JAPAN: The NBAS as a Predictor of Cerebral Palsy in Low Birth Weight Infants

By Tomitaro Akiyama, Shohei Ogi, Tatsuya Takahashi, Masafumi Fukuda, Chisato Kawasaki, YoshikoGoto and Toshiya Tsurusaki (University of Nagasaki)

The purpose of this study was to investigate the relation between newborn behavior patterns as measured by the Neonatal Behavioral Assessment Scale (NBAS) and long-term cerebral palsy (CP) as a neurological outcome among low birthrate infants.

METHODS: The sample for this case-control design study was made up of low birthweight infants admitted to the NICU at the University of Nasgasaki Hospital, between 1988 and 1994. The total sample consisted of 277 infants, with a mean gestational age of 32.6 weeks and a mean birth weight of 1648.6 grams. These infants were examined in the NBAS at 36 weeks PCA, at 40 weeks and at 44 weeks PCA. The infants were again examined at five years of age, on standardized assessments to measure their development status. Logistic regression analysis was used to examine the relationship between newborn behavioral patterns, as measured by the NBAS cluster scores and developmental status at five years.

RESULTS: At five years, 165 infants were categorized within the normal range, 49 were categorized as borderline, 12 died and 15 were diagnosed as having CP. The remaining 36 could not be contacted. The NBAS cluster scores of the 15 infants who were diagnosed as having CP were compared with the NBAS scores of the normal infants. Using Mann-Whitney U Tests, NBAS cluster scores were significantly lower in the 15 newborn infants later diagnosed as having CP. In the logistic regressions analysis, Motor (p<.06) and Autonomic (p<.02) clusters at 36-38 weeks PCA, Motor (p<.02), Autonomic (p<.08) and State Regulation (p<.07) clusters at 40-42 weeks and at 44 weeks the Reflex cluster, was significantly related to 5 year scores (p<.01)..

CONCLUSION: The results of the study confirm the predictive validity of the NBAS and it's validity as a diagnostic tool for identifying the early indicators of CP. The results suggest that the NBAS, when used serially in the postnatal period, not only casn help identify neonates who are at risk for CP but it can help clinicians develop a management protocol for infants with cerebral palsy.