His Honour Judge Wood rejected the Claimant's argument that Noise Induced Hearing Loss (NIHL) is a progressive condition that can deteriorate even after exposure to noise has come to an end.

The Defendant faced a novel argument that an audiogram with no audiometric features of NIHL (whether taken during or after the allegedly noisy employment) does not mean that there was no damage, but damage may have occurred so the effects are only seen later in time with audiometric features only appearing on later audiometry.

The case involved two issues of causation:

  1. The reliability of a historic BUPA audiogram that post-dated the Claimant’s employment with the Defendant.
  2. Whether the Claimant suffered latent damage to his hearing that was not present on the BUPA audiogram, but became evident on a later audiogram.

The Claimant failed to establish causation on both points.

The findings have significant implications for the insurance industry. A finding for the Claimant would have led to a substantial increase in new claims.


The Claimant was employed as an electrician for Lyjon Co Limited between 1979 and 1992. His total lifetime exposure to noise was 1974 to 2000 (26 years), but the other Defendants compromised the claims against them. Breach of duty was admitted by the Defendant.

In 1993, the Claimant underwent an audiogram as part of a BUPA health check. This revealed he had “satisfactory” hearing for his age. It was agreed between the medical experts that the 1993 audiogram showed no characteristics consistent with NIHL. Moreover, the Claimant did not report any hearing loss at the time.

In 2011 the Claimant underwent another audiogram on the instructions of his solicitors. This showed a pattern of sensorineural hearing loss that was consistent with NIHL. This was agreed between the experts. The Claimant also complained of tinnitus.

The timing of the 1993 audiogram was crucial; it was one year after the Claimant’s employment with the Defendant ended. Accordingly causation was denied as these was no evidence the Claimant had any noise damage at the end of his employment with the Defendant.

Claimant's case

The Claimant’s case on causation was two-fold:

  • It was argued the 1993 audiogram was unreliable and could not be considered a true representation of the Claimant’s hearing loss at the time.
  • The 1993 audiogram was correct, but the Claimant suffered latent damage, that was not evident on the audiogram and demonstrated no immediate effects or disability.

In respect of the second causation argument, the Claimant relied on Professor Brian Moore and the Defendant relied on Professor Mark Lutman.

Professor Moore relied on animal studies to support his view that damage occurred to the Claimant’s hair cells before the 1993 audiogram would not necessarily show up on an audiogram. There was a period of time before this damage became evident. Although he conceded that animal studies are imperfect models, there are similarities in the way the human ear behaved.

If there has been a previous damaging effect on an individual’s auditory system, it would only take a small amount of further damage to have a measurable effect. It was also Professor Moore’s view that whatever caused the hearing loss would have contributed to the tinnitus (despite its late onset). Accordingly both could be attributable to exposure by the Defendant.

Professor Moore also referred to three studies which related to speech discrimination and his own recently published paper to support his view that damage that effects speech discrimination may be present, but would not show on an audiogram.

Defendant's case

Professor Lutman did not agree that there were measurable latent effects of noise exposure. In his view the animal studies could not be compared to humans. He relied on a recent study by Hederstierna which found no significant difference in the rate of decline in hearing between the ages of 70 and 75, of those with a history of noise exposure and those without.


In respect of the first argument the judge found that the burden of proof did not shift to the Defendant to prove that the 1993 audiogram was accurate. There was no evidence there were any failures in the way the audiogram was conducted. It was also relevant that the Claimant did not complain of hearing loss in 1993, which undermined his argument that the audiogram was incorrect.

In respect of the second argument, the Court found there was a possibility of latent damage occurring; damage may occur to nerve structures which would not be detected by pure tone audiometry. However the Claimant fell significantly below establishing this.

Professor Moore’s proposition that the Claimant became symptomatic when he was exposed to further noise following the Defendant's exposure relied on an assumption of constant noise exposures. However, there was no engineering evidence to support this and therefore this submission was entirely speculative. It was also relevant that there was no evidence that synaptic damage occurred with the earlier noise damage.

Whilst the Judge limited himself to determination of latency occurring on the facts of the case, he noted that its appears unlikely that there will be sufficient consensus on the generic latency question, or means by which such damage could be measured for some time to come.

The Judge also denied the Claimant's request following judgment that damages be quantified on the hypothetical basis the Claimant had a disability. The Judge noted the Claimant had failed to prove he had an assessable disability attributable to noise exposure. Accordingly there was nothing to assess and it would be artificial to calculate a figure on the basis of the Claimant's audiology expert's evidence. The case is distinguishable from those where the injury is easily identifiable, but breach of duty or causation remains in dispute, such as a straightforward EL matter.

Points for defendants

  • As the Judge himself noted, "an argument of latent damage, that is hearing loss without audiometric threshold measurement, has the potential to send shockwaves through the insurance industry if successful. The fear would be that the conventional method for diagnosing occupational deafness and assessing disability would be cast aside, with the possibility of an avalanche of claims based upon the simple premise that an individual had worked in a noisy environment and now has difficulty in discriminating some speech where there was a background of noise."
  • The proposition that there is possible latent damage to hearing caused by noise exposure is a departure from the received wisdom and the way in which NIHL litigation has been conducted for many years.
  • Had this claim not been successfully defended then it is likely that insurers would have seen an increase in the number of claims presented. A Defendant’s ability to defend claims on the basis of limitation and de minimis would have been undermined, leading to a significant drop in repudiations rates.
  • Limitation: If the Claimant had been successful, defendants' ability to argue that a claimant is statute barred would be compromised. The defences of "date of knowledge" of "significant" symptoms under Section 14 and "length and reasons for the delay" under Section 33(3) of the Limitation Act 1980 would be largely negated. Given the difficulties encountered in mounting arguments on breach of duty and the increasing reluctance of courts to allow defendants to have their own medical evidence, limitation remains one of the most powerful tools available to insurers. Any weakening of the present position would be very damaging and likely to lead to injustice.
  • De minimis: Claimants would also be able to argue that lower levels of loss would be actionable on the basis that the noise element of the hearing loss will or might deteriorate.
  • Claimants would also be able to argue that clear audiometry results completed during the period of employment are not representative of whether noise damage had actually occurred. Cases which would otherwise be defended on the basis of no breach of duty may no longer be so defended.
  • The conventional approach to apportionment between defendants would also be undermined. Defendants responsible for earlier periods of exposure, prior to the manifestation of symptoms may argue that symptoms would not have developed but for the later noise exposure, as has been seen in HAVS litigation.
  • The case is County Court authority only, albeit from a well regarded Designated Civil Judge. It should be noted that the case is fact specific and a decision has to be made upon the evidence presented, of which general scientific research is only a small part. Higher authority on the applicability of latency issues more generally would be welcomed, but unfortunately the Claimant’s solicitors, Roberts Jackson, strenuously resisted an application to transfer the case to the High Court. Further test cases on the issue of latency cannot be ruled out but ATE insurers asked to back such costly cases in the future will be deterred by this case.