Only the study team can determine whether someone qualifies for participation.
Inclusion criteria
fluent in English, and a history of multiple concussions , low exposures , or no concussions (Control group ). Determination of concussion exposure will be determined as follows: Previous concussion will be based on the player's recall of injury and defined as "an injury resulting from a blow to the head that caused an alteration in mental status and one or more of the following symptoms: headache, nausea, vomiting, dizziness/balance problems, fatigue, trouble sleeping, drowsiness, sensitivity to light or noise, blurred vision, difficulty remembering, and difficulty concentrating.
Exclusion criteria
Neurological disorders prior to concussions (e.g.: seizure disorder); systemic illnesses known to affect the brain (e.g., diabetes and lupus); a history of psychotic disorder; known developmental disorders (e.g., attention deficit disorder, dyslexia); history of migraines; and, active engagement in litigation.