Sensorineural hearing loss in cordless telephone injury.

Audiometric data from 19 cases of cordless telephone injury are reviewed, including three cases with pre-insult and post-insult audiograms. In addition, data are presented from analyses of intensity and frequency for the ring signal of three telephones involved in injury cases. The most severe hearing loss was found at 500 Hz and 1000 Hz, where the mean threshold difference in the injured ear was 20 dB and 29 dB, respectively. The three cases for which pre-insult and post-insult data were available exhibited similar audiometric patterns, although the degree of threshold shift varied. Spectral analysis of the ring signal indicated sound-pressure levels of approximately 140 dB, with a fundamental frequency near 750 Hz.