NEW YORK (Reuters Health) – The third edition of the Bayley Scales of Infant and Toddler Development (Bayley-III) overestimates neurodevelopment after early complex cardiac surgery, researchers from Canada report in the September 26th online Pediatrics.

Bayley-III, which replaced the older edition of the test (Bayley Scales of Infant Development, 2nd Edition), has produced higher scores than the previous edition, and there have been concerns that this could have an impact on the interpretation of results in both clinical and research settings.

Dr. Charlene M. T. Robertson from Glenrose Rehabilitation Hospital, University of Alberta, Edmonton, Alberta, Canada and colleagues report the Bayley-III scores after cardiac surgery at age 6 weeks and younger in 110 children (mean age at time of assessment, 21.3 months) and compare the results with those of the 2nd edition in a subset of 25 of these children.

Scores for all children were 4 to 9 points below the mean of the normative sample, but scores differed according to the surgery they had. Children who had the arterial switch operation had the highest scores, whereas children who had total anomalous pulmonary venous correction had significantly lower scores for the cognitive composite score, and children who had the Norwood right ventricle-pulmonary artery (RV-PA) shunt had significantly lower scores on language and motor composite scores.

More than 15% of the overall cohort and more than a quarter of the children with RV-PA had language impairment, a finding the investigators deem clinically significant.

The average difference in mean composite scores between the Bayley-III and the second edition was 6.1 points (consistently higher with Bayley-III), with the differences ranging from 1.4 points higher for the language scale to 10.0 points higher for the cognitive scale.

The authors’ discussion (and recent reports) suggests that Bayley-III is overestimating ability (and not that the earlier edition underestimates ability). “Overestimating a child’s functional ability in comparison with a regionally inappropriate reference group could result in the child not qualifying for early intervention services,” they say, “the lack of which may negatively influence their neurodevelopmental trajectory.”

“More research is needed for all to gain confidence in the interpretation of the results from the Bayley scales, both past and present,” the researchers conclude. “We need to validate the Bayley-III against other measures of cognitive, language, and motor skills, as well as community services such as preschools, to determine if children considered impaired on this measure do need additional support or if come missed early identification.”

Dr. Michael E. Msall from University of Chicago Comer Children’s Hospital, Chicago, Illinois agrees, writing in a related editorial, “These findings suggest that we exercise caution when using new assessments for measuring early childhood developmental outcomes. …It is also critically important to have a subset of the cohort compared with term controls before the new tool is applied on specific at-risk populations from diverse geographic and cultural regions.”

The editorial concludes, “In an era of scarce resources we must develop collaborative tools for measuring health and developmental outcomes after critical illness, which will allow us to go beyond the limitations of a summary score on the Bayley scales in early childhood. It will allow us to focus instead on the complexity of risk and resiliency with respect to neurodevelopmental processes that are most relevant to leaning and school success.”

Reference:

Pediatrics 2011;128:e794-e800,e993-e994.