Introduction and objective: The auditory efferent system connects the auditory cortex with sensory receptor cells in the cochlea through the olivo-cochlear system, which innervates the outer hair cells and the auditory nerve fibers under the inner hair cells. Most of the studies that investigated the efferent activity in humans focused on evaluating the suppression of the otoacoustic emissions by stimulating the contralateral ear with noise, which assesses the activation of the medial olivo-cochlear bundle. However, the neurophysiology and clinical implications of auditory efferent activity, especially on higher regions of the central auditory system, still remain to be investigated. A few researchers have reported the effects of noise on the responses of the late auditory evoked potential P300 but there is no published normative data for pediatric population and no researches testing different parameters in order to set the best protocol for assessing the P300 with noise. For this reason, the aim of the present study is to analyze different parameters for assessing the P300 suppression effect, by testing different stimuli (tone burst and speech sounds) and signal to noise ratios (0 and +10), in order to stablish the best protocol in schoolaged children. Method: 70 tipically developing children with normal hearing aged between 8 to 14 years old will be assessed (G1). P300 will be recorded with and without contralateral white noise in two different signal-to-noise ratios (0 and +10) using tone burst and speech stimuli. In a second phase of the project, 24 children with academic difficulties will be assessed (G2) and compared to a group of tipically developing children who will be matched by sex and age (G1A). Expected outcomes: It is expected that the outcomes of this study will provide data to stablish the best protocol for assessing the effects of contralateral noise on the cognitive potencial P300 and to set normative data for normal developing schoolaged children. The results will provide information about: the maturation of the auditory efferent pathway; the processing of speech stimuli in the ascending and descending auditory systems; and finally, the acoustic signals processing in children with school difficulties.
News published in Agência FAPESP Newsletter about the scholarship: