Keoghs Insight


Matthew Perkins

Matthew Perkins


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Dementia and TBI - An unconventional couple?


Over the course of the last few years there has been an increasing trend for schedules of loss in brain injury claims to argue for either discrete damages in later life or provisional damages to reflect an alleged increased risk of dementia due to traumatic brain injury (TBI).


To date insurers have argued, with success, that such claims are speculative and without merit, principally on the basis of causation. The basis of the defence to such claims is sound; firstly on epidemiological grounds supported by expert evidence and secondly on a strict legal basis. These grounds are of course necessarily linked.

The debate is now set to move forward somewhat, following a recent publication in the Lancet; “Dementia prevention, intervention, and care: 2020 report of the Lancet Commission.” [1]

The study pools the latest available research material, and comments on risk factors as follows:

  • “Overall, a growing body of evidence supports the nine potentially modifiable risk factors for dementia modelled by the 2017 Lancet Commission on dementia prevention, intervention, and care: less education, hypertension, hearing impairment, smoking, obesity, depression, physical inactivity, diabetes, and low social contact. We now add three more risk factors for dementia with newer, convincing evidence. These factors are excessive alcohol consumption, traumatic brain injury, and air pollution.”

At first blush the addition of TBI as a ‘risk factor’ in this authoritative paper could be seen as presenting claimants with a foundation stone for evidential challenge in respect of the epidemiological grounds, however, taking a step back, little if anything has changed in the wider context.  

In the first instance, whether pursuing a stand-alone claim or an award of provisional damages, a claimant will still have to establish a causal link; establishing on a balance of probabilities that if dementia arises in the future it will, on the balance of probabilities, have been caused or materially contributed to by the TBI. 

On this point, the challenge for the Courts will be to dissect the TBI from the multitude of other risk factors, noting the effect of this study is merely to add TBI to some 11 other factors. Indeed if legal arguments develop further, expert evidence may be introduced from insurers which focus on the potential impact from the other factors, akin to the current ‘atypical’ claimant arguments we see in life expectancy evidence cases.

In our view the challenges for a claimant attempting to prove his or her case remain as great as they always have been due to the presence of so many currently indivisible additional factors, both clinical and psycho-social, quite possibly post-dating the injury by decades.  We are, after all, way short of the body of evidence linking epilepsy to TBI.


The report also serves to highlight the range of impact should dementia arise.  On page 25 in the context of end of life care, the authors state:

Most people with dementia might die while still in the mild-to-moderate stages whereas only about a quarter of those dying with dementia have severe dementia.

This may be particularly relevant in those small sub-group of cases where dementia has been detected following TBI, albeit it would of course have general application to any proven future claim, as it suggests that the majority will reach mild to moderate stage at death, with only a minority reaching the severe stage. Taking this to its logical conclusion, there seems a good case to suggest that even in cases where there is an established link either to diagnosed or potential future dementia, the extent to which such a link should sound in damages ought to be limited in the absence of specific evidence to the contrary.

Life Expectancy

Finally, the paper does not extend to life expectancy. Naturally, if the Courts were to factor in the development of dementia in later life then this would have a negative impact on the life multiplier.

In the event of such a claim being introduced it will be necessary to obtain expert evidence in the first instance from a neurologist and or geriatrician to put the claim into its multi factorial context in light of all the most current literature, including this paper and no doubt more in the future.

 [1] 30 July 2020 -