What is the test for ordering a second defence medical?

In Bonello v. Taylor, 2010 ONSC 5723 at para. 16, Brown J. (as he then was), set out the following summary of principles that are to guide the exercise of discretion in ordering subsequent independent medical examinations [citations omitted]: i. The party seeking the order for a further examination must demonstrate that the assessment is warranted and legitimate, and not made with a view to delaying trial, causing prejudice to the other party, or simply corroborating an existing medical opinion; ii. A request may be legitimate where there is evidence that (i) the party’s condition has changed or deteriorated since the date of a previous examination, (ii) a more current assessment of the plaintiff’s condition is required for trial, (iii) the plaintiff served specialist reports from new assessors after the defendants had conducted their medical assessments, or (iv) some of the party’s injuries fall outside the expertise of the first examining health practitioner; iii. Some cases take the view that the need for a “matching report” – i.e. a report from a defence expert witness in the same specialty as a plaintiff’s expert – is not, in and of itself, a sufficient reason to order a further defence medical. In the circumstances of the present case I need not wade deeply into that question. That said, I would venture that trial fairness should operate as the guiding principle in this area, so if the plaintiff has decided that expert evidence from one specialty based on an examination of the plaintiff is relevant to the adjudication of her claim at trial, courts should be loathe to deny the defence a fair opportunity to respond with expert evidence from the same specialty based on an assessment of the plaintiff. Ordering further examinations may be just where they are necessary to enable the defendant fairly to investigate and call reasonable responding evidence at trial; iv. Where the request is for the examination of the plaintiff by a person who is not a health practitioner, such as a rehabilitation expert, the defendant must demonstrate that the proposed examination is necessary as a diagnostic aid to the health practitioner who is conducting the defence medical examination; v. A request for a second examination must be supported by sufficient evidence to persuade a court of the need for the further examination. What constitutes sufficient evidence will vary from case to case. Some cases have suggested that need must be established by filing medical evidence, such as an affidavit from the first examining physician recommending a further examination by a health practitioner competent in another specialty. In other instances, an affidavit from a lawyer or law clerk attaching medical reports has been utilized by the court. But, at the end of the day, determining whether the nature of the evidence filed is sufficient remains essentially an exercise of judicial discretion; vi. While fairness, or “creating a level playing field”, may constitute a legitimate reason for ordering a second examination, someone with knowledge of the evidence in the case must provide evidence of unfairness for the court to consider; and, vii. A court should consider whether the request for a further examination would impose an undue burden on the plaintiff in light of the number of examinations already conducted on her by the defence.