Court of Appeal for Ontario

Date: September 24, 2025

Docket: COA-24-CV-0126

Justices: Simmons, Wilson and Madsen JJ.A.

Between

Paul Taylor and Karen Young Plaintiffs (Respondents)

and

Pamela Zents Defendant (Appellant)

Counsel

Chris G. Paliare and Tina H. Lie, for the appellant

J. Thomas Curry and Derek Knoke, for the respondents

Heard: March 24, 2025

On appeal from: The judgment of Justice Annette Casullo of the Superior Court of Justice, dated January 8, 2024, with reasons reported at 2024 ONSC 166.

Wilson J.A.:

A. Overview

[1] Paul Taylor was injured in a motor vehicle accident when Pamela Zents rear-ended his car, which was stopped, at high speed, pushing it off the road. It became airborne, rolled over, and landed in a ditch. Taylor sued Zents in negligence, claiming damages for personal injuries, past and future income loss, and future care costs. The main injury he alleged was a minor traumatic brain injury or concussion. I will use those terms interchangeably, as the medical experts at trial did. Taylor's wife, Karen Young, sought damages under the Family Law Act, R.S.O. 1990, c. F.3, for loss of care, guidance, and companionship.

[2] The trial began before a jury. On the 12th day of trial, the trial judge, on her own initiative, declared that Zents' counsel had breached the rule in Browne v. Dunn (1893), 6 R. 67 (H.L.). The respondents moved to strike the jury. The trial judge did so, and the trial proceeded before her alone. She awarded the respondents a combined total of more than a million dollars in damages.

[3] Zents appeals. She argues that the trial judge erred in finding a breach of Browne v. Dunn, and furthermore, she erred in discharging the jury. She also contends that the trial judge should not have qualified one of Taylor's treating physicians as a "r. 53 expert", and that the trial judge misapprehended the medical evidence when determining damages.[1]

[4] I do not accept any of these arguments, and I would dismiss the appeal.

B. Factual Background

[5] In March of 2015, while travelling at 80 km/h, Zents rear-ended Taylor's car, propelling him off the road and into a ditch. When paramedics arrived, Taylor told them that he had a bump on his head, but that he had not lost consciousness and felt fine. The paramedics reported that he had a "small head hematoma" and was "conscious, alert and oriented to person, place and time".

[6] But the next morning, Taylor woke up feeling like he had been "hit by a truck". He felt "very out of it, confused and spacy". He went to the emergency room, where Dr. Aidan Cunniff diagnosed a concussion. At the time, Taylor worked as a first camera assistant in the film and television industry, averaging about $56,000 per year in income. He returned to work four days after the accident and remained there until March 2017, when he stopped working, a decision he attributed to his symptoms.

[7] In the years between the accident and the trial, Taylor saw numerous medical practitioners. Below, I summarize some of those consultations and the symptoms he reported, to the extent they are relevant. I then set out the trial process that led to the qualification of one of Taylor's treating physicians as an expert witness, and the breach of Browne v. Dunn.

[8] Zents' position at trial was that Taylor was a malingerer who was feigning, or at least exaggerating, his head injury. To support that theory, she tried to bring out inconsistencies in how Taylor reported his symptoms to various medical practitioners. One inconsistency, which the defence focused on, was a report of fluid leaking from his ear after the accident, which Taylor only mentioned for the first time over three years after the accident when he attended the Mayo Clinic. In cross-examination, Zents' counsel asked three of Taylor's medical witnesses whether that inconsistency undermined his credibility. But Zents' counsel did not ask Taylor about it, and the trial judge found that the failure to do so breached Browne v. Dunn. The third of those medical witnesses was Taylor's psychologist, who was also qualified as a r. 53 expert, and it was the evidence of that witness that prompted the trial judge to raise the Browne v. Dunn issue.

(1) Taylor's Treatment History

[9] Three weeks after the accident, Taylor saw his family doctor, Dr. Craig Maltman. He reported having difficulty processing information, said things were not as "sharp", described feeling foggy and dizzy, and complained of back and knee pain. Taylor saw Dr. Maltman again three weeks later. According to Dr. Maltman's notes, Taylor felt like "his head [was] still not where it was before the accident" but was slowly improving. Three months after that, in August of 2015, Taylor visited Dr. Maltman once more. He reported short-term memory issues and occasional light headedness. He did not report headaches at either of these two visits. Dr. Maltman diagnosed him with post-concussion syndrome.

[10] Taylor also saw a neurologist, Dr. Verity John, in August of 2015. Taylor told Dr. John that he had "blacked out" and lost consciousness in the accident, and that he had "severe, debilitating headaches" for about two weeks after the accident, which had since resolved.

[11] Taylor continued to see Dr. Maltman regularly until 2018. As time passed, his complaints focused less on knee pain and more on persistent cognitive problems: memory loss, word-finding difficulty, inability to focus, vision trouble, and balance issues.

[12] Taylor also began seeing Dr. Joanna Hamilton, a psychologist who practised in the field of neuropsychology, in February of 2017. He saw her about 25 times between then and late 2018. She diagnosed him with post-concussion syndrome, a traumatic brain injury, and adjustment disorder. Dr. Hamilton would later become an important witness at trial. Taylor hired her to conduct a medical-legal evaluation and tendered her evidence at trial as both a treating physician and an expert witness. As I will explain below, the Browne v. Dunn issue arose during her cross-examination.

[13] In August of 2018, on his own volition, having not obtained relief from his symptoms, Taylor went to the Mayo Clinic in Minnesota to see Dr. Jeffrey Staab. Dr. Staab specializes in "persistent postural-perceptual dizziness", or "3PD". During that visit, Taylor reported to the intake doctor, not Dr. Staab, that he had fluid leaking from his ear for a few days after the accident. That was the first time Taylor had ever reported that symptom. The intake doctor did not testify at trial, but this reference was included in the Mayo Clinic brief that was filed at trial and marked as a lettered exhibit. Dr. Staab diagnosed Taylor with 3PD and post-concussion syndrome.

[14] In 2020, Taylor was assessed by a neurologist named Dr. Dale Robinson. Dr. Robinson confirmed Dr. Staab's diagnoses and concluded that Taylor had suffered a permanent and serious brain injury in the accident.

(2) Dr. Hamilton's Qualification as an Expert Witness

[15] Taylor called four of his treating physicians as participant experts: Drs. Cunniff, Maltman, Hamilton, and Staab. He also sought to call Dr. Hamilton as a r. 53 expert. Zents objected to Dr. Hamilton "wearing both hats". She argued that Dr. Hamilton could not objectively assess Taylor, because she had been paid to treat him both before and after preparing her report for the litigation, and her treatment was predicated on the assumption that the accident had caused his injuries.

[16] At a voir dire, Dr. Hamilton testified that she had "taken more of a supportive kind of role" toward Taylor, although her treatment began as cognitive behavioural therapy. She had treated him more than 25 times before her October 2018 assessment and continued to do so without interruption another 25 to 30 times. She acknowledged that, based on records she had been provided with, she had already concluded that the accident was the cause of his symptoms when she began treating him, and Taylor paid her directly following the assessment. In cross-examination, she agreed that it would be "uncomfortable" if she ultimately concluded that the accident did not cause Taylor's symptoms but maintained that she could provide an unbiased opinion and fulfil her duty as a r. 53 expert.

[17] The trial judge qualified Dr. Hamilton as a r. 53 expert. I will summarize her reasons for doing so later, when I discuss that ground of appeal.

(3) The Trial and the Breach of Browne v. Dunn

(a) Taylor's Cross-Examination

[18] Zents' counsel cross-examined Taylor at length across two days of trial. Much of that cross-examination focused on alleged problems with how Taylor reported his symptoms—especially his failure to say anything about headaches or a loss of consciousness until almost six months after the accident.

[19] To accomplish that, Zents' counsel took Taylor through his reports to the paramedics who arrived at the scene of the accident, to Dr. Cunniff at the emergency room the next day, and to Dr. Maltman in the following weeks and months. Then, Zents' counsel suggested that those reports contained material omissions compared to what Taylor told Dr. John about headaches and losing consciousness.

[20] Taylor confirmed that he told the paramedics that he felt "fine" and that he had not lost consciousness. Their notes reported that he was in no distress, and that they did not think he needed further treatment. Taylor agreed on cross-examination that he declined an offer to go to the hospital, because he too thought that was unnecessary. Zents' counsel suggested that Taylor told a police officer on the scene that he had no injuries, and Taylor agreed.

[21] Taylor also agreed that he told Dr. Cunniff that he had not lost consciousness during the accident. When Zents' counsel pressed him on that point, Taylor said that he did not realize that he had lost consciousness until later, when he was trying to recall the entirety of the incident. Taylor admitted that he had also not said anything to Dr. Cunniff about headaches.

[22] Zents' counsel then asked Taylor about his visits to Dr. Maltman. Again, Taylor acknowledged that he said nothing about a headache. When Zents' counsel suggested that this was because he never had headache symptoms, he responded that he was only talking about whether he had a headache at that particular time.

[23] The discussion then turned to Taylor's visit with Dr. John. Taylor agreed that he told Dr. John that he had "blacked out" in the collision. Zents' counsel then took him back through his earlier reports, where he had said nothing about losing consciousness. Taylor responded that he "didn't realize [he] had blacked out at that time." When Zents' counsel remarked that losing consciousness in an accident "would be a significant event" that one would expect him to report immediately, Taylor responded that he disagreed because he "was in shock." During that answer, Taylor became angry with the line of questioning, and the court took a ten-minute break.

[24] When the proceedings resumed, Zents' counsel pointed out that Taylor told Dr. John that he had hit his head on the door frame and head rest but had never mentioned that before. Zents' counsel asked how Taylor could claim to describe how he hit his head, yet also maintain that he had no memory of the collision. Further, he observed that Taylor told Dr. John that he had "severe headaches" after the accident, something that he had also never mentioned to any of the previous doctors. Zents' counsel suggested that the symptoms that Taylor reported to Dr. John were more significant than those he had reported earlier, and that Taylor was "exaggerating" at the time. Those are just some of the ways in which Zents' counsel suggested that Taylor was misrepresenting his injuries.

[25] At no point did Zents' counsel ask Taylor about his report of fluid leaking from his ear.

(b) The Ear Fluid Questions

[26] After completing his own evidence, Taylor called Dr. Staab, who had assessed him at the Mayo Clinic. In cross-examination, Dr. Staab agreed that someone who had researched the diagnosis of 3PD might have learned that fluid leaking from one's ear is a symptom. He also agreed that fluid leaking from the ear is "not a normal thing to happen", and that he would expect a patient with that symptom to report it. Taylor's counsel objected to Dr. Staab being asked whether Taylor was malingering, but not to the line of questioning about ear fluid.

[27] Taylor also called Dr. Robinson, a neurologist and r. 53 expert. Zents' counsel cross-examined him about inconsistencies in how Taylor reported his symptoms. He asked Dr. Robinson whether the headaches and loss of consciousness that Taylor reported to Dr. John represented inconsistencies, and Dr. Robinson acknowledged "I do see inconsistencies there." He then turned to the ear fluid, asking whether "that would be a significant symptom", which Dr. Robinson answered affirmatively. When confronted with Taylor's Mayo Clinic reports, Dr. Robinson conceded that the novel disclosure of leaking ear fluid "appear[ed] to be" an inconsistency.

[28] Neither Dr. Staab nor Dr. Robinson would accede to Zents' counsel's suggestion that these inconsistencies were "marked discrepancies" that raised concerns about malingering. For example, in response to a suggestion that the ear leak report at the Mayo clinic would be a fabrication of a symptom, Dr. Robinson answered, "That, I don't know. I don't know if he didn't report it [earlier] because he didn't remember. I really don't know."

[29] Not so, however, with Dr. Hamilton. In what Taylor's counsel said could be described as a "Perry Mason moment", Dr. Hamilton admitted in light of the ear fluid reports that the inconsistencies were "marked discrepancies". It was then that the trial judge raised Browne v. Dunn.

[30] That admission from Dr. Hamilton came after a number of pointed questions in cross-examination. Dr. Hamilton was first presented with the reports of loss of consciousness and headaches. She either denied that these were discrepancies at all or denied that they were marked discrepancies that raised malingering concerns. But once presented with the ear fluid reports, Dr. Hamilton's testimony shifted. She acknowledged that it brought Taylor's inconsistent reporting to the point of a "marked, material, significant, [or] important" discrepancy. And she admitted that it caused her to "have to think about the confidence of [her] diagnosis". Taylor's counsel did not object.

[31] The court then took its afternoon break. When court resumed, the trial judge raised concerns that the ear fluid line of questioning breached Browne v. Dunn: "You're referencing the ear leakage problem; that was never put to Mr. Taylor." The parties agreed to address the issue the following morning.

(c) Striking the Jury

[32] The next morning, Taylor moved to discharge the jury. The trial judge granted the motion the following day. The ear fluid evidence, she wrote, had "irreparably tainted the jury." Worse yet, that evidence was hearsay, because Taylor reported it to the intake doctor who had not testified. In the trial judge's view, that "further complicate[d] the breach."

[33] In written reasons she released later, the trial judge said that she was "confident that [Zents' counsel] deliberately chose not to question Mr. Taylor on this piece of evidence." She repeated her conclusion that the evidence was hearsay. The trial judge found there was no other option but to discharge the jury. She determined that Taylor's counsel's description of Dr. Hamilton's concession as a "Perry Mason moment" was "not hyperbole". "The courtroom was so quiet a pin drop would have sounded deafening." As she put it, "[t]he jury was hanging on Dr. Hamilton's every word at this stage. Her answer prompted an audible reaction from the jury. There was no walking back from this moment. The horse was already out of the barn."

[34] Given that state of affairs, the trial judge concluded that no correcting instruction could remedy the damage. Nor would recalling Taylor fix things because if recalled, Taylor would be examined about an issue that his counsel never raised during his examination-in-chief. That might lead the jury to conclude that Taylor had hidden the evidence, feeding directly into Zents' theory of inconsistent reporting.

(d) The Judgment

[35] There was no dispute that Taylor struck his head when Zents rear-ended him, and that his car rolled over and ended up in a ditch. Nor was there any dispute that the collision occurred when Taylor was stopped, and Zents was travelling at a high rate of speed. The dispute was on the issue of causation. The respondents took the position that Taylor suffered at the very least, a mild traumatic brain injury ("mTBI") and that he experienced post-concussion syndrome, which affected virtually every aspect of his life. Conversely, Zents argued that Taylor had not suffered a brain injury in the accident. Rather, she suggested that Taylor was a malingerer whose evidence was not credible and should not be accepted by the court.

[36] Credibility was a critical issue in the trial. Because of the stark contrast between the positions of the parties at trial and the opinions of the various medical experts, the trial judge had to evaluate Taylor's credibility and reliability and decide which party's evidence she found persuasive.

[37] In assessing the consequences of the accident, the trial judge considered Taylor's evidence and described the medical experts' evidence in significant detail. She accepted the opinions of the medical experts who testified on behalf of Taylor, and she rejected those of Zents' experts. The medical witnesses who testified on Taylor's behalf all agreed that he suffered a concussion in the accident and that he continued to exhibit manifestations of that injury at the time of trial. In contrast, she found that the medical witnesses who testified for the appellant displayed partisanship and a lack of objectivity.

[38] The trial judge concluded that the evidence overwhelmingly showed that Taylor suffered a traumatic brain injury in the collision, and that he experienced post-concussion syndrome. She largely accepted the expert evidence that Taylor led, and she found Taylor himself credible and reliable. She found that his evidence disclosed no major inconsistencies, and that the minor inconsistencies were understandable, given the evidence as a whole.

[39] The trial judge observed that Taylor's job could not be modified to accommodate his impairments, nor performed part-time. She awarded the respondents a combined total of more than a million dollars in damages.

C. Issues on Appeal

[40] Zents advances four grounds of appeal:

• the trial judge erred in finding a violation of the rule in Browne v. Dunn[2]
• the trial judge erred in discharging the jury;
• the trial judge erred in qualifying Dr. Hamilton as an expert under r. 53; and
• the trial judge misapprehended the evidence in her assessment of the appropriate damages.

I do not agree that the trial judge made any of the alleged errors and would dismiss the appeal.

D. Analysis

(1) Did the Trial Judge Err in Finding a Browne v. Dunn Violation?

(a) Governing Legal Principles

[41] The rule in Browne v. Dunn is a confrontation principle that governs the impeachment of witnesses and it is a rule that is rooted in trial fairness. If one party wants to impeach another's witness, they must put the impeaching material to that witness in cross-examination to give them a chance to explain any contradiction: Browne v. Dunn, at pp. 70-71. The rule protects the witness whose credibility is attacked by alerting them that the other party intends to impeach their evidence. It protects the party whose witness is impeached by, among other things, giving them an opportunity to decide what—if any—evidence to lead in support of their witness's testimony. And it protects the truth-seeking function of the trial by ensuring that the trier of fact has the benefit of any explanation the impeached witness can offer: R. v. Quansah, 2015 ONCA 237, 125 O.R. (3d) 81, at para. 77, leave to appeal refused, [2016] S.C.C.A. No. 203.

[42] Browne v. Dunn does not require that every possible shred of impeachment material be put to a witness. Counsel need only cross-examine the witness on matters of substance that the witness has not yet had a chance to explain. Counsel need only confront the witness with the nature of the impeachment evidence and its significant aspects, not its granular details: Quansah, at para. 81. The impeacher "need not descend into the muck of minutiae to demonstrate compliance with the rule": Quansah, at para. 86.

[43] The rule in Browne v. Dunn is not hard and fast. It is flexible, and its application in any given proceeding is firmly "within the discretion of the trial judge after taking into account all the circumstances of the case": R. v. Lyttle, 2004 SCC 5, [2004] 1 S.C.R. 193, at para. 65. The trial judge is in the best position to "take the temperature" of the trial and to assess whether a failure to cross-examine has resulted in unfairness to the other party: Quansah, at para. 90. A trial judge's decision about whether the rule has been breached is therefore entitled to significant appellate deference.

(b) The Principles Applied

[44] Zents argues that the trial judge erred in finding a breach of Browne v. Dunn for three reasons. First, she says that the ear fluid evidence impeached Dr. Hamilton's opinion, not Taylor's credibility. Second, she submits that Taylor was cross-examined on inconsistently reporting his symptoms, so a failure to raise this particular symptom does not breach Browne v. Dunn. Third, she contends that the trial judge erred in principle by concluding that the ear fluid evidence was hearsay.

[45] I do not accept any of these arguments. I begin, however, by remarking that it would have been preferable for counsel to have raised the Browne v. Dunn issue when Zents' counsel cross-examined Drs. Staab and Robinson on the ear fluid issue. It could have been dealt with at that time. Raising it later in the trial, after other witnesses have testified is problematic, as happened here. Ultimately, a trial judge is responsible for ensuring that the trial process is fair to all parties. Trial judges have the authority to control the proceedings over which they preside, and that authority entitles them to intervene when those proceedings run afoul of the law of evidence or when unfairness in the process occurs: R. v. John, 2017 ONCA 622, 350 C.C.C. (3d) 397, at para. 47; Cannon v. Cemcor Apartments Inc., 2017 ONCA 378, at para. 13. If counsel fail to raise an issue in a timely fashion that could be prejudicial to a fair trial, the trial judge must deal with it appropriately.

[46] The trial judge did that here, and Zents' arguments for disturbing her conclusion on appeal must be rejected.

[47] First, attacking the foundations of Dr. Hamilton's opinion about the nature and extent of the head injury sustained by Taylor necessarily includes an attack on his credibility. The two are inextricably woven together. It was not possible to impeach the first without also impeaching the second. The core of Zents' cross-examination was a suggestion that Dr. Hamilton could not rely on the symptoms Taylor reported, because his inconsistent reporting of other symptoms undermined his credibility. The admission of a "marked discrepancy" that Zents' counsel sought and received from Dr. Hamilton necessarily entailed an admission that the ear fluid evidence impugned his credibility.

[48] Zents argues that any explanation Taylor had for the inconsistency was irrelevant. The line of questioning, she says, was about how that inconsistency affected Dr. Hamilton's opinion, not how Taylor would have explained it. That argument fails precisely because Dr. Hamilton's opinion was inextricably tied to Taylor's credibility, which is often the case when a plaintiff cannot point to something objective, such as an x-ray or other imaging, as an explanation for the symptoms. Dr. Hamilton's concession—that the inconsistency amounted to a marked discrepancy—reflected poorly on the credibility of Taylor's reports of his symptoms. Taylor's explanation for why he reported as he did and in particular, failed to report fluid leaking from his ear to any of his treating practitioners for years, would have been relevant to that credibility assessment. It follows that failing to elicit that explanation from him in cross-examination breached Browne v. Dunn, even if the violative question also probed Dr. Hamilton's opinion.

[49] Second, while Zents' counsel did cross-examine Taylor about other inconsistencies in his reporting to the ambulance personnel at the scene and to other treatment providers, that did not relieve her of the obligation to put another significant piece of evidence to him. Browne v. Dunn does not require that a witness offer answers on "every scrap of evidence", but this was no mere scrap: Quansah, at para. 81. This line of cross-examination suggested that Taylor invented a significant symptom three years after the fact to exaggerate his injuries. It went to the heart of the dispute being tried and the nature and extent of the injuries suffered in the accident, and it also went to the heart of the defence theory, that Taylor ought not to be believed about his symptoms. Trial fairness required that Taylor have an opportunity to address it. While he had an opportunity to address other questions that also impugned his credibility, that does not obviate the need to put the evidence about the fluid leaking from his ear to him, since it was such an important piece of evidence to the defence.

[50] As the medical experts agreed, fluid leaking from one's ear after a blow to the head is a significant symptom. Zents used the fact that Taylor had not reported this symptom for three years to suggest to the jury that he was a malingerer who was trying to maximize his financial recovery from the lawsuit. Indeed, Zents' counsel suggested to Dr. Staab that if a person researched the symptoms of a serious head injury, one of them could be fluid leaking from the ear. The trial judge found that Zents' counsel made a deliberate decision not to cross-examine Taylor on this issue. That factual finding is unchallenged on appeal. It is not clear why Zents' counsel made that decision, but it was a clear violation of the rule in Browne v. Dunn and the trial judge did not err in so finding.

[51] Third, Zents argues that the trial judge incorrectly concluded that the ear fluid evidence was hearsay. This, Zents says, led her to err in principle by concluding that the hearsay character of the evidence "further complicate[d] the breach". As I will explain whether the trial judge was incorrect to describe the ear fluid evidence as hearsay is irrelevant, because it did not affect the trial judge's ultimate holding.

[52] Before I address that issue, I pause to note that the trial judge seems to have viewed the hearsay nature of the evidence as relevant to remedy, not to whether a breach occurred at all. In her oral reasons, the trial judge referred to hearsay to explain why she chose to strike the jury, not to explain why she found a breach of Browne v. Dunn:

Of course, [the breach of Browne v. Dunn], in and of itself, is no reason to strike the Jury. There are options available to the Court including providing a mid-trial instruction to the Jury and/or recalling Mr. Taylor. However, the use this evidence has been put to and its method of introduction through a participant expert and two medical/legal experts called by the plaintiff, has irreparably tainted the Jury. And I agree with Mr. Lehman of fluid leaking from the ear is hearsay. This is not something Mr. Taylor reported to Dr. Staab, the participant witness but to the Mayo Clinic's intake clinician. This further complicates the breach. Recalling Mr. Taylor will not suffice and I find there is no instruction strong enough to walk the Jury back from the evidence they have heard over the past two days.

[53] So too in her written reasons, although they are less clear on this point:

I am confident that [Zents' counsel] deliberately chose not to question Mr. Taylor on this piece of evidence. I say this with the utmost respect. [Zents' counsel] displayed an encyclopaedic memory for each and every fact in this case. It was astonishing to behold, frankly. The failure to take Mr. Taylor to the notation in the Mayo Clinic records was by design. It was not an inadvertent slip. …

I find favour with Mr. Lehman's argument that the fluid leaking from Mr. Taylor's ears was hearsay. It was a statement attributable to the plaintiff made out of court, which was not put to him, in breach of the rule in [Browne v. Dunn].

As I noted in my Reasons for Decision, dated January 8, 2024, [Taylor's counsel] referred to Dr. Hamilton's concession that the inconsistences amounted to marked discrepancies as a "Perry Mason" moment. This is not hyperbole. The courtroom was so quiet a pin drop would have sounded deafening. The jury was hanging on Dr. Hamilton's every word at this stage. Her answer prompted an audible reaction from the jury. There was no walking back from this moment. The horse was already out of the barn.

In these particular circumstances, no correcting instruction would be strong enough to remedy the damage, as the jury's ability to assess not only Mr. Taylor's credibility, but also the credibility of the expert witnesses, was already poisoned.

[54] As these passages show, the trial judge referred to the hearsay issue when refusing a lesser remedy, not to finding a breach in the first place. The trial judge should not have characterized the hearsay nature of the evidence as further complicating the breach, but that did not affect her finding that Browne v. Dunn was breached, nor her decision to strike the jury as a result. In my view, the problem is not with the trial judge's characterization of the nature of the records from the Mayo Clinic; it lies in the fact that the records were not put to Taylor to provide him with the opportunity to make a response notwithstanding it was Zents' counsel's plan to use those records to impeach Taylor's credibility with the experts. That is what led to the breach of Browne v. Dunn and the unfairness the trial judge found could not be remedied short of discharging the jury.

[55] The trial judge's conclusion that the ear fluid evidence was hearsay did not impact her conclusion that Browne v. Dunn was breached. She gave unassailable reasons for this finding that did not include hearsay. She explained that Zents' counsel chose not to take Taylor to a "keystone piece of evidence that was going to be used to impeach him", that Zents' counsel chose to do so deliberately, and that doing so deprived Taylor of the opportunity to respond to that evidence. Those reasons, taken together, justify her conclusion that Browne v. Dunn was breached, and she made no error in her finding of the breach.

[56] Moreover, as I will explain below, even assuming the intake doctor's notes were properly admitted for the truth of the information recorded under common law or statutory provisions, the trial judge provided cogent reasons for striking the jury regardless of her characterization of the ear fluid evidence as hearsay and a factor that complicated the breach.[3]

(2) Did the Trial Judge Err in Discharging the Jury?

(a) Governing Legal Principles

[57] The right to a civil trial by jury is a fundamental substantive right. Litigants must not be deprived of it lightly: King v. Colonial Homes Ltd., [1956] S.C.R. 528, at p. 533; Penate v. Martoglio, 2024 ONCA 166, 496 D.L.R. (4th) 50, at para. 18. Discharging a jury is a drastic remedy of last resort that demands reasoned justification. The trial judge may only do so if the proceedings have prejudiced one party to such an extent that a corrective instruction will not cure it: Hamstra (Guardian ad litem of) v. British Columbia Rugby Union, [1997] 1 S.C.R. 1092, at paras. 17, 23; Penate, at para. 19.

[58] If a trial judge is concerned that a fair trial by jury is under threat, they have several options. They may do nothing and adopt a "wait and see" approach. That is often wise: in some cases, a concern about evidence or the inflammatory submissions of counsel may seem critical early on, but become of little significance later in the proceedings, often as a result of further evidence.

[59] The trial judge may also choose to issue a corrective instruction about the prejudice at issue. Juries are generally capable of following those instructions, so in "most cases" discharging the jury is not appropriate: Penate, at para. 19. The standard for discharging a jury is high, other options are available, and trial judges should not take that drastic step lightly.

[60] Despite that high standard, this court reviews decisions to discharge a jury deferentially. So long as the trial judge provides a reasoned basis for doing so, this court will interfere only if "the appellant shows that the trial judge acted on a wrong principle, arbitrarily, capriciously, or unreasonably": Penate, at para. 20; Hamstra, at para. 26. As with breaches of Browne v. Dunn, the trial judge is in by far the best position to assess what is transpiring in the courtroom with the jury and to determine whether a corrective instruction will cure whatever ails the proceedings.

(b) The Principles Applied

[61] Zents offers three reasons for this court to interfere with the trial judge's decision to discharge the jury. First, she says that the trial judge should have considered a "wait and see" approach to decide whether the trial could continue by jury. Second, she claims that the trial judge failed to explain why other options would be inadequate. Third, she argues that the trial judge's failure to raise this issue until Dr. Hamilton's testimony makes her decision capricious.

[62] I do not agree. Zents argues the fundamental nature of the right to a civil trial by jury, which I accept entirely. However, that right must be balanced against the overarching right of all parties to a fair trial. The right to a trial by jury may be a fundamental and substantive right, but it is not absolute. It is subject to the discretion of the trial judge, so long as it is supported by reasoned justification. The trial judge supplied that justification here, untainted by any of the errors Zents now alleges. Part of her explanation for discharging the jury draws on her own observations of the jury and the courtroom and is a useful reminder of why significant deference is owed in this context. It bears setting out again, verbatim:

[Taylor's counsel] referred to Dr. Hamilton's concession that the inconsistences amounted to marked discrepancies as a "Perry Mason" moment. This is not hyperbole. The courtroom was so quiet a pin drop would have sounded deafening. The jury was hanging on Dr. Hamilton's every word at this stage. Her answer prompted an audible reaction from the jury. There was no walking back from this moment. The horse was already out of the barn. [Footnote omitted.]

[63] The trial judge was in the best position to determine whether the jury's Rubicon had been crossed, and she concluded that it had. I would defer to that conclusion.

[64] Second, the trial judge explained why remedies short of discharge would not suffice. She expressly considered recalling Taylor but determined that it would be inappropriate because the jury might misunderstand and conclude that he had tried to hide evidence, which would affect his credibility. She also considered a corrective instruction but explained, given her assessment of the courtroom environment, that no such instruction "would be strong enough to remedy the damage". These are clear and cogent reasons for the trial judge's decision to dismiss the jury and why she felt it was the only remedy that could ensure trial fairness. It is clear that she recognized that dismissing the jury was a drastic remedy, but she explained why she concluded it was the only one that was available.

[65] Zents says that the trial judge should have considered whether a corrective instruction would have addressed her concerns about recalling Taylor, and whether she could have managed his recall to avoid further prejudice. I disagree. The trial judge explained in cogent reasons why she doubted that the other available options would suffice.

[66] Finally, Zents submits that the timing of the trial judge's decision to raise the Browne v. Dunn issue makes her decision to strike the jury capricious. Quansah, she argues, says that a timely objection to a Browne v. Dunn breach is important, and that a failure to provide one narrows the scope of the available remedies. She contends that the "Perry Mason" moment would never have occurred, so other remedies might have been feasible, had the trial judge flagged the issue sooner.

[67] As I have noted, it would have been preferable for the trial judge to have raised the issue when Zents' counsel asked Dr. Staab, or Dr. Robinson, about the ear fluid. However, the rule in Browne v. Dunn is subtle and its breaches are not always easy to detect. The significance of the variance in Taylor's reporting may not have been obvious earlier in the trial and Taylor's own counsel did not object at the time. The trial judge's failure to address a potential breach of the rule in Browne v. Dunn at the first available opportunity does not render her later decision to strike the jury "capricious" within the meaning of this deferential standard of review.

[68] The failure to report a significant symptom, like fluid leaking from one's ear after a blow to the head, is not a minor point. Zents' counsel intended to use it to undermine the credibility of Taylor as well as the foundations of his expert opinions. Trial fairness mandated that Taylor be given an opportunity to answer why he failed to report this symptom earlier on to his treating practitioners.

[69] Finally, if the reference to hearsay is understood as relevant to the trial judge's decision to strike the jury, and not as to whether a Browne v. Dunn breach occurred, it did not impact the trial judge's ultimate decision to strike the jury. As with the breach of Browne v. Dunn, the trial judge gave cogent reasons for striking the jury that had nothing to do with hearsay: the "Perry Mason" moment with the jury's audible reaction, the insufficiency of a corrective instruction, and the unfeasibility of recalling Taylor without potentially affecting the jury's view of him.

[70] For all of these reasons, the trial judge made no reversible error in exercising her discretion to discharge the jury.

(3) Did the Trial Judge Err in Qualifying Dr. Hamilton as a R. 53 Expert?

[71] Dr. Hamilton was Taylor's treating psychologist. She testified as a participant expert. Zents objected to her also being qualified to testify as a r. 53 expert. She took the position that Dr. Hamilton could not be impartial due to her role as one of Taylor's treating physicians. The trial judge held a voir dire and concluded Dr. Hamilton should be qualified as a litigation expert pursuant to r. 53. In an oral ruling delivered midtrial, the trial judge found that Dr. Hamilton "presented as anything but an advocate for Mr. Taylor" and "appeared neutral and objective when answering [Zents' counsel's questions during the voir dire]". She relied on Dr. Hamilton's presentation on the stand when addressing this issue in her eventual reasons for judgment, observing that Dr. Hamilton handled Zents' counsel's questions "with dignity", and that she was "credible and believable."

[72] On appeal, Zents renews her objection to this "dual" qualification. She argues that the trial judge erred in concluding that Dr. Hamilton would be able to fulfill her duty to the court as an expert considering her therapeutic relationship with Taylor of more than five years. I do not accept this argument and would not give effect to this ground of appeal.

(a) Governing Legal Principles

[73] In personal injury actions, the "participant expert" is often a treating practitioner of the plaintiff, as was the case here. Because of their involvement with the plaintiff, such a witness may have a different and valuable perspective to offer the court on the issues in dispute. A participant expert can also be qualified as a "r. 53 expert", as long as the court is satisfied that their relationship with the plaintiff does not preclude them from adhering to their duty to assist the court by providing fair, impartial, and objective evidence, which is the role of a litigation expert.

[74] Any expert who offers opinion evidence beyond the bounds of their own participation in the events at issue must comply with r. 53.03: Westerhof v. Gee Estate, 2015 ONCA 206, 124 O.R. (3d) 721, at para. 61, leave to appeal refused, [2015] S.C.C.A. No. 201 (McCallum), and [2015] S.C.C.A. No. 198 (Westerhof). That means that r. 53 experts must be impartial and independent: White Burgess Langille Inman v. Abbott and Haliburton Co., 2015 SCC 23, [2015] 2 S.C.R. 182, at para. 34. That is no less true of treating physicians who testify both as "participant experts" and as "r. 53 experts".

[75] An expert occupying that dual role is subject to the same impartiality inquiry as any other r. 53 expert. When it comes to the expert's relationship with a litigant, "the question is not whether a reasonable observer would think that the expert is not independent. The question is whether the relationship or interest results in the expert being unable or unwilling to carry out his or her primary duty to the court to provide fair, non-partisan and objective assistance": White Burgess, at para. 50. Once an expert acknowledges their duty of impartiality, the party opposing the admission of their evidence bears the burden of showing a realistic concern that they are unable or unwilling to comply with that duty. If they succeed, the burden shifts to the proponent of the expert's evidence to demonstrate the expert's impartiality on a balance of probabilities: White Burgess, at para. 48.

[76] This court owes deference to a trial judge's admissibility decision, absent an error in principle: R. v. McManus, 2017 ONCA 188, 353 C.C.C. (3d) 493, at para. 68.

(b) The Principles Applied

[77] Zents argues that the trial judge erred in principle by failing to apply the principles governing expert impartiality as set out in White Burgess. The trial judge, she says, never asked whether Dr. Hamilton's therapeutic relationship with Taylor created a "realistic concern" that she would be unable to fulfill her duty to the court. The trial judge should have confined her analysis to that question, Zents argues, rather than focusing on Dr. Hamilton's presentation on the stand during the voir dire.

[78] The trial judge did not expressly proceed through the discrete steps set out in White Burgess, nor did she specifically consider the potential assistance of Dr. Hamilton's evidence against any dangers inherent in her testimony due to her relationship with Taylor. It would have been preferable if she had done so. Still, I am persuaded that in substance, she properly applied White Burgess. She plainly appreciated that independence and impartiality were at issue, and she gave thorough reasons for concluding that Dr. Hamilton was capable of being objective and impartial. While it may have been preferable that the trial judge place less emphasis on Dr. Hamilton's presentation on the stand, that consideration is relevant to the analysis and should not be ignored. This court has relied on it to perform this very part of the White Burgess analysis: McManus, at paras. 71 and 72. In any event, that focus did not exclude other relevant considerations. The trial judge reviewed the contents of Dr. Hamilton's report and concluded that she "arrived at her diagnosis and conclusions in a fair and even-handed manner", and that neither her written report nor her responses in cross-examination suggested she was acting as an advocate for Taylor.

[79] Relying on McManus, Zents argues that Taylor could have called other neuropsychologists who were strictly r. 53 experts, and that the trial judge failed to consider that possibility. That argument misses the point, in my view. The availability of an unconnected witness was not an independent ground of legal error in McManus. It was an additional consideration after this court concluded that the expert at issue raised a "realistic concern" about impartiality. Absent such a realistic concern, the respondents were entitled to put in their case as they saw fit, and to offer Dr. Hamilton as both a participant expert and a litigation expert.

[80] Zents has not demonstrated that the trial judge's reasons on this point reflect an error in principle. Absent such an error, I reject this ground of appeal.

(4) Did the Trial Judge Err in Her Apprehension of the Evidence Resulting in an Erroneous Assessment of Damages?

[81] Zents argues that the trial judge erred in her assessment of the medical evidence by relying on hearsay. Specifically, she submits that the trial judge found "overwhelming evidence" that Taylor suffered a minor traumatic brain injury in the collision by relying on records of treating doctors who did not testify.

[82] I reject that submission. The trial judge made no error in finding the evidence supporting the conclusion that Taylor suffered a head injury in the accident was "overwhelming". Her reference to the evidence of non-testifying physicians was, at most, background. The rest of her findings were firmly rooted in admissible evidence.

[83] Zents observes that the trial judge referred to the fact that five non-testifying physicians had diagnosed Taylor with a concussion. But that was not the basis on which she ultimately concluded that Taylor had indeed suffered a concussion. Instead, she set out the consensus definition of a concussion as described by the expert evidence she did accept, and then explained why the evidence showed that Taylor met that definition. She made no reference to any hearsay evidence in her reasoning process.

[84] Zents says that the trial judge made a similar error by mentioning that two non-testifying physicians had diagnosed Taylor with post-concussion syndrome. The trial judge referred to the non-testifying physicians to clarify that "post-concussion syndrome" is the appropriate terminology, not to buttress her own conclusion that Taylor's symptoms had developed into post-concussion syndrome. She made no error in doing so.

[85] The trial judge did not err in her assessment of damages. Her damages assessment flowed directly from her acceptance of Taylor's evidence, the other lay witnesses' evidence, and the evidence of the medical witnesses who agreed that Taylor suffered a life-altering brain injury in the accident and that he would never return to his pre-accident level of function or be able to work in his former occupation. I would not give effect to this ground of appeal.

E. Disposition

[86] I would dismiss the appeal, and award costs to the respondents in the agreed-upon sum of $30,000, all-inclusive.

Released: September 24, 2025

"J.S."

"D.A. Wilson J.A."

"I agree. Janet Simmons J.A."

"I agree. L. Madsen J.A."

Footnotes

[1] An "r. 53 expert" refers to an expert witness under r. 53.03 of the Rules of Civil Procedure, R.R.O. 1990, Reg. 194.

[2] While the appellant did not advance this as an independent ground of appeal, it is important to consider the violation of Browne v. Dunn as a separate ground for two reasons. First, this violation is the sole reason the trial judge found that the remedy of discharging the jury was necessary. Second, the appellant argued that the trial judge made errors in the review and application of the rule of Browne v. Dunn, which can be viewed as errors independent of the remedy she chose to apply.

[3] It is unclear from the appeal record whether the Mayo Clinic notes were marked only as a lettered exhibit at trial for background purposes to explain the basis of Dr. Staab's opinion or whether they were admitted into evidence under a common law or statutory exception to the hearsay rule.