TY  - JOUR
PY  - 2014//
TI  - Cortical hypoexcitability persists beyond the symptomatic phase of a concussion
JO  - Brain injury
A1  - Powers, Kaley C.
A1  - Cinelli, Michael E.
A1  - Kalmar, Jayne M.
SP  - 465
EP  - 471
VL  - 28
IS  - 4
N2  - Primary objective: The purpose of this research was to assess cortical excitability, voluntary activation of muscle and force sensation beyond the initial highly symptomatic period post-concussion (1-4 weeks post-injury). It was hypothesized that reduced excitability of the motor cortex may impair muscle activation and alter perceptions of force and effort. Research design: Eight concussed varsity football players were age- and position-matched with eight healthy teammates to control for training and body size. Healthy controls had not suffered a concussion in the previous 12 months. <br><br>METHODS and procedures: Paired-pulse transcranial magnetic stimulation was used to assess cortical excitability, voluntary activation was calculated using cortical twitch interpolation technique and sense of force was determined using constant-force sensation contractions. Main outcomes and results: The concussed group had lower intra-cortical facilitation (p = 0.036), lower maximal voluntary muscle activation (p = 0.038) and greater perceptions of force (p < 0.05), likely due to compensatory increases in upstream drive, than their healthy matched teammates. <br><br>CONCLUSIONS: Taken together, these findings suggest a state of hypoexcitability that persists beyond the immediate acute phase of a concussion and may result in neuromuscular impairments that would call to question the athlete's readiness to return to sport.    Keywords: American football; Canadian football; soccer<p />  <p>Language: en</p>
LA  - en
SN  - 0269-9052
UR  - http://dx.doi.org/10.3109/02699052.2014.888759
ID  - ref1
ER  -