Artikel
Amplitude shift of distortion-product otoacoustic emission (DPOAE) following sound and noise exposures
Suche in Medline nach
Autoren
Veröffentlicht: | 8. August 2007 |
---|
Gliederung
Text
Introduction: In the last years the application of distortion-product otoacoustic emission (DPOAE) became a very important differential diagnostic method in series of audiological measurements. DPOAE gained popularity as an indicator of changes in thresholds and the activity of outer hair cells. Our previous results showed that the amplitudes of DPOAEs increased at high frequency range (2-6 kHz) right after noise exposure (intensity: 80 dB HL, duration: 3 minutes).
Methods: Our aim was to determine the shortest time interval of exposure which causes significant amplitude shift, and to show the intensity changes in time following sound and noise exposures. We performed examinations on 20 healthy hearing persons. DPOAEs were recorded by scanning the 2-6 kHz frequency interval (3 points per octave) before and after the exposures. The subjects were exposed to 1 kHz sound and wide-band noise (intensity: 80 dB HL) with different durations (0.5, 1, 1.5, 2, 2.5, 3 minutes).
Results and conclusions: Our results show that significant amplitude increase was caused by 2 minutes exposure in every measured frequency. After 2 minutes the values returned exactly to the amplitude levels which were measured before the exposure. We can conclude that after noise exposure there is a quick phase when the activity of hair cells increases.