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Less severe neurodevelopmental impairments experienced by preterm neonates
Contemporary neurodevelopmental outcomes have shifted for extremely premature infants, with researchers observing a decrease from severe to more mild motor and sensory impairment, according to findings published in Pediatrics.
“Historically, authors of clinical trials and outcome studies involving preterm infants have focused on rates of moderate to severe impairment at 2 years of age,” Ira Adams-Chapman, MD, MPH, from the department pediatrics in the School of Medicine at Emory University and Children’s Health Care of Atlanta, and colleagues wrote. “The prevalence and significance of less severe impairment is unclear.”
“The decreased prevalence of neonatal morbidities associated with adverse neurologic outcomes highlights the importance of evaluating trends and the full spectrum of neurodevelopmental outcomes to guide evidence-based counseling and identify early predictors for poor performance at school age,” the researchers continued.
To assess the varying degrees of neurodevelopmental outcomes in extremely preterm infants, Adams-Chapman and colleagues conducted a retrospective analysis that included neonates no older than 27 weeks’ gestational age. These infants were examined during a neurodevelopmental follow-up in a National Research Network center between April 1, 2011, and Jan. 1, 2015. When infants reached 18 to 26 months’ adjusted age, the researchers used the Bayley Scales of Infant Development-III (BSID-III) and performed a standardized neurosensory examination.
Once data were collected, the researchers analyzed neurologic examination diagnoses, cognitive and motor scores achieved on the BSID-III, sensory impairment and composite outcome of neurodevelopmental impairment. The composite outcome of impairment was calculated using BSID-III cognitive scores, which included a cutoff of less than 85 or less than 70, in addition to a motor score of less than 70. Additionally, the researchers included information related to moderate or severe cerebral palsy, bilateral blindness and hearing impairment.
Of the 2,113 infants included in the study, the average recorded age was 25 weeks’ gestation ±1 weeks and an average weight of 760 g ±154 g. At follow-up, 11% of infants were lost. These infants were less likely to be privately insured or to develop late-onset sepsis or severe intraventricular hemorrhage.
When Adams-Chapman and colleagues assessed neurologic examination results, they observed that 59% were normal and 19% were suspected to be abnormal. Of the infants examined, 22% had results that the researchers determined to be definitely abnormal. The severity of certain conditions changed in prevalence over the course of the study, with severe cerebral palsy decreasing by 43% and mild cerebral palsy increasing by 13%.
Overall, neurodevelopmental impairment dropped from 21% to 16% during the study period when the researchers used a cognitive score cutoff of less than 70. A decrease was also observed from 34% to 31% when the cognitive score cutoff was less than 85.
“Having an accurate and contemporary baseline rate of impairment is important as new therapies are introduced in neonatal intensive care so that we can quickly identify therapies that may be adversely affecting what are now rare outcomes,” Adams-Chapman and colleagues wrote.
“The public health impact of milder forms of disability, including mild cerebral palsy, unilateral vision impairment or hearing impairment, and hearing impairment corrected with amplification is important because these children often use additional medical resources and require support in the classroom, although they are considered functional overall,” the researchers added. – by Katherine Bortz
Disclosures: The authors report no relevant financial disclosures.
