Desenvolvimento da codificação neural de fala desde o período neonatal à adolescência: investigação em neurotípicos e na toxoplasmose congênita

• Ano de defesa: 2024
• Autor(a) principal: Ferreira, Laís
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Santa Maria; Brasil; Fonoaudiologia; UFSM; Programa de Pós-Graduação em Distúrbios da Comunicação Humana; Centro de Ciências da Saúde
• Palavras-chave em Português: Audição; Eletrofisiologia; Potenciais evocados auditivos; Desenvolvimento infantil; Toxoplasmose congênita; Hearing; Electrophysiology; Auditory evoked potentials; Child development; Congenital toxoplasmosis; CNPQ::CIENCIAS DA SAUDE::FONOAUDIOLOGIA
• Link de acesso: http://repositorio.ufsm.br/handle/1/33057

This thesis presents evidence on the evaluation of the development of neural speech encoding in the face of the maturational process of the Central Auditory Nervous System during childhood and adolescence in neurotypical individuals and those with congenital toxoplasmosis. This thesis involved 152 healthy volunteers and 13 volunteers diagnosed with congenital toxoplasmosis, resulting in three scientific studies: Neurophysiological responses of neural speech encoding from infancy to adolescence in typical individuals (Study 1); Congenital toxoplasmosis and auditory disorders: a literature review (Study 2); Neural representation of the coding process of language and speech aspects in children with congenital toxoplasmosis (Study 3). Each of these studies had specific objectives presented in the following sections, as well as study design and method to meet those objectives. The research procedure shared by the three studies was the evaluation of the Frequency-Following Response, with a /da/ stimulus, analyzing variables corresponding to the time domain: absolute latencies of components V, A, C, D, E, F, and O (ms); shifts A-O, D-O, D-F, and A-D (ms), and slope measurement (ms/µV). In Study 1, basic frequency analysis of the FFR was also performed using the time-frequency distribution (TFD) of the spectrogram available in the software of the equipment used. Based on the results of Study 1, it was observed that infants from one day to five months old have prolonged responses to FFR components and a decreased slope compared to older children. Additionally, it was found that between six months and two years, neural timing responses and synchronization in the speech encoding process begin to become more robust and stable, resembling the FFR recording of older children. In Study 2, through the systematic review conducted on congenital toxoplasmosis, it was observed that there is a greater association between this infection and mild to moderate hearing losses, as well as alterations in exams evaluating the central auditory pathway. In the longitudinal research described in Study 3, it was found that children diagnosed with congenital toxoplasmosis presented prolonged absolute latency values for FFR waves and a decrease in slope measurement compared to children without congenital toxoplasmosis, regardless of the evaluation time during early childhood. Additionally, a correlation exists between INFONO assessment outcomes and the A-D intervals of the FFR, further emphasizing the impact of this condition on speech development. Together, the results of Study 3 suggest that the prolongation of FFR waves observed in the neonatal period extends until the age of four to six years and reflects aspects related to language. This thesis provides support for new evidence on the characterization of FFR evaluation in the child population, as it indicated notable differences in neural responses to speech between infants and older children. Congenital toxoplasmosis should remain among the risk factors for impairment of both peripheral and central auditory pathways. Finally, it is highlighted that children with congenital toxoplasmosis show alteration in the process of speech sound encoding and in language development, which may be related.