Maximum steepness of slopes in hearing-threshold curves.

Abstract

The maximum steepness of slopes in pathological hearing-threshold curves has been determined in 41 patients having purely sensorineural hearing loss with extremely steep slopes. Below 500 Hz, a slope steepness of maximally 70–90 dB per octave was found while in the octave range from 2 500 to 5 000 Hz, the steepness could amount to 300–350 dB per octave, or, in some single cases, to still higher values. Thus, for an increase in frequency by a factor of 2, i.e. by 1 octave, the increase in slope steepness corresponded to roughly 75 dB per octave, possibly with a somewhat higher increase in steepness in the middle frequency range and a smaller increase in the higher frequency range.The patients' hearing impairments in this specific material showed a variety of etiologies, such as bacterial meningitis, viral infections, hereditary deafness and noise trauma by light and heavy weapons. In a number of cases, the hearing impairment could not be linked to a specific causes.The different etiological groups show a t...