BALTIMORE – Most infants prenatally exposed to Zika showed relatively normal neurodevelopment if their fetal MRI and birth head circumference were normal, but others with similarly initial normal measures appeared to struggle with social cognition and mobility as they got older, according to a new study.
Dr. Sarah Mulkey
“I think we need to be cautious with saying that these children are normal when these normal-appearing children may not be doing as well as we think,” lead author Sarah Mulkey, MD, of Children’s National Health System and George Washington University, Washington, said in an interview. “While most children are showing fairly normal development, there are some children who are … becoming more abnormal over time.”
Dr. Mulkey shared her findings at the Pediatric Academic Societies annual meeting. She and her colleagues had previously published a prospective study of 82 Zika-exposed infants’ fetal brain MRIs. In their new study, they followed up with the 78 Colombian infants from that study whose fetal neuroimaging and birth head circumstance had been normal.
The researchers used the Alberta Infant Motor Scale (AIMS) and the Warner Initial Developmental Evaluation of Adaptive and Functional Skills (WIDEA) to evaluate 72 of the children, 34 of whom underwent assessment twice. Forty of the children were an average 5.7 months old when evaluated, and 66 were an average 13.5 months old.
As the children got older, their overall WIDEA z-score and their subscores in the social cognition domain and especially in the mobility domain trended downward. Three of the children had AIMS scores two standard deviations below normal, but the rest fell within the normal range.
Their WIDEA communication z-score hovered relatively close to the norm, but self-care also showed a very slight slope downward, albeit not as substantially as in the social cognition and mobility domains.
The younger a child is, the fewer skills they generally show related to neurocognitive development, Dr. Mulkey explained. But as they grow older and are expected to show more skills, it becomes more apparent where gaps and delays might exist.
“We can see that there are a lot of kids doing well, but some of these kids certainly are not,” she said. “Until children have a long time to develop, you really can’t see these changes unless you follow them long-term.”
The researchers also looked separately at a subgroup of 19 children (26%) whose cranial ultrasounds showed mild nonspecific findings. These findings – such as lenticulostriate vasculopathy, choroid plexus cysts, subependymal cysts and calcifications – do not usually indicate any problems, but they appeared in a quarter of this population, considerably more than the approximately 5% typically seen in the general population, Dr. Mulkey said.