Commentary on “Comparison of Motor and Cognitive Performance in Infants During the First Year of Life”

Abstract

“How should I apply this information?” The Bayley Scales of Infant Development II (Bayley II) were used in this study to determine Motor and Mental Index Scores. The authors suggest that in the first year of life there might be differences between motor and cognitive performance at 1, 2, and 3 months of age, but not at 6, 9, and 12 months of age. They also found the mean motor index score of their sample was below the cutoff for normal performance at 3 months and would be considered “mildly delayed.” These data do not have immediate or direct implications for clinical practice. However, the results can be used to demonstrate that for infants born at term development across domains may be synchronous and asynchronous at different periods in the first postnatal year. From the data in this article we can cautiously assume that it is atypical for infants aged 6 to 12 months to score differently on the motor and cognitive domains. We feel that an individualized evaluation, consideration of the referral source and current services, assessment of risk status, and birth history should always be used in combination with standardized clinical assessment tools. “What should I be mindful about when applying this information?” The Bayley II differs from the current version of the Bayley in test items, scoring, and domain specificity. The Bayley Scales of Infant and Toddler Development III (Bayley III) has been available for clinical use since 2006 and may be more familiar to clinicians. It is unknown if the infants tested in the article would have scored similarly on the Bayley II and the Bayley III. The infants tested were Brazilian and a majority was of lower socioeconomic status. Cultural differences such as common sleeping position, floor-time play, swaddling, and handling practices may contribute to scores, especially in the motor domain and could have affected the results. Importantly, the normative data for the Bayley II was obtained in the United States. Thus the normative population may or may not compare to the Brazilian population. We feel this may be especially true of the lower motor index score reported at 3 months of age. Jill C. Heathcock, PT, PhD The Ohio State University Columbus Natalie Goodrich, DPT Nationwide Children.s Hospital The Ohio State University Columbus