Auditory brainstem in Zika virus: Insights about brain development in microcephaly

Abstract The appearance of the first cases of microcephaly related to the Zika virus (ZIKV) and the massive dissemination of the congenital syndrome have required the investigation of the CNS function in the vertically infected population. In the congenital ZIKV syndrome, swallowing dysphagia and the thinning of the brainstem detected in MRI images were described and justified a study on the implication level of the brainstem in the syndrome. Aiming to shed light on this question, we studied the auditory function in microcephalic children by short-latency brainstem auditory evoked potentials (BAEPs), the most sensitive method for describing topographic alterations in the brainstem by measuring electrical responses of auditory pathways after an acoustic stimulus. Surprisingly, our results returned a normal function of the brainstem in these children. This finding suggests that brainstem alterations are probably secondary to the effects on telencephalon and that brainstem progenitor cells that generate brainstem nuclei may not present the same tropism for the virus or may be further from virus entry sites.