COGNITIVE DEFICIT, CAPACITY AND QUANTUM : A fresh look at how to approach cognitive deficit in PI claims.

pi_kate_mckinlay By Kate McKinlay 

In the recent decision of


The Court of Appeal found a significant cognitive deficit, and consequent lack of capacity, notwithstanding recent evidence of minimal cognitive dysfunction, resulting in damages of equivalent to £2.3 million on a full liability basis.



On 30th January 2006 the Claimant was involved in a road traffic accident as a result of which he was seriously injured.  The Defendant was uninsured and played no part in the proceedings. Liability was agreed 80:20 in the Claimant’s favour.  Stuart-Smith J heard the issues as to quantification of damages over 12 days in December 2012.


The Defendant’s key argument was that the Claimant was either a malingerer, or had exaggerated the extent of cognitive deficit, but that either way, he did not as pleaded suffer from significant cognitive deficit. The cornerstone of their argument was the agreed evidence that the Claimant had successfully completed a Citizenship Test in the months before the hearing.  There was also a factual issue as to whether or not the Claimant had completed the test without assistance.

At first instance, Stuart-Smith J concluded that

  • the Claimant managed to pass the test without assistance,
  • he had passed by sheer luck: he had learned answers by rote and then ‘struck very lucky indeed with the questions that came up’.

The judge then went on to find that, notwithstanding his successful completion of the Citizenship Test, the Claimant still lacked capacity for the purposes of the Mental Capacity Act such that he would need ongoing care and support for the remainder of his lifetime and had no residual earning capacity.

The Defendant appealed all these findings.


The Defendant’s first ground of appeal was that Stuart-Smith LJ had failed properly to consider the consequences of having found that the Claimant had passed the UK citizenship test without assistance; and placed weight on evidence that was no longer reliable so as to find that the Claimant continued to suffer from significant cognitive deficits; did not have capacity and had no residual earning capacity. The Defendant submitted on appeal that the only logical conclusion for passing the test was that the Claimant did not suffer from significant cognitive deficit, malingerer or not. This led to the Defendant’s second and third grounds of appeal namely that he had capacity to manage his own affairs, and finally that he had a residual earning capacity.

The main issue therefore was what the judge made of the agreed evidence that the Claimant had passed the citizenship test and whether he was entitled on the evidence to make the consequential findings that he did as to the Claimant’s cognitive deficit.


The Citizenship Test

The CoA roundly dismissed the Claimant’s cross-appeal as to the circumstances in which the Claimant passed the test. It agreed with Stuart-Smith J that, whilst surprising, the evidence that there was as to the sitting of the test, all pointed to a finding that the Claimant sat it himself, without assistance.  Furthermore the medico-legal evidence in the case did not suggest that it was impossible for the Claimant to pass the test:-  merely unlikely.

The extent of the Claimant’s cognitive deficit

The CoA unanimously agreed that Stuart-Smith LJ did take into account and give proper weight to all the evidence, including of course the citizenship test.  Once the citizenship test was put into context with all the other evidence, and in its proper place, then, as per MosCombe LJ’s leading judgment, the Defendant’s principal submission that the Claimant did not suffer from a significant cognitive deficit, fell away. The CoA found that the Defendant’s argument over-emphasised the impact of the factor of the test success in the context of the evidence as a whole.

Additionally the CoA agreed with Stuart-Smith J, that there was ample evidence, including from the medical experts to support a finding that the Claimant was not a person who could have kept up a mere pretence of capacity, capable of fooling so many people for so long.

Mental Capacity

The Defendant secondly submitted on appeal that Stuart-Smith LJ did not properly apply the provision of the Mental Capacity Act 2005.  The sections which were relevant sections are as follows:-

Sections 1

1 The principles

(1) The following principles apply for the purposes of this Act.

(2) A person must be assumed to have capacity unless it is established that he lacks


(3) A person is not to be treated as unable to make a decision unless all practicable

steps to help him to do so have been taken without success.

(4) A person is not to be treated as unable to make a decision merely because he

makes an unwise decision.


2 People who lack capacity

(1) For the purposes of this Act, a person lacks capacity in relation to a matter if at

the material time he is unable to make a decision for himself in relation to the

matter because of an impairment of, or a disturbance in the functioning of, the

mind or brain.

(2) It does not matter whether the impairment or disturbance is permanent or


(3)A lack of capacity cannot be established merely by reference to—

(a) a person’s age or appearance, or

(b) a condition of his, or an aspect of his behaviour, which might lead

others to make unjustified assumptions about his capacity.

3   Inability to make decisions

(1) For the purposes of section 2, a person is unable to make a decision for himself

if he is unable—

(a) to understand the information relevant to the decision,

(b) to retain that information,

(c) to use or weigh that information as part of the process of making the

decision, or

(d) to communicate his decision (whether by talking, using sign language

or any other means).

(2) A person is not to be regarded as unable to understand the information

relevant to a decision if he is able to understand an explanation of it given to

him in a way that is appropriate to his circumstances (using simple language,

visual aids or any other means).

(3) The fact that a person is able to retain the information relevant to a decision for

a short period only does not prevent him from being regarded as able to make

the decision.

(4) The information relevant to a decision includes information about the

reasonably foreseeable consequences of—

(a) deciding one way or another, or

(b) failing to make the decision.

The Court of Appeal reminded itself at the outset that the question the Court had to answer as to whether or not a person has a capacity, was fact specific, and depended on the answer to the question ‘capacity to do what?’

In this case the Court was concerned with the Claimant’s capacity to manage his property and financial affairs.   At first instance Stuart-Smith J considered the evidence as to the Claimant’s capacity to be very finely balanced.

Having considered the evidence, he found, based on direct evidence from a number of experts, that the Claimant would be unable to use or weigh information properly to foresee the consequences of his decision.

The CoA found that the judge had taken the correct approach. He was entitled to take account of evidence that the Claimant would struggle to handle large sums of money, and to consider the evidence of neuropsychologists in the round, rather than as the beginning and the end of the evidence, as the Defendant inferred.

In particular the CoA found that the Claimant was not akin to a hypothetical lottery winner who needed advice as to how manage his winnings.  LJ Moscombe commented “the lottery winner has a basic understanding to recognise when advice and assistance might be desirable and will usually have the basis financial means to provide for himself in any event.  If he decides to behave irrationally in disposing of money that is one thing. It is quite another to view with such equanimity the position of this Claimant when in receipt of an award of damages, designed to provide for him throughout life” [paragraph 68].

Unsurprisingly in the light of these comments, this ground of the Defendant’s appeal was also dismissed.


  • In cognitive deficit/ capacity cases evidence that is inconsistent with the overall picture of the Claimant’s cognitive ability will not be the death-knell of the claim and ought to be considered in the round.
  • If you have piece of damaging evidence, work extra hard to build a context for that evidence which offsets its effects as much as you can.


The Judgment :

The Mental Capacity Act 2005:


  1. […] involved in a head injury case will benefit from reading Kate McInlay’s Cognitive Deficit, Capacity and Quantum which examines  the Court of Appeal decision in Jubair Ali in […]

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