Early gross motor development of preterm infants according to the Alberta Infant Motor Scale.

OBJECTIVE: To systematically examine gross motor development in the first 18 months of life of preterm infants. STUDY DESIGN: A total of 800 preterm infants (356 boys), ages between 1 and 18 months and corrected for degree of prematurity, were assessed with the use of the Alberta Infant Motor Scale. RESULTS: Comparison of the mean Alberta Infant Motor Scale scores of the preterm infants with the norm-referenced values derived from term infants revealed that as a group, the preterm infants scored significantly lower at all age levels, even with full correction for degree of prematurity. CONCLUSIONS: In general, preterm infants exhibit different gross motor developmental trajectories compared with term infants in the first 18 months of life. The gross motor developmental profile of preterm infants may reflect a variant of typical gross motor development, which seems most likely to be specific for this population. As a consequence, adjusted norms should be used for proper evaluation and clinical decision-making in relation to preterm infants.

Motor nerve conduction velocity in very preterm infants in relation to L-thyroxine supplementation.

BACKGROUND: Transient hypothyroxinemia is common in preterm infants and has been associated with neurodevelopmental dysfunction and slow nerve conduction velocity. It is still unknown whether L-thyroxine supplementation is required. During an L-thyroxine supplementation trial, motor nerve conduction velocity was measured to answer the question whether L-thyroxine supplementation improves motor nerve conduction velocity. METHODS: Two hundred infants < 30 weeks' gestational age were enrolled in a randomized, double-blind, placebo-controlled L-thyroxine supplementation trial. L-Thyroxine (8 micrograms/kg birthweight per day) or a placebo was administered during the first 6 weeks of life. Motor nerve conduction velocity was measured in the ulnar and posterior tibial nerve shortly after birth, at 2 weeks, at 40 weeks, and at 66 weeks postmenstrual age. RESULTS: At 2 weeks, the ulnar motor nerve conduction velocity had improved in the L-thyroxine group compared with the placebo group, although the difference was not statistically significant (difference between means: 0.8 msec; 95% CI: -0.13 to 1.80; p = 0.06). Later on, no effect of L-thyroxine supplementation on motor nerve conduction velocity was found. CONCLUSION: This study shows that in infants < 30 weeks' gestational age L-thyroxine supplementation during the first 6 weeks of life does not clearly improve motor nerve conduction velocity.

Cerebral ventricular dilation in congenital myotonic dystrophy.

Ultrasonography or computed tomography scanning of the brain was performed in 10 infants with congenital myotonic dystrophy between the age of 1 day and 2 months, and showed intracranial abnormalities in all. Ventricular dilation was diagnosed in eight (80%), subarachnoid hemorrhage in one, and white matter infarcts in one. The common finding of ventricular dilation is probably related to developmental brain abnormality dating back to fetal life, because it was already present in three infants scanned on the first day of life. Neonatal asphyxia was present in seven infants, associated with intraventricular hemorrhage in two. The relationship between these changes and mental retardation, which is a common feature in this disease, is unclear.

Hearing threshold in preterm and term infants by auditory brainstem response.

Hearing thresholds were established in preterm and term newborn infants by auditory brainstem responses in the first week of life. The presence of wave V was the criterion for threshold sensitivity in infants considered neurologically optimal on the basis of stringent clinical criteria and sequential ultrasound examination. The hearing threshold was found to be at 40 dB in preterm infants between 28 and 34 weeks gestational age, at 30 dB in infants between 35 and 38 weeks, and below 20 dB in term infants. This study confirms that the thresholds of newborn infants diminish with increasing age, and there is no apparent difference whether maturation occurs inside or outside the uterus. The data should provide a baseline for objective and quantitative assessment of hearing loss early in the neonatal period.