In the year 2000, the Journal of Clinical Otolaryngology first shared guidelines for diagnosing Noise Induced Hearing Loss.
Guidelines for diagnosing Noise Induced Hearing Loss were first published in the Journal of Clinical Otolaryngology in 2000 by the authors, Coles, Lutman and Buffin. For many years, they were regarded by most clinicians as a reliable indicator as to whether a patient with a history of sufficient noise exposure has a Noise Induced Hearing Loss.
The diagnostic criteria has important ramifications in a medico-legal context where a claimant has to establish medical causation in order to secure an award of financial compensation. They have been brought into sharper focus in recent years due to large numbers of claims brought by servicemen and former servicemen who claim that their exposure to military noise has damaged their hearing and, in some cases, affected their career and future earnings.
In 2022, three clinicians, Moore, Lowe and Cox published an alternative set of guidelines (referred to as The MLC guidelines), arguing that the existing Coles, Lutman, Buffin (CLB) guidelines were not adequate to deal with more impulsive noises including military exposures or very intense tones.
Generally, The MLC guidelines are regarded as more permissive than the original guidelines and concern was expressed by the authors of this rebuttal study that applying The MLC guidelines to medico-legal cases would increase the number of patients who had a falsely positive diagnosis of NIHL.
In November 2024, a peer reviewed study was accepted for publication in Clinical Otolaryngology. Messrs Lutman, De Carpentier and Green provided a rebuttal to the Guidelines for Diagnosing and Quantifying Noise Induced Hearing Loss, (“Guidelines for the diagnosis of NIHL and their specificity”). We understand that it will appear in a future issue of the journal.
The authors applied The MLC Guidelines to three data sets including 536 patients with hearing difficulties and/or tinnitus who denied any material exposure, and, to a further 3,250 patients taken from archival population studies, also without material noise exposure.
Conclusions
The authors conclude that applying The MLC Guidelines to both study groups demonstrated high false positive rates of NIHL. The MLC Guidelines propose three separate processes to reach a possible diagnosis, dependent upon whether the patient has been exposed to steady broadband noise exposure, impulse sounds in industry or intense impulse sounds.
The authors of the Lutman study conclude that false positive rates average 56% in the population study for broadband noise exposure, compared to around 30% for CLB. In other types of exposue, the false positive rate is higher than 70%.
Commentary
The publication of this Peer Review Rebuttal Study of The MLC guidelines is a further chapter in the dispute between two separate groups of clinicians as to which guidelines are more appropriately to be used to diagnose Noise Induced Hearing Loss.
It is recognised that both sets of guidelines will produce false positive diagnoses of NIHL. The question is whether this renders either or both unreliable, particularly when military noise is cited as the source of exposure.
We expect any Judicial resolution of the issue in 2025 or beyond. So far, the MLC guidelines have been a central feature in a surprisingly small number of cases to reach trial, although that may reflect the practice of the market rather than the issues at stake.
The significance of the MLC Guidelines in practice as applied to broadband noise, is its lower NIL requirements and the fact that all noise exposure should be taken into account rather than just that at or above 85dB(A) LEP,d.
The authors note it has been commented that, under the MLC Guidelines, it is theoretically possible that someone with a 40 year career as a librarian could be diagnosed with noise damage. Clinical judgment may prevent this in practice of course.
That, on its face, it has significantly higher false positive rates than CLB may prevent it from becoming accepted in a medico-legal sense.
In this regard, it is noted that aspects of the CLB were approved in the Nottinghamshire Textile litigation and the approach of the first instance judge was approved by the Supreme Court. That is a high hurdle to cross for any new guidelines. In addition, taking account of the court’s approach to the balance of probabilities, a 56% prospect of a false positive result means, on balance, that is a false positive result. A 30% prospect of a false positive result meanwhile, is not, on balance, a false positive result.
For further information, contact our occupational disease solicitors.