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

Grant number: 13/09384-6
Support Opportunities:Scholarships in Brazil - Master
Effective date (Start): August 01, 2013
Effective date (End): March 31, 2015
Field of knowledge:Health Sciences - Speech Therapy
Principal Investigator:Renata Mota Mamede Carvallo
Grantee:Natalia Faria Siqueira Brito
Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil


The cochlea can be described as a frequency analyzer characterized by a set of juxtaposed three channel-shaped loop.The phenomenon of otoacoustic emissions (OAE) is considered as one of the greatest scientific discoveries in the field of Audiology. Your exam provides evaluate the motor activity of the cochlea and brings new knowledge about cochlear physiology. However, such records provide information only on the afferent auditory system. Studies on the suppression of the OAE contributed to the assessment of the efferent auditory system. Currently, there are known other audiologic tests that can evaluate the activity of the efferent olivocochlear system.When EOAE are registered with the presentation of noise, either ipsilateral, against lateral or bilateral efferent pathways of the medial 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. There is interest, therefore, in studies that indicate the clinical applications of this suppression effect, for a better understanding of the possibilities of application test in diagnostic audiology.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: speech stimuli, white noise and speech noise.Specifically the study aims to:I. Quantifying the inhibitory effect for each of the three contralateral simultaneous stimuli.II. Comparing the variation of inhibitory effect among the three types of stimuli simultaneously on opposite sides.III. Compare the inhibitory effect between right and left ears.IV. To analyze the inhibitory effect by sex.The battery of tests will be performed in 30 subjects aged between 18 and 30 years, 15 males and 15 females, who have hearing thresholds at intensities below 20 decibel hearing level (dB HL) at frequencies of 250 to 8.000 HzThe procedures will be applied in a single session, comprising approximately one hour.The procedures are all non-invasive, consisting of analysis of electroacoustic responses to sound stimuli presented using headphones, insert earphones or acoustic probes insertion in the ear canal. All stimuli are calibrated at a comfortable intensity for the listener, not reaching or exceeding the threshold of hearing discomfort.

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Academic Publications
(References retrieved automatically from State of São Paulo Research Institutions)
BRITO, Natalia Faria Siqueira. Activation of the inhibitory effect of auditory efferent pathway by speech stimulus. 2015. Master's Dissertation - Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD) São Paulo.

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