The authors analysed statistically audiometric investigations of bone conduction at frequencies of 0.25, 0.5, 1, 2, 3 and 4 kHz. A group of 17 patients with exostoses in the external auditory canal was observed. Ten subjects of the group were exposed to noise in their employment. The aim of the analysis was to compare audiometric findings in bone conduction in the observed group with the literature dealing with hearing loss in the general population. It was found that patients with external auditory canal exostoses had a permanent auditory threshold shift in the range up to 2 kHz, however there is no evidence of this feature in the rest of the population. The auditory threshold shift is not dependent on noise exposure in the case-history. The authors suggest that different acoustic characteristics of external auditory canals with exostoses could explain these audiometric findings.

        Key words: exostosis, external auditory canal, noise-induced hearing loss, acoustics.