Original articleNutritional state, maturational delay on electroencephalogram, and developmental outcome in extremely low birth weight infants
Introduction
The recent advance of neonatal medicine resulted in an increasing survival rate of extremely low birth weight infants [1]. However, long-term neurodevelopmental outcome of the survivors is not sufficiently good. The EPIPAGE study group recently reported that neurological disability was observed in 49% of children born at 24–28 completed weeks of gestation, and that special health-care resources were used by 42% of children born at 24–28 weeks and 31% born at 29–32 weeks [2].
The cause of neurological sequelae is considered to be multifactorial. There are many pre-, peri- and postnatal factors that affect neurodevelopmental outcome of extremely low birth weight infants. Nutritional state during the neonatal period will be one of these factors. Our previous study demonstrated that undernutritional condition during the neonatal period was associated with poor head growth and delay in electroencephalographic maturation in extremely low birth weight infants [3]. However, their long-term neurodevelopmental outcome has not been clarified.
Dysmature patterns were a type of chronic stage electroencephalographic abnormalities, and were related to poor cognitive development [4], [5], [6]. Our previous study demonstrated that a postnatal undernutritional condition was associated with dysmature patterns in extremely low birth weight infants [3]. Although this suggested that undernutrition may affect electrophysiologic maturation, the effects on developmental outcome have not been elucidated.
The aim of this study is to report a long-term outcome of extremely low birth weight infants enrolled in our previous study and clarify the relation between neurodevelopmental outcome, and nutritional state during the neonatal period. We also investigated the relation between dysmature patterns on electroencephalogram (EEG) and the neurodevelopmental outcome.
Section snippets
Methods
This study is a continuum of our previous study in which we prospectively studied the relation between nutritional state, and growth and functional maturation of the brain in extremely low birth weight infants [3]. The original cohort was 21 infants who were admitted to the neonatal intensive care unit of Ogaki Municipal Hospital from June 1997 to December 2000 and fulfilled all the following conditions: gestational age between 24 and 28 weeks, birth weight <1000 g, no congenital anomaly,
Results
Clinical characteristics and neonatal clinical events are shown in Table 1. Gestational age, birth weight, head circumference at birth, Apgar score, and the rate of neonatal events did not differ significantly between the two groups. Dysmature patterns were seen in six of eight infants with undernutrition. Dysmature patterns were persistent in four of them. On the other hand, dysmature patterns were present in no infants with normal nutrition. The rate of dysmature patterns was significantly
Discussion
Our study revealed that IQ during childhood was lower in infants with undernutrition than those with normal nutrition. It is natural that neonatal morbidities such as necrotizing enterocolitis, late onset infection, and chronic lung disease are closely related to poor nutritional state. There have been several studies that these neonatal morbidities are important risk factors for poor developmental outcome [10], [11], [12]. In our study, the rate of these neonatal morbidities was not different
Acknowledgement
This work was supported by the grant from the Ministry of Education, Culture, Sports, Science and Technology (20591306).
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