Upping The Ante: Can Agility Performance Differentiate Previously Concussed From Healthy Controls?

Returning to sport or active duty has the potential to put athletes or service members at risk. Yet, post-concussion assessments primarily rely on subjective reporting or simple clinical tests - tasks that lack ecologic validity in comparison with sport or combat environments. Both environments may require fast-paced movements such as turning, which involves the integration of oculomotor and vestibular information, as well as cognitive control for execution. Testing anticipated and unanticipated turns during agility tasks performed at high speeds may provide a more valid test setting, and help to quantify differences between previously concussed and healthy persons performing more complex movement tasks. PURPOSE: To compare performance on unanticipated and anticipated agility tasks between previously concussed and healthy controls. METHODS: We tested agility performance, defined by peak turning velocity (yaw, °/s), in previously concussed and healthy controls in two participant samples: athletes (concussed n=5, control n=5) and a general population (concussed n=8, controls n=10). Athletes completed unanticipated turns cued by a light stimulus, and the general population completed anticipated turns using a modified Illinois Agility task (IAT). Peak turning velocity was extracted from a waist worn inertial sensor. Athlete and general population data were compared separately. Cohen’s d effect size was used to evaluate between-group differences due to small sample sizes. RESULTS: The concussed athletes (mean(SD); 239(46) °/s) turned slower than the control athletes (300(37) °/s; d = -1.45, large effect) completing unanticipated turns. In the general population performing anticipated turns, the concussed group (220(23) °/s) turned slower than the healthy controls (237(33) °/s; d = -0.57, medium effect). CONCLUSION: Findings suggest differences between groups in both samples, despite using different agility tasks. Moving forward, we plan to evaluate anticipated turns performance in an active military duty population. However, unanticipated turn tasks, which require a movement coupled in response to stimulus are an interesting area for future exploration. Supported by the Assistant Secretary of Defense for Health Affairs (#W81XWH-18-2-0049) and the Medical Research Foundation of Oregon.