Somatosensory differences between symptomatic and non-symptomatic retired contact sport athletes.

Aim of the study Interest continues investigating pathophysiology of athlete cohorts with a history involving cumulative career exposure of repeated concussion and non-concussion impacts. One area yet to be explored involves the somatosensory system. Using a novel sensorimotor technique, this study measured the somatosensory system in retired contact sport athletes exposed to repetitive neurotrauma. Materials and Methods Retired athletes (n=85, mean age 48.6 +/- 10.6 years, all male) completed a self-report survey on their playing career, number of concussions, and continuing symptoms. Participants completed somatosensory vibrotactile tasks assessing reaction time, amplitude discrimination (sequential, simultaneous), and temporal discrimination (temporal order judgment, duration discrimination). Participants were divided between those reporting persistent symptoms (Symptomatic, n=63) and those without concerns (Nonsymptomatic, n=22). Results Symptomatic participants scored higher symptom scores compared to the Nonsymptomatic group (P<0.001). No differences were found between groups for age (P=0.152), number of concussions (P=0.193), total years played (P=0.385), or professional career length (P=0.711). Symptomatic group reaction times were slower to the Nonsymptomatic group (P<0.001). Reaction time variability were greater in the symptomatic group (P=0.002). Differences between groups were found for amplitude discrimination (sequential: P=0.031; simultaneous: P=0.036) and temporal order judgment (P=0.032). Significant correlations were found between total symptom scores and all somatosensory tasks. Correlations showed associations between total exposure years with temporal order judgement and reaction time. Conclusions. This novel study showed altered sensorimotor perception in retired athletes with persistent symptoms. Our data adds to the growing pathophysiological evidence in those who experience repetitive neurotrauma during their playing careers.