Frequency Following Response (FFR) in children with developmental language disorder

Objective To study the frequency following response in children with developmental language disorder. Methods An exploratory pilot, observational, cross-sectional, and prospective study was conducted with children aged four to eleven years, divided into a Developmental Language Disorder group and a typical development control group, focusing on the feasibility of FFR acquisition and time- and frequency-domain analysis. The Frequency Following Response was elicited using the synthesized syllable /da/ at eighty decibels sound pressure level. The responses were analyzed in both time and frequency domains. In the time domain, the amplitude of the waves V and A complex and absolute latencies of waves V, A, C, D, E, F, and O were evaluated. Crucially, frequency-domain analysis was performed using MATLAB software, where the Fast Fourier Transform was applied to the sustained portion of the response to quantify the amplitudes of the fundamental frequency and the first two formants. Results The time-domain analysis revealed no statistically significant differences in the mean latencies of the waves or the amplitude between the groups. In the frequency-domain analysis using MATLAB, the comparison of amplitudes for the fundamental frequency and the first formants also showed no significant differences between the Developmental Language Disorder and control groups. However, the large wave summation averages demonstrated wave latencies, fundamental frequency, and first formants consistent with the literature, confirming the reproducibility of the test. Conclusion The Frequency Following Response is a viable auditory evoked potential in clinical settings for evaluating speech-sound coding in the auditory brainstem. Although no statistical significance was found between the groups, likely due to sample size and clinical heterogeneity, the method proved reliable, and frequency-domain analysis using MATLAB provided a robust objective assessment of temporal processing.