Disrupted or delayed? Stress discrimination among preterm as compared to full-term infants during the first year of life

Background: Several papers pointed out that the language disorders are the most commonly reported cognitive deficits of the preterm (PT) infants. However, neither the exact interpretation (disrupted or delayed) of their language development nor the most powerful perinatal risk factors have been specified yet.

Aims: We aimed to determine whether postnatal development of prosodic processing of PT infants is disrupted or delayed in the first year of life? We also tested the role of Birth Weight (BW) and Gestational Age (GA) regarding the PT and full-term (FT) infants' language perception.

Method: We registered the mismatch responses (MMR) of 34 PT (at 6 and 12 month of ages) and 33 FT infants (at 4 and 10 month of age) elicited by bisyllabic pseudo-words in two oddball conditions.

Result: Contrary to their FT peers, younger PT group detected stress changes of the legal stress form only. Analogously, a positive MMR (P-MMR) was found for the legal form discrimination exclusively in PT12 group. Furthermore, the lack of sensitivity to the standard vs. deviant difference was identified in the PT infants. In PT infants, BW explained 21 % of the total variance of the P-MMR.

Conclusion: Consequently, we argue that the stress sensitivity of the PT infants is unimpaired, but their stress processing seems to be disrupted from the 6th month on. We suggest for further studies to take BW into account in studies using MMR paradigms in PT infants.