An Ontario tribunal has cancelled a ruling that kept an injured driver out of the province's highest tier of accident benefits, over one unexplained definition.

Vice-Chair Craig Mazerolle released the reconsideration decision on September 8, 2026, in a case against Intact Insurance Company. The claimant, hurt in a July 2020 crash, was told after a four-day hearing that her injuries didn't add up to catastrophic impairment, the designation that unlocks Ontario's most extensive accident benefits. Her combined score came in at 50 percent, just short of the 55 percent cutoff.

One of the disputed findings involved vertigo. Her neurologist believed she had nystagmus, an involuntary eye movement, and scored that impairment at 7 percent. The original adjudicator rejected the diagnosis, but leaned on a detailed technical description of the condition that appeared in the decision from no identifiable source.

Mazerolle found that gap mattered. The definition went further than anything the neurologist himself had said in his testimony, and adjudicators can only draw on medical knowledge that is genuinely well-established and widely recognized, not a definition of their own making. That, he ruled, was an error serious enough to have changed the result.

There was a second problem, this time over her psychological impairment score. Her own assessor put it at 15 percent; the insurer's expert put it at 10 percent. The two agreed on one clinical scale but split sharply on two others, and the original decision picked the insurer's number without explaining why, even describing her assessor's opinion as severe without saying what that meant.

Mazerolle called that a real fairness problem rather than a stylistic one. Catastrophic impairment findings carry serious consequences for claimants and insurers alike, he wrote, and deserve a clear, traceable explanation, one the original decision never gave.

He was careful to note that reconsideration is not a chance to reargue a case just because a party dislikes how the evidence was weighed, and the bar for reopening a decision stays high. But he found that accepting the claimant's numbers on vertigo and psychological impairment would have pushed her combined score over the catastrophic impairment threshold.

The tribunal cancelled the original decision and ordered a new hearing before a different adjudicator, working from the same hearing transcripts and exhibits rather than starting the case over from scratch. Whoever arranged the court reporter for the original hearing now has 30 days to share a copy with both the other side and the tribunal. Mazerolle will not be involved going forward.