A simple screening test may help identify those at risk.
Most infants who are exposed prenatally to Zika virus and do not develop microcephaly have normal neurodevelopment. But roughly 20% do not, and a simple screening test called the general movement assessment (GMA) exam may help identify those at risk, according to a study published recently in JAMA Network Open.1
The study is the first to do a detailed analysis of neurodevelopment in infants with prenatal exposure to Zika virus.
“The GMA should be incorporated into routine infant assessments to enable early entry into targeted treatment programs,” wrote first author Christa Einspieler, PhD, of Medical University of Graz, Graz, Austria.
The 2015-2016 Zika epidemic in Brazil left researchers with lingering questions about how the virus affects neurodevelopment in children who are exposed in utero. Addressing such questions is important for reassuring families that their child is developing normally, and for starting earlier intervention if that turns out not to be the case.
To explore the issue, researchers performed GMA exams in 9- and 20- week old infants with and without exposure to Zika virus during the Brazilian outbreak.
The GMA is a validated diagnostic tool that evaluates fidgety movements typical of normal development at 3 to 5 months of life. Research suggests that the test may predict normal as well as abnormal neurodevelopment.
The analysis included 444 infants: 111 with prenatal exposure to Zika matched by sex, age, and gestational age at birth to 333 infants without Zika exposure. Of those exposed to Zika virus, 76 had microcephaly.
Results showed that 82.1% of Zika-exposed infants without congenital microcephaly remained healthy on their first birthday. These children had normal fidgety movements at 3 months of age, and use of the GMA test at this time correctly predicted normal development in 44 of 46 of these infants, or 95.7%.
That’s good news. But almost 20% of Zika-exposed infants without microcephaly still had abnormal neurodevelopment at 12 months. The GMA test at 3 months of age correctly identified 70% of these children, or 7 out of 10.
The test had a sensitivity of 70%, specificity of 96%, positive predictive value of 78%, negative predictive value of 94%, and accuracy of 91%.
The authors emphasized the GMA’s high specificity, which means that it can help weed out false-positives so that children are not unnecessarily referred to rehabilitation services. That may be especially useful in overburdened settings.
“In this context, we emphasize that GMA is easy to apply and is a cost-effective method, especially for low- and middle-income countries,” they concluded.
• 82% of infants exposed prenatally to Zika virus and without microcephaly may have normal neurodevelopment at 12 months
• Almost 20% of these infants may have abnormal development
• The GMA test conducted at 3 months of age can accurately identify Zika-exposed infants at risk for abnormal neurodevelopment at 12 months of age
1. Einspieler C, Utsch F, Brasil P, et al. Association of infants exposed to prenatal zika virus infection with their clinical, neurologic, and developmental status evaluated via the general movement assessment tool. JAMA Netw Open. 2019;2:e187235. doi: 10.1001/jamanetworkopen.2018.7235.