Assessment of the impact of complex noises with different temporal structures on the transmission function of the outer ear

Introduction. The transmission function of the outer ear (TFOE), determined by the acoustic properties, geometry, and dimensions of the auricle and ear canal, is one of the main characteristics of the organ of hearing. The most informative indicators of the transfer function of the outer ear are its values, measured by: 1) at the frequency of the first resonance — in the third-octaves 2.0–3.15 kHz, 2) in the third-octave frequency bands 0.5–4.0 kHz, 3) in the frequency correction A.

The study aims to evaluate the transmission function of the outer ear under the influence of non–constant noises of various temporal structures and its relationship to the hearing thresholds of workers with hearing impairments from industrial noise.

Materials and methods. The male subjects, 20 people, aged 41–72 years, with 18–50 years of experience working in noise conditions, were exposed for 16 minutes to 12 sound fragments of noise of various temporal structures with equivalent sound levels from 80 to 100 dBA. The authors performed TFOE measurements using the F-MIRE method in the third-octave frequency ranges and with frequency correction A. The frequency characteristics of TFOE of the right and left ears of the subjects were determined and compared. In clinical and experimental conditions, the researchers measured the subjects' hearing thresholds at audiometric frequencies of 0.5–6.0 kHz and assessed the correlation of hearing thresholds and TFOE.

Results. The absence of dependence of the transmission function of the outer ear on the different temporal structure of complex noises has been established. In most of the subjects, the authors revealed the presence of a right-sided asymmetry of the acoustic characteristics of the outer ear.

Limitations. There are quantitative limitations due to the number of subjects.

Conclusion. The study of the relationship between hearing loss and TFOE frequency response requires the accumulation of updated data on audiometry and TFOE measurements.

Ethics. In preparing the article, the authors were guided by the ethical principles set out in the Helsinki Declaration of 2024.

Contributions:
Prokopenko L.V. — research concept and design, results analysis, article editing;
Bulgakova M.V. — conducting experimental research;
Courierov N.N. — research concept and design, analysis of normative and methodological documentation, experimental research, analysis of results, writing the text;
Lagutina A.V. — review of literary sources, text editing.

Funding. The study had no funding.

Conflict of interest. The authors declare no conflict of interest.

Received: 22.06.2026 / Accepted: 25.06.2026 / Published: 27.07.2026

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