.

LEVEL OF EVIDENCE

2a.

Risk Factors for Mild Traumatic Brain Injury and Subsequent Post-Traumatic Stress Disorder and Mental Health Disorders among United States Army Soldiers

The purpose of this study was to determine the association of mild traumatic brain injury (mTBI) with subsequent post-traumatic stress disorder (PTSD) and mental health disorders (MHD), and the intervening role of acute stress disorder (ASD). This matched case-control study utilized the Total Army Injury and Health Outcomes Database (TAIHOD) to analyze soldiers' (n = 1,261,297) medical encounter data between 2002 and 2011. International Classification of Diseases, Ninth Revision (ICD-9) codes were used to identify: mTBI (following Centers for Disease Control [CDC] surveillance definition for mTBI), MHD (ICD-9 codes for depression and anxiety, excluding PTSD), PTSD (ICD-9 309.81), and ASD (ICD-9 308.3). Incident cases of mTBI (n = 79,505), PTSD (n = 71,454), and MHD (n = 285,731) were identified. Overall incidence rates per 1000 soldier years were: mTBI = 17.23, PTSD = 15.37, and MHD = 67.99. mTBI was associated with increased risk for PTSD (risk ratio [RR] 5.09, 95% confidence interval [CI] 4.82-5.37) and MHD (RR 2.94, 95% CI 2.84-3.04). A sub-analysis of the mTBI-only soldiers found that a diagnosis ASD, compared with a diagnosis of no ASD, was associated with greater risk for subsequent PTSD (RR 2.13, 95% CI 1.96-2.32) and MHD (RR 1.90, 95% CI 1.72-2.09) following mTBI. Results indicate that soldiers with previous mTBI have a higher risk for PTSD and MHD, and that ASD may also mediate PTSD and MHD risk subsequent to mTBI. These data may help guide important surveillance and clinical rehabilitation considerations for high-risk populations.

Decreased Anticipatory Postural Adjustments During Gait Initiation Acutely Postconcussion

OBJECTIVE

To investigate anticipatory postural adjustments (APAs) during the transitional movement task of gait initiation (GI) in individuals acutely after a concussion.

DESIGN

Cohort study.

SETTING

University research center.

PARTICIPANTS

A population-based sample of participants (N=84) divided into 2 equal groups of acutely postconcussion and healthy student athletes.

INTERVENTION

Participants were tested on 2 occasions: a preinjury baseline test and then the concussion group was retested acutely postconcussion and the healthy student athlete group again at a similar time. All participants completed 5 trials of GI on 4 forceplates.

MAIN OUTCOME MEASURES

The dependent variables were the displacement and velocity of the center of pressure (COP) during the APA phase and initial step kinematics. Comparisons were made with a 2 (group) × 2 (time) repeated-measures analysis of variance.

RESULTS

There was a significant interaction for COP posterior displacement (P<.001) and lateral displacement (P<.001). Posteriorly, post hoc testing identified a significant reduction in the concussion group (pretest: 5.7±1.6cm; posttest: 2.6±2.1cm; P<.001), but no difference in the healthy student athlete group (pretest: 4.0±1.6cm; posttest: 4.0±2.5cm; P=.921). Laterally, post hoc testing identified a significant reduction in the concussion group (pretest: 5.8±2.1cm; posttest: 3.8±1.8cm; P<.001), but no difference in the healthy student athlete group (pretest: 5.0±2.5cm; posttest: 5.2±2.4cm; P=.485).

CONCLUSIONS

The results of this study suggest difficulty in the planning and execution of GI acutely postconcussion, and posterior APA displacement and velocity are highly effective measures of impaired postural control. Finally, the APA phase is linked to the supplementary motor area, which suggests a supraspinal contribution to postconcussion impaired postural control.

Dual-task gait differences in female and male adolescents following sport-related concussion

Concussion may affect females and males differentially. Identification of gender-related differences after concussion, therefore, may help clinicians with individualized evaluations. We examined potential differences in dual-task gait between females and males after concussion. Thirty-five participants diagnosed with a concussion (49% female, mean age=15.0±2.1 years, 7.5±3.0 days post-injury) and 51 controls (51% female, mean age=14.4±2.1 years) completed a symptom inventory and single/dual-task gait assessment. The primary outcome variable, the dual-task cost, was calculated as the percent change between single-task and dual-task conditions to account for individual differences in spatio-temporal gait variables. No significant differences in symptom severity measured by the post-concussion symptom scale were observed between females (32.0±18.0) and males (27.8±18.2). Compared with males, adolescent females walked with significantly decreased cadence dual-task costs after concussion (-19.7%±10.0% vs. -11.3%±9.2%, p=0.007) when adjusted for age, height, and prior concussion history. No significant differences were found between female and male control groups on other dual-task cost gait measures. Females and males with concussion also walked with significantly shorter stride lengths than controls during single-task (females: 1.13±0.11m vs. 1.26±0.11m, p=0.001; males: 1.14±0.14m vs. 1.22±0.15m, p=0.04) and dual-task gait (females: 0.99±0.10m vs. 1.10±0.11m, p=0.001; males: 1.00±0.13m vs. 1.08±0.14m, p=0.04). Females demonstrated a significantly greater amount of cadence change between single-task and dual-task gait than males after a sport-related concussion. Thus, differential alterations may exist during gait among those with a concussion; gender may be one prominent factor affecting dual-task gait.

Physical Activity and Intermittent Postconcussion Symptoms After a Period of Symptom-Limited Physical and Cognitive Rest

Reference: Schneider KJ, Iverson GL, Emery CA, McCrory P, Herring SA, Meeuwisse WH. The effects of rest and treatment following sport-related concussion: a systematic review of the literature. Br J Sports Med. 2013;47(5):304-307.

CLINICAL QUESTION

After concussion and a period of symptom-limited physical and cognitive rest, do athletes who experience intermittent symptoms return to asymptomatic condition more quickly with physical activity than with prolonged physical rest?

DATA SOURCES

One investigator performed an individual search for each research question using the following databases: CINAHL, Cochrane Controlled Trials Registers, EMBASE, HealthSTAR, ProQuest, PsychInfo, PubMed, SPORTDiscus, and Web of Science. Search terms for rest were brain concussion, cognitive rest, mild traumatic brain injury, physical exertion, postconcussive syndrome, rehabilitation, sport-related concussion, therapy, treatment, and treatment outcome. Search terms for treatment were the same terms as for rest, as well as brain training, cervical spine, cognitive therapy, dizziness, exercise, headache, neck, pharmacotherapy, postural balance, and vertigo. The authors included peer-reviewed, published articles and abstracts and performed a citation search.

STUDY SELECTION

Studies were included based on the following criteria as determined before searching: classified as original research, symptoms resulted after sport-related concussion, and investigation of the effects of either rest or treatment on symptoms. Abstracts that were excluded failed to evaluate rest, omitted sport-related concussion as the cause of symptoms, failed to evaluate a treatment's effect on sport-related concussion, or did not present original research.

DATA EXTRACTION

The following data were extracted from each study that fit the selection criteria: study design; sample size; participants' demographic information (age and sex); type, duration, and intensity of treatment; key findings including effect sizes and means with 95% confidence intervals (calculated when possible using the data provided in the original study, even if not presented in the original study); and relevant comments.

MAIN RESULTS

The search revealed 749 articles evaluating the effects of rest and 1175 articles evaluating the effects of treatment. Of the 749 articles evaluating the effects of rest, only 2 met all the inclusion criteria. Of the 1175 articles evaluating the effects of treatment, only 10 met all the inclusion criteria. Ultimately, the authors were able to identify additional treatment articles that met the inclusion criteria, for a total of 12. The nature of the treatments and the participants differed enough that meta-analysis was not possible.  One of the 2 articles that evaluated rest was a retrospective analysis of athletes that showed those who were prescribed a period of cognitive rest had a longer duration of symptoms. The other study followed athletes postconcussion who were retrospectively assigned to groups based on self-reported activity level after injury. Those who reported moderate levels of cognitive and physical exertion over the first month postinjury appeared to demonstrate improved outcomes compared with those who pursued small or large amounts of activity.  Twelve studies evaluated the effects of treatment on symptoms after sport-related concussion. Various interventions were reviewed, including pharmacotherapy, light aerobic activity, graded exercise treadmill test, hyperbaric oxygen therapy, vestibular physiotherapy, and cervical spine manual therapy. Unfortunately, the authors did not report effect sizes for specific interventions, and due to the varied nature of each study and its respective treatment approach, no pooled data could be analyzed. However, a group of adolescents treated with submaximal aerobic and coordination exercises, visualization, and imagery returned to full normal physical activity at a mean duration of 4.4 weeks (95% confidence interval = 3.1, 5.7 weeks). Furthermore, a randomized controlled trial of patients experiencing persistent neck pain, dizziness, and headaches who underwent manual and physical therapy showed they were more likely to return to sport after 8 weeks of treatment. Despite the inability to pool data, the authors concluded that each treatment appeared to positively influence specific aspects of certain patients' symptoms.

CONCLUSIONS

Little high-quality evidence has addressed the effects of rest and treatment after sport-related concussion. Current evidence suggests that an initial period of rest appears to be beneficial. Further research is needed to evaluate the long-term outcomes of rest (including the quality and quantity of the rest). Low levels of exercise may benefit the athlete postinjury, but additional study is required to determine the optimal timing for initiation of treatment postinjury. Patients with cervical spine or vestibular dysfunction may benefit from rehabilitation techniques targeted at their individual symptom profile to facilitate recovery. Overall, we need high-quality studies evaluating resting period, pharmacologic interventions, rehabilitative techniques, and exercise and their effects on patients slow to recover from concussion symptoms.

Executive dysfunction following a mild traumatic brain injury revealed in early adolescence with locomotor-cognitive dual-tasks

OBJECTIVE

To compare gait parameters between children in early adolescence (EA) with and without a mild traumatic brain injury (mTBI) during dual-task walking (DTW).

METHODS

Children in EA with mTBI (n = 14; six girls) were compared to those without (n = 13; five girls) while walking in different combinations of obstacle avoidance and cognitive dual-tasks. Gait speed and fluidity and their related dual-task costs (DTC) were analysed along with foot clearance and proximity to the obstacle.

RESULTS

No group effects were found for gait speed, proximity or clearance, but were found for fluidity DTC, specifically during the dual Stroop task and when crossing the deeper obstacle. There were also group differences for fluidity during the planning of obstacle avoidance for the narrow obstacle combined with the verbal fluency task and the deep obstacle with no cognitive task. Finally, gait fluidity showed group differences across unobstructed dual-task situations.

CONCLUSIONS

Gait fluidity may be a more sensitive variable than gait speed for revealing executive dysfunction following mTBI in EA. Assessing DTW in level walking also seems to show a potential to reveal executive dysfunctions in this age group. These results provide direction for future research on clinical assessment using DTW post-mTBI in adolescents.

Do children and adolescent ice hockey players with and without a history of concussion differ in robotic testing of sensory, motor and cognitive function?

Background

KINARM end point robotic testing on a range of tasks evaluating sensory, motor and cognitive function in children/adolescents with no neurologic impairment has been shown to be reliable. The objective of this study was to determine whether differences in baseline performance on multiple robotic tasks could be identified between pediatric/adolescent ice hockey players (age range 10–14) with and without a history of concussion.

Methods

Three hundred and eighty-five pediatric/adolescent ice hockey players (ages 10–14) completed robotic testing (94 with and 292 without a history of concussion). Five robotic tasks characterized sensorimotor and/or cognitive performance with assessment of reaching, position sense, bimanual motor function, visuospatial skills, attention and decision-making. Seventy-six performance parameters are reported across all tasks.

Results

There were no significant differences in performance demonstrated between children with a history of concussion [median number of days since last concussion: 480 (range 8–3330)] and those without across all five tasks. Performance by the children with no history of concussion was used to identify parameter reference ranges that spanned 95 % of the group. All 76 parameter means from the concussion group fell within the normative reference ranges.

Conclusions

There are no differences in sensorimotor and/or cognitive performance across multiple parameters using KINARM end point robotic testing in children/adolescents with or without a history of concussion.

The Effect of Prior Concussion History on Dual-Task Gait following a Concussion

Sustaining repeated concussions has been associated with worse outcomes after additional injuries. This effect has been identified using symptom inventories and neurocognitive tests; however, few investigations have examined how a prior concussion history affects gait soon after a subsequent concussion. We examined the gait characteristics of athletes with no documented concussion history (n = 31), athletes recovering from their first lifetime concussion (n = 15), and athletes recovering from their second or greater lifetime concussion (n = 22). All participants completed a single-task and dual-task gait examination, a medical history questionnaire, and a postconcussion symptom scale. Multivariate analyses of covariance (MANCOVA) models were used to evaluate mean gait differences among groups, and Spearman's ρ analyses were used to assess correlations between the number of lifetime concussions and gait characteristics. Patients reporting to the clinic with their second or greater lifetime concussion demonstrated smaller stride lengths than healthy control participants during dual-task walking (p = 0.01; d = 0.70). A moderate but insignificant correlation was detected between dual-task gait speed and the number of prior concussions (ρ = 0.41, p = 0.07). These results indicate that a cumulative effect of concussions across the lifetime may contribute to worsening dual-task dynamic motor function after concussion.

Consistency and cost of dual-task gait balance measure in healthy adolescents and young adults

Matched control data are commonly used to examine recovery from concussion. Limited data exist, however, examining dual-task gait data consistency collected over time in healthy individuals. The study purposes were to: 1) assess the consistency of single-task and dual-task gait balance control measures, 2) determine the minimal detectable change (MDC) of gait balance control measures, and 3) examine the extent to which age and task complexity affect dual-task walking costs in healthy adolescents and young adults. Twenty-four adolescent (mean age=15.5±1.1years) and 21 young adult (mean age=21.2±4.5years) healthy participants completed 5 testing sessions across a two-month period, which involved analyses of gait balance control and temporal-distance variables during single-task and dual-task walking conditions in a motion analysis laboratory. Cronbach's α and MDCs were used to determine the consistency of the gait balance control variables and the smallest amount of change required to distinguish true performance from change due to the performance/measurement variability, respectively. Dual-task costs were evaluated to determine the effect of task complexity and age across time using 3-way ANOVAs. Good to excellent test-retest consistency was found for all single-task and dual-task walking (Cronbach's α range: 0.764-0.970), with a center-of-mass medial-lateral displacement MDC range of 0.835-0.948cm. Greater frontal plane dual-task costs were observed during more complex secondary tasks (p<0.001). The results revealed good-excellent consistency across testing sessions for all variables and indicated dual-task costs are affected by task complexity. Thus, healthy controls can be effective comparators when assessing injured subjects.

Evaluation of postural stability in youth athletes: the relationship between two rating systems

OBJECTIVES

The Balance Error Scoring System (BESS) has been documented as a useful way to evaluate postural control following sport-related concussions sustained by youth athletes. However, limitations have been reported with its use due to the reliance on visual observation as the primary measurement outcome. The primary purpose of this study was to examine the correlation between the modified BESS (mBESS) as rated by a clinician and a simultaneous analysis performed by an integrated video-force plate system. The secondary purpose was to assess if a history of prior concussion affected postural control.

METHODS

A group of healthy youth athletes (n = 398; mean age 13.7 ± 2.4 years) completed the mBESS while simultaneously undergoing an integrated video-force plate evaluation to measure postural stability. Spearman rank-order correlations were used to determine the strength of correlation between the 2 rating systems. In addition, performance on the mBESS between those with and without a history of concussion was compared using univariate ANCOVAs.

RESULTS

A moderately high correlation was found during single-leg stance (ρ = -0.64, p < .001), while a weak correlation was found during tandem stance (ρ = -0.30, p < .001). No postural control differences were found between groups with and without a concussion history.

CONCLUSION

The video-force plate rating system correlates well with the clinician rating during the single-leg stance of the mBESS, but not during double-leg or tandem stances. A history of concussion did not affect mBESS scores.