Validity of hearing thresholds obtained from the rising portion of the audiogram in sensorineural hearing loss.

Two experiments were performed for this study. The purpose of both experiments was to examine the validity of pure-tone hearing thresholds obtained near the rising portion of a sensorineural hearing loss. Recent work by other investigators has suggested that thresholds obtained near the rising portion of the audiogram may not correspond to the severity of damage at the cochlear place associated with the test frequency. In the first experiment this issue was addressed in 11 subjects having low-frequency sensorineural hearing loss, whereas 12 subjects (19 ears) having notch-shaped high-frequency sensorineural hearing losses were examined in the second experiment. The results indicated that thresholds obtained from the rising portion of the audiometric configuration were, in most instances, determined by sensitivity at test frequency. An exception to this generalization involved low-frequency sensorineural hearing loss with a slope for the rising portion of the audiogram exceeding -25 dB/octave. In these cases the severity of the loss may be underestimated for test frequencies immediately adjacent to the rising portion of the audiogram.