Criterion 4 of the Catastrophic Impairment Determination

When assessing for Catastrophic Impairment, for accidents post-June 1, 2016, an individual may be assessed under criterion 4 if there was a traumatic brain injury at the time of the motor vehicle accident and the individual was at least 18 years old. As part of the analysis, the injury must have occurred as a result of the motor vehicle accident.


There also must have been positive findings on computerized axial tomography (CAT) scan, a magnetic resonance imaging (MRI) or any other medically recognized brain diagnostic technology indicating intracranial pathology. It is not yet clear if the Licence Appeal Tribunal (LAT) will accept that, other medically recognized brain diagnostic technology can include Single Photon Emission Computed Tomography (SPECT) or neuropsychological assessments, but these issues will likely be addressed by the LAT in the future. Finally, the Extended Glasgow Outcome Scale (GOS-E) must be considered. The individual must meet one of the following criteria to qualify for Catastrophic Impairment:


  1. Vegetative State (VS or VS*), one month or more after the accident,
  2. Upper Severe Disability (Upper SD or Upper SD*) or Lower Severe Disability (Lower SD or Lower SD*), six months or more after the accident, or
  3. Lower Moderate Disability (Lower MD or Lower MD*), one year or more after the accident.


As part of the GOS-E assessment, the cause of the impairment must be determined and as instructed in the GOS-E Guide and as confirmed in Hilded Abdi vs. TD General Insurance Company, released on December 6, 2021, the cause of the impairment as rated on the GOS-E must be the Traumatic Brain Injury and not other physical or psychological impairments.


While an Occupational Therapist can complete the GOS-E, as outlined in Hilded Abdi vs. TD General Insurance Company, it is best left to physicians and neuropsychologists to determine the cause. Physicians, and more specifically psychiatrists, are well-suited to opine on the cause of the impairment because of their training in evaluating individuals’ psychological impairments. Furthermore, as physicians, psychiatrists are trained in assessing medical conditions that may contribute to psychological impairments. For example, when determining relevant psychiatric diagnoses according to the Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DSM-5), which is the most widely used psychiatric diagnostic system in Canada, most diagnoses require the clinician to consider if the symptoms could be explained by another medical condition or the effects of a substance.


About the Author:

At PsycIME, Dr. Emily Gavett-Liu has a broad experience in evaluating and treating individuals with traumatic brain injuries. Dr. Gavett-Liu’s depth of experience allows her to provide reasoned and educated opinions on criterion 4 catastrophic impairment determinations.

Dr. Emily Gavett-Liu
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