The Journal of Pediatrics
Volume 156, Issue 3 , Pages 347-349, March 2010

Role of Intervention Strategies for At-risk Preterm Infants

  • Arend F. Bos, MD, PhD

      Affiliations

    • Corresponding Author InformationReprint requests: Arend F Bos, Beatrix Children's Hospital, Division of Neonatology, University Medical Center Groningen, University of Groningen Hanzeplein 1, 9713 GZ Groningen, The Netherlands.

Beatrix Children's Hospital, Division of Neonatology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands

Article Outline

DCD, Developmental coordination disorder, FM, Fidgety general movement, IBAIP, Infant Behavioral Assessment and Intervention Program, NNNS, Neonatal Intensive Care Unit Network Neurobehavior Scales, PDI, Psychomotor developmental index, VLBW, Very low birth weight

 

See related articles, p 359 and p 366

Despite increased survival rates of preterm infants, the prevalence of developmental disabilities in preterm survivors is still high.1 Although the rates of major handicaps have remained relatively constant in the last decade, the prevalence of milder dysfunctions seems to be increasing. Cognitive, behavioral, and mild motor problems without major motor deficits are now the most dominant neurodevelopmental sequelae in children born preterm.2, 3 These problems include learning disabilities, borderline to low IQ scores, attention-deficit, and specific neuropsychological deficits affecting visuomotor integration and executive function.3 These abnormalities occur in >50% of children born preterm with very low birth weight (VLBW; < 1500 g) and often do not occur in isolation.2 The situation is further confounded by the social, ethnic, and educational background of the parents also possibly influencing the prevalence of these disabilities.

In early infancy, it is difficult to identify the individual infant at highest risk for mild motor, cognitive, and behavioral problems. Models of pathogenesis include changes related to developmental disruptions and brain injury.2, 4 Although global white matter damage revealed with ultrasound scanning and magnetic resonance imaging is quite common in children born preterm, and volumes of gray matter are also diminished, clear associations of cognition with pathological changes on neuroimaging have not been definitely demonstrated.5 Another method to identify infants at risk is some form of neurobehavioral assessment at an early age.6 Of these, the assessment of the quality of spontaneous general movements has emerged as a reliable and valid predictor of major motor deficits for the individual infant.7 This method is based on visual Gestalt perception of the quality of general movements in the preterm, term, and post-term periods, as long as 5 months post-term. The quality of so called fidgety general movements (FMs), present between 9 and 20 weeks post-term and defined as continuous small movements of moderate speed in all directions, is a particularly accurate marker for neurological outcome. Most infants (96%) with normal FMs have normal neurological outcomes, and cerebral palsy develops in most infants (95%) in whom FMs are absent during this period.8 An early indicator with prognostic value for the development of milder neurological deficits (eg, developmental coordination disorder [DCD]) is the concurrent motor repertoire at 3 to 4 months post-term.9 When FMs are normal, a smooth, variable concurrent motor repertoire is a marker for a normal outcome, and the risk for the development of DCD is low (5%). When the concurrent motor repertoire is monotonous, the risk for the development of DCD is approximately 30%.9 Although prediction of neurodevelopmental outcome at an early age is difficult, these and other neuromotor tests show that the best prediction is achieved when some form of qualitative aspect of motor behavior is considered.6

In this issue of The Journal, Stephens et al 10 adds to our knowledge of early prediction by means of neurobehavioral assessment. They showed that their previously developed neurobehavioral scale can help to predict poor motor outcome at 24 months of age. Originally, the Neonatal Intensive Care Unit Network Neurobehavior Scales (NNNS) was developed to investigate the effects of cocaine exposure. The authors have now investigated the predictive value of the NNNS for cerebral palsy at 12 to 36 months and low psychomotor developmental index (PDI) at 24 months in a cohort of nearly 400 preterm infants, born before 36 weeks gestation. The NNNS provides a comprehensive assessment of 3 dimensions of the newborn: neurologic integrity, behavioral functioning, and stress behavior. Each dimension has a number of scores, from which 13 summary scores are calculated. Cerebral palsy and low PDI (<70) at 24 months were associated with 4 items from the NNNS administered at 4 weeks post-term: low quality of movement, high lethargy, low handling, and hypotonia. In various combinations, these items contributed 19% to the variance in cerebral palsy diagnosis and 26% in low PDI. The authors conclude that the neurobehavioral profile of under-arousal at 4 weeks post-term may predict poor motor outcome in preterm infants. This information about the risk of poor motor outcome was the addition to other predictors, such as chronic lung disease, intraventricular hemorrhage, and periventricular leukomalacia.

The study by Stephens et al is part of a larger project and an extension of previously published data. There are some limitations, which the authors recognize. Approximately half the infants had been exposed to intrauterine cocaine, and further prospective studies are needed to determine the predictive value for all preterm infants. However, the under-arousal at 44 weeks as a risk factor for cerebral palsy and low PDI at follow-up is an interesting new finding. It is already known that monotonous movements (as opposed to variable and complex movements) at this age are related to cerebral palsy,8, 9 and the low quality of movements reported in this study may reflect brain damage. The under-arousal, low movement quality, and lethargy may also reflect the role motor activity has at this early age in normal development. Rapid brain development in the early post-term months is accompanied by equally rapid motor and psychological development. The infants' exploration of their environment with several motor strategies, integrating and refining neural input and output, may lead to better neurological and cognitive development. The absence of such a variable motor repertoire at this particular age (eg, because of the under-arousal) might hamper the infants' abilities to interact with the world around them, which leads to delayed or impaired development.11 This would imply that early intervention, aimed at stimulation of more variable motor strategies, may result in a better functional outcome.

This brings us to another study in this issue of The Journal, about an early intervention program for VLBW infants.12 The authors conducted a multi-center randomized controlled trial of 176 infants to determine whether the Infant Behavioral Assessment and Intervention Program (IBAIP) improved development and behavior in VLBW infants at 24 months corrected age. The intervention group received 6 to 8 post-discharge interventions until 6 months corrected age. The intervention consisted of supporting the infants' self-regulation and development and facilitating sensitive parent-infant interactions. The control infants received regular care. Unfortunately, more children in the intervention group were <28 weeks gestational age than in the control group, despite randomization. As a result, the authors had to adjust for differences in perinatal characteristics. They found an intervention effect of 6.4 points on the PDI at 24 months, favoring the intervention infants. Significant intervention effects on mental development and behavior were not found. The authors conclude that the IBAIP showed sustained motor improvement in VLBW infants until 2 years corrected age. This study adds to the growing literature on the effects of early developmental interventions in preterm infants. The authors found a positive effect on motor development, rather than on mental or behavioral development. Only subgroup analysis revealed that mental and motor outcomes improved in intervention infants with bronchopulmonary dysplasia and with combined biological and social risk factors.

Early intervention programs may have positive effects, particularly on the cognitive development of preterm infants.13 The effect size is approximately 0.4 to 0.5 SD, thus 6 to 8 IQ points. These effects are mostly short-term, until the age of 3 years, and not seen anymore at school age. At any age, intervention has limited effects on motor outcomes,13 although specific developmental training in which parents learn how to promote infant development may produce a positive effect on motor development.14 It would be helpful to know which particular aspects of the IBAIP produced the marked improvement of motor development. In an earlier study, the authors described the IBAIP in more detail:15

“The intervention aims to enhance the infant's social and environmental interactions without causing distress, which reinforces the infant's motivation and autonomy to explore and learn from the information. The IBAIP builds on both the infant's and parent's strengths, seeking opportunities instead of problems in behavior, enhancing mutually satisfying interaction and parental involvement.”

From this description, one may hypothesize that parental involvement, stimulating a playful and interactive environment, and promotion of self-produced motor behavior play a key role. The children from families that combine several risk factors, including low education attainment of the parents, may benefit from this type of intervention.16 This was also the case in this study.12

There exists a large variety in early developmental intervention programs. Because of the resources required to provide early intervention, there is urgent need for further research on the identification of the children at highest risk and on the effects of early intervention throughout childhood. It will be fascinating to see whether these efforts would succeed in improving the motor, cognitive and behavioral outcome of the preterm children in the next decade.

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References 

  1. Saigal S, Doyle LW. An overview of mortality and sequelae of preterm birth from infancy to adulthood. Lancet. 2008;371:261–269
  2. Aylward GP. Neurodevelopmental outcomes of infants born prematurely. J Dev Behav Pediatr. 2005;26:427–440
  3. Johnson S. Cognitive and behavioural outcomes following very preterm birth. Sem Fetal Neonatal Med. 2007;12:363–373
  4. Volpe JJ. Brain injury in premature infants: a complex amalgam of destructive and developmental disturbances. Lancet Neurol. 2009;8:110–124
  5. Hart AR, Whitby EW, Griffiths PD, Smith MF. Magnetic resonance imaging and developmental outcome following preterm birth: review of current evidence. Dev Med Child Neurol. 2008;50:655–663
  6. Heineman KR, Hadders-Algra M. Evaluation of neuromotor function in infancy—a systematic review of available methods. J Dev Behav Pediatr. 2008;29:315–323
  7. Einspieler C, Prechtl HFR. Prechtl's assessment of general movements: a diagnostic tool for the functional assessment of the young nervous system. Ment Retard Dev Disabil Res Rev. 2005;11:61–67
  8. Prechtl HFR, Einspieler C, Cioni G, Bos AF, Ferrari F, Sontheimer D. An early marker for neurological deficits after perinatal brain lesions. Lancet. 1997;349:1361–1363
  9. Bruggink JLM, Einspieler C, Butcher PR, van Braeckel KNJA, Prechtl HFR, Bos AF. The quality of the early motor repertoire in preterm infants predicts minor neurologic dysfunction at school age. J Pediatr. 2008;153:32–39
  10. Stephens BE, Liu J, Lester B, LaGasse L, Shankaran S, Bada H, et al. Neurobehavioral assessment predicts motor outcome in preterm infants. J Pediatr. 2010;156:366–370
  11. Butcher PR, Bos AF, van Braeckel KNJA, Einspieler C, Stremmelaar EF, Bouma JM. The quality of infants' spontaneous movements: an early predictor of intelligence and behavior at school age. J Child Psychol Psychiatry. 2009;50:920–930
  12. Koldewijn K, van Wassenaer A, Wolf MJ, Meijssen D, Houtzager B, Beelen A, et al. An infant behavioral assessment and intervention program in very low birth weight infants: outcome at 24 months. J Pediatr. 2010;156:359–365
  13. Orton J, Spittle A, Doyle L, Anderson P, Boyd R. Do early intervention programmes improve cognitive and motor outcomes for preterm infants after discharge? A systematic review. Dev Med Child Neurol. 2009;51:851–859
  14. Blauw-Hospers CH, Hadders-Algra M. A systematic review of the effects of early intervention on motor development. Dev Med Child Neurol. 2005;47:421–432
  15. Koldewijn K, Wolf MJ, van Wassenaer A, Meijssen D, van Sonderen L, van Baar A, et al. The Infant Behavioral Assessment and Intervention Program for very low birth weight infants at 6 months corrected age. J Pediatr. 2009;154:33–38
  16. Bonnier C. Evaluation of early stimulation programs for enhancing brain development. Acta Paediatr. 2008;97:853–858

PII: S0022-3476(09)01212-8

doi:10.1016/j.jpeds.2009.11.077

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    The Journal of Pediatrics March 2010 (Vol. 156, Issue 3, Pages 359-365)

The Journal of Pediatrics
Volume 156, Issue 3 , Pages 347-349, March 2010

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