Registro e caracterização da atividade eletroencefalográfica associada a microcefalia congênita

Abstract

During the years of 2015 and 2016, Brazil has suffered an epidemic due to Zika virus in its territory. The incidence of babies born with microcephaly was 56.7 cases per 10,000 births (2015), ratio larger than the 2.2 cases per 10.000 births observed in previous years. Besides the nervous system’s malformations, the viral infection within the gestational period lead to eye lesions, joint contractures and epileptic seizures. Since the treatment with antiepileptic drugs depends on both the epilepsy type and its seizures, we pursued the characterization of the electroencephalographic patterns of children with microcephaly with the objective of comprehend the diversity and complexity of this neurological syndrome and its electrophysiological correlates. To achieve such, we analyzed 71 EEGs of 50 patients from the pediatrics’ ambulatory of the Hospital Universitário Onofre Lopes (UFRN). Epileptiform events were observed in 30 patients, including focal unilateral spikes (56% of the population) and bilateral spike complexes (44%). Hemispheric asymmetry and high-amplitude diffuse lowvoltage waves were recorded, as burst-suppression and spike-and-wave patterns. Once the majority of the recordings were made while the patients were asleep (42/50), we quantified the frequency, spatial distribution and potency of sleep spindles, thalamocortical events characteristic of the slow-wave sleep. To our surprise, only 17 of the 42 patients (40%) presented the sleep spindles (~12Hz, asymmetric, predominantly frontal), from which 12 of these patients didn’t showed any epileptic activity (Fisher’s Exact Test, p<0.005). In 31 of the 42 (73%) we observed a slow oscillation of about 6Hz in frontal regions yet to be documented. This results suggest that besides the encephalic malformations, patients with microcephaly due to congenital Zika virus infection have greater chances of reporting generalized epileptic seizures and multiple epileptic focus, alongside with sleep spindles prejudices. So, we reinforce the importance of the EEG recording, specifically during sleeping, to better diagnose epilepsy in this patients. Future works might show if the occurrence of sleep spindles can be correlated with the cognitive development of these patients.