Brazilian Study Assesses Developmental Delays in Children with Congenital Zika Syndrome

As children born in 2015 and 2016 with congenital Zika syndrome age, investigators are gradually able to assess neurodevelopmental outcomes.

The team behind a recent study published in JAMA Network Open observed substantial developmental delays at ages 2-3 years across all areas evaluated. The investigators also found that severity of microcephaly at birth was significantly associated with the severity of these developmental delays.

The study was a case series of behavioral and medical needs of 121 young children with serologic confirmation of congenital Zika syndrome. Children were assessed at a rehabilitation center in the Brazilian city of Recife, starting in January 2018 and intended to continue for a five-year total longitudinal term.

The comprehensive assessment was based on the Brazilian edition of the Bayley Scales of Infant and Toddler Development, administered by trained specialists. Interviews with caregivers and reviews of medical records provided basic demographic information and comorbid medical conditions.

The median age of participants was 31.2 months. The gender distribution was 58 boys and 61 girls. Out of 121 children, 99 children had microcephaly at birth with 74 cases classified as severe. A majority of participants, between n106 to 118, scored at the floor of 1 or more scales. There was, however, variability on raw and age-equivalent scores. A standard score of 55 for the cognitive domain was assigned to children with raw scores between 1-42, for example.

Comparisons revealed no significant differences based on gender. In the regression model analysis, only head circumference at birth was significant across cognitive (β = 1.41; SE, 0.67; P = .04) and fine motor (β = 1.36; SE, 0.49; P = .007) scales. Maternal age and birth weight were associated with better receptive language scores (maternal age at birth: β = 0.11; SE, 0.05; P = .02; birth weight: β = 2.29; SE, 0.92; P = .02).

The fact that maternal age was positively associated with receptive language led investigators to speculate an environmental component, such as a behavioral pattern where older parents spoke to children more.

The relative strength in receptive language also fits with the substantial visual and motor impairments the study population faces. The most immediate route of access to the external environment these children have is auditory input. Most children in the study were responsive to sounds and voices, were able to differentiate voices, and would respond to their names. The children also socially engaged people vocally, making sounds to interact and convey mood.

“This relative strength could provide important direction for intervention and support,” investigators wrote. The results also provided a baseline understanding from which to monitor developmental trajectories as the study moves forward and investigators continue to explore this population’s unique social needs.

In a 2018 study, 15% of toddlers who had been exposed to Zika in the womb had severe developmental impairments rather than moderate or nonexistent.