The Effect of Repetitive Head Impact in Sensory Reweighting in Collision College Athletes

Abstract

ObjectiveTo compare sensory reweighting for upright stance between collegiate collision and non-contact sport athletes.BackgroundThe potentially adverse effects of repetitive head impact (RHI) exposure through routine collision sport participation have become a major public health concerns.Design/MethodsThirty male collegiate athletes were grouped by sport type, including collision (n = 15, 21.2 ± 2 years, 85.9 ± 13.8 kg, 179.7 ± 8.2 cm) and non-contact (n = 15, 20.8 ± 2.1 years, 72.9 ± 4.8 kg, 178.3 ± 4.3 cm) sport athletes. Participants underwent a standing balance assessment; they experienced simultaneous perturbations to visual, vestibular, and somatosensory systems. The visual stimulus consisted of 500 pyramids displayed on a virtual reality cave and translated in the anterior-posterior direction at 0.2 Hz in a sinusoidal waveform. The vestibular stimulus consisted of binaural-monopolar galvanic vestibular stimulation (GVS) at 0.36 Hz in a sinusoidal waveform. The somatosensory stimulus consisted of bilateral Achilles’ tendon vibration at 0.28 Hz in a square waveform with equal on/off times. Different frequencies were chosen for each modality so that we could calculate the gain to each stimulus independently. There were four conditions: two conditions of each high amplitude (0.2 m) and low amplitude (0.8 m) visual scene translation and two conditions of each vibration on and vibration off. The leg segment gain to each modality was compared between groups and across conditions using a repeated-measures ANOVA.ResultsThere were no changes in leg segment gain to vision (i.e. group effect; F = 2.624, p = 0.094, η2 = 0.086), gain to GVS (F = 1.341, p = 0.266, η2 = 0.46), or gain to vibration (F = 3.124, p = 0.088, η2 = 0.100). In addition, there were no changes in sensory reweighting for any modality (i.e. condition X group effect; vision, F = 0.074, p = 0.788, η2 = 0.003; GVS, F = 0.547, p = 0.46, η2 = 0.019; vibration, F = 0.734, p = 0.399, η2 = 0.026).ConclusionsOur findings suggest that there are no differences in sensory reweighting between collegiate collision and non-contact sport athletes. Despite concerns that RHI exposure through routine collision sport participation may result in balance disturbances, our results do not support this association.