Traumatic Brain Injury

Location and Definition

A traumatic brain injury (or TBI) is an injury to the brain caused by an external physical force, which can have temporary or permanent cognitive, behavioral and/or physical impairments. The brain consists of the cerebellum, brainstem, corpus collosum and four lobes (frontal, temporal, parietal and occipital).


The frontal lobe is responsible for motor planning, motor movement, executive functions, personality and memory. The parietal lobe is responsible for goal-directed voluntary movement, spatial and touch perception, visual attention and perception, integration of sense and manipulation of objects. The temporal lobe is responsible for understanding language, sequencing, organization, memory acquisition and hearing abilities. The occipital lobe is responsible for vision. The cerebellum is responsible for voluntary movement, balance and equilibrium. The brainstem is responsible for heart rate, swallowing, breathing, the autonomic nervous system, balance, alertness and ability to sleep. The corpus collosum enables the two brain hemispheres to communicate and coordinate activities.


Primary injuries to the brain include diffuse axonal injury (i.e. stretching and tearing of brain cell axons), contusion (i.e. a bruise to the brain surface) and penetrating direct laceration (i.e. a cut to the brain). Secondary injuries to the brain include epidural hematoma (i.e. an accumulation of blood between the inner tables of the skull and the stripped-off dural membrane), subdural hematoma (i.e. a buildup of blood on the surface of the brain), hypoxia (i.e. a condition where the brain is not getting enough oxygen) and increased intracranial pressure (i.e. growing pressure within the craniospinal compartment).

A brain injury can also be classified as open, closed, coup-contrecoup or penetrating. An open head injury is where the skull is fractured or displaced. A closed head injury is where no fractures are present. A coup-contrecoup is where contusions are present on the side of the brain that was impacted, as well as the opposite side. A penetrating head injury is where the dura mater, the outermost layer of the brain, is breached, caused by objects of higher or lower velocity.

A brain injury can also be classified as mild, moderate or severe. A mild TBI is characterized by no loss of consciousness or a very brief loss of consciousness, usually no post-traumatic amnesia and may result in temporary or permanent behavioral, cognitive impairments and/or physical impairments. A moderate TBI is characterized by loss of consciousness that lasts between a few minutes and a few hours, post-traumatic amnesia for up to 96 hours and results in temporary or permanent behavioral, cognitive and/or physical impairments. A severe TBI is characterized by a loss of consciousness for days, weeks, months or indefinitely, extensive pre- and post-traumatic amnesia and results in permanent behavioral, cognitive and/or physical impairments, a persistent vegetative state or a minimally responsive state.


A TBI can be caused by either a physical trauma to the neck and/or head or by a sudden acceleration and deceleration of the brain in the skull. A TBI can be caused by a wide range of different situations including motor vehicle accidents and sporting accidents.

Short-Term Treatment

Acute medical treatment of a brain injury can include the applicable head injury routine, medications, hospitalization, surgery, and rehabilitation and assessment.

Potential Ongoing Sequelae

Someone with brain injury may experience aftereffects of the injury, including: cognitive and behavioral impairments such as impulsivity and chronic fatigue; psychological impairments such as clinical depression and anhedonia; physical impairments such as spasticity and impaired balance; headaches, seizures and sleep disorders; and increased risk of future brain injury.

Potential Long-Term Functional Limitations

Potential long-term impairments can occur to self-care and caregiving ability, to ability to sustain relationships, to ability to participate and work in leisure roles and to ability to live independently.

Long-Term Treatment

Depending on the level of injury, a patient with brain injury may need, in terms of future care, one or more of the following: attendant care services; rehabilitation support workers; speech therapy; physiotherapy; occupational therapy; social work; psychological counseling; family counseling; vocational rehabilitation; housekeeping and home maintenance services; various devices (e.g. mobility-related, etc.); and transportation.

Legal Ramifications

People who have suffered a TBI in a MVA may qualify to be deemed to be catastrophically impaired. Recall that different benefits and maximum benefit levels apply according to whether an injury is a minor injury, catastrophic injury or neither. An example of a TBI that qualifies as a catastrophic impairment is if the patient is 18 years of age or older and there is diagnostic evidence of diffuse axonal injury. Consult with your lawyer about the legal classification of your TBI.


In Z.R. v. A.R. Certas Direct Insurance Company (, the applicant sought a determination that he was catastrophically impaired pursuant to s. 3.1(1) 5.i of the SABS (as amended June 2016). On October 13, 2016, the applicant was struck by a vehicle while trick or treating. He was 13 years old at the time of the accident. The respondent insurer denied that the applicant sustained a catastrophic impairment. The applicant disagreed with the respondent’s position and applied to the License Appeal Tribunal for dispute resolution. The issue in this hearing was whether the applicant sustained a catastrophic impairment. The Tribunal decided that he had not. The applicant had been immediately rushed to Sick Kids Children’s Hospital to correct the fracture of his right femur (thigh bone). A CT scan was taken of the applicant’s brain which showed normal. He was an in-patient from October 31 to November 8, 2016. Later in November 2016, the applicant was seen at Holland Bloorview for headaches, noise and light sensitivity, fogginess and nausea, but the CT scan showed normal, although the doctors noted that he may have sustained a concussion. At a follow-up in December 2016, the symptoms of headaches and sound sensitivity had resolved, and it was expected all of his symptoms would resolve with no long-term effects. On February 22, 2017 he had tests conducted at Southlake and the doctor concluded that the applicant had sustained a previous TBI and completed an OCF-19; however, the respondent referred the document to a radiologist who concluded that the Southlake test results did not indicate a TBI. The Tribunal reasoned that the injury did not constitute a catastrophic impairment within the meaning of s. 3.1(1) 5.i “accepted for admission, on an out-patient basis, to a public hospital named in the Guideline with positive findings on a CT scan, MRI or any other medically recognized brain diagnostic technology indicating intracranial pathology that is a result of the accident …”. The Tribunal found that the applicant had not met this legal definition because he was not admitted to the hospital because of positive findings on a brain diagnostic technology and because the results were not made while the applicant was an in-patient at the hospital (which was from October 31 to November 8, 2016) but well after (on February 22, 2017).


Mayo Clinic Staff, “Traumatic Brain Injury – Symptoms and Causes” (February 4, 2021):

Lisa Zaretsky and Bonnie Koreen, “Spinal Cord Injuries”, Sprains, Strains and Automobiles: A Medically Illustrated Guide to Commonly Litigated Injuries. Toronto, Ontario: Carswell, January 1, 2011.

Statutory Accident Benefits Schedule (or “SABS”), made under the Insurance Act, R.S.O. 1990, c.I.8, s 3(1).