The neural legacy of a single concussion.

It has been hypothesized that concussions impart lasting brain damage, even after a patient has ostensibly recovered. This hypothesis is based largely upon neuropathological studies in deceased athletes, however, leaving open the question of whether it can be detected in vivo. We measured neural responses to speech in collegiate student-athletes with a history of a single concussion from which they had recovered. These student-athletes had weaker responses to speech than age- and position-matched peers. This group difference suggests that concussions engender small, but detectable, changes in brain function prior to the emergence of frank behavioral indications.