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Signs and Symptoms

Signs and symptoms of an injury to the brain may include:2, 8, 9, 11

Cognitive symptoms

  • Attention difficulties, 
  • Concentration problems,
  • Memory problems, and/or
  • Orientation problems.

Physical symptoms

  • Headaches,
  • Dizziness,
  • Insomnia,
  • Fatigue,
  • Uneven gait,
  • Nausea,
  • Blurred vision, and/or
  • Seizures.

Behavioral changes 

  • Irritability,
  • Depression,
  • Anxiety,
  • Sleep disturbances,
  • Problems with emotional control,
  • Loss of initiative, and/or
  • Problems related to employment, marriage, relationships, home management, or school 


MTBI diagnosis should be considered when one or more of the following conditions occur following a brain injury:2, 8

  • Confusion or disorientation,
  • Amnesia near the time of the injury,
  • Loss of consciousness up to 30 minutes, 
  • Neurological or neuropsychological problems, and/or
  • Score of 13 or higher on the Glasgow Coma Scale (GCS).

Diagnosing MTBIs can be challenging because symptoms often are
common to other medical problems, and onset of symptoms may occur days, weeks, or months after the initial injury.2, 8  In diagnosing children, physicians can refer to the 1999 recommendations of the American Academy of Family Physicians and the American Academy of Pediatrics contained on the CD-ROM in this brain injury tool kit and available at the AAP website

In assessing patients for possible MTBI, it is important for physicians to determine whether there is any evidence that a brain or other intracranial injury is present or is likely to have occurred, especially among:

  • Patients who did not see a physician after sustaining an injury,
  • Patients referred by an emergency department,
  • Patients facing orthopedic or facial trauma surgery, and
  • Patients who did not receive follow-up care following admission to a hospital for an injury.

Diagnostic Tests

Diagnostic tests may include imaging. In certain circumstances (for example, when a patient is a participant in sporting events) evidence-based evaluation guidelines, such as the American Academy of Neurology Practice Parameter: The Management of Concussion in Sports, can be used. The CD-ROM in this brain injury tool kit contains the summary statement of these guidelines. For information about non-sports-related concussions, refer to the McCrae, Kelly, et al. article, also contained on the CD-ROM. Neuropsychological tests are useful to identify cognitive deficits, both acutely and during the follow-up period.

History Taking

Close, careful history taking is essential in diagnosing MTBI. Questioning patients as to whether they have had an injury or accident is an important first step because some patients may not mention it to their physicians. Reasons for this may include: 

  • Some may not consider the injury serious because they were told the condition was mild or just a "bump on the head,"
  • Some may not realize they received a head injury because they were briefly unconscious at the time of the incident,
  • Some may focus on a more severe injury that occurred at the same time, 
  • Some may be too embarrassed to mention certain symptoms, such as memory problems.2 

For these reasons careful history taking to ascertain the nature of the problem is very important.

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This page last reviewed September 07, 2006.

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Centers for Disease Control and Prevention
National Center for Injury Prevention and Control