Sleep EEG of Microcephaly in Zika Outbreak

Abstract

Microcephaly (MC), previously considered rare, is now a health emergency of international concern because of the devastating Zika virus pandemic outbreak of 2015. The authors describe the electroencephalogram (EEG) findings in sleep EEG of epileptic children who were born with microcephaly in areas of Brazil with active Zika virus transmission between 2014 and 2017. The authors reviewed EEGs from 23 children. Nine were females (39.2%), and the age distribution varied from 4 to 48 months. MC was associated with mother positive serology to toxoplasmosis (toxo), rubella (rub), herpes, and dengue (1 case); toxo (1 case); chikungunya virus (CHIKV) (1 case); syphilis (1 case); and Zika virus (ZIKV) (10 cases). In addition, 1 case was associated with perinatal hypoxia and causes of 9 cases remain unknown. The main background EEG abnormality was diffuse slowing (10 cases), followed by classic (3 cases) and modified (5 cases) hypsarrhythmia. A distinct EEG pattern was seen in ZIKV (5 cases), toxo (2 cases), and undetermined cause (1 case). It was characterized by runs of frontocentrotemporal 4.5-13 Hz activity (7 cases) or diffuse and bilateral runs of 18-24 Hz (1 case). In ZIKV, this rhythmic activity was associated with hypsarrhythmia or slow background. Further studies are necessary to determine if this association is suggestive of ZIKV infection. The authors believe that EEG should be included in the investigation of all newly diagnosed congenital MC, especially those occurring in areas of autochthonous transmission of ZIKV.

Identification of Hypsarrhythmia in Children with Microcephaly Infected by Zika Virus

“…Carvalho et al (2017) found hypsarrhythmia in EEGs of newborns infected by the Zika Virus and with microcephaly [ 1 ]. The presence of hypsarrhythmia in EEGs in the sleep of children with microcephaly was also found by Kanda et al (2018) [ 9 ]. It is worth mentioning that these works performed only the visual description of EEG signals due to the lack of mathematical and computational methods that can assist experts carrying out these types of tasks.…”

Association between brain morphology and electrophysiological features in Congenital Zika Virus Syndrome: A cross-sectional, observational study

“…An earlier study described EEG abnormalities in 62% of subjects with CZVS (similar to the proportion described here), including unilateral and bilateral interictal spikes, hypsarrhythmia and abnormal slow oscillations [11] . Another study also described a wide variety of epileptiform discharges, including hypsarrhythmia, slow waves, and fast runs of 4–12 Hz (usually 6 Hz) [12] . However, none of those previous studies demonstrated the existence of correlations between clinical, structural, and electroencephalographic findings.…”

“…Congenital syphilis and toxoplasmosis also lead to EEG abnormalities, including hypsarrhythmia [10] . Recent reports described that ZIKV infection during pregnancy could also lead to seizures and epilepsy in approximately half of the cases [ 11 , 12 ].…”

“…Despite many of the clinical presentations of the Congenital Zika Virus Syndrome (CZVS) having been described so far [13] , few studies attempted to portray the electrophysiological patterns associated with ZIKV-induced microcephaly and brain volume [ 11 , 12 , 14 ]. No study has quantified physiological brain oscillations, such as those observed during sleep, or its relation to pathological brain activity.…”

Time to Evaluate the Clinical Repercussions of Zika Virus Vertical Transmission? A Systematic Review

“…19,27,31,35,36,42,45,46,48,50,51,FIGURE 2 | Zika studies reviewed by year of publication and country of origin. 54, 56, 61, 62, 66, 69-71, 74, 77).…”