Concussion: Symptoms & Signs

  • Medical Author:
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

Medically Reviewed on 1/25/2016

A concussion is a form of minor brain trauma in which the function of the brain becomes altered but no abnormalities can be detected by imaging tests such as CT scans. Symptoms of a concussion are typically short-lived and go away on their own. The symptoms may be obvious or may be so subtle that the affected person does not realize they have suffered a concussion. Some of the more common symptoms of concussion include

  • headache,
  • feeling foggy, or that one's thinking is slowed or altered,
  • nausea,
  • lightheadedness,
  • dizziness,
  • irritability or emotional changes,
  • problems concentrating or remembering new information.

Sometimes people with a concussion will lose consciousness (pass out), but this does not happen in most cases. Not all symptoms of concussion will occur in every case; sometimes the symptoms differ depending on the location and extent of the injury. For example, some people suffering from a concussion may sleep excessively while others have insomnia. Symptoms of concussion can last for days, weeks, or occasionally even longer.

Concussion causes

Concussion is caused by a traumatic injury to the head. Concussion injuries are particularly common in those (including children and teens) who participate in athletic events.


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.

United States. Centers for Disease Control and Prevention. "Facts About Concussion and Brain Injury." <>.

Medically Reviewed by a Doctor on 1/25/2016

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