Objective case study presents data using multimodal assessment using impact sensors, oculomotor function and transcranial magnetic stimulation (TMS) to quantify neurophysiological changes in the acute period following concussion.
Design Case control study.
Participants Over one season, we evaluated a male rugby union player (age: 29 years; prior concussions: 1; last concussed >120 months) for head impacts using impact sensors (X2 Biosystems, USA) and oculomotor function (King-Devick test).1 TMS (MagVenture, Denmark) protocols utilised previously published methods for concussion studies2,3 with data compared to our normative database of age-group controls (33 males; mean age: 28.6±3.9 years).
Intervention Any impact that resulted in a concussion, confirmed by the team doctor, required post-match testing utilising the King-Devick test and follow up testing for TMS at 5 d and 12 d.
Outcome measures Time and errors completing the King-Devick test. TMS measures included latency (TMS stimulus to evoked potential onset ), evoked potential amplitude, and intracortical inhibition (TMS onset to return of uninterrupted electromyography activity).
Main results An impact of 60.7 g/17, 114.1 rads/s2 revelead a decreased King-Devick performance of 3.8 s. At 30 d King Devick remained below pre concussion baseline. Compared to controls, TMS revealed increased intracortical inhibition duration of 20.6 ms at 5 d post concussion, and returning to baseline/control levels by 12 d.
Conclusions This novel case study demonstrates the value of using multimodal measurements in the assessment of concussion and return to play decisions.
Competing interests None.
AJP is supported, in part, by a research grant by the Australian Football League.