The Court as Gatekeeper of Concussion Diagnosis Evidence

Diagnosing Concussion

Claims of minor traumatic brain injury (MTBI), more commonly known as concussion, have long been the subject of intense legal battles in the courtrooms of British Columbia. At the heart of the dispute is that there is no single determinative test to diagnose or rule out an MTBI. For example, MRI scans (which can track structural changes in the brain) are often normal following an MTBI, as the damage from an MTBI manifests on a microscopic level. As a result, MTBI is generally diagnosed on clinical assessment, based on the plaintiff’s report of impaired consciousness, amnesia, and/or cognitive/memory complaints, among other diagnostic indicators.

That said, certain imaging tests may be more informative than others. In contrast to MRI or CT scans, which capture structural information, functional imaging tests such as Single Photon Emission Computed Tomography (SPECT) show blood flow activity in tissue and provide insight into their functioning. For instance, in the brain, SPECT can not only identify parts of the brain affected by certain vascular and seizure disorders, but it can also be used to reliably distinguish between them, as they show distinct blood flow patterns.

As for its application in the diagnosis of an MTBI, there is significant contention in the scientific community on this point. In recent years, courts in British Columbia and Ontario have been asked to weigh in on the reliability of SPECT from a legal standpoint.

Gutfriend v. Case

Most recently, the Supreme Court of British Columbia in the case of Gutfriend v. Case, 2022 BCSC 2055 (“Gutfriend”), conducted a voir dire on the issue of whether SPECT results and interpretations of such tests were admissible as part of the plaintiff’s expert evidence.

The underlying action arose out of a multiple-vehicle collision as a result of which the plaintiff allegedly sustained physical, psychological, and cognitive injuries. The plaintiff sought to tender an expert report opining that she suffers from post-concussion syndrome and posttraumatic stress disorder. The defence expert report opined that the plaintiff suffers from posttraumatic stress disorder, major depressive disorder, and anxious distress. The disputed sections of the plaintiff’s expert report were the results and interpretation of SPECT scans of the plaintiff’s brain used to confirm clinical findings of concussion and post-concussion syndrome.

In the voir dire, the Court analyzed the threshold preconditions for admitting expert evidence (as set out in White Burgess Langille Inman v. Abbott and Haliburton Co., [2015] 2 S.C.R. 182):

1. The evidence must be logically relevant;
2. The evidence must be necessary to assist the trier of fact;
3. There must be no exclusionary rule prohibiting the reception of the evidence;
4. The expert must be properly qualified;
5. For opinions based on novel or contested science or science used for a novel purpose, the underlying science must be judged legally reliable for that purpose.

At this threshold stage of the analysis, the disputed evidence was found to meet the first four preconditions. Additionally, the parties agreed at the outset that the use of SPECT scans to diagnose or assist in the diagnosis of a MTBI should be characterized as novel science. Therefore, the bulk of the Court’s analysis was centred around whether the underlying science was legally reliable with respect to the issue of distinguishing MTBI from other psychiatric conditions.

The factors informing reliability, as set out in R. v. J.-L.J, 2000 SCC 51, include:

• Whether the theory or technique can be or has been tested;
• Whether the theory has been subjected to peer review and publication;
• The known or potential rate of error for the existence of standards; and
• Whether the science and methodology have found general acceptance within the scientific community.

The Court analyzed a number of articles and guidelines on the use of SPECT for diagnosing brain injury and heard oral evidence from several experts on the current state of the science.

Having regard to the above reliability factors, the Court found that while SPECT could detect changes in blood flow associated with neuropsychological sequela associated with brain injury, it could not determine, on an individual patient level, whether the changes were due to other conditions, such as depression, posttraumatic stress disorder, anxiety, and/or lack of sleep.

In other words, SPECT was found to be a sensitive, but not a specific, test for MTBI. SPECT could not provide legally reliable diagnostic information to distinguish brain injury from other psychiatric disorders.

As a result, the Court ordered that the SPECT results and any opinions arising out of same were not admissible.

Implications

The Court in Gutfriend arrived at a similar result to the Ontario Supreme Court decision of Meade v. Hussein, 2021 ONSC 7850 (“Meade”), which did not find SPECT evidence reliable as a primary diagnostic tool where it was necessary to distinguish brain injury from anxiety or depression. The same court subsequently distinguished Meade in Wabie v Wilson, 2022 ONSC 4296 (“Wabie”), which admitted SPECT scan results as evidence at trial as it was tendered to support an existing diagnosis of traumatic brain injury, and it was not necessary to distinguish the injury from other psychiatric conditions.

In Gutfriend, the Court did not consider whether the SPECT results were relied on as a primary or supporting diagnostic tool. Instead, it appears the Court was primarily concerned with the reliability of SPECT to diagnose an MTBI where the plaintiff was claimed to have other psychiatric conditions which could present in SPECT scan imaging in the same way as an MTBI. It remains to be seen in British Columbia whether SPECT results may be admitted where other psychiatric conditions are not at issue, as in Wabie.

While the Court did not necessarily close the door on admitting SPECT evidence outright, Gutfriend serves as a reminder to plaintiff and defence counsel alike that proposed evidence based on novel science will be subject to rigorous analysis by the trial judge in their role as gatekeeper of expert evidence.

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