Dementia risk and provisional damages

Mathieu v Hinds and Aviva Plc [13.04.22]


The claimant, who was studying for a Master's degree in Fine Art, suffered a significant brain injury as a result of a road traffic accident in November 2015. Although he made a very good recovery and has gone on to enjoy a successful artistic career, he pursued a claim for compensation (over £30 million) on the basis that ongoing symptoms of headaches, fatigue and cognitive issues meant that he could not produce the art he would have ‘but for’ the accident.

In this article, we focus on two of the most interesting aspects of the case that could have wide ranging consequences. These are:

  • Provisional damages for a risk of dementia.
  • Mitigation of loss.

Provisional damages for a risk of dementia

The claimant sought provisional damages to cover the suggested risk of dementia arising from the traumatic brain injury. Whilst the chance of developing the condition need only be small, the claimant has to also prove on the balance of probabilities the causal link with the traumatic brain injury (TBI).

The case of Wilson v Ministry of Defence [1991] was referred to and the three stage test applied, namely:

  1. Is there a chance of the claimant developing the disease or deteriorating?
  2. Is the disease or deterioration serious?
  3. If so, should the court exercise its discretion to make an award of provisional damages?
Mrs Justice Hill took the view that based on the current state of science, the claimant could not show that on the balance of probabilities “the existence of a more than fanciable chance that TBI will lead to him developing dementia”.

On this basis, the claimant could not meet the requirement of Wilson question one resulting in the provisional damages award being dismissed.

Mrs Justice Hill went on to state that “on the basis of the current scientific evidence, any post TBI dementia that develops would not be reasonably clear cut” and that “the most recent meta-analysis is itself leaving open the question of whether there is a sound scientific basis for the assertion that a single TBI can cause dementia”.

Mitigation of loss

By refusing to consider medication in an effort to reduce his headaches and not undertaking further fatigue management sessions, the defendants contended that the claimant had failed to mitigate his loss.

Dr Foster, neurology expert for the defendant, stated that taking Amitriptyline or a similar prescription drug was likely to substantially ameliorate the claimant’s headaches to a nuisance level within just three to six months. He suggested it could also help with the claimant’s sleep and therefore, the combined effect would be to reduce the claimant’s fatigue which was a major limiting factor. On the other hand, Dr Orrell, neurology expert for the claimant, believed that medication was unlikely to be effective.

The claimant explained that his refusal to take the medication was based on the risk of it making him feel drowsy which would further interfere with his artistic process. Drowsiness is a known and accepted potential side effect of Amitriptyline, although the experts in this case agreed that drowsiness does not occur with everybody and there are other drugs that could be tried.

Mrs Justice Hill concluded that when taking into consideration the claimant’s individual circumstances, it was understandable for him to decline to take medication which might generate side effects of which he was particularly fearful.

Further, she held that the claimant had not been given fair notice of the issue around fatigue management. In any event, the defendants had failed to discharge the burden proving that the claimant had acted unreasonably. They also failed to advance any clear evidence that further fatigue management sessions would have made any difference to the claimant’s outcome.


There is an ever growing body of research into the possible link between brain trauma and dementia. We can only speculate on where that research may take us. However, this judgment provides a clear view on the current judicial position and as such, should assist those addressing the issue of provisional damages and dementia in the future.

Mrs Justice Hill’s conclusion that the defendant failed to show that taking medication would have made a significant difference in outcome is perhaps the most troubling aspect of the judgment on mitigation. It is often the case that medical experts are unable to say with any degree of certainty that a particular treatment option will result in a positive outcome because there is often a range of outcomes. It is only when the treatment is actually tried that a clear idea can be formed as to whether or not it is going to be successful.

The defendant’s expert was clearly of the view that the medication was likely to succeed and the claimant’s expert thought that it was certainly worth trying. The claimant had not, by his own admission, discussed it as an option with his treating physicians. Despite this, the Judge concluded that there was insufficient evidence that the claimant was acting unreasonably or that the medication would have made any difference. Such an outcome reinforces the point that it is a high hurdle for the defendant to prove failure to mitigate.

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