A preliminary investigation of motor evoked potential abnormalities following sport-related concussion

Brain Inj. 2010;24(6):904-13. doi: 10.3109/02699051003789245.


Background: Assessment of concussion is primarily based on self-reported symptoms, neurological examination and neuropsychological testing. The neurophysiologic sequelae and the integrity of the corticomotor pathways could be obtained by evaluating motor evoked potentials (MEPs).

Objectives: To compare MEPs obtained through transcranial magnetic stimulation (TMS) in acutely concussed and non-concussed collegiate athletes.

Methods: Eighteen collegiate athletes (12 males, six females, aged 20.4 +/- 1.3 years) including nine subjects with acute concussion (<or=24 hours) matched to nine control subjects. TMS was applied over the motor cortex and MEP responses were recorded from the contralateral upper extremity. MEP thresholds (%), latencies (milliseconds per metre) and amplitudes were assessed. Central motor conduction time (CMCT) was calculated from MEP, M response and F wave latencies. Testing was performed on days 1, 3, 5 and 10 post-concussion.

Results: Ulnar MEP amplitudes were significantly different between post-concussion days 3 and 5 (F(3,48) = 3.13, p = 0.041) with smaller amplitudes recorded on day 3 (0.28 +/- 0.10 ms m(-1)). Median MEP latencies were significantly longer (F(3,48) = 4.53, p = 0.023) 10 days post-concussion (27.1 +/- 1.4 ms m(-1)) compared to day 1 (25.7 +/- 1.5 ms m(-1)). No significant differences for motor thresholds or CMCTs were observed (p > 0.05).

Conclusion: MEP abnormalities among acutely concussed collegiate athletes provide direct electrophysiologic evidence for the immediate effects of concussion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Athletic Injuries / physiopathology*
  • Brain Concussion / physiopathology*
  • Electric Stimulation
  • Electromyography
  • Evoked Potentials, Motor / physiology*
  • Female
  • Humans
  • Male
  • Neuropsychological Tests
  • Students
  • Universities
  • Young Adult