The tandem gait (TG) test is commonly administered to evaluate and diagnose possible sports-related concussions. To date, head position is not controlled for, nor has its potential influence been studied during TG testing. PURPOSE: Examine the difference in the mediolateral (ML) sway and velocity and time to complete between two head positions of cervical neutral and cervical flexion during single and dual-task tandem gait. METHODS: 25 apparently healthy subjects (age=21.9±1.41 years) performed tandem gait walking along a 3-meter piece of tape affixed to an instrumented walkway (30 Hz, Tekscan Strideway, Tekscan Inc., South Boston, MA). Each participant completed 3 randomized trials of 2 different head positions, cervical neutral (CN) and cervical flexion (CF). The time to complete and center of pressure (COP), filtered using empirical mode decomposition, were measured during the tasks and analyzed by the 1st pass (FP), turn (T), and 2nd (SP) using a custom MATLAB code. The time to complete the task and average mean excursion in the ML direction, velocity in the ML direction, were ensemble averaged and compared using a repeated measures ANOVA. RESULTS: A significant difference was found for single-task FP mean excursion ML (CN=1.78±0.54cm, CF=1.49±0.38cm; p=0.007), SP mean excursion ML (CN=1.72±0.44cm, CF=1.53±0.39cm; p=0.03). A significant difference was found for dual-task FP mean excursion ML (CN=1.80±0.37cm, CF=1.52±0.40cm; p=0.002), SP mean excursion ML (CN=2.00±0.50cm, CF=1.58±0.34cm; p<0.001), and T mean excursion ML (CN=2.81±0.80cm; CF=2.29±0.58cm; p=0.004) by head position. There was no significant difference was found in single-task or dual-task trials in the ML velocity or time by head position. CONCLUSION: The results of this study suggest that during a fixed head position of CN during dual-task TG, the COP ML sway increases during the FP, SP, and T when the participants are unable to look around. Secondly, there is an increase in COP ML sway during single-task TG when controlling head position. This research provides preliminary evidence that fixed head positions may alter the clinical application of concussion TG testing
