Pilot use of the early motor repertoire in infants with inborn errors of metabolism: outcomes in early and middle childhood.

BACKGROUND Predicting later outcome in neonates presenting with severe inborn errors of metabolism (IEM) is difficult. The assessment of the early motor repertoire is a reliable method of evaluating the integrity of the central nervous system in young infants. This method is based on an age-specific qualitative assessment of general movements (GMs, 0-8 weeks of age), fidgety movements (FMs) and the concurrent motor repertoire (9-20 weeks of age). AIM To determine the quality of the early motor repertoire (at 0-20 weeks post term age) in relation to later neurological outcome in infants with severe IEM. STUDY DESIGN Prospective cohort study. The quality of the motor repertoire was assessed from serial videotape recordings. SUBJECTS Five infants with IEM. Four presented with a severe IEM in the neonatal period: an undefined gluconeogenesis defect, propionic acidemia, arginosuccinate synthetase and arginosuccinate lyase deficiency. One neonate was antenatally diagnosed with arginosuccinate synthetase deficiency. OUTCOME MEASURES Outcome at the age of at least 18 m was determined by neurological examination and developmental tests. RESULTS All infants initially had abnormal GMs: hypokinesia, followed by GMs of a poor repertoire. The quality of the early motor repertoire normalised in 3 infants, and remained abnormal in 2. The more severe and persistent abnormalities of the motor repertoire were considered with the more abnormal neurological and developmental scores, later on. CONCLUSIONS The quality of the early motor repertoire might be related to later neurological outcome in infants with inborn errors of metabolism.