Vestibulospinal component of postural control (vestibular function) in very preterm infants (25 to 27 weeks) at 3, 6, and 12 months corrected age

Postural control, which is important for the development of all movement, balance, and locomotion, depends a great deal on the vestibulospinal component of vestibular function in early childhood. Vestibulospinal input is important for muscle power regulation, which, in turn, influences postural control. The aim of this study was to focus particularly on this component of vestibular function during the first year of life in 67 infants with a very short gestational age (25-27 weeks), to search for possible neonatal confounders, and to see whether it influences the course of muscle power development in preterm infants. Outcome was described as being optimal, suspect, or abnormal. The infants were categorized into the Neonatal Medical Index according to the severity of neonatal illness and separately into three groups for neonatal brain ultrasonography findings (normal to severe abnormalities). At the age of 3 months, 20 infants performed optimally on all items testing vestibular function, increasing to 40 at 6 months and 48 at 12 months. This significant improvement (also seen in muscle power regulation) was primarily caused by better head control (during the traction response and prone position), whereas less shoulder retraction and hyperextension were found in the sitting position. Vestibular function was significantly related to brain ultrasonography classification but not to gestational age, birthweight, the Neonatal Medical Index, or gender.