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

A Survey of Canadian Physiotherapists' and Physiotherapy Students' Knowledge and Use of Executive Functioning Assessments in Clinical Practice

Purpose

This study examined what physiotherapists and physiotherapy students understand and know about executive functioning (EF), what EF outcome measures they use clinically, and whether their primary area of practice influences their assessment practices.

Method

An open online survey was distributed to registered members of the Canadian Physiotherapy Association, its various divisions, and colleges of physiotherapy within Canada that took approximately 15 minutes to complete and was available for 13 months. Pearson correlation was used to assess the relationship between subjective and objective understanding and knowledge of EF (UKEF) and a one-way multivariate analysis of variance was used to analyze differences in survey responses based on respondents' primary area of practice.

Results

A total of 335 respondents consented to participate (completion rate = 78.4%). There was a significant moderate positive correlation between subjective and objective UKEF (r = 0.43; 95% CI: 0.32, 0.54; n = 260; p < 0.001). Significant differences in survey responses were related to physiotherapists' primary areas of practice (i.e., musculoskeletal, neurological, cardiorespiratory, or multi-systems; F12,555.89 = 2.29, p = 0.008; Wilks Λ = 0.880; partial η2 = 0.042).

Conclusions

Respondents reported that they had good subjective UKEF, but this was only moderately correlated with objective UKEF.

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.

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.

Relationship Between Dual-Task Walking and Level of Conflict Between Gait and Concurrent Tasks in Adolescents

This study aimed to determine the role of resource conflict in dual-task (DT) effects on gait and concurrent tasks in children and adolescents. Gait was evaluated with and without concurrent tasks (visual-manual, visual-vocal and auditory-vocal). The roles of condition (single vs dual) and type of concurrent task in DT effect were tested by Repeated Measured of ANOVA. Relative changes from single to DT conditions were compared using One-Way ANOVA. There were significant reductions in gait speed, cadence, and stride length, and increases in double support time, step time and variability in step time, and no change in variability in stride length, step width, and concurrent task performance from single to DT conditions. DT effects on gait parameters and concurrent tasks were comparable across DT conditions.

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.

An Investigation of Sensorimotor Impairments in Individuals 4 weeks to 6 months following mild traumatic brain injury

OBJECTIVE

To identify whether adults 4 weeks to 6 months post mild traumatic brain injury (mTBI) have sensorimotor impairments when compared to healthy controls. A secondary aim was to determine if impairments were evident irrespective of participant perceived absence of symptoms.

DESIGN

Observational cohort study SETTING: Tertiary University and Hospital PARTICIPANTS: Participants included 113 individuals aged 18 to 60 years consisting of 39 controls with no prior concussion history, and 74 individuals, 4 weeks to 6 months post mTBI of which 35 considered themselves asymptomatic (Asymp), and 37 symptomatic (Symp).

MAIN OUTCOME MEASURES

Assessments of oculomotor, vestibulo-ocular reflex (VOR) control, balance, single and dual task tandem walk (TTW-S, TTW-D) and vestibular positional testing.

RESULTS

Poorer balance and tandem walk performance, and a higher frequency of positive oculomotor, VOR and vestibular positional tests were evident in the mTBI group compared to controls. In particular ≥ 2 positive oculomotor findings were evident in 53.7% of the participants with mTBI compared to 10.8 % of controls. The mTBI group who considered themselves recovered (Asymp) demonstrated significantly increased TWT-D time, and a higher proportion 53% had ≥ 2 positive oculomotor tests compared to controls.

CONCLUSION

Persistent sensorimotor impairments, particularly evidenced by disturbed oculomotor function and deficits in dual task tandem walking were identified among adults 4 weeks to 6 months post mTBI. These disturbances were evident regardless of whether ongoing symptoms were reported. The findings support recommendations for routine clinical assessment of sensorimotor function post mTBI with implications for injury prevention.

Acute cognitive impairment after traumatic brain injury predicts the occurrence of brain atrophy patterns similar to those observed in Alzheimer's disease

Traumatic brain injuries (TBIs) are often followed by persistent structural brain alterations and by cognitive sequalae, including memory deficits, reduced neural processing speed, impaired social function, and decision-making difficulties. Although mild TBI (mTBI) is a risk factor for Alzheimer's disease (AD), the extent to which these conditions share patterns of macroscale neurodegeneration has not been quantified. Comparing such patterns can not only reveal how the neurodegenerative trajectories of TBI and AD are similar, but may also identify brain atrophy features which can be leveraged to prognosticate AD risk after TBI. The primary aim of this study is to systematically map how TBI affects white matter (WM) and gray matter (GM) properties in AD-analogous patterns. Our findings identify substantial similarities in the regional macroscale neurodegeneration patterns associated with mTBI and AD. In cerebral GM, such similarities are most extensive in brain areas involved in memory and executive function, such as the temporal poles and orbitofrontal cortices, respectively. Our results indicate that the spatial pattern of cerebral WM degradation observed in AD is broadly similar to the pattern of diffuse axonal injury observed in TBI, which frequently affects WM structures like the fornix, corpus callosum, and corona radiata. Using machine learning, we find that the severity of AD-like brain changes observed during the chronic stage of mTBI can be accurately prognosticated based on acute assessments of post-traumatic mild cognitive impairment. These findings suggest that acute post-traumatic cognitive impairment predicts the magnitude of AD-like brain atrophy, which is itself associated with AD risk.

The use of inertial measurement units to assess gait and postural control following concussion

BACKGROUND

Impairments in gait and balance function are typical after concussion. There is evidence that these neuromuscular deficits persist past the typical time of symptom resolution. The ability to quantify these changes in gait and balance may provide useful information when making return to play decisions in clinical settings.

RESEARCH QUESTION

Are changes in gait function and postural control evident across the course of a concussion management program?

METHODS

A retrospective analysis of a convenience sample of 38 patients who were seen for concussion between October 2017 and May 2019 was performed. Gait and balance measures were assessed at their initial clinic visit post-injury and at their clearance visit using inertial measurement units. During dual-task walking trials, the medial-lateral motion of the center of mass and gait velocity were measured. Postural sway complexity and jerk index were measured during both eyes-open and eyes-closed balance trials.

RESULTS

Paired samples t-tests and Wilcoxon signed rank tests were used to determine whether statistically significant changes occurred for the gait and balance variables, respectively. Medial-lateral sway decreased (4.4 ± 1.3 cm to 4.0 ± 1.2 cm, p = 0.018) and gait velocity increased (0.78 ± 0.23 m/s to 0.91 ± 0.18 m/s, p <  0.001) from initial to clearance testing. Jerk index decreased (6.41 ± 11.06 m²/s⁵ to 5.73 ± 4.28 m²/s⁵, p = 0.031) and (11.87 ± 26.42 m²/s⁵ to 7.87 ± 8.38 m²/s⁵, p = 0.003) from initial to clearance testing for the eyes-open and eyes-closed conditions, respectively. Complexity index increased (2.38 ± 1.08-2.86 ± 0.72, p = 0.010) from initial to clearance testing for the eyes-closed condition. There was no change in complexity index for the eyes-open condition.

SIGNIFICANCE

These preliminary results support the potential use of measures of gait and postural control to assess recovery following a concussion in a clinical setting.

Differential Effects of Concurrent Tasks on Gait in Typically Developing Children: A Meta-Analysis

The objective of this study was to systematically analyze the literature surrounding dual-task (DT) effects on gait in typically developing children (TDC) and to conduct meta-analyses where applicable. After reviewing the abstracts of 676 articles, a total of 22 studies were included. The outcomes of interest were relative change in gait speed, cadence, stride length, double support time, variability in stride length between single and DT walking; and the exposures were concurrent tasks used for DT gait assessment. DT significantly affected each gait parameter (point estimate (PE), ranged from PE, -0.10; 95% CI, -0.13 to -0.08; p < .001 to PE, -0.66; 95% CI, -0.94 to -0.38; p < .001). The strength of DT effects varied by the concurrent task used. The greatest DT effect on gait speed, which was the most commonly presented outcome, was reported when upper extremity complex functional tasks (PE, -0.36; 95% CI, -0.49 to -0.23; p < .001, fine motor tasks (PE, -0.35; 95% CI, -0.38 to -0.32; p < .001), and verbal fluency tasks (PE, -0.26; 95% CI, -0.30 to -0.21; p < .001) were completed concurrently with gait. Children and adolescents experience performance decrements when they walk under DT conditions. Concurrent tasks differentially affect the degree of DT interference for each gait parameter.

No differences in tandem gait performance between male and female athletes acutely post-concussion

OBJECTIVES

To test whether 1) concussed athletes demonstrate slower tandem gait times compared to controls and 2) concussed female athletes display greater post-injury deficits than males.

DESIGN

Prospective longitudinal METHOD: Fifty concussed collegiate student-athletes (32% female, age=20.18±1.27 years) completed tandem gait tests during pre-season (Time 1) and acutely (<72hours) post-concussion (Time 2), and twenty-five controls (52% female, age=21.08±2.22 years) completed tandem gait at two time points, 1.96±0.46 days apart. Participants completed four single-task (ST) and dual-task (DT) trials. During DT trials, they simultaneously completed a cognitive assessment. The best ST and DT times were recorded, along with cognitive accuracy, and the change score between the two assessments was calculated. A positive change in tandem gait time was indicative of worsening performance. A 2×2 (group*sex) ANOVA was used to examine change between pre-injury and post-injury tests for ST/DT tandem gait time and DT cognitive accuracy.

RESULTS

The change in tandem gait time from Time 1 to Time 2 was significantly higher for the concussion group relative to controls during both ST (Concussion: 1.36±2.6 seconds, Controls: -1.16±0.8 seconds, p<0.001) and DT (Concussion: 1.70±3.8 seconds, Controls: -0.94±1.7 seconds, p=0.002) tandem gait. There were no interactions or main effects of sex for tandem gait time or cognitive accuracy.

CONCLUSIONS

There were no sex-specific differences in the change in tandem gait performance among concussed collegiate athletes or controls. However, all concussed participants, regardless of sex, performed significantly worse on tandem gait than male and female controls, who both improved between testing time points.

Mangiferin ameliorates collateral neuropathy in tBHP induced apoptotic nephropathy by inflammation mediated kidney to brain crosstalk

The kidneys and brain share similarities in anatomy and vaso-regulation and exhibit clinical interactions in various diseases. To investigate the probable mechanism of kidney to brain crosstalk, we developed an in vivo model of renal injury in mice through intoxication with the oxidative stress inducer, tBHP. Proteinuria, abnormalities in the renal tubules and KIM1 activation were found in tBHP intoxicated animals. Due to this renal pathophysiology, various pro-inflammatory molecules (TNF-α, IL-1β, IL-6, ICAM-1, VCAM-1) especially TNF-α, entered into the brain from kidneys, triggering cerebral inflammatory cascades leading to behavioral anomalies in association with membrane lipid peroxidation, BBB disruption and brain morphological alterations. Moreover, increased levels of reactive oxygen species, decreased antioxidant enzyme activity and an altered GSH/GSSG ratio were found in both these organs. Here, we introduced mangiferin as a protective molecule because of its anti-inflammatory and antioxidant properties. Mangiferin via inhibition of apoptosis and activation of the PI3K/Akt pathway protected the kidneys. It restored the deleterious phenomena in the damaged brain by downregulating the JNK and p38MAPK mediated pro-apoptotic cascade and activating the intracellular antioxidant thioredoxin, thereby protecting against tBHP induced nephropathy mediated neuropathophysiology.

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.

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.

Longitudinal Assessment of Balance and Gait After Concussion and Return to Play in Collegiate Athletes

CONTEXT

In longitudinal studies tracking recovery after concussion, researchers often have not considered the timing of return to play (RTP) as a factor in their designs, which can limit the understanding of how RTP may affect the analysis and resulting conclusions.

OBJECTIVE

To evaluate the recovery of balance and gait in concussed athletes using a novel linear mixed-model design that allows an inflection point to account for changes in trend that may occur after RTP.

DESIGN

Cohort study.

SETTING

University athletics departments, applied field setting.

PATIENTS OR OTHER PARTICIPANTS

Twenty-three concussed (5 women, 18 men; age = 20.1 ± 1.3 years) and 25 healthy control (6 women, 19 men; age = 20.9 ± 1.4 years) participants were studied. Participants were referred by their team athletic trainers.

MAIN OUTCOME MEASURE(S)

Measures consisted of the Balance Error Scoring System (BESS) total score, sway (instrumented root mean square of mediolateral sway), single-task gait speed, gait speed while simultaneously reading a handheld article (dual-task gait speed), dual-task cost of reading on gait speed, and dual-task cost of walking on reading.

RESULTS

We observed no significant effects or interactions for the BESS. Instrumented sway was worse in concussed participants, and a change in the recovery trend occurred after RTP. We observed group and time effects and group × time and group × RTP change interactions (P ≤ .046). No initial between-groups differences were found for single-task or dual-task gait. Both groups increased gait speed initially and then leveled off after the average RTP date. We noted time and RTP change effects and positive group × time interactions for both conditions (P ≤ .042) and a group × RTP change interaction for single-task gait speed (P = .005). No significant effects or interactions were present for the dual-task cost of reading on gait speed or the dual-task cost of walking on reading.

CONCLUSIONS

Changes in the rate of recovery were coincident with the timing of RTP. Although we cannot suggest these changes were a result of the athletes returning to play, these findings demonstrate the need for further research to evaluate the effects of RTP on concussion recovery.

Examining Motor Tasks of Differing Complexity After Concussion in Adolescents

OBJECTIVES

(1) To determine the effects of concussion-related motor impairments at different task complexities in isolation and with a cognitive dual-task and (2) to determine if self-reported balance deficits after concussion are associated with gait, quiet stance, or cognitive dual-task impairments.

DESIGN

Cross-sectional study.

SETTING

Sports medicine clinic.

PARTICIPANTS

Adolescent athletes clinically diagnosed with a sport-related concussion and those without concussion. Forty-nine patients with concussion (mean age=14.9±1.9y; 51% female; tested 7.0±3.0d postinjury) and 65 control participants (mean age=14.9±1.6y; 52% female) completed the study (N=114).

INTERVENTIONS

Athletes with concussion completed a single-task and dual-task standing and walking protocol within 14 days of injury and were compared to those without concussion.

MAIN OUTCOME MEASURES

Outcome measures included gait speed, quiet stance (root mean square [RMS] coronal/sagittal plane sway), and cognitive performance (accuracy). Dual-task costs were calculated as the percentage change between single-task and dual-task conditions. Participants with concussion were then stratified by those who did and did not report subjective balance problems at the time of testing and compared using objective balance and gait metrics.

RESULTS

The concussion group walked slower during dual-task gait than controls (0.83±0.17 m/s vs 0.92±0.15 m/s; Cohen's d=0.53). Dual-task quiet stance RMS sway values were similar for concussion and control groups in coronal (1.20±0.52 m/s^-2 vs 1.26±0.65 m/s^-2; d=0.09) and sagittal (0.56±0.24 m/s^-2 vs 0.73±0.44 m/s^-2; d=0.20) movement planes. The concussion participants with subjectively-reported balance problems had significantly greater walking speed dual-task costs than concussion participants without self-reported balance problems (-25±10% vs -19±9%; P=.02).

CONCLUSIONS

Following concussion, adolescents demonstrate slower gait speeds, but similar quiet stance values relative to those without concussion. The study results indicate that tasks requiring greater motor coordination may elicit greater alterations following a concussion.

Worsening Dual-Task Gait Costs after Concussion and their Association with Subsequent Sport-Related Injury

Prior studies suggest that concussion may lead to an increased risk of a subsequent time-loss sport-related injury, but the mechanisms responsible are unknown. We measured the symptom and dual-task gait outcomes for athletes initially post-concussion and after clinical recovery. Participants then self-reported any additional injuries incurred in the year after their concussion. Forty-two athletes (52% female, mean age = 16.8 ± 3.2 years) completed the study. They underwent a dual-task gait evaluation and symptom inventory within 21 days post-concussion, and again after they were deemed clinically recovered. Approximately one year later, participants documented if they had sustained any subsequent sport-related injuries. The repeated measures analysis of variance (ANOVA) was used to evaluate changes in dual-task gait and symptoms across time and between groups. A significant group*time interaction (p = 0.02) indicated that the group that went on to sustain a subsequent time-loss injury after returning to sports (n = 15) demonstrated significant average walking speed dual-task cost worsening across time (-17.9 ± 9.1% vs. -25.1 ± 12.5%; p = 0.007). In contrast, the group that did not sustain an additional injury walked with consistent dual-task cost values across time (-25.2 ± 9.2% vs. -24.6 ± 8.4%; p = 0.76). Symptoms improved for all participants (main effect of time, p < 0.001; Post-Concussion Symptom Scale [PCSS] = 25.0 ± 16.9 vs. 2.8 ± 7.5; p < 0.001), but did not differ between groups (p = 0.77). Significant dual-task gait cost worsening throughout concussion recovery was associated with time-loss injuries during sports in the year after a concussion. These findings indicate that worsening ability to execute a concurrent gait and cognitive task may relate to the risk of incurring an injury during sports after clinical concussion recovery.

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.

Decomposition of leg movements during overground walking in individuals with traumatic brain injury

OBJECTIVE

Walking requires precise coordination of bilateral lower extremity motions at all joints. This ability can be affected by traumatic brain injury (TBI). The study investigated inter-joint coordination of lower extremities during overground walking after TBI.

METHODS

Ten individuals with post-injury ataxia, postural stability and gait abnormalities, as well as 10 sex- and age-matched control subjects were involved in the study. Participants walked at self-selected speed in three experimental conditions: normal walking without any additional task; walking with a narrow base of support, and walking while holding a cup full of water. Inter-joint coordination was analysed as the percentage of gait cycle during which the leg movement was decomposed with 0% indicating simultaneous motion of the two joints (i.e. hip-knee, knee-ankle, and hip-ankle) through the entire gait cycle or 100% indicating motion of only one joint. Decomposition was calculated for each pair of joints and for the left and right leg separately.

RESULTS

Participants with TBI showed greater decomposition indices and poorer inter-joint coordination respectively than control individuals for all joint pairs (p < 0.01). Walking with the narrower base of support or with a cup, increased movement decomposition in the TBI group, but not in the control group.

CONCLUSION

The results revealed post-injury gait impairment that manifests as decomposition of multi-joint motions of the lower extremities during overground walking.

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.

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.