Concussion: Causes, Signs, & Symptoms

A concussion is a term used for a head injury that causes a traumatic brain injury which results in a disturbance of brain function.

Concussions can be caused by a direct blow to the head. They can also occur when blows to other parts of the body result in rapid movement of the head (e.g. whiplash type injuries).

Any alteration in an individual’s mental status from a head injury (whether or not they lose of consciousness) will be considered a concussion.  Loss of consciousness (being knocked out) occurs in less than 10% of concussions.  Despite popular belief, loss of consciousness is not a requirement for diagnosing a concussion. It is, however, a clear indication that a concussion may have been sustained.

An individual with a history of two or more concussions within the past year is at a greater risk for further brain injury and slower recovery.  They should seek medical attention from an experienced concussion health care provider immediately. Concussions can be fatal, and an athlete should not return to an event, practice, or play if symptoms persist.

Symptoms of a concussion

Symptoms may not show immediately and can present at any time.  The symptoms typically become evident in the first 24 to 48 hours following a head injury but can occur at any time. Symptoms showing minutes after the injury to hours are considered early symptoms. Those that occurs days and/or weeks later are considered late symptoms.

Early symptoms include headache, dizziness, confusion, visual problems, nausea, fatigue, difficulty concentrating, sensitivity to light, pressure in the head, and more.

Late symptoms can include: persistent low-grade headaches, lightheadedness, poor concentration, memory dysfunction, quick fatigability, irritability, light sensitivity, vision problems, intolerance to loud noises, ringing in ears (tinnitus), neck pain, anxiety, depressed mood, and sleep disturbances.

Other signs of a concussion may include any of the following: seizures, loss of consciousness, confusion, memory deficits, inability to focus attention, unsteady on feet or balance problems, poor coordination, disorientation (not aware of where they are, who they are, or time of day), dazed, blank, or vacant look, behavioral changes (more emotional or more unstable), delayed verbal or motor responses, slurred or incoherent speech.  Lying motionless on the ground, slow to get up, and grabbing or clutching the head are also considered signs of a concussion after an injuring event.

Key takeaways:

• It is important to remember that a Concussion is a traumatic injury resulting in a disturbance of brain function.
• Concussions can be caused by a direct head injury, but can also occur when an injury or impact to another part of the body result in a rapid movement of the head (e.g. whiplash).
• A Loss of consciousness occurs in less than 10% of concussions and should never be the only requirement for diagnosing a concussion.
• Symptoms of a concussion can present at any time, but typically become evident in the first 24-48 hours following a head injury.
• Common concussion symptoms include; headache, dizziness, memory disturbance, and/or balance problems.