Repeatability of transiently evoked otoacoustic emissions in normally hearing humans.

Transiently evoked otoacoustic emissions (TEOAEs) were stimulated using clicks. Responses were measured in each ear of 10 adult subjects during three test sessions separated by 3-day intervals. The purpose was to determine the amount of short-term variability in the amplitude of the emissions when measured under similar test conditions. For each of two modes of determining the stimulus level, mean overall response levels varied approximately 1 dB with repeated measurements. The spectra of the responses were analyzed in discrete frequency bands from 0.7 to 5.8 kHz. Response energy peaked at 1.2 kHz and was reduced markedly above 4 kHz. Variability within individual spectral bands was approximately 1 dB from 0.9 to 4.1 kHz and was slightly greater for 0.7 kHz. The amplitude of TEOAEs is stable over successive short-term measurements. The technique can be used as a sensitive means of monitoring cochlear function.