Elsevier

Early Human Development

Volume 51, Issue 3, 10 July 1998, Pages 235-245
Early Human Development

Neurobehavioral development at term in very low-birthweight infants and normal term infants in Taiwan

https://doi.org/10.1016/S0378-3782(98)00035-8Get rights and content

Abstract

We compared the neurobehavioral performance at term between very low-birthweight (VLBW) infants and term infants in Taiwan, and investigated the relationships between neonatal factors and neurobehavioral performance in VLBW infants. Sixty VLBW infants and 58 healthy term infants were examined using the Neonatal Neurobehavioral Examination–Chinese version (NNE–C) at 40 weeks postmenstrual age. Medical records of the VLBW infants were reviewed to assess neonatal factors. The mean total score of the preterm infants (67.4±5.0) was significantly lower than that of the term infants (73.8±3.0) (t=8.51, P<0.0001). Furthermore, respiratory illness had a marginal effect on the rate of low neurobehavioral score (defined as 2SD below the mean score of term infants) in the preterm infants after adjustment for gestational age (odds ratio=7.67, χ2=3.36, P=0.067). Our findings indicate that preterm infants have lower neurobehavioral scores at term than their healthy term counterparts. Furthermore, respiratory illness may be a potential risk factor for low neurobehavioral score at term in preterm infants when gestational age is adjusted for.

Introduction

Recent advances in perinatal care have resulted in a marked improvement in the survival rate of very low-birthweight (VLBW) infants (birth weight <1501 g) 21, 30. However, the surviving infants are at increased risk of long term neurodevelopmental disabilities 21, 28, 32. Early intervention programs have been introduced to identify and remediate the neurodevelopmental abnormalities of these preterm infants.

The Neonatal Neurobehavioral Examination (NNE) [19]is particularly valuable for use in early intervention programs. This scale provides information to assist clinicians in determining the neuromaturational status of an infant and to help the parents understand the behavioral characteristics of their child, which is beneficial to the parent–child relationship [34]. The instrument simplifies the five- or nine-point scoring system used in other tests 5, 8into a three-point system that allows the examiner to detect differences in infant performance with less difficulty. Furthermore, acceptable levels of clinical feasibility, reliability, and discriminative validity were demonstrated for its application to preterm infants and healthy term infants in the USA [19].

We recently translated the NNE into a Chinese version (NNE–C) and standardized it for the testing procedures. The NNE–C has high internal consistency (alpha coefficient=0.84), as well as good inter-rater reliability and test–retest reproducibility (intraclass correlation coefficients >0.80) in preterm and healthy term infants in Taiwan [15]. In addition, the instrument shows responsiveness to neurobehavioral maturation in preterm Taiwanese infants [6]. In the current study, we further examine the discriminative validity of the NNE–C scale in differentiating the neurobehavioral development at term between VLBW infants and healthy term infants in Taiwan. This information is crucial before the measurement tool can be used for early detection of neurodevelopmental abnormalities in preterm infants.

Although preterm infants are at increased risk for neurodevelopmental abnormalities, the specific factors leading to this vulnerability remain unclear. Neonatal factors examined include prematurity and medical complications. Palmer et al. [22]and Aylward et al. [3]found that infants born at lower gestational age had more extended postures, poorer neck control, and greater extension of legs in ventral suspension at term age than infants born at higher gestational age. In contrast, Howard et al. [12]and Piper et al. [25]noted no significant impacts of gestational age on the early neurobehavioral performance of preterm infants. As for the effects of medical complications, Piper et al. [25]and Stjernqvist and Svenningsen [29]showed that preterm infants with seizure, intracranial haemorrhage, prolonged ventilation, or bronchopulmonary dysplasia exhibit poorer neurobehavioral outcome during the neonatal period than infants without these complications. Conversely, Kurtzberg et al. [17]and Morgan et al. [19]observed no correlation between medical complications and early neurobehavioral performance in preterm infants.

These incongruous findings may be in part due to the use of univariate models for risk analysis, in which the effects of confounding factors were not controlled for. Therefore, the second purpose of this study was to examine the relationships between potential neonatal risk factors and the neurobehavioral outcome at term in VLBW infants in Taiwan, using both univariate and multivariate regression analysis.

Section snippets

Infants

There were 103 VLBW infants born and admitted to the neonatal intensive care unit at the National Taiwan University Hospital, Taipei, from November 1, 1994, to July 31, 1996. The selection criteria of VLBW infants in our study were: gestational age less than 37 weeks, birth weight less than 1501 g, absence of chromosomal or other genetic anomalies, and absence of physiological instability for neurobehavioral examination at term postmenstrual age. Gestational age was estimated by maternal

Results

Comparison of the score distributions of the VLBW and term groups revealed significant differences in 15 of the 27 items (Table 2). In the tone and motor patterns section, lower scores were found significantly more often in the preterm group than in the term group in the scarf sign, popliteal angle, ankle dorsiflexor, prone suspension, slip through, pull to sit, and head righting items. In the primitive reflexes section, lower scores were found significantly more often in the preterm group than

Discussion

Our results have substantiated the data of previous reports 3, 9, 12, 17, 18, 19, 25that preterm infants at term age perform differently from healthy term infants in neurobehavioral development. Assessed with the NNE–C scale, the majority of term infants achieved a score of 3 in most of the test items, whereas the preterm infants more frequently attained lower scores. The results indicate that the NNE–C scale provides a quantitative and valid measurement for the discrimination of the early

Acknowledgements

This study was funded by a grant (D0H86-HR-619) from the National Health Research Institute of the Department of Health, Taiwan. The authors thank the infants and their parents for participation in the study, Ms Li-Chiou Chen, Ae-Weng Huang, Shwu-Fang Hsiao, Chia-San Wu, Shiu-Ying Yu, Cheng-Chi Tsao and Chun-Hua Wang for their assistance in data collection, and Dr. Wei J. Chen for his help in statistical analysis.

References (35)

  • C.M Drillien et al.

    Low birthweight children at early school-age: a longitudinal study

    Dev. Med. Child Neurol.

    (1980)
  • Dubowitz L, Dubowitz V. The neurological assessment. In: Dubowitz L, Dubowitz V, editors. The Neurological Assessment...
  • F Ferrari et al.

    Neurobehavioral comparison of low-risk preterm and fullterm infants at term conceptional age

    Dev. Med. Child Neurol.

    (1983)
  • D.G Freedman et al.

    Behavioral differences between Chinese–American and European–American newborns

    Nature

    (1969)
  • M.K Georgieff et al.

    Abnormal truncal muscle tone as a useful early marker for developmental delay in low birth weight infants

    Pediatrics

    (1986)
  • J Howard et al.

    A neurologic comparison of pre-term and full-term infants at term conceptional age

    J. Pediatr

    (1976)
  • T.T Hsieh et al.

    Analysis of birth weight and gestational age in Taiwan

    J. Formosan Med. Assoc.

    (1991)
  • Cited by (0)

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