Electrophysiological Assessment of Auditory Function in Fetal Alcohol Spectrum Disorders (FASD): Insights from FFR and LLR Analysis

Background: Fetal Alcohol Spectrum Disorder (FASD) is an affliction caused by prenatal exposure to alcohol due to maternal consumption during pregnancy. Several alterations have been described in the phenotype; including learning difficulties, attention deficits, memory impairments, language deficits and listening difficulties in noisy enviroments with normal thresolds. Methods: A total of 25 normal-hearing have participated in the study, including 11 individuals with FASD. We recorded Frequency-Following Responses (FFR) and Cortical Auditory Evoked Potentials (CAEPs) with stimulus /Da/ of 160ms and 80 dBnHL, at 4.35/s for FFR; and at 1.1/s for LLR; and, with simultaneous adquisition with CLAD at 3.9/s Rate. Results: The FFR results showed significant latency delays, weaker cross correlation, lower pitch tracking, and smaller Signal-to-Noise Ratio, in the FASD group compared to the control group. The CAEPs results showed significant latency and amplitude changes within (rate associated) and between groups. In addition, morphological changes were observed in FASD group, at higher stimulation rate. Conclusion: This results shows a functional problem with neurophisiological substrate of auditory system in patients with prenatal alcohol exposure, at the cortical (CAEPs) and subcortical (FFR) levels. FFR and CAEPs may be used as a neurobiological marker of auditory processing disorders (APD), in children and young adults with prenatal alcohol exposure. The use of higher stimulation rates sensitizes the LLR measures. Is important understanding and the need to incorporate auditory electrophysiological test in the evaluation of this patients and to know that they can contribute to diagnosis of APD in this cases.