Concussion, also known as mild traumatic brain injury (mTBI), is  caused by either a direct blow to the head, face, neck, or elsewhere on the body with an impulsive force transmitted to the head which typically results in the rapid onset of short-lived impairment of neurological function that resolves spontaneously. However, in some cases signs and symptoms evolve over a number of minutes to hours.

The acute clinical signs and symptoms largely reflect a functional disturbance rather than a structural injury with abnormality is seen on standard structural neuroimaging studies.

 It presents with a range of clinical signs and symptoms that may or may not involve loss of consciousness. Resolution of clinical and cognitive features typically follows a sequential course which in some cases may be prolonged.