Longitudinal evolution of electroencephalogram (EEG): Findings over five years of follow-up in children with Zika-related microcephaly from the Microcephaly Epidemic Research Group Pediatric Cohort (2015-2020)

OBJECTIVE

To assess the longitudinal evolution of EEG findings in children with Zika related-microcephaly (ZRM) and to evaluate the associations of these patterns with the children's clinical and neuroimaging characteristics.

METHODS

As part of the follow-up of the Microcephaly Epidemic Research Group Pediatric Cohort (MERG-PC) in Recife, Brazil, we performed serial EEG recordings in a subgroup of children with ZRM to evaluate changes in background rhythms and epileptiform activity (EA). Latent class analysis was used to identify patterns in the evolution of EA over time; clinical and neuroimaging findings were compared across the identified groups.

RESULTS

Out of the 72 children with ZRM who were evaluated during 190 EEGs/videoEEGs, all participants presented with abnormal background activity, 37.5% presented with an alpha-theta rhythmic activity, and 25% presented with sleep spindles, which were less commonly observed in children with epilepsy. EA changed over time in 79.2% of children, and three distinct trajectories were identified: (i) multifocal EA over time, (ii) no discharges/focal EA evolving to focal/multifocal EA, and (iii) focal/multifocal EA evolving to epileptic encephalopathy patterns (e.g., hypsarrhythmia or continuous EA in sleep). The multifocal EA over time trajectory was associated with periventricular and thalamus/basal ganglia calcifications, brainstem and corpus callosum atrophy and had less focal epilepsy, whereas the children in the trajectory which evolved to epileptic encephalopathy patterns had more frequently focal epilepsy.

SIGNIFICANCE

These findings suggest that, in most children with ZRM, trajectories of changes in EA can be identified and associated with neuroimaging and clinical features.

Epilepsy and EEG Abnormalities in Congenital Zika Syndrome

SUMMARY

The congenital Zika syndrome is a new entity of a group of etiologies that can lead to microcephaly and other brain damages during pregnancy, such as toxoplasmosis, rubeola, cytomegalovirus, and herpes simplex. The Zika virus crosses the placental barrier and, predominantly, affects neuronal progenitor cells. This disruptive process results in severe cortical developmental disorder, calcifications, cortical and subcortical atrophies, and malformations of the cerebellum, brain stem, and spinal cord. Children with congenital Zika syndrome have a set of clinical findings, such as cerebral palsy, dysphagia, orthopedic deformities, visual and auditory impairment, and, rarely, hydrocephalus. Because of the severity of brain lesions, epilepsy is a common finding and a frequent cause of increased morbidity. The prevalence of epilepsy in different series of patients ranges from 37.7% to 71.4%. The aim of this study is to review the studies published so far regarding epilepsy and the EEG pattern in series of patients with congenital Zika syndrome.

Early epilepsy in children with Zika-related microcephaly in a cohort in Recife, Brazil: Characteristics, electroencephalographic findings, and treatment response

Objective

To estimate the incidence of epilepsy in children with Zika‐related microcephaly in the first 24 months of life; to characterize the associated clinical and electrographic findings; and to summarize the treatment responses.

Methods

We followed a cohort of children, born during the 2015‐2016 Zika virus (ZIKV) epidemic in Brazil, with congenital microcephaly and evidence of congenital ZIKV infection on neuroimaging and/or laboratory testing. Neurological assessments were performed at ≤3, 6, 12, 15, 18, 21, and 24 months of life. Serial electroencephalograms were performed over the first 24 months.

Results

We evaluated 91 children, of whom 48 were female. In this study sample, the cumulative incidence of epilepsy was 71.4% in the first 24 months, and the main type of seizure was infantile spasms (83.1%). The highest incidence of seizures occurred between 3 and 9 months of age, and the risk remained high until 15 months of age. The incidence of infantile spasms peaked between 4 and 7 months and was followed by an increased incidence of focal epilepsy cases after 12 months of age. Neuroimaging results were available for all children, and 100% were abnormal. Cortical abnormalities were identified in 78.4% of the 74 children evaluated by computed tomography and 100% of the 53 children evaluated by magnetic resonance imaging. Overall, only 46.1% of the 65 children with epilepsy responded to treatment. The most commonly used medication was sodium valproate with or without benzodiazepines, levetiracetam, phenobarbital, and vigabatrin.

Significance

Zika‐related microcephaly was associated with high risk of early epilepsy. Seizures typically began after the third month of life, usually as infantile spasms, with atypical electroencephalographic abnormalities. The seizure control rate was low. The onset of seizures in the second year was less frequent and, when it occurred, presented as focal epilepsy.

Ophthalmological findings in infants with microcephaly and presumable intra-uterus Zika virus infection

PURPOSE

In 2015, a twenty-fold increase in the prevalence of microcephaly in Brazil was reported, and the Ministry of Health associated this abnormal prevalence with the maternal-fetal Zika virus (ZIKV) transmission.

METHODS

We assessed the ophthalmological findings of ten mothers and their infants that had been clinically diagnosed with ZIKV-related microcephaly and presented ocular abnormalities, born from May to December 2015.

RESULTS

Seven mothers (70.0%) referred symptoms during pregnancy (malaise, rash and arthralgia), of which six (85.7%) were in the first trimester. At the time of exam, no ophthalmological abnormalities were identified in the mothers and they did not report ocular symptoms during pregnancy. Serology was negative in all infants for Toxoplasmosis, Rubella, Cytomegalovirus, Syphilis and Human Immunodeficiency Viruses. Ocular findings included macular alterations (gross pigment mottling and/or chorioretinal atrophy) in fifteen eyes (75.0%), and optic nerve abnormalities (hypoplasia with double-ring sign, pallor, and/or increased cup-to-disk ratio) in nine eyes (45.0%).

CONCLUSIONS

Patients presented normal anterior segment and important macular and optic nerve abnormalities. Further studies will assess the visual significance of these alterations.