Audiometric profile of civilian pilots according to noise exposure

Frequency-Following Response (FFR) in Military Pilots

Introduction  Good hearing in pilots, including central auditory skills, is critical for flight safety and the prevention of aircraft accidents. Pure tone audiometry alone may not be enough to assess hearing in the members of this population who, in addition to high noise levels, routinely face speech recognition tasks in non-ideal conditions. Objective  To characterize the frequency-following response (FFR) of a group of military pilots compared with a control group. Methods  Twenty military pilots in the Study Group and 20 non-pilot military personnel, not exposed to noise in their work, in the Control Group, all with normal hearing, aged between 30 and 40 years old, completed a questionnaire to assess their hearing habits, and their FFRs were measured with a /da/ syllable (duration 40 milliseconds, speed 10.9/s), at 80 dB NA in the right ear. All procedures were approved by the ethical committee of the institution. Statistical analysis was performed using the t-Student or Mann-Whitney tests for quantitative variables, and the Fisher or chi-squared tests for qualitative variables, and a value of p  < 0.05 was considered to be statistically significant. Results  There was no significant difference between the groups regarding auditory habits. In the FFR, wave amplitudes A ( p  = 0.01) and C ( p  = 0.04) were significantly lower in the Study Group. Conclusion  Working as a military pilot can be a crucial factor in determining an individual's typical FFR pattern, demonstrated in the present study by statistically significant reductions in the amplitudes of the A and C waves.

Masking level difference among brazilian military personnel: a comparison between pilots and non-pilots

OBJECTIVES

The aims of this study were to investigate auditory habits and binaural interaction among pilot and non-pilot military personnel from the Brazilian Air Force.

DESIGN

A cross-sectional study using (1) an auditory habits questionnaire to outline the groups auditory profile and (2) the masking level difference test (MLD, Auditec, Saint Louis®) to evaluate and compare the groups.

STUDY SAMPLE

Forty military male personnel aged between 30-40 years old, all with normal hearing, comprising 20 pilots in the study group (SG), and 20 non-pilots, not exposed to noise, in the control group (CG).

RESULTS

There was no significant difference between groups regarding auditory habits. In the MLD test, a significantly better performance under the homophasic condition (S0N0) was found in the SG. Under the antiphasic condition (SπN0) there were no differences between groups. This combination resulted in a significantly lower MLD in the SG compared to the CG.

CONCLUSIONS

Repeated exposure to conditions where active pilots have to learn to recognise speech in noisy backgrounds may lead to a better performance in the MLD's homophasic condition (S0N0).

[The clinical aspects of occupational sensorineural impairment of hearing of the acoustic origin]

The objective of the present study was to elucidate the specific clinical features of occupational sensorineural impairment of hearing (OSNHI) depending on the origin of this pathology, viz. noise, infrasound and/or their combination. The review of research concerning this problem made it possible to systematize variants of ODNHI based on the clinical signs taking into consideration the influence of these physical factors. Pathophysiological features of the exposure of the organs of hearing to infrasound are described.