Guidelines for Diagnosis of Noise-Induced Hearing Loss and Their Specificity.

OBJECTIVES

A recent paper by Moore, Lowe and Cox has proposed guidelines for diagnosing noise-induced hearing loss (NIHL). It is referred to here as the MLC guidelines. Our aim was to assess the specificity of those guidelines (i.e., freedom from false-positive outcomes) and compare with pre-existing guidelines.

DESIGN

We applied the MLC guidelines and pre-existing guidelines to three data sets composed of adults who do not have a history of material noise exposure and therefore cannot have NIHL.

SETTING

National Health Service (NHS) ENT clinic.

PARTICIPANTS

Five hundred thirty-six patients with hearing difficulty and/or tinnitus who denied material noise exposure. Two large archival population studies of hearing were also assessed, which included 3250 participants without material noise exposure.

MAIN OUTCOME MEASURE

False-positive outcome from guidelines.

RESULTS

The MLC guidelines demonstrated moderate or high false-positive rates overall, the magnitude depending on the noise exposure scenario and whether clinical or population samples were considered. For the procedure applicable to steady broadband noise exposure, the false-positive rate averaged 56% in the population samples, compared to 31% for previous guidelines. For exposure to intense impulse sounds, the MLC guidelines take a different approach and the false-positive rate was about 70% in the population samples and even higher in the clinic sample. For exposure to intense tones, the MLC guidelines take yet another approach and the false-positive rate reached 80%.

CONCLUSIONS

The MLC guidelines demonstrate poorer specificity than previous guidelines. Medical experts should be aware of their poor specificity and consequential likelihood of false-positive diagnoses of NIHL.