March 2019 By

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 are major neurocognitive disorder or mild neurocognitive disorder Due to Traumatic Brain Injury.[1]


About 2% of the population lives with TBI-associated disability. Males account for the majority of TBI cases.


Individuals with TBI can also present with Posttraumatic Stress Disorder (PTSD). Both have common neuropsychiatric symptoms including anxiety, irritability, insomnia, personality changes, and memory problems, and this overlap can sometimes complicate the diagnostic picture.[2]

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.


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[3]

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.


The cognitive presentation and symptoms of a TBI 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. Traumatic brain injuries may also be associated with:

  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

Severity ratings for traumatic brain injury

Injury characteristic Mild TBI Moderate TBI Severe TBI
Loss of consciousness <30 min 30 minutes-24 hours >24 hours
Posttraumatic amnesia <24 hours 24 hours-7 days 7 days
Glasgow Coma Scale on assessment 13-15 (not below 13 at 30 minutes) 9-12 3-8

Biomarkers for acute concussion have been identified, including ubiquitin carboxy-terminal hydrolase L1 (UCH-L1).[4] The FDA has recently approved this for clinical use.

There are no approved pharmacological treatments for TBI, and use is off-label to address neuropsychiatric symptoms related to the injury, including medications such as SSRIs.[5] Rivastigmine has been demonstrated to have some benefits in cognitive function for traumatic brain injury patients with moderate to severe memory deficits.[6]

Neurobehavioral symptoms tend to be most severe in the immediate aftermath of a TBI. Unless there is a severe TBI, the typical course is complete or substantial improvement of neuropsychiatric symptoms. Approximately 80% of all TBIs are of mild severity.[7]


Mild Moderate-Severe
The symptoms associated with mild TBI tend to resolve within days to weeks after the injury, with complete resolution typical by 3 months. Other symptoms that may potentially co-occur with the neurological symptoms (e.g., depression, irritability, fatigue, headache, photosensitivity, sleep disturbance) also tend to resolve in the weeks following mild TBI. With moderate and severe TBI, in addition to persistence of neurocognitive deficits, there may be associated neurophysiological, emotional, and behavioural complications. These include seizures (particularly in the first year), photosensitivity, hyperacusis, irritability, aggression, depression, sleep disturbance, fatigue, apathy, inability to resume occupational and social functioning at pre-injury level, and deterioration in interpersonal relationships. Moderate and severe TBI have been associated with increased risk of depression, aggression, and possibly neurodegenerative diseases such as Alzheimer's disease.

In some instances, the severity of neurocognitive symptoms may appear to be inconsistent with the severity of the TBI. After previously undetected neurological complications (e.g., chronic hematoma) are excluded, the possibility of diagnoses such as somatic symptom disorder or factitious disorder need to be considered. Posttraumatic stress disorder can co-occur with the neurocognitive impairment and have overlapping symptoms (e.g. - difficulty concentrating, depressed mood, aggressive behavioural disinhibition).