Language Exposure of Preterm Infants in the Neonatal Unit: A Systematic Review

Abstract

Background: Elevated sound levels and low language exposures of preterm infants (< 37 weeks) cared for in the neonatal unit contribute to poorer growth, cognition, language and motor outcomes. These delays can have lasting effects on childhood development and continue throughout adult life. Whilst recommendations have been established for appropriate sound exposure levels in neonatal units, very little is known about the optimal level of language exposure. Objectives: To examine the evidence regarding language exposure, both measured (observational) and prescribed (interventional), in preterm infants (< 37 weeks) cared for in neonatal units and to identify optimal exposure levels to promote neurodevelopment. Search Methods: An electronic search of English-language articles with an open date range was conducted in the PubMed, MEDLINE, Joanna Briggs, CINAHL and Cochrane databases and in Google Scholar. The criteria were limited to original research studies of preterm infants (< 37 weeks) in which language was either measured as it naturally occurred in the neonatal unit environment or through a language intervention. Results: The search produced a total of 2,367 articles, 49 of which were related to language. A full-text review of these articles identified 10 eligible studies and 6 studies from reference searches. Conclusions: Preterm infants experience low levels of language exposure and high sound exposures in neonatal units. There is a lack of conclusive evidence to recommend an optimal level of language exposure to support improved neurodevelopmental outcomes in preterm infants. Further research from large, good-quality clinical trials is required before clear direction can be provided to inform clinical practice.

Communication in children born very preterm: a prospective cohort study

“…Bayley Scales of Infant Toddler Development) lends additional credence to our findings with regard to low language difficulty rates and risk factors affecting language outcomes in this group. The language difficulties shown here, poorly predicted by medical factors, may support emerging arguments that the linguistic environment of the neonatal intensive care unit is a powerful contributor to later language performance . However, further research will be required to determine the contribution of linguistic deprivation in the neonatal period versus other possible predictors such as parent–child interaction style and exposure to early learning environments.…”

“…The language difficulties shown here, poorly predicted by medical factors, may support emerging arguments that the linguistic environment of the neonatal intensive care unit is a powerful contributor to later language performance. 23 However, further research will be required to determine the contribution of linguistic deprivation in the neonatal period versus other possible predictors such as parent-child interaction style and exposure to early learning environments. Our findings indicate that children born preterm vary substantially in their communication profiles.…”

Music therapy for neurodevelopment in hospitalised infants

“…due to preterm birth) are widely known to experience adverse neurodevelopmental outcomes . Researchers have suggested that some of these neurodevelopmental outcomes might be attributed to the sensory and linguistic deprivation that characterises time spent in hospital, rather than to the medical conditions and interventions that necessitate hospitalisation . Thus, there is an increasing interest in non‐invasive environmental enrichment therapies in the neonatal intensive care unit (NICU), including music therapy .…”

The language environment of the hospitalised neonate

“…In this systematic review, Best, Bogossian, and New examined observational and intervention studies of language exposure for hospitalised preterm neonates. Ten studies met their inclusion criteria.…”

“…Adequately powered, randomized controlled trials using appropriate stimuli will be critical, and, as the authors suggest, longer term follow‐up is indicated. The authors suggest ‘2 years’ corrected age and beyond’ as a target for longitudinal studies of intervention outcomes. We emphasise ‘and beyond’, given that language development is notoriously unstable at two years’, and longer term follow‐up may be necessary to obtain valid outcomes .…”