Distinct Neural Signatures of Auditory Processing in Contact versus Non-contact Sports Athletes

Abstract Repetitive sub-concussive head impacts are emerging as one of the most urgent and overlooked challenges in neurotrauma. Despite growing evidence of their neurological consequences, there is no validated objective biomarker for early and reliable detection. Cortical (N100) and subcortical (frequency following responses) to a speech syllable presented in (1) quiet and (2) six-talker background noise listening conditions were assessed using EEG in 60 tier-2 athletes (30 contact, 30 non-contact; age-, sex-, height-, body mass- and BMI-matched). Reduced cortical N100 amplitudes in contact athletes were confirmed by a significant group effect ( F (1,54) = 9.16, p = .004), indicating early auditory cortical dysfunction as a measurable biomarker of sub-concussive exposure. Contact athletes also exhibited subtle hearing deficits and impaired self-reported speech perception, linking neural changes to real-world communication deficits. These findings were not related to cortical response amplitudes, suggesting that peripheral and cortical changes may occur independently following repetitive head impacts. Response timing and subcortical encoding were unaffected under both listening conditions. Our findings establish a selective auditory cortical vulnerability to repeated sub-concussive head impact exposure, providing the basis of an objective EEG-based monitoring tool that could help support athlete brain health and safety, and inform future research in contact sports.