ORIGINAL ARTICLES   

Otorinolaringologia 2000 June;50(2):99-102

Copyright © 2009 EDIZIONI MINERVA MEDICA

language: English

Contralateral suppression of evoked otoacoustic emission during meaningful speech stimulation. A role for selective attention in cochlear activity?

Neglia C. B., Arisi E., Schindler A. *, Ottaviani F. **

From the Dipartimento di Scienze Otorinolaringologiche Università degli Studi - Milano Ospedale Maggiore IRCCS - Milano *Istituto Auxologico Italiano IRCCS - Milano **Divisione di Otorinolaringoiatria Azienda Ospedaliera Polo Universitario San Paolo - Milano

Background. Contralateral sup­pres­sion of tran­sient ­evoked oto-a­cous­tic emis­sions (TEOAEs) con­sists of the ­decrease of TEOAEs inten­sity, dur­ing the con­tra­lat­er­al ­ear’s simul­ta­ne­ous stim­u­la­tion ­with ­white ­noise. Physiological mean­ing of ­this mech­a­nism has not ­been entire­ly under­stood so far. Aim of the ­study was, to inves­ti­gate con­tra­lat­er­al inhi­bi­tion dur­ing hear­ing atten­tion.
Methods. TEOAEs ­were record­ed in 32 nor­mal-hear­ing sub­jects in the ­absence of inhib­i­to­ry stim­u­lus, dur­ing con­tra­lat­er­al 40 dB SPLpe ­white-­noise stim­u­la­tion and dur­ing con­tra­lat­er­al 40 dB SPLpe ­speech stim­u­la­tion.
Results. Response inten­sity of TEOAEs dur­ing ­white ­noise stim­u­la­tion and dur­ing ­speech stim­u­la­tion ­proved sig­nif­i­cant­ly low­er ­than ­basal TEOAEs inten­sity Similarly TEOAEs repro­du­cibil­ity dur­ing ­white ­noise stim­u­la­tion and dur­ing ­speech stim­u­la­tion ­proved sig­nif­i­cant­ly low­er ­than ­basal TEOAEs repro­du­cibil­ity. A sta­tis­ti­cal­ly sig­nif­i­cant dif­fer­ence was ­found ­between TEOAEs repro­du­cibil­ity dur­ing ­white ­noise and dur­ing ­speech stim­u­la­tion. TEOAEs inten­sity dur­ing ­white ­noise stim­u­la­tion and dur­ing ­speech stim­u­la­tion, ­proved sig­nif­i­cant­ly low­er com­pared to ­basal ­records at ­each of the FFT ana­lyzed fre­quen­cies, ­with the excep­tion of 4 KHz. A sta­tis­ti­cal­ly sig­nif­i­cant dif­fer­ence was ­found ­between ­white ­noise and ­speech stim­u­la­tion inten­sity at 1 kHz.
Conclusions. In con­clu­sion, the ­results of the ­present ­work ­show ­that con­tra­lat­er­al sup­pres­sion of TEOAEs dur­ing ­speech stim­u­la­tion is great­er ­than dur­ing ­white ­noise stim­u­la­tion at the mid­dle fre­quen­cies, sug­gest­ing a ­role of selec­tive hear­ing atten­tion in coch­le­ar phys­iol­o­gy.