ONTARIO

SUPERIOR COURT OF JUSTICE

COURT FILE NO.: 13325/13
DATE: 201508­­16

BETWEEN:

HER MAJESTY THE QUEEN

– and –

TIN WAI HONG, MASON GILLARD-GATZA, NATHANIEL CAIN and RAPHAEL GUERRA

Defendants

Ronald Davidson and Lucas O’Neill, for the Crown

Michael Strathman for Tin Wai Hong

Stephen T. Lyon for Mason Gillard-Gatza

Anthony G. Bryant and Karen E. Symes for Nathaniel Cain

David G. Bayliss for Raphael Guerra

HEARD: August 14, 2015

RULING No. 2 on Mohan Voir Dire

RESTRICTION ON PUBLICATION: Pursuant to subsection 648(1) of the Criminal Code, no information regarding this portion of the trial shall be published in any document or broadcast or transmitted in any way before the jury retires to consider its verdict.

BOSWELL j.

[1] Nathaniel Cain is on trial; charged with murdering Ryan Kennedy, a young man who had the great misfortune of being in the wrong place at the wrong time.

[2] Mr. Cain wants to present expert evidence about a heart condition he suffers from. He says the evidence is relevant to his state of mind at the time Mr. Kennedy was killed. The Crown opposes the evidence on the basis that it is not relevant, not necessary and more likely to mislead the jury than to help them.

[3] The following reasons explain why the jury will be hearing from Mr. Cain’s expert.

BACKGROUND

[4] Expert opinion evidence is presumptively inadmissible. Mr. Cain bears the onus, on a balance of probabilities, of establishing that the evidence should be admitted. The basic analytical framework for assessing the admissibility of expert opinion evidence was formulated in the Supreme Court’s ruling in R. v. Mohan, 1994 80 (SCC), [1994] 2 S.C.R. 9 (“Mohan”). Since that decision was released, admissibility hearings of this nature have come to be referred to as “Mohan voir dires”.

[5] A Mohan voir dire was conducted in this instance on August 14, 2015. The parameters of the voir dire were contested. They are for the trial judge to determine and accordingly I issued a ruling, reported as 2015 ONSC 5114, establishing the procedure to be followed in this case. Some of the content of that ruling is equally applicable to this ruling and will be repeated here.

The Offences

[6] The alleged offences occurred inside a bungalow located on a rural sideroad in Minden, Ontario close to midnight on October 19, 2011. The bungalow was the home of a young man named Justin McKelvey. Mr. McKelvey worked in the landscaping business. He also trafficked in marijuana. He was a fan of the Toronto Maple Leafs hockey club. The Leafs were playing the Winnipeg Jets that night and he had some friends over to drink some beer, smoke some dope and watch hockey. By 10:30 p.m., only Mr. McKelvey and his friend, Ryan Kennedy remained in the home.

[7] Mr. McKelvey and Mr. Kennedy did not know it, of course, but at some point during the first period of the hockey game, four other young men set off together from Scarborough, with a plan to go to Minden to conduct a home invasion. Their target was Mr. McKelvey’s home. They wanted his drugs and his money. Those four young men are the defendants on trial here. Their identity is not in issue.

[8] The wheelman was Mr. Guerra. By all accounts he remained with his car at all material times. The other three defendants, including Mr. Cain, entered Mr. McKelvey’s home, sometime between 11:00 and 11:30 p.m., wearing dark clothing, masks and gloves, and armed with a baseball bat, bear spray, and a roll of duct tape.

[9] During the invasion Mr. Kennedy was bludgeoned to death. Mr. McKelvey survived. According to his testimony, he was being beaten when a car pulled into his driveway. The headlights startled the intruders who fled, taking with them about four pounds of marijuana and about $350.

[10] A pathologist – Dr. Michael Polanan – has testified that Mr. Kennedy died from blunt force trauma to his head. That trauma appears to have been inflicted by the baseball bat and/or a heavy metal pellet rifle that Mr. McKelvey had resting against a wall in his living room, which is where the killing occurred. Dr. Polanen indicated that Mr. Kennedy sustained a number of blows to his head. He could not pinpoint which blow(s) actually killed him; he said that Mr. Kennedy died from a combination of blows.

[11] Mr. Gillard-Gatza has testified in his own defence. He admitted that he struck Mr. Kennedy in the head with the baseball bat, knocking him unconscious. According to his testimony, when the intruders entered the McKelvey residence, Mr. Kennedy began to grapple with Mr. Cain. He said he was carrying the baseball bat and he panicked and struck Mr. Kennedy. He denied having an intention to kill.

[12] Mr. Gillard-Gatza described Mr. Cain striking Ryan Kennedy in the head with the butt end of the pellet rifle, as Mr. Kennedy lay unconscious on the floor. Mr. McKelvey similarly testified that Mr. Cain struck Ryan Kennedy in the head with the butt end of the rifle. Their accounts varied in terms of the force applied by Mr. Cain. Suffice it to say that one of the live issues at trial is whether Mr. Cain caused the death of Ryan Kennedy.

Mr. Cain’s Defence

[13] Mr. Cain testified in his own defence. At the time of this ruling, his testimony is ongoing; he is only partway through the Crown’s cross-examination.

[14] Mr. Cain denied that he struck Mr. Kennedy in the head with the pellet rifle. He said he only struck Mr. Kennedy across the chest, with a little plastic oar, which shattered on impact.

[15] He also said that he never had an intention to kill Mr. Kennedy or anyone else. Moreover, he testified about a serious health condition he suffers from and indicated that he was experiencing symptoms associated with that condition which may raise a reasonable doubt about whether he formed the intention to kill.

[16] Mr. Cain has congenital heart disease. Described in its most layman-esque terms, the plumbing to and from his heart is mixed up. As a result, oxygenated blood returning to his heart from his lungs ends up mixing with deoxygenated blood returning to the heart from his body. The blood that gets pumped out from his heart to his organs and tissues is significantly less oxygenated than would normally be the case. His resting oxygen saturation rate is in the range of 82-85% of normal.

[17] Mr. Cain testified about the nature and effects of his heart disease. He said that at times, when he does something physical, he gets tired and has to stop. He gets dizzy. He gets confused. At times he has passed out.

[18] He said that his heart disease affects his ability to communicate. It affects his ability to concentrate; to absorb information; and to process what’s going on around him. He sometimes doesn’t think clearly. He can be at a loss for words.

[19] With respect to the charged offences, he testified that his journey from Mr. Guerra’s car to the target house was about 350 metres long. The first 40 metres he jogged; the balance he walked. He said that when he went into the McKelvey residence he began to grapple with Mr. Kennedy. He confirmed Mr. Gillard-Gatza’s evidence that Mr. Gillard-Gatza came to his aid and struck Mr. Kennedy with the bat, knocking him unconscious.

[20] He said that as he was grappling with Mr. Kennedy, he was scared. His adrenaline was going. He was short of breath because he’d just come from the walk to the house. He was “fuzzing out”. After Mr. Kennedy was struck with the bat, things are really blurry for him. He remembers walking around, filling a bag with weed, pulling wires out of the wall, and talking to Justin McKelvey.

[21] He went on to testify that during all the activity he was feeling adrenaline. At parts he was confused. His mind was “fogging out”. He knows things were going on, but he is not sure what was happening. He was on the brink of passing out. He was “fuzzing out”. He was lost and confused.

Dr. Colman’s Proposed Evidence

[22] Dr. Colman is a cardiologist of over forty years’ experience. He is associated with both Mount Sinai Hospital and Toronto General Hospital (now known as the University Health Network). Since 1988 he has been an attending cardiologist at the Toronto Congenital Cardiac Centre for Adults at Toronto General Hospital. He has dedicated most of his career to the care of adults living with congenital heart disease. He has been Mr. Cain’s treating cardiologist since June 2004, when Mr. Cain was nineteen years old.

[23] Dr. Colman provided relatively brief evidence during the Mohan voir dire regarding his qualifications and the specific opinion to be adduced from him.

[24] It is proposed that Dr. Colman will provide factual evidence relating to the nature of Mr. Cain’s congenital heart disease. He will provide factual evidence about the correlation between Mr. Cain’s physiology and reduced oxygenation of his blood (a condition known as hypoxemia). He will provide factual evidence about the ways in which hypoxemia, or a related condition known as hypoxia (reduced oxygen in the tissues) may affect physical and mental functioning.

[25] It is further proposed that Dr. Colman will be provided with the following hypothetical scenario regarding physical exertion on Mr. Cain’s part:

Mr. Cain jogged for about 40 metres, then walked over uneven terrain for about 300 metres more. He paused briefly, then walked up a small incline, climbed five stairs and entered a house. Inside the house, Mr. Cain immediately grappled with another male for a short period of time.

[26] Dr. Colman will then be asked, based on the hypothetical scenario, what he would expect to see in terms of the oxygen saturation level in Mr. Cain’s blood by the time he was done grappling with Mr. Kennedy. Dr. Colman testified on the voir dire that he would expect Mr. Cain’s oxygen saturation level to drop quite low – consistent with the results of an endurance test he performed at the Cardiac Centre in August 2011, known as the 6-Minute Walk Test (the “Walk Test”). The Walk Test measures how far the patient can walk in six minutes. Oxygen saturation levels are measured continuously throughout the test. Mr. Cain completed the test on August 22, 2011. He walked 470 metres, which is less than 65% of what would be expected in normal circumstances. His oxygen saturation level dropped to as low as 53% over the course of the test.

[27] Dr. Colman indicated that the physical exertion associated with the hypothetical scenario put to him by counsel would be greater than that required during the Walk Test. Accordingly, he would expect to see a similar significant drop in oxygen saturation.

[28] Dr. Colman will also be asked to assume that the court has heard descriptions from Mr. Cain such as blurred vision, confusion, “fuzzing out”, “fogging out”, and “out of it” as symptoms he was experiencing inside the McKelvey residence. He will be asked if these symptoms are consistent with the expected symptomatology of persons suffering from low oxygen levels in their blood. He is expected to opine, as he did during the voir dire, that these self-descriptions of Mr. Cain are indeed consistent with a person experiencing an hypoxic event.

THE LEGAL FRAMEWORK

Risk Management

[29] Litigation is, in many respects, an exercise in risk management. This is inevitably so when one’s rights are submitted to a third party decision-maker for determination. Counsel and the parties they represent must constantly assess the risks and potential rewards of their decisions, positions and tactics.

[30] Risk management is of daily concern to trial judges as well. Trial judges are charged with ensuring that accused persons receive fundamentally fair trials. They have a gatekeeping function which requires them to assess and exclude evidence that may jeopardize the fundamental fairness of a trial. That gatekeeping function is, at its core, a risk management function. It frequently involves the weighing of risks and rewards, though since the court is not ultimately a stakeholder, the analysis is really about weighing costs and benefits to the trial process itself.

[31] The goal of the trial process is to get at the truth of the matters in issue. Evidence which furthers that goal is generally admissible. Evidence which does not further that goal, or indeed which tends to distract the fact-finder or distort the truth, is generally not admissible. In other words, the rules of evidence are generally designed to enhance the accuracy of the court’s findings of fact, not to impede its truth-finding function: R. v. Khelawon, 2006 SCC 57, at para. 2.

[32] These general observations are reflected in the basic organizing principles of the law of evidence. Those principles were succinctly stated by LaForest J. in R. v. Corbett, 1988 80 (SCC), [1988] 1 S.C.R. 670, at para. 99:

The organizing principles of the law of evidence may be simply stated. All relevant evidence is admissible, subject to a discretion to exclude matters that may unduly prejudice, mislead or confuse the trier of fact, take up too much time, or that should otherwise be excluded on clear grounds of law or policy.

[33] These organizing principles, and more particularly, the general discretion to exclude unduly prejudicial evidence, are at the heart of the court’s gatekeeping function.

[34] As Watt J.A. observed in R. v. Spackman, 2012 ONCA 905, at para. 115, the exercise of the court’s discretion to exclude otherwise relevant evidence involves a cost-benefit analysis; an inquiry into whether the value of the proposed evidence to the correct disposal of the litigation is worth its cost to the litigation process.

Managing the Risk – Expert Opinion Evidence

[35] Expert opinion evidence tends to contravene the fundamental rule restricting witnesses to testifying about what they have actually seen, heard, felt or done. Moreover, it is fraught with risks. Principal among the risks are two concerns: (1) the risk that the jury will give expert evidence more weight than it deserves; and (2) the risk that the jury will accept the expert’s opinion without subjecting it to an appropriate level of scrutiny.

[36] Cromwell J. recently elaborated on the risks associated with expert opinion evidence in White Burgess Langille Inman v. Abbott and Haliburton Co., 2015 SCC 23 (“White Burgess”), at para. 18:

The point is to preserve trial by judge and jury, not devolve to trial by expert. There is a risk that the jury “will be unable to make an effective and critical assessment of the evidenceˮ… The trier of fact must be able to use its “informed judgment”, not simply decide on the basis of an “act of faith” in the expert’s opinion…The risk of “attornment to the opinion of the expertˮ is also exacerbated by the fact that expert evidence is resistant to effective cross-examination by counsel who are not experts in that field... The cases address a number of other related concerns: the potential prejudice created by the expert’s reliance on unproven material not subject to cross-examination…; the risk of admitting “junk science”…; and the risk that a “contest of experts” distracts rather than assists the trier of fact... Another well-known danger associated with the admissibility of expert evidence is that it may lead to an inordinate expenditure of time and money… (internal citations removed).

[37] Given the concerns generally associated with expert opinion evidence, it is presumptively inadmissible. Despite that fact, expert opinion evidence frequently finds its way into trials taking place in all branches of the Superior Court – civil, criminal and family. As Doherty J.A. put it, in R. v. Abbey, 2009 ONCA 624 (“Abbey”) at para. 73,

Put bluntly, many cases, including very serious criminal cases, could not be tried without expert opinion evidence. The judicial challenge is to properly control the admissibility of expert opinion evidence, the manner in which it is presented to the jury and the use that the jury makes of that evidence.

[38] The means of controlling the admissibility of expert evidence – of managing its risks – was the central feature of the Supreme Court’s decision in Mohan. There, Sopinka J. established an analytical framework to be applied when assessing the admissibility of expert opinion evidence. Four criteria were identified, such that subsequent to Mohan, admission of expert evidence was dependent on the following prerequisites:

(a) Relevance;

(b) Necessity in assisting the trier of fact;

(c) The absence of any exclusionary rule; and,

(d) A properly qualified expert.

[39] Sopinka J. described the relevance threshold as incorporating two distinct concepts. First, the low threshold test of logical relevance. In other words, whether as a matter of logic and human experience, the evidence has a tendency to make a fact in issue more likely than it would otherwise be: see R. v. Cloutier, 1979 25 (SCC), [1979] 2 S.C.R. 709. Second, the further inquiry as to whether the benefit to be gained by admission of the evidence is worth its costs.

[40] In other words the concept of relevance, as used by Sopinka J., includes both logical and legal relevance. Legal relevance engages the court’s gatekeeping function, which, as I noted, includes the discretion to exclude otherwise relevant and material evidence where:

(a) The probative value of the evidence is overborne by its prejudicial effect;

(b) The introduction of the evidence would involve an inordinate amount of time not commensurate with its value to the determination of the dispute; or

(c) The evidence is misleading because its effect on the trier of fact, especially a jury, is disproportionate to its reliability as proof.

See Mohan, para. 18.

[41] Concerns surrounding the risks associated with too liberal an approach to the admission of expert evidence continued to mount even after Mohan was released. Those concerns arguably reached their zenith around the time of the Inquiry into Pediatric Forensic Pathology in Ontario, which led to the Goudge Report[1]. That highly publicized inquiry involved a number of miscarriages of justice traced to a common root cause: the unreliable evidence of Dr. Charles Smith, who for a time was regarded as the leading pediatric pathologist in Ontario.

[42] Following the Goudge Report, appellate courts have refined the Mohan analysis in a manner that I would suggest is intended to engage the trial judge more actively in the risk assessment portion of the analysis – the balancing of costs and benefits: see Abbey and White Burgess.

[43] Trial courts are now directed to approach the analysis in two steps (see White Burgess, paras. 23-24):

(a) First, the party proposing to call the expert evidence must establish the threshold requirements of admissibility. These include the factors initially identified in Mohan: (1) that the evidence is logically relevant; (2) that it is necessary to assist the trier of fact; (3) that it is not subject to an exclusionary rule apart from the rule relating to expert opinion evidence; and (4) that it is tendered through a properly qualified expert; and,

(b) Second, the court must engage in its discretionary gatekeeping function. This is loosely described as a determination of whether the proffered opinion evidence is “worth the candle”. It involves conducting a cost/benefit analysis; a determination of whether the evidence is sufficiently beneficial to the trial process to warrant its admission despite the potential harm to the trial process that may flow from its admission.

[44] In a moment I will summarize the positions of the parties in relation to the analysis to be undertaken. Before doing so, I want to make note of one further refinement that must necessarily be imported into the cost/benefits analysis where, like here, the impugned evidence is tendered by a defendant. The necessary recalibration of the test was explained by McLachlin J., as she then was, in R. v. Seaboyer, 1991 76 (SCC), [1991] 2 S.C.R. 577, at para. 43:

Canadian courts, like courts in most common law jurisdictions, have been extremely cautious in restricting the power of the accused to call evidence in his or her defence, a reluctance founded in the fundamental tenet of our judicial system that an innocent person must not be convicted. It follows from this that the prejudice must substantially outweigh the value of the evidence before a judge can exclude evidence relevant to a defence allowed by law.

THE PARTIES’ POSITIONS

[45] The position of Mr. Cain’s counsel is pretty straightforward. Mr. Cain has a constitutional right to make full answer and defence. An important part of his defence is the effort to raise a reasonable doubt about his state of mind at the time the offences were committed. Dr. Colman’s evidence is an integral element of that part of his defence. In the submissions of counsel, it ticks all the boxes: it is relevant, probative, and necessary. It comes from a properly qualified expert, and, on balance, it is beneficial to the trial process.

[46] The Crown’s position is essentially the polar opposite. The Crown argues that the proposed expert evidence is not relevant, not probative, not necessary and, on balance, more harmful than beneficial. Moreover, the Crown challenges the qualification of the proposed expert.

[47] The thrust of the Crown’s position is that the hypothetical question to be put to Dr. Colman is so deficient in terms of Mr. Cain’s actual experience that it can be of little, if any, assistance to the jury.

[48] More particularly, the hypothetical question fails to take into account: (1) the impact that Mr. Cain’s adaptation to his chronic hypoxia might have had on his experience on the night of October 19, 2011; (2) the effect that adrenaline may have had on Mr. Cain’s alleged hypoxic state; and (3) the relationship between hypoxia and memory - the Crown’s assertion being that Mr. Cain’s apparently unimpaired memory of his cognitive impairments undermines the assertion that he was indeed suffering cognitive impairments.

[49] Dr. Colman candidly conceded during his voir dire testimony, that he does not know whether adrenaline may attenuate the negative effects of cerebral hypoxia. He was also candid in admitting that he is not an expert on the relationship between cerebral hypoxia and memory. The Crown’s position, in the result, is that he is not properly qualified to give an opinion that might actually be of assistance to the jury. If all he can say is that low oxygen may impair mental functioning, such an opinion is too general to be of assistance in terms of the facts of this case and frankly, not necessary because jurors will all understand that a lack of oxygen can impair cognitive functioning without having to be told as much by an expert.

[50] Moreover, the Crown asserts that the opinion of Dr. Colman is heavily dependent on the results of the Walk Test. The Crown submits that the test results are unreliable and have been misinterpreted. In addition, they differ significantly from the results of a similar test in 2009. While the test results are a major pillar of the opinion, the Crown is not in a position to reasonably cross-examine on them because Dr. Colman did not participate in the administration of the test. There is, in the result, a risk that the jury will be misled by test results that are simultaneously wrong and resistant to cross-examination.

[51] In the final analysis, the risks associated with the introduction of the evidence substantially exceed the very slight benefits it offers.

[52] None of the other defendants took a position on the admissibility of Dr. Colman’s evidence.

DISCUSSION

[53] I intend, in this section, to work through the Mohan analysis, as refined by later appellate cases, on a step by step basis.

The Evidence is Relevant

[54] At this stage, the concern is logical relevance. The threshold for logical relevance is not high: R. v. Candir, 2009 ONCA 915, para. 48. Again, the question is whether, as a matter of human experience and logic, the existence of a particular fact makes the existence of a material fact more probable than it would be otherwise.

[55] In my view, this is a straightforward assessment.

[56] Mr. Cain’s state of mind during the commission of the offences is clearly a material issue in this case. Mr. Cain has testified that, subsequent to the moment in time when he was grappling with Ryan Kennedy, he experienced cognitive impairments. He described those impairments variously as “fogging out”, “fuzzing out”, “out of it”, being “confused” and “lost”. He associated these symptoms with his congenital heart disease. Those types of symptoms, if accepted by the jury, may be important to their determination of whether Crown counsel has proven, to the reasonable doubt standard, that Mr. Cain had the requisite intent for murder.

[57] There is no question that Mr. Cain’s heart disease is real. I would describe it as profound. Dr. Colman’s evidence will explain the nature of that heart disease and some of the symptoms commonly associated with it. Those symptoms can sometimes involve impairments of mentation. Dr. Colman’s evidence will assist the jury in understanding and assessing Mr. Cain’s evidence about his experiences during the commission of the offences. And for that reason, it is, in my view, logically relevant.

The Evidence is Necessary

[58] In Mohan, Sopinka J. related the necessity factor to the concern that expert evidence not be permitted to usurp the fact-finding function of the jury. If the jury is capable of coming to their own conclusions without the help of an expert, then the evidence is not necessary.

[59] There is no way the jury will understand the nature and extent of Mr. Cain’s congenital heart disease absent the evidence from his cardiologist. The disease is complex and profound and a proper understanding of it requires the evidence of a cardiologist.

[60] The Crown argued that Dr. Colman is limited to offering only generic opinion evidence about possible symptoms associated with hypoxia. This is so, according to the Crown, because he concedes that he is unable to comment on the effect of a combination of aerobic and anaerobic activities on Mr. Cain’s oxygen saturation level, and unable to comment on the effect of adrenaline on Mr. Cain’s physical and mental functioning during an hypoxic event. These two significant features appear to have been in play during the commission of the offences.

[61] The Crown submits that all Dr. Colman can do is confirm that Mr. Cain’s general complaints of mental impairment are consistent with hypoxia and that one would expect Mr. Cain to be experiencing hypoxia in view of his physical exertion leading up to and including the grappling with Mr. Kennedy. Such generic opinion evidence is not necessary in the submission of the Crown. The jury will be able to appreciate and understand the connection between low blood oxygen levels and mental impairments. They will be able to reach their own conclusions without the assistance of Dr. Colman.

[62] In my view, the Crown’s position is an over-simplification of the evidence of Dr. Colman.

[63] First, as I have indicated, Dr. Colman’s evidence is necessary for the jury to understand the exact nature of the heart disease and just how profound it is. Second, based on Mr. Cain’s physiology and his performance on the Walk Test, Dr. Colman will testify about the significant effect that even modest exertion has on Mr. Cain’s blood oxygen saturation levels. That evidence will otherwise not be before the jury. Third, he will testify about the way in which low oxygen levels in the blood may lead to mental impairments.

[64] I agree that it is not “rocket science” that lack of oxygen to the brain can affect mental performance. As I suggested to counsel, anyone prepared to hold their breath long enough will be able to experience a range of such symptoms. That said, it is the connection between the profound heart disease and hypoxia and between hypoxia and mental impairments that is significant. For the jury to truly appreciate Mr. Cain’s condition, to understand the nature of his disease and how it might affect him, Dr. Colman’s evidence is required. Only in the context of his evidence will the jury really be able to assess the evidence that Mr. Cain gave about his cognitive experiences while inside the McKelvey residence.

The Evidence is Not Subject to an Exclusionary Rule

[65] No counsel suggested that any exclusionary rule, apart from the rule relating to the admissibility of expert evidence, applies to the proffered evidence of Dr. Colman.

Dr. Colman is a Properly Qualified Expert

[66] There is no dispute that Dr. Colman is an expert cardiologist. He has specialized, throughout his long and distinguished career, in the care of adults with congenital heart disease. He has also been Mr. Cain’s treating cardiologist for more than a decade. There is likely to be no one more qualified to provide evidence about Mr. Cain’s heart disease and the way it affects him.

[67] His anticipated opinion consists of two main parts:

(a) That Mr. Cain would likely be in an hypoxic state after the physical exertion necessary to walk the 350 or so metres into the McKelvey residence and then grapple with Mr. Kennedy; and

(b) That the symptoms described by Mr. Cain are consistent with a person experiencing an acute hypoxic episode.

[68] Dr. Colman is more than qualified, in my view, to give the opinion he is being offered to give.

[69] The Crown challenged him on the limits of his qualifications. During the voir dire, the Crown established that Dr. Colman is not qualified to give an opinion about the effect of hypoxia on memory formation, retention and/or recall. He is also not qualified to opine about the effect of adrenaline on the symptoms normally associated with an hypoxic event. And he is not qualified to opine about the effect of a combination of aerobic and anaerobic activity on the extent of any hypoxia experienced by Mr. Cain. Clearly there are limits to what he can, or is prepared, to say.

[70] It is important to be clear, however, that Dr. Colman is not being asked to opine about the impact of adrenaline on symptoms of hypoxia, nor about the impact of hypoxia on memory. Those factors may ultimately affect the weight that the jury will attribute to his opinion, but in my view, they do not affect his qualification to give the opinion on offer.

[71] I add, parenthetically, that Dr. Colman testified in a fair and candid manner during the voir dire. He is not a witness likely to exceed the comfortable boundaries of his expertise. That said, I note that the court’s risk management function does not end with the release of this ruling. It is an ongoing task.

The Evidence is Legally Relevant

[72] The bulk of the argument on the voir dire was directed at the cost/benefit analysis – the question of whether, while arguably logically relevant, the evidence on offer is legally relevant.

[73] In many respects, the Crown’s arguments in relation to the basic threshold elements of relevance, necessity and qualification, also relate to the costs/benefits assessment.

[74] The Crown made an interesting argument. Mr. Davidson pointed out that Mr. Cain has expressed difficulty remembering many of the details from the night of October 19, 2011. But he had no difficulty remembering and recounting the symptoms of impaired mentation he says he experienced while inside Mr. McKelvey’s house. Apart from the impact that such an incongruence of recall may have on Mr. Cain’s credibility, the Crown suggested that if Mr. Cain’s memory was intact in terms of those symptoms, he could not have been suffering any significant mental impairment. Dr. Colman is not able to comment on how hypoxia might affect memory retention and subsequent recall. He said that evidence about the relationship between memory and cerebral hypoxia should come from a neurologist. Had he been able to provide such evidence, his opinion may be of even greater benefit than it is.

[75] On three occasions during his examination-in-chief, Mr. Cain mentioned that he was feeling the effects of adrenaline during the commission of the offences inside the McKelvey residence. Dr. Colman conceded that adrenaline may have an impact on performance – both mental and physical. But he is not able to say how or even if the difference would be important. Again, if he were qualified to provide such an opinion, his evidence may be even more helpful than it otherwise is.

[76] All this is to sa