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.

Muscle power development in preterm infants with periventricular flaring or leukomalacia in relation to outcome at 18 months.

Periventricular flaring (PVF) or periventricular leukomalacia (PVL) was diagnosed by brain ultrasound during the neonatal period in 44 infants (34 males, 10 females; mean gestational age 31 weeks 2 days, SD 2 weeks 1 day) admitted between 1995 and 1997. The infants were divided into three groups according to the severity of their condition. At 0, 3, and 6 months' corrected age an age-adequate neurological examination with special emphasis on the relation between active and passive muscle power was performed and symmetry between right and left sides was assessed. Results for the whole body, as well as for the shoulders, trunk, and legs were classified as optimal, suspect, or abnormal. Motor outcome at 18 months' corrected age was graded in the same way. An overall optimal muscle power regulation was found in one infant at 0, two at 3, and one at 6 months. Suspect outcome was found at all ages in the three groups. At 0 months muscle power regulation did not differ between the three groups. At 3 and 6 months overall poor muscle power, primarily caused by poor muscle power regulation in the shoulders and trunk, was found in infants with PVL grades III or IV. At 18 months' corrected age 24 infants showed no neurological impairment, eight infants had minor impairment, and 12 infants had severe impairment, including all 10 infants categorized as having PVL grades II or IV. The best predictors of impairment at 18 months were the combined results of muscle power in the shoulders and trunk at 3 months with those of the shoulders at 6 months.

Neuromotor function and school performance in 7-year-old children born as high-risk preterm infants.

Neuromotor behavior was studied in 63 children at a mean age of 7 years. They were born at a gestational age less than 32 weeks and/or birthweight under 1500 g and were categorized according to their medical history in conformance with the Neonatal Medical Index (from category I to V, from few to serious complications). We included only children considered at high risk as categorized in III to V. The neuromotor behavior study focuses on different subcategories, such as hand function, quality of walking, posture, passive muscle tone, coordination, and diadochokinesia. Hand preference and/or lateralization, the presence of associated movements, and/or asymmetry were noted, as was school performance. Then gender, gestational age, birthweight, and dysmaturity were investigated as confounding factors. The outcome at 7 years was correlated with the Neonatal Medical Index and the neonatal brain ultrasonography classification. None of the children scored 100% on the combined subcategories. Nineteen children (30%) had an overall score between 75 and 99%. Significant relationships between all different subcategories were found. Lack of hand preference, poor lateralization, and male gender were related to poor overall outcome. Poor motor control was correlated to special schooling and education below age level. The Neonatal Medical Index proved to have a significant influence on total outcome and the subcategories at the age of 7 years, with the worst outcome in children formerly classified in category V. Neuromotor behavior at 7 years of age was not related to birthweight, gestational age, dysmaturity, and neonatal brain ultrasonography classification only.

Muscle power development during the first year of life predicts neuromotor behaviour at 7 years in preterm born high-risk infants.

The aim of the study was to find if neurological function during the first year of life could predict neuromotor behaviour at 7 years of age in children born preterm with a high risk. A follow-up study of neuromotor behaviour in 52 children at a mean age of 3, 6, 12 months (corrected age) and 7 years was performed. All children were born with a gestational age less than 32 weeks and/or a birthweight under 1500 g and the infants were categorised according to their medical history in the three highest categories of the 'Neonatal Medical Index' (NMI, from category I to V, from few to serious complications). In addition, neonatal cerebral ultrasound abnormalities were used to divide the infants further into the different NMI categories. At 3 and 6 months, the relationship between active and passive muscle power was measured in shoulders, trunk and legs and (a)symmetry between right and left was noted. The results at 3 and 6 months were ranged from 1 for optimal to 5 for poor muscle power regulation. At 12 months of age, a neurological examination was done with special emphasis on the assessment of postural control, spontaneous motility, hand function and elicited infantile reactions with special attention to (a)symmetry. Outcome at 12 months was expressed as percentage of the optimal score on each subcategory. At 7 years, the motor behaviour study based on Touwen's examination for minor neurological dysfunction was performed. This investigation focuses on different functions, such as hand function, quality of walking, posture, passive muscle tone, coordination and diadochokinesis. The outcome was expressed as percentage of the optimal score on the combined subcategories. The best prediction of neuromotor behaviour at 7 years was assessed with stepwise linear multiple regression, using as potential predictors perinatal factors and outcome of motor behaviour at the corrected age of 3, 6 and 12 months. At 7 years none of the children scored 100% on the combined subcategories, 15 children (29%) scored between 75% and 99%, whereas 15 children scored less than 50%. Neuromotor behaviour at 7 years could be predicted by the NMI categorisation and gender with a sensitivity of 92% (specificity 47%; positive and negative predictive value 81% and 70%). No direct relation was found between neuromotor behaviour and cerebral ultrasound classification only, days on the ventilator and/or continuous positive airway pressure, birthweight, gestational age and dysmaturity. The best predictor of neuromotor behaviour at 7 years was the combination of outcome of muscle power in shoulders and legs at 3 months and postural control at 12 months, taking into account the gender of the child (sensitivity 95%; specificity 40%; positive predictive value 80%; negative predictive value 75%).