Early communication in preterm infants following intervention in the NICU
Introduction
Preterm infants face long-term developmental difficulties across many functional domains. Despite substantial improvements in survival rates, the incidence of preterm birth has shown a steady rise in Western countries [1]. Meta-analyses of studies of very preterm infants (< 32 weeks gestational age) have found moderate-to-severe effects to school age on academic achievement, attention problems, behavioural problems and executive functioning (e.g. [2]) as well as motor impairment [3]. In a recent cohort study of 7650 children, a decrease was found in overall achievement, including mathematical abilities, social relationships and emotional development by early school age, all correlated with the level of prematurity [4].
Poor development may in part be exacerbated by the experience of acute and chronic stressors in the Neonatal Intensive Care Unit (NICU), including overstimulation and necessary medical and nursing procedures [5], [6], [7]. To address this, a number of early interventions have been developed to protect the preterm infant from stress. These are either delivered in the NICU by nursing, allied and medical staff (e.g. ‘Developmental Care’ which aims to minimise medical and nursing stressors) or via training of parents to recognise and minimise signs of infant stress. Furthermore, amongst parent-training interventions, some begin during the infants' hospitalisation and some within the first post-discharge year of life. The parent-training approach stems back to a landmark study [8], [9] of the Mother–Infant Transaction Program (MITP), a major focus of which is sensitising parents to infant cues, in particular those which signal “stimulus overload, distress, or readiness for interaction”. The MITP began during the babies' hospitalisation in the NICU and extended after discharge. Children's development was followed longitudinally and a difference of 10.6 IQ points was demonstrated favouring intervention infants at 9 years of age, but this group difference only began to emerge after 2 years of age.
The longer-term efficacy of this intervention has resulted in several research groups using MITP-type interventions and replicating positive results on cognitive development up to 5 years of age [10]. At least two studies using MITP-type interventions are in the follow-up stage [10], [11], [12], [13], [14], [15] and improvement in some earlier indices of child development is also emerging [16]. In our first application of an enhanced version of the MITP (the PremieStart programme) we extended the length of intervention and included additional targets (see Methods below). Following the first trial of PremieStart we found early communication abilities to be better developed in children of intervention mothers at 3 months corrected-age [17].
Such gains may be due to a direct effect of early stress reduction in promoting early brain development. A small number of intervention studies suggest such an effect. Using our PremieStart programme in a previous randomised trial, we found enhanced white matter connectivity at term-equivalent age [18]. This is consistent with the findings of McAnulty and colleagues [19] who found enhanced neurobehavioural scores, more mature cerebral white matter at 2 weeks corrected-age (CA) and behavioural advantages at 9 months of age in preterm infants who had received NIDCAP (Newborn Individualized Developmental Care and Assessment Program). Subsequent controlled trials of NIDCAP, delivered by nurses, have demonstrated associations (through electro-encephalography) of improved connectivity between temporal regions measured at term-equivalent age and at 8 years of age in intervention children [20]. Furthermore, very early brain structure and brain connectivity in preterm infants are known to correlate with later child outcomes [21], [22], [23].
Here we report on the earliest results from a second, larger, randomised controlled trial of PremieStart, which is currently the subject of a longer-term follow-up. The primary outcome of interest in the overall trial is the impact of the intervention on child's cognitive and behavioural development at 2 years of age. Earlier proxies of development at 6 months, along with short-term medical data, are reported in the present paper. We also report data on the efficacy of the intervention in enhancing maternal sensitivity and reducing signals of infant stress. Our main hypothesis was that the PremieStart intervention would result in improved outcomes for preterm infants compared with a control group receiving standard clinical care. Specifically, we predicted that compared to controls, the intervention group would show:
- 1.
Improved short-term measures of medical stability.
- 2.
Improvement in early communication abilities and behaviour.
Section snippets
Design and sample
The study was a parallel, two-group randomised controlled trial (RCT) of an enhanced MITP intervention (PremieStart) versus standard care (Trial Registration Number: ACTRN12606000412538), which was approved by the Human Research Ethics Committees of the Royal Women's Hospital and the Mercy Hospital for Women, both located in Melbourne, Australia. Between April 2007 and September 2009, women who delivered at < 30 weeks gestation were enrolled at the NICUs of both hospitals when infants were 30–32
Sample
In total, 732 women (with 852 infants) were screened for eligibility by the end of the study recruitment period (Fig. 1). Screened infants had an average gestational age of 27.4 weeks and an average birth weight of 1014 g. Three hundred and seventy eight women met exclusion criteria (> 100 km from central Melbourne, n = 185; treating clinician judged infant/mother too severely ill/medically unstable, n = 76; non-English speaking, n = 32; drug and alcohol issues, n = 27; other, n = 43; multiple criteria, n =
Discussion
Cognitive deficits, including language delay, are common problems in children born very preterm [34]. Such adverse developmental outcomes in preterm infants may be exacerbated by environmental stressors. We hypothesised that training parents of preterm infants in stress reduction in the NICU can protect infants.
We found that our parent-training programme, PremieStart, was successful in enhancing maternal sensitivity to infant cues, replicating our previous findings [17]. In the current study,
Conflict of interest statement
The authors declare no conflicts of interest.
Acknowledgements
We thank the families who took part in this study. The work was supported by a Project Grant from the National Health & Medical Research Council (ID: 364902). The funding body had no role in the study design, collection, analysis and interpretation of data; in the writing of the manuscript; or in the decision to submit the manuscript for publication. Dr Justin Biltsza generated the secure allocation schedule and translated it to sequentially numbered sealed envelopes. Thanks also to Dr
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