Influence of Contralateral Stimulation by Two-tone Complexes, Narrow-band and Broad-band Noise Signals on the 2f 1 -f 2 Distortion Product Otoacoustic Emission Levels in Humans

• Published in: Acta oto-laryngologica Vol. 122; no. 6; pp. 613 - 619
• Main Authors: Lisowska, Grazyna, Smurzynski, Jacek, Morawski, Krzysztof, Namyslowski, Grzegorz, Probst, Rudolf
• Format: Journal Article
• Language: English
• Published: Informa UK Ltd 2002; Taylor & Francis
• Subjects: Bundle; Contralateral; Efferent; Emission; Olivocochlear; Otoacoustic; Stimulation; Suppression; System
• ISSN: 0001-6489; 1651-2251
• DOI: 10.1080/000164802320396286

In order to test the frequency specificity of the efferent suppressive effect on otoacoustic emissions, changes in the 2f 1 -f 2 distortion product otoacoustic emission (DPOAE) levels induced by contralateral stimuli of different spectra were measured in 10 normally hearing adults. Three types of contralateral stimuli were used: ( i ) a set of 6 pairs of pure tones with the same frequencies as used for DPOAE stimulation; ( ii ) 6 narrow-band noise signals with cut-off frequencies equal to the frequencies of the primary tones used for DPOAE stimulation; and ( iii ) broad-band noise with a bandwidth of 840-6,000 Hz. A small suppressive effect was observed mainly in the mid-frequency region. Broad-band noise was more effective at suppressing DPOAEs than narrow-band noises and two-tone complexes. Occasionally, small enhancements in DPOAE amplitudes were observed. Based on the results of this study, it is concluded that DPOAE changes induced by contralateral stimuli are not frequency-specific, and are too small to have routine clinical value.