Changes in hearing thresholds as measured by decibels of hearing loss in British Army Air Corps lynx and apache pilots.

OBJECTIVE

Helicopter pilots are exposed to noise at work and are at risk of developing hearing loss in excess of that which naturally results from aging. We investigated whether Lynx pilots demonstrated changes to hearing thresholds that differed from Apache pilots.

METHODS

Survey responses were combined with audiometric data from a retrospective cohort of 59 Lynx and 87 Apache pilots. Subjects' audiograms were analyzed for air conduction thresholds with age correction performed in accordance with ISO 7029. Annual changes in low frequencies (0.5-2 kHz) and high frequencies (3-6 kHz) were calculated. Subjects were categorized for time in service and flying hours.

RESULTS

Hearing was better than predicted at nearly all frequencies in both ears for Lynx and Apache pilots. There were no differences in hearing between groups of pilots. Significant differences in hearing threshold changes existed for pilots with 20 or more years of service compared to those in other categories.

DISCUSSION

The results suggest that the circumaural earmuffs currently incorporated into the flying helmet mitigate the risk of noise-induced hearing loss in these pilots.