Advanced search
Start date
Betweenand


Activation of the inhibitory effect of auditory efferent pathway by speech stimulus

Full text
Author(s):
Natália Faria Siqueira Brito
Total Authors: 1
Document type: Master's Dissertation
Press: São Paulo.
Institution: Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD)
Defense date:
Examining board members:
Renata Mota Mamede de Carvallo; Liliane Desgualdo Pereira; Seisse Gabriela Gandolfi Sanches
Advisor: Renata Mota Mamede de Carvallo
Abstract

Introduction: The phenomenon of otoacoustic emissions (OAE) is considered as one of the greatest scientific discoveries in the field of Audiology. The exam provides the access to the motor activity of the cochlea and brings new knowledge about cochlear physiology. However, such records provide information only from the afferent auditory system. Studies on the suppression of the OAE contribute to the assessment of the efferent auditory system. Currently, there are known other audiologic tests that could evaluate the activity of the efferent olivocochlear system. When OAE are registered with noise presentation (whether ipsilateral, contralateral or bilateral), the efferent pathways of olivocochlear system are activated in order to affect the cochlear process. This fact can be observed with the reduction in the level of OAE responses and is called Effect Suppression of otoacoustic emissions. This test evaluates the inhibitory effect of efferent auditory function on the CCE. Objective: This study aims to establish the occurrence of the inhibitory effect of auditory efferent pathway in the responses of transient evoked otoacoustic emission, with different stimuli presented in contralateral suppressors: White Noise, Talk Noise and Recorded History. Method: The battery of tests was performed in 30 subjects aged between 18 and 35 years and auditory thresholds in intensity level less than 20 decibel hearing level (dB HL) at frequencies 250-8000 Hz. Were performed six tests, two initial measures OAE Transient without contralateral noise a measure of TOAE with white noise, a measure of TOAE with speech noise, a measure of TOAE with recorded history and finally a final measure of TOAE without contralateral noise. Results: There is no average difference statistically significant for measures of TOAE between the ears in all variables. The contralateral white noise showed the highest average in inhibitory effect of efferent auditory for the two situations without contralateral noise. There is a statistically significant difference between White Noise, Talk Noise and Recorded History only for the right ear. Conclusion: The inhibitory effect of the efferent pathway was observed in the three studied contralateral stimuli. It can be concluded that there was a greater mean values for inhibitory effect of efferent auditory in the condition with the contralateral white noise stimulus. All tested ears, after the presentation of the three contralateral stimuli, showed a value of TOAE end without noise around the values found initially, which shows us that once the contralateral noise is no longer displayed, the activation of the inhibitory effect of the efferent ceases instantly and all olivocochlear system back to its initial state (AU)

FAPESP's process: 13/09384-6 - Activation of the inhibitory effect of auditory efferent pathway by speech stimulus.
Grantee:Natalia Faria Siqueira Brito
Support type: Scholarships in Brazil - Master