Hearing loss and quantum: When the Audiogram is Not the Whole Story.
Abuse Aware | February 2020
Hearing loss has long been assessed using the thresholds identified on an audiogram. Medical experts generally use the Coles, Lutman, Buffin 2000 guidelines and the now updated Lutman, Coles, Buffin (2016) paper. This approach means that both claimant and defendant representatives can take an initial view and settle claims at an early stage. Recent novel arguments on speech intelligibility and latent damage are beginning to muddy the waters. The first case to explore this issue was Ross.
Ross v Lyjon CC Liverpool 
Breach of duty was conceded but causation remained at issue. The defendant said that a 1993 audiogram, close to the date the claimant left employment, had no diagnostic characteristics of NIHL and showed no hearing loss apart from ageing. A 2011 audiogram did show NIHL. The defendant said that this couldn’t have been caused by them as loss couldn’t develop after exposure ceased.
The claimant said that the 1993 audiogram was unreliable. He also argued that hearing damage could be latent. The claimant relied on Professor Moore on the second point. He argued that:
- The obvious effect of noise exposure would be damage to cells within the cochlea which was usually identifiable on an audiogram. However;
- Animal studies suggested that even mild damage to the outer hair cells reduced their ability to amplify sound. This led to interference between those cells and the auditory nerve, which in turn led to degeneration.
- None of the above would be shown on an audiogram but could lead to problems in understanding speech, particularly in background noise.
This was not an argument of true latency. The damage is supposedly already there, but is not apparent from audiometry. An audiogram is therefore not a true reflection of the claimant’s disability.
The Court concluded that whilst there was a possibility of latent effect, this fell below the balance of probabilities on the evidence. In other words, all Mr Ross could prove was the possibility that damage may have occurred.
Whilst the claimant did not succeed on this case, these arguments have significant consequences for defendants. If the audiogram is not the measure of disability then how can we assess claims? Might a claimant’s own evidence supplant the audiogram?
Inglis v MOD  EWHC 153
These issues were raised again in Inglis. The claimant was a former member of the Royal Marines. He claimed for hearing loss and tinnitus. Liability was agreed on an 80:20 split in his favour so the trial concerned quantum only. At the time of the judgment Mr Inglis was 39 years old.
The main factors driving quantum were the level of the claimant’s hearing loss and whether damage continued after exposure to noise stopped.
As in Ross, Professor Moore argued that a normal audiogram does not mean that there is no damage to hearing. There was a difference, he said, between being able to detect sound measured on the audiogram and speech intelligibility. He considered that the claimant had a 20% decrease in speech intelligibility. The claimant’s NIHL was calculated from the audiogram to be 11.8Db. This is relatively mild.
The judge agreed with the claimant and found that objective investigations such as audiograms are only part of the evidence of hearing loss. The Court should also consider whether the claimant was a credible witness when reporting his symptoms.
It was found that the claimant’s hearing loss was permanent, had an adverse effect on his work and was more than trivial. This made a crucial difference to quantum as it ‘proved’ that the claimant was disabled within the definition of the Ogden tables. This led to the application of a multiplier/multiplicand approach to future loss. In Mr Inglis’ case it was accepted that his disability would stop him being promoted. He recovered damages of £545,766 – even after the 80/20 split.
If the court had taken the audiogram at face value this would have been considered mild hearing loss. Quantum would have been far lower.
The Inglis case is unusual in that the level of hearing loss was mild, yet a substantial payment was made. Military claims often involve specific complex loss of earnings issues. What impact might these arguments have on standard industrial deafness claims?
The arguments regarding speech intelligibility were largely accepted in Inglis, but this depended on credible witness evidence describing the level of disability. The issue of latency was only mentioned in obiter in Inglis and left open by Ross. The Inglis case was a first instance decision which was not appealed. However these issues will not go away. It may well be easier for some claimants to prove a higher level of disability. They would recover higher damages and their solicitors could avoid fixed costs.
Defendants must be aware of these arguments from the outset of claims to obtain the best evidence to stop these novel causation points from setting precedents on methodology used by claimant experts. Defendants need to get strong medical and audiology reports to strengthen arguments that the correct and reliable way to calculate the level of loss is to use the Coles/Lutman/Buffet guidelines at frequencies 1, 2, 3 kHz and that hearing loss remains static when exposure ceases.
Author - Eleanor Fox - Associate.