Remote concussion history does not affect visually-guided reaching in young adult females

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.

Lower Kinetic Chain, Meet the Thinking Brain: A Scoping Review of Cognitive Function and Lower Extremity Injury Risk

The classic model of non-contact ACL injury includes environmental, anatomical, hormonal and biomechanical risk factors which directly impact either the amount of stress placed on the ligament or the relative capacity of ligament to withstand the forces placed on it. However, cognition also clearly plays a role in successful athletic performance, yet diminished cognitive function is rarely considered a risk factor for injury.

Objective

To examine the existing literature to determine the extent to which cognitive function (both cognitive ability and task cognitive load) influences non-contact lower extremity injury risk in male and female athletes with a broad variety of athletic expertise.

Study Design

Scoping Review.

Methods

An electronic search was conducted of CINAHL, SPORTDiscus, Google Scholar, and MEDLINE using the PRISMA method. Search terms included Boolean combinations of "cognition", "concussion", "ImPACT", "cognitive deficit", "mild traumatic brain injury (mTBI)", and "neuropsychological function" as cognitive descriptors and the terms "injury risk" and "lower extremity injury" as injury descriptors. Inclusion criteria included papers written in English published between 2000-2021. Exclusion criteria included neurological and cognitively atypical populations, except for concussion (included). Included articles were appraised using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies.

Results

Fifty-six studies utilizing across the spectrum of levels of evidence met inclusion criteria. Forty-one articles had good, fourteen had fair, and one had poor methodological quality. Studies examined baseline cognitive function in healthy athletes (n=7); performance during dual-task paradigms (n=13); and the impact of concussion on dual-task performance (n=4), LE injury risk (n=22), or post-concussion testing (n=10). Six articles examining cognitive function and all dual-task studies (including concussion studies) found altered biomechanics associated with injury or increased processing demands. Studies related to concussion and injury incidence consistently found an increased risk of LE injury following concussion. Half of the studies that examined concussion and post-concussion cognitive testing demonstrated significant effects.

Discussion

Consistent across participant demographics, tasks, and dependent measures, fifty-one of fifty-six assessed articles concluded that decreased cognitive ability or increased cognitive load led to risky LE mechanics or a direct increase in non-contact LE injury risk.

Conclusion

The robustness of results across gender, performance level, sport, cognitive ability, task cognitive load suggest that the inclusion of cognitive training in the design of optimal LE injury prevention programs warrants further study. Level of Evidence: Ia.

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.