Desenvolvimento da decodificação neural para a fala em lactentes, crianças e adultos típicos e crianças com sífilis congênita

Abstract

Introduction: Child development includes several stages and can be influenced by some infections, including congenital syphilis, which is considered a risk indicator for hearing impairment. Frequency Following Response (FFR) is an auditory evoked potential that non-invasively evaluates the neural decoding of speech and can be used in the early stages of child development. Objectives: Study 1: study FFR responses with speech stimuli in the frequency and time domains in typical infants, children and adults depending on age and ear evaluated. Study 2: analyze the development of the auditory pathway using Frequency Following Response with speech stimulation in babies with congenital syphilis treated during the first two years of life. Method: Cross-sectional study, approved by the Research Ethics Committee nº 5,685,328. FFR performed with the speech stimulus /da/ synthesized with a fundamental frequency of 100 Hz, duration of 170 ms, speed of 3.70/s. The first 10 ms of onset, 47 ms of the consonant-vowel transition and 113 ms of vowel sustain. Four measurements of 1,000 sweeps were presented, analysis window from -40 to 270.27 ms at 80dBnHL on the SmartEP platform. Artifacts below 10% and online bandpass filter of 30-3000 Hz. Descriptive and inferential analysis was applied in both studies according to the distribution of data and variables, adopting a significance level of 5%. Results: Study 1: 63 subjects, 12 infants, 10 children and 41 adults. Root Mean Square pre-neural activity showed better results for adults in both ears, whereas the spectral amplitude of the fundamental frequency was greater in the right ear in babies up to 60 days old. The spectral amplitude of the harmonics of the consonant and vowel portion is influenced by increasing age, whereas neural lag is suggestive of reaching maturity first in the left ear than in the right ear in all groups. Study 2: sample consisting of 84 babies with congenital syphilis and 58 controls. In babies up to 60 days old, the spectral amplitude of the harmonics of only the consonant portion was greater in the Group Siphilis Congenital than the Control Group. In the SC group, an increase in Fo spectral amplitude was evident with increasing age. The neuro lag in the GSC showed a decrease in time with increasing age, with a significant difference between all age groups. Conclusions: Study 1: Speech decoding is influenced by age, which differs between ears over time in the time and frequency domains. Study 2: Sound processing tends to show better responses with increasing age in both control children and children with adequately treated congenital syphilis