Examining motor tasks of differing complexity after concussion in adolescents
Howell DR, Myer GD, Grooms D, Diekfuss J, Yuan W, Meehan WP. Arch Phys Med Rehabil. 2018. [Epub ahead of print]
Take Home Message: Following a concussion, athletes typically walk slower and perform poorly on cognitive tasks compared to controls. Hence, a gait task test may be a beneficial concussion assessment.
Many athletes who sustain a concussion suffer motor control deficits, specifically the inability to optimally perform dual tasks (motor and cognitive tasks). However, a challenge to assessing motor control deficits is that we often rely on self-reported balance issues to assess postural control abnormalities, which may lead to inaccuracies in diagnosis and returning an athlete to play. Therefore, the authors sought to determine if an athlete with a concussion completes motor tasks of different complexity (in isolation or when combined with a cognitive task) worse than healthy athletes. Furthermore, they aimed to determine if athletes who have self-reported balance problems following a concussion demonstrate worse gait, stance, or cognitive deficits than those who do not report balance problems. The authors evaluated motor and cognitive function in 49 athletes who sustained a concussion and 65 healthy athletes using the following protocol:
1. Static standing (single-task standing)
2. Static standing while completing a cognitive test (dual-task standing)
3. Walking only (single-task walking)
4. Walking while completing cognitive test (dual-task walking)
Cognitive tests included spelling a word backwards, subtracting, or reciting the months backwards. Athletes suffering from concussion were further grouped by reporting balance deficits on the post-concussion symptoms scale (PCSS; 59%) or those that self-reported no balance deficits (41%). The concussion group walked slower and performed less accurately with the cognitive tasks than the healthy group in both single and dual walking tasks. Both groups performed similarly during dual tasks regarding cognitive accuracy and postural sway during the standing tasks. Similarly, concussed athletes who reported balance deficits displayed similar cognitive accuracy scores and postural sway values compared to the concussed athletes who did not report balance deficits. However, the concussed athletes who reported balance deficits had greater decrements in gait speed when performing a dual-task compared to athletes that did not report balance deficits.
The authors found that following a concussion, an athlete typically walks slower and has lower cognitive accuracy than healthy peers. However, there were no differences between groups during static standing tasks. This suggest that there is an increased motor demand imposed during gait tasks compared to stance tasks that may affect athletes with a concussion to a greater degree. Clinically, medically professionals rely on common balance assessments tests to make safe return-to-play decisions; however, it seems subtle motor control deficits may not be detected with these assessments, which could result in early return to play and could lead to a greater likelihood of sustaining a subsequent injury during sport participation. Further research in a larger cohort that measures walking speed in a clinical setting is necessary to verify if a simple test could help differentiate people with a concussion or perceived balance impairment. Currently, medical professionals should consider implementing a gait task (tandem gait test) into the concussion assessment protocol to help diagnosis, curate rehabilitation plans, and provide safer return to play decisions.
Questions for Discussion: Would you consider implementing dual task assessment into your concussion protocol? If so, would you include this task in both baseline and post-concussion assessment?
Written by: Jane McDevitt
Reviewed by: Jeffrey Driban