Frequency-Following Response Characteristics in Brazilian Portuguese-Speaking Children: Age, Sex, and Ear Effects

Introduction: Understanding auditory processing of verbal and non-verbal stimuli is essential to assess the auditory pathways, which are crucial for the development of language skills. Auditory evoked potentials are widely used to investigate neural transmission and diagnose auditory disorders. Although clicks and chirps are commonly used, they do not reflect the complexity of verbal sounds. The Frequency-Following Response has emerged as a biomarker of central auditory processing, offering a faithful representation of speech sounds, especially with the consonant-vowel /da/ stimulus. However, specific studies on Brazilian children using this 170 ms stimulus are lacking, which is essential for establishing normative parameters. Purpose:The purpose of this study was to investigate the characteristics of the frequency-following response in normal-hearing, typically developing Brazilian Portuguese-speaking children, focusing on the absolute latency values of waves V, A, D, E, F, and O. Methods:The study follows a cross-sectional observational design and included 37 children aged 8 to 10 years, all with typical development and good academic performance. It was approved by the Ethics in Research Committee of the Research Instituiton under protocol number 3.349.549. A comprehensive hearing screening was conducted, including tympanometry and a school performance test. Participants meeting the inclusion criteria underwent peripheral auditory evaluations, behavioral central auditory processing assessments, brainstem auditory evoked potentials with a click stimulus, and frequency-following response evaluation using a 170 ms [da] stimulus. Results: The findings revealed significant ear effects, with differences in latencies between the right and left ears for waves D and E. No significant effects were observed regarding age or sex. Additionally, a relevant effect size was found between central auditory processing and latencies of waves D, E, and F, and between waves V and A when correlated with school performance test results. Conclusion: These findings contribute to establishing normative frequency-following response data for Brazilian children and highlight the importance of considering ear differences in clinical assessments.