Vocal and gestural modalities in a lexical task: a comparison between preterm and typically developing infants at 2 years.

In typical development (TD), gestures support the building of meanings and convey them in combination with vocal production. Lexical development can be affected by preterm birth showing delays with respect to TD children. However, the early lexical abilities and the spontaneous use of gestures supporting lexical development of preterm infants and, in particular, of extremely low gestational age (ELGA: <= 28 weeks) preterms, have not been investigated till now. Our study aimed to examine the emergence of lexicon in ELGA preterms compared to TD infants, by considering vocal and spontaneous gestural responses in a task of word comprehension and production. Forty monolingual Italian ELGAs with no major cerebral damage and a comparison group of 40 full-terms (FT) were assessed at 2 years through a task of lexical comprehension and production of nouns and predicates (PinG). Compared to FTs, some ELGAs were unable to complete the tasks. ELGAs who completed them, produced significantly fewer correct responses in the comprehension as well as in the production tasks (p values <.05). Error analyses revealed that ELGAs produced more non responses, while FTs tried more frequently to retrieve the referent by giving uncorrected responses. The analysis of vocal and gestural responses in the production task revealed that both groups used mainly unimodal vocal and bimodal gestural-vocal strategies. Deictic gestures were frequently accompanied to vocal responses by both groups, while some referential gestures were produced especially in the predicates task, but less frequently by ELGA with respect to TD infants. The use of the PinG task highlighted ELGA preterms’ difficulties to retrieve and produce lexical referents by both vocal and referential gestural modalities. An integrated model relying upon linguistic, cognitive and motor factors is proposed for the interpretation of the results.