Development of an auditory fitness-for-duty standard for military personnel

The ability to hear clearly is critically important for the successful conduct of military operations. Unfortunately, military operations are also very noisy, and this has historically resulted in a high prevalence of hearing loss in active-duty personnel and veterans. Thus, one of the important roles of hearing surveillance programs in the military is to identify individuals with severe enough hearing impairments to endanger themselves or others when performing their mission. Most current military hearing conservation programs require annual audiometric testing to monitor Service Members for significant changes in their hearing. Those with thresholds that exceed some predefined set of frequency-dependent limits are referred to an audiologist for further testing. The results of this testing are used to make a recommendation for retention or separation. A research program is now underway to replace the current fitness-for-duty standards, which are based primarily on historical precedent, with evidence-based fitness-for-duty standards that provide a direct link between the results of clinical hearing tests and the functional hearing tasks that Service Members might need to perform on the battlefield. The proposed standards are based on the assumption that speech-in-noise perception is the task that is most likely to limit operational performance in hearing-impaired listeners. The proposed hearing threshold limits were derived from a data set containing audiometric thresholds and speech-in-noise scores for 5,487 ears. This data set was used to identify the threshold cutoffs that best identified individuals with poor speech scores without changing the total number of people referred for testing. The proposed standard also incorporates a closed-set speech-in-noise test based on the Modified Rhyme Test. We hope these new recommendations will improve the efficiency and credibility of fitness-for-duty evaluations in the military. [The views expressed are those of the authors and do not necessarily reflect the official policy or position of the Departments of the Navy, the Army, the Department of Defense, or the US Government.]