The purpose of this study is to prospectively collect a comprehensive, multi-modality set of diagnostics on patients who have had a concussion, repeating some of these tests serially over time, so that the investigators may then in the future perform retrospective data mining to determine if there were a biomarker or risk calculator that could be used to guide return-to-play and other medical decisions.

Concussions comprise a type of mild traumatic brain injury in which mechanical forces disrupt brain metabolism causing transient neurological symptoms.

At the current time, there is no universally agreed-upon objective biomarker or risk calculator of concussion upon which physicians can prognosticate future risk, identify optimal treatments, and for sports medicine physicians, decide if and when a particular player were safe to be returned to play.

While the majority of patients experience a full recovery within a few weeks of a concussion, several going on to have chronic, debilitating symptoms, and all patients experience a permanently increased risk of experiencing more debilitating and long-lasting symptoms with each subsequent concussion. For certain people with certain genetic (e.g., ApoE status) and psychosocial (e.g., alcohol abuse, depression) risk factors, even a single concussion can put them at greater risk for earlier and more severe forms of dementia decades hence.

The purpose of this study is to prospectively collect a comprehensive, multi-modality set of diagnostics on patients who have had a concussion, repeating some of these tests serially over time, so that the investigators may then in the future perform retrospective data mining to determine if there were a biomarker or risk calculator that could be used to guide return-to-play and other medical decisions.

This study plans to collect biological specimens (blood, saliva, urine, hair follicles), electrophysiological (EEG, EKG), imaging (HCT, MRI, PET, SPECT), ambulatory (actigraphy), sensory thresholds (Von Frey), ophthalmologic (fundoscopic photographs, OCT, SSVEPs), vestibular (ENG, BESS, BioSway) along with demographic, medical history, medication, psychosocial data and the results on validated instruments of cognition, mood, sleep, head discomfort and quality of life.

Because it is important to determine the variability not only within the concussion group but also between groups, the investigators will also recruit a control cohort, specifically athletes who are already undergoing baseline cognitive testing pre-season. The clinical focus of this study will be on concussed athletes, both children and adults, and the investigators will also include non-sports patients who have mild traumatic brain injury due to other situations including slip and fall, occupational, motor vehicle accidents, assault, and blast exposure.

Inclusion Criteria:

• All patients, 10 years of age or older with concussion being evaluated at the Jefferson Comprehensive Concussion Center in Philadelphia, PA, or by Jefferson Comprehensive Concussion Center physicians at other locations (including Rothman Institute sports medicine clinics in Bryn Mawr, PA, Marlton, NJ, Washington Township, NJ). The target population will be those with suspected concussions.

Exclusion Criteria:

• Patients not presenting at the Jefferson Comprehensive Concussion Center or affiliated locations.

Individuals ages 10 or older. If the patient has experienced a suspected concussion, must be a patient at the Jefferson Comprehensive Concussion Center.