Contralateral noise effects on cortical potentials in school aged children: different parameters of evaluation

Author(s)

Thalita Ubiali

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Médicas
• Defense date: 2020-02-19

Examining board members

Maria Francisca Colella Santos; Christiane Marques do Couto; Ana Carolina Constantini; Carla Gentile Matas; Ana Cláudia Mirândola Reis

• Advisor: Maria Francisca Colella Santos

Abstract

Introduction: One of the functions attributed to the auditory efferent system is related to the processing of acoustic stimuli in noise backgrounds. However, clinical implications and the neurophysiological mechanisms of this system is not fully understood, especially on higher regions of the central nervous system. Most of the studies that investigated efferent activity in humans used the inhibition of the otoacoustic emissions (OAE), which assesses the caudal region of the system when stimulated with competing noise. A few researchers studied the effects of noise on long latency auditory evoked potentials (LLAEP), but the lack of studies and contradictory results, especially in children, points out to the need of investigating different protocols and parameters that could allow the study of top-down activity in humans. Aim: to analyze different parameters for assessing the LLAEP in competing noise in school-aged children, and verify the effects of noise on cortical processing of verbal and nonverbal stimuli. Method: 78 tipically developing children aged between 8 to 13 years old were assessed (phase 1). LLAEP were recorded using tone burst stimuli with and without contralateral white noise in two different signal-to-noise ratios (SNR +10 and 0), and using speech stimuli in the SNR +10. In a second phase of the project, 24 children with reading difficulties were assessed (phase 2). Children were evaluated by the oddball paradigm and stimuli were 2000 Hz (rare) and 1000 Hz (standard) in nonverbal assessment, and /da/ (rare) and /ba/ (standard) in verbal assessment. Stimuli intensity was 70 dB SPL. OAE suppression were also assessed using linear clicks at 60 dB SPL and contralateral white noise at 60 dB SPL. Results: Phase 1 results showed that P300-ToneBurst latencies were prolonged and amplitudes reduced in the presence of noise, but no differences were observed between SR +10 and SR 0; P1-speech latencies were significantly prolonged in the noise condition. In phase 2, children with reading difficulties had shorter N2-speech and P300-speech amplitudes compared to control children. OAE suppression was observed only in typically developing group. Conclusion: LLAEP in noise results associated with OAE suppression can provide relevant information about the differential diagnosis of the auditory deficits in school aged children (AU)

• FAPESP's process: 16/06578-2 - CONTRALATERAL NOISE EFFECTS ON P300 IN SCHOOLAGED CHILDREN: DIFFERENT ASSESSMENT PARAMETERS.
• Grantee: Thalita Ubiali
• Support Opportunities: Scholarships in Brazil - Doctorate