Balance Performance With a Cognitive Task: A Continuation of the Dual-Task Testing Paradigm

Context: To ensure that concussed athletes return to play safely, we need better methods of measuring concussion severity and monitoring concussion resolution. Objective: To develop a dual-task model that assesses postural stability and cognitive processing in concussed athletes. Design: Repeated measures study. Setting: University laboratory. Patients or Other Participants: Twenty healthy, college-aged students (10 men, 10 women; age = 20 +/- 1.86 years, height = 173 +/- 4.10 cm, mass = 71.83 + 35.77 kg). Intervention(s): Participants were tested individually in 2 sessions separated by 2 days. In one session, a balance task and a cognitive task were performed separately. In the other session, the balance and cognitive tasks were performed concurrently. The balance task consisted of 6 conditions of the Sensory Organization Test performed on the NeuroCom Smart Balance Master. The cognitive task consisted of an auditory switch task (3 trials per condition, 60 seconds per trial). Main Outcome Measure(s): For the balance test, scores for each Sensory Organization Test condition; the visual, vestibular, somatosensory, and visual-conflict subscores; and the composite balance score were calculated. For the cognitive task, response time and accuracy were measured. Results: Balance improved during 2 dual-task conditions: fixed support and fixed visual reference (t(18) = -2.34, P < .05) and fixed support and sway visual reference (t(18) = -2.72, P = .014). Participants' response times were longer (F(1,18) = 67.77, P < .001, eta(2) = 0.79) and choice errors were more numerous under dual-task conditions than under single-task conditions (F(1,18) = 5.58, P = .03, eta(2) = 0.24). However, differences were observed only during category-switch trials. Conclusions: Balance was either maintained or improved under dual-task conditions. Thus, postural control took priority over cognitive processing when the tasks were performed concurrently. Furthermore, dual-task conditions can isolate specific mental processes that may be useful for evaluating concussed individuals.