|Pivik, Rudolph -|
|Andres, Aline -|
Submitted to: Developmental Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 4, 2010
Publication Date: July 1, 2011
Citation: Pivik, R.T., Andres, A., Badger, T.M. 2011. Diet and gender influences on processing and discrimination of speech sounds in 3 and 6 month-old infants: A developmental ERP study. Developmental Science. 14(4):700-712. Interpretive Summary: There are no studies comparing brain function in healthy infants fed the three major infant diets (breast milk, milk-based and soy-based formula) even though these diets differ significantly in nutrients. We looked at whether these diets influenced brain responses to two different syllables when babies were 3 and 6 months old. All groups showed syllable-specific responses at both ages, but response differences between syllables were greater in breastfed than formula-fed infants at 6 months. Response changes from 3 to 6 months suggest better development of processes related to sensory memory in females. Discrimination of speech sounds is important for later language development and the results indicate early advantages for this ability in breastfed infants. Response similarities between formula-fed groups are notable and suggest that milk-based formula and soy-based formula equally support brain development and function during the first postnatal 6 months. These are early results in a long-term study, and the meaning of these findings for language development may become clear as this study progresses.
Technical Abstract: Although early post-natal nutrition influences later development, there are no studies comparing brain function in healthy infants fed the three major infant diets (breast milk, milk-based and soy-based formula) even though these diets differ significantly in nutrient composition. We have studied brain responses (event-related potentials: ERPs) to speech sounds in infants fed breast milk, milk-based or soy-based formula during the first 6 months of life. Two syllables presented in an oddball paradigm elicited a late positive wave (P350) from temporal and frontal brain regions involved in language processes. All groups showed significantly greater response amplitudes to the infrequent syllable across sites at 3 months and frontally at 6 months, but significant discrimination at temporal sites was only observed at 6 months in breastfed infants. Decreases in response amplitudes to both syllables from 3 to 6 months were greater for the frequently presented syllable, most prominent in BF infants, and greater in females than males. The results indicate greater syllable discrimination in BF than formula-fed infants, but whether this can be attributed to dietary influences alone remains unclear. Feeding method and background factor differences between breastfed and formula-fed infants may also contribute to the observed differences. The general absence of differences between formula-fed groups is notable and suggests that milk-based formula and soy-based formula equally support brain development and function during the first postnatal 6 months. Finally, the results indicate gender differences in the development of neural and temporal processes involved in sensory discrimination, and suggest that at 6 months these processes are better developed in females.