Submitted to: Developmental Neuropsychology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/15/2006
Publication Date: 6/15/2007
Citation: Dykman, R.A., Szabo, J.S., Casey, P., Kim, E.Y., Pivik, R.T. 2007. Growth status related to brain responses, nutrition, home environment, and behavior in infants and toddlers. Developmental Neuropsychology. 31(3):397-428. Interpretive Summary: Early physical growth and cognitive development are related, but the basis for their interactive effects is still unclear. This study compared brain wave responses to spoken syllables in healthy infants and toddlers (ages 6-24 months) who were either low (< 25th percentile) or normal (25th – 75th percentile) on standardized growth measures. Brain wave measures showed that both groups perceived the stimuli, but only normal growth status babies discriminated between different syllables. Furthermore, the discrepancy between groups was much larger for boys than girls. It appears that difficulties in language perception are associated with reduced growth, and that this relationship can been seen in babies who fall into the low end of the normal growth range.
Technical Abstract: To investigate whether growth status in infants and toddlers affects processes involved in speech perception and discrimination, cortical event-related potentials (ERPs) to consonant-vowel syllables were recorded from 48 healthy babies: 26 low in growth status (LGS, <25th percentile in growth measures) and from 22 normal growth status (NGS, 25th-75th percentile in growth measures). Food records indicated no significant differences in the amounts of various nutrients consumed in the two groups, but LGS babies consumed slightly more of most nutrients than NGS babies. In response to speech stimuli (either /pa/ or /ba/ presented with 20 and 80% randomized occurrence), brain ERPs showed two prominent post-stimulus components: a large positive wave peaking at about 484 msec and a negative but positive going slow wave (SW) between 867 and 1199 msec. Principal components analysis followed by promax rotation revealed four additional important components. Maximum peak and latency values for these components showed that NGS and LGS babies differed from one another on all measures in either amplitude, latency, or both. Comparing the two groups of babies, only the LGS group demonstrated a deficit in the phonetic discrimination of speech sounds. The growth deficiencies of the LGS group could not be attributed to the lack of an adequate diet. These negative findings are present in babies generally considered to be healthy (lowest 10-25% in growth measures). This underscores the need for research examining in more detail the relationship between growth status and cognitive growth.