Effects of prematurity on language acquisition and auditory maturation: a systematic review

Purpose  To verify which damages prematurity causes to hearing and language.

Research strategies  We used the decriptors language/linguagem, hearing/audição, prematurity/prematuridade in databases LILACS, MEDLINE, Cochrane Library and Scielo.

Selection criteria  randomized controlled trials, non-randomized intervention studies and descriptive studies (cross-sectional, cohort, case-control projects).

Data analysis  The articles were assessed independently by two authors according to the selection criteria. Twenty-six studies were selected, of which seven were published in Brazil and 19 in international literature.

Results  Nineteen studies comparing full-term and preterm infants. Two of the studies made comparisons between premature infants small for gestational age and appropriate for gestational age. In four studies, the sample consisted of children with extreme prematurity, while other studies have been conducted in children with severe and moderate prematurity. To assess hearing, these studies used otoacoustic emissions, brainstem evoked potentials, tympanometry, auditory steady-state response and visual reinforcement audiometry. For language assessment, most of the articles used the Bayley Scale of Infant and Toddler Development. Most studies reviewed observed that prematurity is directly or indirectly related to the acquisition of auditory and language abilities early in life.

Conclusion  Thus, it could be seen that prematurity, as well as aspects related to it (gestational age, low weight at birth and complications at birth), affect maturation of the central auditory pathway and may cause negative effects on language acquisition.

Keywords
Language; Hearing; Prematurity; Child Development; Child Health