The influence of postural control on motility and hand function in a group of 'high risk' preterm infants at 1 year of age.

The functional outcome of a group of 75 'high-risk' preterm infants was studied at the corrected age of 12 months. Only infants with high-risk for developmental deviance with gestational ages below 32 weeks and/or birthweights less than 1500 g were included in the study. Additionally the infants were categorised according to their medical history conforming with the 'Neonatal Medical Index' (NMI I to V), with category I describing infants with few medical problems and V characterizing those with the most serious complications. In this study we included only infants with 'high-risk' as categorised in NMI III to V, since infants with 'low-risk' have been described earlier. Infants with cerebral ultrasonographic abnormalities were incorporated into the NMI categories, but also analysed separately to compare outcomes. At 12 months (corrected age) apart from pediatric follow-up, a full neurological assessment was done with emphasis on postural control, spontaneous motility and hand function. Special attention was given to symmetrical development. The infants were then categorised as having optimal, non-optimal or asymmetrical outcomes. An overall optimal outcome on postural control was found in 64% of all infants (67% in NMI III, 60% in NMI IV and 62.5% in NMI V). Too much extension interfering with postural control was found significantly more often in infants in NMI V (15%), compared to infants in NMI IV (8%) and NMI III (4.5%). Poor postural control had a significant influence on other domains of development such as motility (P=0.00), asymmetry (P=0.00) and hand function (P=0.00). Cerebral ultrasonographic abnormalities seemed to have an influence on motility (P=0.03), while no direct relationship was found with postural control, hand function or asymmetry. It is unclear whether this poor coordination of gross motor function will have consequences for appropriate visual-motor and sensorimotor integration therewith hampering later cognitive function, as often described in preterm infants. It is suggested that the poor postural control found in many infants is the result of both myogenic and/or neurogenic deviations and associated with cerebral pathology, but is also caused by the preterm birth and its nursing consequences.