Non-Military Noise Induced Hearing Loss Claims after Abbott v Ministry of Defence

The recent High Court decision in Abbott & others v Ministry of Defence was highly anticipated by those handling noise induced hearing loss (“NIHL”) claims and whilst the judgment focusses on military deafness claims it is likely to have a wider impact and is of general application to those handling NIHL claims arising from industrial and other non-military settings.

For those handling such claims, Garnham J’s lengthy and comprehensive judgment provides important clarification in several areas. The judgment makes for fascinating reading and particularly the “Judicial Primer” set out at Chapter 3 of the judgment is essential reading for anyone handling claims in this field.

This insight focusses on the potential impact of the judgment in non-military claims.

Guidelines for Diagnosis

The Court did not upend the existing diagnostic frameworks and the established approaches such as the CLB guidelines remain appropriate. However, what is clear from the judgment is that a medical expert’s clinical judgment is crucial in NIHL claims and it is imperative that such clinical judgment is demonstrable rather than a simple mechanical reliance on guidelines, notches, or algorithms.

In industrial NIHL claims, where historic workplace noise exposure is often lower or more intermittent, and affects hearing differently to military noise, age related hearing loss (presbycusis) plays a greater role and there is a heightened risk of over diagnosis. Experts must demonstrate that they have genuinely considered and excluded age related hearing loss, idiopathic loss, and non occupational noise exposure.

Box ticking exercises or formulaic conclusions are unlikely to survive scrutiny. Diagnosis remains a clinical judgment, not a mathematical one. Time will tell if claimants will seek to rely upon alternative diagnostic models such as the various versions of the Moore papers as opposed to the tried and tested CLB and LCB methods.

For industrial claims, this reinforces the expectation that experts must be able to explain how and why they reached their conclusions; probability tools, however advanced, cannot replace reasoned analysis.

TDH-39 Headphones

For a long time where TDH-39 earphones have been utilised in audiometric testing there has been an automatic 6dB deduction applied to readings at 6 kHz required due to ‘audiometric artefact’. However, the judgment confirms that a routine 6 dB correction is inappropriate, as while many of this type of earphone produce this error not all do. Any correction must be applied on a case by case basis, supported by proper reasoning. Given this, and whilst it is of course for medical experts to determine diagnosis, in situations where practitioners wish to carry out their own analysis, it would be prudent from now on that they should determine whether a correction has an impact on a likely diagnosis. If a diagnosis is dependent on the correction being made or not, then it may be a case suitable for further audiology so that it can be better considered whether it is appropriate to make a correction.

Occupational Health audiometry 

A feature of the military claims being considered in this case was that there are a large number of military audiograms and a key area of disagreement between the parties was whether such audiometry could be relied upon and the weight to be given to it. It is submitted that the judgment on this issue is of wider relevance in that many workplaces carry out audiometric audiometry or screening. It is clear from the judgment that Pure Tone Audiometry conducted in compliance with the protocol and standards of the British Society of Audiology is the gold standard of audiometric testing and should be used in medico legal cases, but other audiometry ought to form part of the ‘exercise of clinical judgment’ of experts advising in medico-legal claims. Routine workplace or screening audiograms can be reliable and probative particularly where they show a consistent pattern over time. Medical experts who simply ignore or discount historic occupational audiograms are vulnerable to criticism. Employers’ health surveillance records will undoubtedly carry evidential weight unless there is a clear reason to doubt them. This aspect of the judgment will assist those defendants who have a long history of undertaking good quality health surveillance including regular audiology.

Tinnitus

The Court considered the issue of the onset of tinnitus after exposure to noise has ceased. The Court’s conclusion is that there can be no firm cut-off date by which tinnitus should have manifest and that the cause of such tinnitus is something to be considered on a case by case basis. However, the longer the gap between noise exposure and onset, the more closely causation of tinnitus must be examined.

In industrial disease claims it is not unusual for Claimants to report first noticing tinnitus many decades after leaving noisy employment. The decision strengthens arguments that temporal distance undermines causation, particularly in the absence of contemporaneous complaint and that greater scrutiny of the circumstances of the case should be given in those circumstances. 

Age related hearing loss datasets

The judgment also made it clear that ISO 7029:2017 (as corrected in 2024) was preferred over older datasets for both diagnosis and quantum considerations. A baseline correction of 2.4dB is to be applied to convert figures relative to a normal 18 year old to absolute figures. This dataset generally produces lower calculated NIHL, reducing the risk of overstating occupational loss in older claimants.

Quantification and De Minimis

The Court confirmed the general practice that NIHL should be quantified based on the hearing at 1, 2 and 3 kHz though it is ‘entirely legitimate to consider supplementary metrics that incorporate 4 kHz, particularly where speech-in-noise difficulty is a prominent feature" and endorsed using a weighted binaural calculation weighted 4:1 in favour of the better ear.

When considering de minimis the Court found that a loss below 4 dB will usually be de minimis but could still be actionable if it produces real functional consequences or if there were other consequences of noise exposure such as tinnitus. This provides a basis for resisting claims with low level losses which rely on measurement alone, without demonstrable day to day impact, though does not represent a ‘line in the sand’ below which an injury is not compensable.

Hearing Aids

The Court determined that there is no objective threshold dB loss value which justifies hearing aids in every case. The Court rejected awards based on the possibility that hearing aids might help or based on expert opinion that hearing aids are “often recommended” at a particular level of loss. Instead, there must be evidence that hearing aids would materially improve the claimant’s hearing function, especially speech discrimination, hearing in noise or work‑related communication. If hearing aids would produce little perceptible improvement, they are not recoverable. The Court was clear that damages should not fund equipment the claimant will not actually wear.

Evidence undermining intention included a long delay in seeking treatment, stated reluctance to wear aids, inconsistent accounts of difficulty, or a history of declining NHS aids. Where NIHL is mild, borderline de minimis, or largely masked by age‑related loss, the Court accepted that hearing aids may be unnecessary or disproportionate, even if they could technically be prescribed. The Court endorsed that current costs were around £4,200 to £5,000 including fitting and adjustments and that aids would need replacing every 5 years. 

Latency and Acceleration of hearing loss

It was determined that whilst theoretically possible, medical evidence does not allow a finding that noise‑induced hearing loss progresses after exposure ceases and does not accelerate age‑related hearing loss once exposure has ended.

Future loss of earning claims

While not common in industrial disease claims due to the age of many Claimants this part of the decision will have a wider impact on claims involving other types of diseases. The Court dismissed the use of the Ogden tables for calculating loss of earnings and allowed for a much smaller Smith v. Manchester award. The Court did this on the basis that the Claimant has been employed since he was 18, remained in employment, was not under threat of redundancy, was valued by his employer and wished to stay on in that employment. The Court described the large Ogden based claim, on those facts, as ‘unconscionable’. 

Conclusions

This decision is not one that will necessarily revolutionise how NIHL claims will be considered but it will certainly have some impact. The overarching theme of the decision is the rejection of hard rules and confirmation that each issue needs to be considered in the context of the individual claim. The decision provides Defendants with a basis for challenging weak or exaggerated industrial deafness claims and now, more than ever, it is important to have knowledgeable and experienced handlers defending these claims.