Effects of concussions on visually guided motor actions: A literature review

Neck strength and force in reaction time task of adolescent athletes with and without concussion history: A pilot study

OBJECTIVES

Assess the impact of concussion by comparing reaction time, peak force recruitment, and rate of force development of adolescent athletes returning from concussion against age- and sex-matched controls in visual-elicited neck movement.

DESIGN

Athletes sat secured in a custom-built isometric device with their heads secured in a helmet and attached to a 6-axis load cell. They performed neck flexion, extension, and lateral flexion in response to a visual cue. Three trials in each direction were used for statistical analyses; peak force and rate of force development were normalized against athlete mass.

SETTING

Laboratory.

PARTICIPANTS

26 adolescent/young adult athletes (8F/18M), either recently concussed (and cleared for return to sport) or an age- and sex-matched healthy control.

MAIN OUTCOME MEASURES

Reaction time, angle, standard deviation of angle, deviation from target angle, peak force, and RFD over 50, 100, 150,and 200 ms of movement were measured for each trial.

RESULTS

Concussed athletes had decreased normalized peak force (P = 0.008) and rate of force development (P < 0.001-0.007). In neck extension, concussed athletes also had decreased movement precision (P = 0.012).

CONCLUSIONS

Concussion is associated with alterations of neck biomechanics that decrease overall neck strength.

Prolonged eye-hand decoupling deficits in young adults with a history of concussion from adolescence

Previous studies reported that adolescents with a sport-related concussion history showed prolonged visuomotor deficits during an eye-hand decoupling task until around 1.5-2 years post-event. The present study expands this work, examining whether such deficits do or do not emerge when testing individuals in young adulthood, i.e. later post-event. Twenty-one non-athlete college students with sport-related concussion history from adolescence (CH; M = 21 yrs.; M = 46 months post-concussion, range 10-90 months) and twenty controls with no history of concussion (NoH; M = 21 yrs.) performed two touchscreen-based visuomotor tasks. It included a coupled task where eyes and hand moved in similar directions, and decoupled-task with eyes and hand going to different directions. Movement planning (e.g. reaction time, initial direction error) and execution (e.g. movement time, path length) related variables were analyzed in both groups and conditions. Movement execution measures were similar for both groups and conditions (all p > 0.05). However, movement planning was impaired in the CH participants in the eye-hand decoupling condition (p < 0.05). CH's initial direction error was larger (i.e. worse spatial movement planning) than in the NoH group. Although movement execution deficits shown in earlier work in youth were not present in young adults, the present results suggest that a sport-related concussion sustained in adolescence can lead to prolonged deficits with spatial movement planning processes while performing eye-hand decoupling tasks about four years post-injury. Further research should investigate whether these deficits continue into adulthood and expand control on time since concussion and number of concussion metrics.Highlights Young adult college students with a history of a sport-related concussion from adolescence, tested about four years post-incident, showed spatial movement preparation deficits during an eye-hand decoupling visuomotor task.Eye-hand reversal decoupling errors also correlated with time since concussion in those with concussion history.These prolonged eye-hand decoupling deficits may emerge with ongoing time post-event, as comparable deficits were absent in previous work where youth were tested sooner post-injury.Our current findings point towards long-lasting performance impairments in young adult non-athletes after a sport-related concussion from adolescence.

A Novel Approach to Assessment of Perceptual-Motor Efficiency and Training-Induced Improvement in the Performance Capabilities of Elite Athletes

Standard clinical assessments of mild traumatic brain injury are inadequate to detect subtle abnormalities that can be revealed by sophisticated diagnostic technology. An association has been observed between sport-related concussion (SRC) and subsequent musculoskeletal injury, but the underlying neurophysiological mechanism is not currently understood. A cohort of 16 elite athletes (10 male, 6 female), which included nine individuals who reported a history of SRC (5 male, 4 female) that occurred between 4 months and 8 years earlier, volunteered to participate in a 12-session program for assessment and training of perceptual-motor efficiency. Performance metrics derived from single- and dual-task whole-body lateral and diagonal reactive movements to virtual reality targets in left and right directions were analyzed separately and combined in various ways to create composite representations of global function. Intra-individual variability across performance domains demonstrated very good SRC history classification accuracy for the earliest 3-session phase of the program (Reaction Time Dispersion AUC = 0.841; Deceleration Dispersion AUC = 0.810; Reaction Time Discrepancy AUC = 0.825, Deceleration Discrepancy AUC = 0.794). Good earliest phase discrimination was also found for Composite Asymmetry between left and right movement directions (AUC = 0.778) and Excursion Average distance beyond the minimal body displacement necessary for virtual target deactivation (AUC = 0.730). Sensitivity derived from Youden's Index for the 6 global factors ranged from 67 to 89% and an identical specificity value of 86% for all of them. Median values demonstrated substantial improvement from the first 3-session phase to the last 3-session phase for Composite Asymmetry and Excursion Average. The results suggest that a Composite Asymmetry value ≥ 0.15 and an Excursion Average value ≥ 7 m, provide reasonable qualitative approximations for clinical identification of suboptimal perceptual-motor performance. Despite acknowledged study limitations, the findings support a hypothesized relationship between whole-body reactive agility performance and functional connectivity among brain networks subserving sensory perception, cognitive decision-making, and motor execution. A complex systems approach appears to perform better than traditional data analysis methods for detection of subtle perceptual-motor impairment, which has the potential to advance both clinical management of SRC and training for performance enhancement.

Return-to-driving following acquired brain injury: A neuropsychological perspective

BACKGROUND

Return to driving after an acquired brain injury (ABI) has been positively associated with return to employment, maintenance of social relationships, and engagement in recreational and other community activities. Safe driving involves multiple cognitive abilities in a dynamic environment, and cognitive dysfunction resulting from ABI can negatively impact driving performance.

OBJECTIVE

This manuscript examines the post-injury return-to-driving process, including performances on the in-office and on-road assessments, and the role of a rehabilitation neuropsychologist in helping patients resume driving.

METHOD

In this study, 39 of 200 individuals (approximately 20%) treated at an outpatient neurorehabilitation facility, who performed satisfactorily on a pre-driving cognitive screening, completed a behind-the-wheel driving test.

RESULTS

Of the 200 individuals, 34 (87%) passed the road test. Among the remaining five individuals who did not pass the road test, primary reasons for their failure included inability to follow or retain examiner directions primarily about lane position, speed, and vehicle control. The errors were attributable to cognitive difficulties with information processing, memory, attention regulation, and dual tasking.CONCLUSIONThe rehabilitation neuropsychologist contributed to the process by assessing cognition, facilitating self-awareness and error minimization, providing education about driving regulations and safety standards, and preparing for the road test and its outcomes.

Wellness Survey Responses and Smartphone App Response Efficiency: Associations With Remote History of Sport-Related Concussion

Recent research findings have strongly suggested that sport-related concussion (SRC) increases risk for subsequent injury of any type, as well as a potential for long-term adverse effects on neurological and psychological well-being. The primary purpose of this study was to explore the reliability and discriminatory power of clinical testing procedures for detecting persisting effects of SRC. We used a cross-sectional study design to assess both self-reported symptoms commonly associated with post-concussion syndrome, and the effects of mental or physical activity on metrics derived from a smartphone app designed to test perceptual-motor responses. Among 30 physically active college students, 15 participants reported a SRC occurrence prior to testing (M time-since-injury = 4.0 years, SD = 3.1, range = 5 months to 11 years). We found good test-retest reliability for key metrics derived from the smartphone app (ICC ≥ .70); and the internal consistency for the Overall Wellness Index (OWI) for 10 categories of 82 post-concussion symptoms was ideal (Cronbach's α ≥ .80). Moderate intensity treadmill running demonstrated the strongest differential effect on perceptual-motor responses between participants with a history of SRC (HxSRC) and those with no such history (No SRC), which was best represented by the speed-accuracy trade-off quantified by the inverse efficiency index (IEI: group X trial interaction p = .055). Self-reported OWI symptoms ≥4 and post-physical activity IEI ≥ 568 ms provided the strongest discrimination between HxSRC and NoSRC participants (≥1 versus 0: OR = 9.75). Our findings suggest that persisting effects from a remote SRC occurrence can be detected by easily administered screening procedures that have the potential to identify individual athletes who might derive benefit from interventions to restore their optimal function and well-being.

Concussion History and Neuromechanical Responsiveness Asymmetry

CONTEXT

Detection of subtle changes in brain sensorimotor processes may enable clinicians to identify athletes who would derive the greatest benefit from interventions designed to reduce the risk for future injury and progressive neurologic or musculoskeletal dysfunction.

OBJECTIVE

To develop a generalizable statistical model for identifying athletes who possess subtle alterations in sensorimotor processes that may be due to previous concussion.

DESIGN

Cross-sectional study.

SETTING

Residential Olympic Training Center sports medicine clinic.

PATIENTS OR OTHER PARTICIPANTS

A primary cohort of 35 elite athletes and a secondary cohort of 40 elite athletes who performed identical tests the preceding year.

INTERVENTION(S)

Two upper extremity tests of visual-motor reaction time and 2 tests of whole-body reactive agility were administered. The whole-body tests required lateral or diagonal responses to virtual-reality targets, which provided measures of reaction time, speed, acceleration, and deceleration.

MAIN OUTCOME MEASURE(S)

Sport-related concussion history, which was reported by 54% (n = 19) of the athletes in the primary cohort and 45% (n = 18) of the athletes in the secondary cohort.

RESULTS

Univariable analyses identified 12 strong predictors of sport-related concussion history, which we combined to create a composite metric with maximum predictive value. Composite lateral asymmetry for whole-body reactive movements and persisting effects of previous musculoskeletal injury yielded a logistic regression model with exceptionally good discrimination (area under the curve = 0.845) and calibration (predicted-observed probabilities within 7 subgroups: r = 0.959, P = .001). Application of the derived model to compatible data acquired from another cohort of elite athletes demonstrated very good discrimination (area under the curve = 0.772) and calibration (within 8 subgroups: r = 0.849, P = .008).

CONCLUSIONS

Asymmetry in whole-body reactive movement capabilities may be a manifestation of a subtle abnormality in the functional connectivity of brain networks that might be relevant to previously reported associations between sport-related concussion history and musculoskeletal injury occurrence.

Driving Behaviors 2-3 Years After Traumatic Brain Injury Rehabilitation: A Multicenter Case-Control Study

Introduction: Driving an automobile is an important activity for the social participation of individuals with traumatic brain injury (TBI). Return to safe driving is usually addressed during rehabilitation, but we know little about driving behaviors in the years following TBI rehabilitation.

Objective: To explore self-reported and objective (official driving records) post-rehabilitation driving behaviors and offenses in individuals with TBI: (a) having passed a driving evaluation, (b) who did not undergo a driving evaluation, and (c) non-injured controls.

Methods: Cross-sectional design with 162 adults: (a) 48 participants with mild, moderate, or severe TBI whose drivers' license was suspended and reinstated following a driving evaluation during rehabilitation (TBI-DE; M = 42.2 years of age, SD = 11.5); (b) 24 participants with TBI who maintained their driving privileges without undergoing a driving evaluation (TBI-NE; M = 36.5 years of age, SD = 9.9); (c) 90 non-injured controls (M = 43.8 years of age, SD = 11.4). Participants with TBI were recruited from seven rehabilitation centers, 2–3 years after the end of rehabilitation in the province of Quebec, Canada. During a telephone interview, data were obtained regarding self-reported driving: (a) habits; (b) self-efficacy; (c) anger expression; (d) sensation-seeking; (e) violations/errors; (f) accidents, driving offenses, and demerit points for the two-year interval predating the study. Objective data for driving offenses, accidents, and demerit points were obtained from the automobile regulatory body for the same period and for the two-year interval before the injury for the TBI groups.

Results: Compared to non-injured controls, the TBI-DE group reported significantly lower scores for self-reported verbal aggressive expression of anger and driving violations/errors. Conversely, their official driving records showed significantly more demerit points for the last 2 years, and a significantly higher frequency of serious post-rehabilitation accidents (10), compared to the TBI-NE group (one) and the control group (none). Compared to pre-injury levels, individuals with TBI had significantly more demerit points post-rehabilitation.

Conclusions: Individuals with TBI may underestimate risky driving behaviors even if they have been deemed fit to drive. Reduced self-awareness, memory, and dysexecutive problems following TBI could influence self-report of driving behaviors and explain discrepancies between self-reported and objective driving-related behaviors. Recommendations for research and practice are provided.