Traumatic Brain Injury

Traumatic Brain Injuries (TBIs) is an intracranial injury that occurs when an external force injures the brain. When clinically significant, the DSM-5 diagnoses these for these injuries are Major/Mild Neurocognitive Disorder Due to Traumatic Brain Injury.[1]


Concussions can be considered a form of mild traumatic brain injury. A regional study of Canadian adolescents found that approximately 20% had sustained a concussion[2]

Chronic Traumatic Encephalopathy (CTE)

Chronic traumatic encephalopathy (CTE) is a term used to describe brain degeneration likely caused by repeated head trauma. A diagnosis of CTE can only be made during autopsy. CTE is a rare condition and usually found in individuals who play contact sports.

Criterion A

The criteria are met for major or mild neurocognitive disorder

Criterion B

There is evidence of a traumatic brain injury—that is, an impact to the head or other mechanisms of rapid movement or displacement of the brain within the skull, with one or more of the following:

  1. Loss of consciousness.
  2. Posttraumatic amnesia.
  3. Disorientation and confusion.
  4. Neurological signs (e.g., neuroimaging demonstrating injury; a new onset of seizures; a marked worsening of a preexisting seizure disorder; visual field cuts; anosmia; hemiparesis).
Criterion C

The neurocognitive disorder presents immediately after the occurrence of the traumatic brain injury or immediately after recovery of consciousness and persists past the acute post-injury period.

Major or mild NCD due to traumatic brain injury (TBI) is caused by an impact to the head, or other mechanisms of rapid movement or displacement of the brain within the skull, as can happen with blast injuries. Traumatic brain injury is defined as brain trauma with specific characteristics that include at least 1 of the following (Criterion B):

  1. Loss of consciousness
  2. Post-traumatic amnesia
  3. Disorientation and confusion, or, in more severe cases, neurological signs (e.g., positive neuroimaging, a new onset of seizures or a marked worsening of a pre-existing seizure disorder, visual field cuts, anosmia, hemiparesis).

To be attributable to TBI, the NCD must present either immediately after the brain injury occurs or immediately after the individual recovers consciousness after the injury and persist past the acute post-injury period (Criterion C).

The cognitive presentation is variable. Difficulties in the domains of complex attention, executive ability, learning, and memory are common as well as slowing in speed of information processing and disturbances in social cognition. In more severe TBI in which there is brain contusion, intracranial hemorrhage, or penetrating injury, there may be additional neurocognitive deficits, such as aphasia, neglect, and constructional dyspraxia.

Associated Features Supporting Diagnosis

Major or mild NCD due to TBI may be accompanied by:

  1. Disturbances in emotional function (irritability, easy frustration, tension and anxiety, affective lability)
  2. Personality changes (disinhibition, apathy, suspiciousness, aggression)
  3. Physical disturbances (headache, fatigue, sleep disorders, vertigo or dizziness, tinnitus or hyperacusis, photosensitivity, anosmia, reduced tolerance to psychotropic medications)
  4. Seizures, hemiparesis, visual disturbances, cranial nerve deficits (particularly in more severe TBI, neurological symptoms and signs)
  5. Evidence of orthopedic injuries

Biomarkers for acute concussion have been identified, including ubiquitin carboxy-terminal hydrolase L1 (UCH-L1). [3] The FDA has recently approved this for clinical use.