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Case Note

Can an Ontario LAT Catastrophic Impairment Decision Be Reconsidered?

A 2026 LAT reconsideration decision was overturned after the adjudicator used an unexplained medical definition and gave inadequate reasons on psychological impairment.

6 min readReviewed by Sunish Rai Uppal2026 CanLII 94563 (ON LAT) (CanLII) ↗

Case snapshot

At a glance

Case
Can an Ontario LAT Catastrophic Impairment Decision Be Reconsidered?
Court / Tribunal
ONLAT
Date
September 8, 2026
Area of law
Motor Vehicle Accident
Key issue
Whether the Licence Appeal Tribunal erred in law and breached procedural fairness when it used an unexplained definition of nystagmus and failed to give adequate reasons for preferring one psychological expert's WPI rating over another in a catastrophic impairment determination.
Outcome
The reconsideration was granted, the original decision was cancelled, and the application was ordered to be reheard before a new adjudicator on the existing record.
Why it matters
This decision confirms that accident benefit claimants can challenge a LAT ruling when an adjudicator relies on unexplained technical definitions or fails to clearly explain why one expert's opinion was preferred over another's.

Legal principle

The rule from this case

When the Licence Appeal Tribunal decides a catastrophic impairment claim, it must ground every key factual finding in the evidence actually before it. If an adjudicator uses a technical medical definition that did not come from any witness or document in the hearing, that is a legal error — not a permissible exercise of the Tribunal's specialized knowledge. The Tribunal can only take notice of facts that are genuinely "generally recognized" within its expertise, and where an expert witness was called specifically to explain a medical term, that term is not generally recognized enough to be assumed. Beyond factual accuracy, the Tribunal owes a high level of procedural fairness in catastrophic impairment cases because the consequences are so significant for the injured person. That means the Tribunal must explain, clearly and in enough detail, why it preferred one expert's scoring on tools like the GAF and PIRS over another's. A decision that simply announces a preference without walking through the reasoning on the key scoring differences does not meet that standard. Taken together, a legal error on one impairment category and a fairness breach on another can be enough to overturn an entire catastrophic impairment ruling.

Important limits

What this does not mean

This decision does not mean that every LAT ruling on catastrophic impairment can be reopened simply because a claimant disagrees with how the adjudicator weighed the evidence. The reconsideration threshold is deliberately high. A party cannot succeed by arguing that the Tribunal got the facts wrong or gave too little weight to their expert — that is ordinary disagreement, not a legal error or procedural fairness breach. The ruling also does not guarantee that the injured person will ultimately be found catastrophically impaired. The case has been sent back for a full rehearing before a new adjudicator, who will review the existing record and reach their own conclusions. The outcome of that rehearing is entirely open. What the reconsideration decision establishes is a procedural right to a fair, adequately reasoned decision — not a substantive right to any particular WPI rating.

What Is a LAT Reconsideration and When Can You Request One?

A LAT reconsideration is a formal process that allows a party to ask the Licence Appeal Tribunal to review its own decision — but only on specific, limited grounds. It is not a chance to re-argue the case or complain that the adjudicator weighed the evidence differently than you would have liked.

Under Rule 18.2 of the LAT Rules, a reconsideration can succeed only if the Tribunal acted outside its jurisdiction, committed a material breach of procedural fairness, made a legal or factual error that likely changed the outcome, or if genuinely new evidence has emerged that could not have been obtained earlier. The bar is intentionally high, and most reconsideration requests are dismissed.

In Blackwell v. Intact Insurance Company, 2026 CanLII 94563 (ON LAT), the Vice-Chair granted reconsideration on two separate grounds — a legal error about a medical definition and a procedural fairness breach in the psychological impairment analysis.

What Happened in This Catastrophic Impairment Case?

The injured person was involved in a motor vehicle accident in July 2020 and applied for accident benefits under Ontario’s Statutory Accident Benefits Schedule. The central dispute was whether she met the threshold for catastrophic impairment under Criterion 7, which requires a combined Whole Person Impairment (WPI) rating of at least 55%.

After a four-day hearing, the original adjudicator found a combined WPI of 47% — rounded up to 50% — which fell short of the 55% threshold. The injured person then requested reconsideration, arguing the adjudicator made errors in the vertigo and psychological impairment ratings. If those two categories had been assessed differently, the combined WPI would have crossed the 55% line.

Can an Adjudicator Use a Medical Definition That Was Not in Evidence?

No — not when the definition is specialized enough that an expert was needed to explain it in the first place. This was the core legal error identified in the reconsideration decision.

The original adjudicator dismissed the neurologist’s diagnosis of nystagmus by applying a detailed definition of the condition — including specific references to the vestibular-oculocephalic pathway and the requirement that the condition persists at rest. The problem: that definition did not appear in any witness’s testimony or report. The adjudicator did not explain where it came from.

The LAT is permitted to take notice of genuinely well-known scientific facts. But the Vice-Chair found that nystagmus is not that kind of general knowledge — the very fact that a specialist was called to define it at the hearing proved the point. Using an unexplained definition to reject an expert’s diagnosis, without grounding it in the record, was a legal error that likely changed the outcome of the vertigo WPI rating.

What Level of Reasons Is Required in a Catastrophic Impairment Decision?

Catastrophic impairment decisions require a higher standard of explanation than ordinary benefit disputes. The Vice-Chair applied the Supreme Court of Canada’s guidance from Vavilov and Baker, which together require decision-makers to show a clear and intelligible chain of reasoning — especially when the stakes are high.

In this case, the two psychological experts disagreed on their scores for the GAF (Global Assessment of Functioning) and PIRS (Psychiatric Impairment Rating Scale). The adjudicator preferred the insurer’s expert at 10% WPI over the applicant’s expert at 15% WPI, but the reasons did not explain how those specific scoring differences were weighed against each other.

The adjudicator also used the word “severe” to describe the applicant’s WPI rating — a characterization that was then used to find the applicant’s expert internally inconsistent — without explaining which scale or category that label came from. The Vice-Chair found this lack of clarity was not a minor wording issue. It was a material gap in the reasoning that left the injured person unable to understand how a critical part of the decision was reached.

What Happens After a Successful LAT Reconsideration?

When reconsideration is granted, the Tribunal has several options under Rule 18.4. In this case, the Vice-Chair cancelled the original decision entirely and ordered a full rehearing before a new adjudicator. The rehearing will be based on the existing record — the transcript or recording of the original hearing, plus the exhibits — rather than starting from scratch with new evidence.

This approach balances fairness to the injured person with the practical goal of resolving the dispute efficiently. A new adjudicator will review the same evidence and reach their own conclusions, this time with the obligation to explain the reasoning on the contested WPI categories clearly.

Does Winning a Reconsideration Mean You Win the Case?

No — a successful reconsideration means the original decision is set aside and the matter gets a fresh look, not that the outcome is decided in your favour. The injured person in this case still needs to establish catastrophic impairment at the rehearing.

What the reconsideration does establish is that the process must be fair and the reasoning must be transparent. For anyone navigating Ontario’s accident benefits system, this is a meaningful protection: a decision that cannot be understood cannot be properly challenged, and the LAT is expected to explain its work.

Questions and Records to Discuss with a Lawyer

If you are involved in a catastrophic impairment dispute at the LAT, the following points may be worth raising with legal counsel:

  • Whether the adjudicator’s decision explains, in specific terms, why one expert’s WPI scores were preferred over another’s on each contested scale
  • Whether any factual or medical statements in the decision can be traced back to a witness, exhibit, or recognized source
  • Whether the language used in the decision accurately reflects the rating categories in the tools actually applied (such as the PIRS or GAF)
  • Whether the combined WPI ratings, if any errors are corrected, would cross a relevant threshold under the Schedule
  • The timelines that apply to requesting reconsideration under the LAT Rules

Our Ontario motor vehicle accident lawyers work with people who have been injured in collisions and are navigating the accident benefits system. If you have questions about your own situation, you are welcome to reach out through /connect to discuss the specifics with a member of our team.


This article is automated commentary on a public court decision and is for general information only — not legal advice. Decisions rely on facts unique to each case. If you are affected by a similar issue, contact a lawyer for advice specific to your situation.

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