Frequency-Following Response and Auditory Behavior in Children with Prenatal Exposure to the Zika Virus

Introduction  Prenatal exposure to the Zika virus can impair neurodevelopment and cause auditory damage. Objective  To analyze the frequency-following response (FFR) and the auditory behavior (with the LittlEars ^® questionnaire) of children with and without prenatal exposure to Zika virus infection. Methods  A total of 30 children participated in the present study, divided into 3 groups: 10 children with microcephaly and prenatal exposure to the Zika virus; 10 normocephalic children with prenatal exposure to the Zika virus; and 10 children with no evidence of prenatal exposure to the virus. The FFR test was performed with the /da/ syllable. The LittlEars ^® questionnaire was used with parents/guardians. Results  For the FFR measurements, there was no difference between the groups. The children with exposure to the Zika virus presented a final score in the questionnaire below what is expected from children with normal hearing. A significant difference was observed for the final, semantic, and expressive scores between the group with microcephaly and the other groups. A strong negative correlation was seen between the LittlEars ^® questionnaire final score and the FFR measurements for the group with microcephaly when compared with the other groups. Conclusion  Children exposed to the Zika virus, with and without microcephaly, presented FFR patterns similar to what was seen in children with no evidence of virus exposure. However, they showed signs of immature auditory behavior, suggesting auditory development delay.