Does early object exploration support gesture and language development in extremely preterm infants and full-term infants?

Background: An increasing body of research on typically and atypically developing infants has shown that motor skills play an important role in language development. To date, however, the role of specific object exploration skills for early gesture and vocabulary development has not been investigated in extremely low gestational age infants (ELGA, GA < 28 weeks), who are at greater risk for motor and language delays than full-term (FT) infants. Purpose: This longitudinal study examined relations between 6-month active exploratory beha- viors and 12- month word comprehension, gestures and vocal production, controlling for cog- nitive performance and neonatal condition (ELGA vs FT). Methods: Forty infants, 20 ELGA and 20 FT, and their mothers participated in the study. Mother- infant play interaction was video-recorded at 6 and 12 months. Oral and manual object ex- ploration at 6 months and spontaneous gestures and vocal production at 12 months were coded. Word comprehension was evaluated with the Italian version of the MacArthur-Bates CDI parent questionnaire at 12 months. Cognitive performance was examined with the Griffiths Mental Developmental Scales at 6 months and the Bayley-III Scales at 12 months. Results: Regression analyses showed that after accounting for cognitive performance and neo- natal condition, oral exploration was related to word comprehension, and manual exploration to gestures and vocal production in the overall sample. Conclusions: Cascading effects of specific object exploration skills on gestures and language comprehension and production in preterm infants and FT infants are discussed. Clinical im- plications for early assessment of and interventions involving object exploration skills, which may affect language development, are considered for the preterm population.