Janny F. Samsom

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. (J Child Neurol 2002;17:325-332).

Muscle power in "high-risk" preterm infants at 12 and 24 weeks corrected age:a measure for early detection

A group of 72 “high‐risk” preterm infants was studied at the corrected ages of 12 and 24 wk. Only infants with a high risk for developmental deviance with gestational ages below 32 wk and/or birthweights of less than 1500 g were included in the study. In addition, the infants were categorized according to their medical history, as confirmed by 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 “high‐risk” infants as categorized in NMI III to V, since infants with a “low risk” have been described earlier. Apart from the standard paediatric follow‐up, an age‐adequate neurological assessment was made, with special emphasis on the relationship between active and passive muscle power. When development is optimal, these two components of muscle power should be in balance in order to create a stable posture and fluent motility. We compared muscle power at the corrected ages of 12 and 24 wk to determine whether the method employed to assess muscle power could enhance early detection of deviant development. At 12 wk of age, only 5 infants showed overall optimal muscle power, while at 24 wk this figure had increased to 27. Significantly more infants in NMI III had optimal outcomes at 24 wk of age. When muscle power in the different parts of the body was studied separately at 24 wk, outcomes in shoulders and trunk still showed significant discrepancies in all NMI groups. At this age, fewer asymmetries were found compared to outcomes at 12 wk.

Study of a group of extremely preterm infants (25-27 weeks): how do they function at 1 year of age?

The functional outcome of 49 extremely preterm infants (gestational age: 25—27 weeks) was studied at the corrected age of 12 months. Apart from pediatric follow-up, a full neurologic assessment and the Bayley Motor and Mental Scales of Infant Development was done. Emphasis was placed on postural control, spontaneous motility, hand function, and elicited infantile reactions. Special attention was given to symmetric development. The infants were then categorized as having optimal or nonoptimal or asymmetric outcome. Overall, an optimal outcome was found in 19 infants (39%) and nonoptimal outcome in 30 infants (61%), 7 of whom failed on all domains of function. Postural control had a significant influence on the different domains of development such as motility (P ≤ .001) and persistent infantile reactions (P ≤ .001) and slightly less on hand function (P = .08) and asymmetry (P = .06). The outcome on spontaneous motility was significantly related to the results on infantile reactions (P ≤ .005) and hand function (P = .05). Also, the score on the motor scale of the Bayley Developmental test was clearly related to outcome on spontaneous motility (P ≤ .001) and reactions ( P ≤ .02). Abnormal brain ultrasonograms were related to the asymmetry of the infantile reactions (P ≤ .05). Poor coordination of gross motor function will have consequences for appropriate visuomotor and sensorimotor integration, thereby hampering motor learning and later cognitive function, as is often described in preterm infants. It is suggested that the poor postural control found in many infants born preterm is the result of both myogenic and neurogenic deviations caused by the preterm birth and its nursing consequences. (J Child Neurol 2001;16:832—837).

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. (J Child Neurol 2004;19:614-618).

De neuromotore ontwikkeling van het prematuur geboren kind: diagnostiek en interventie

Het motorisch gedrag van het jonge kind kan worden gezien als een afspiegeling van zijn neurologisch functioneren. Nauwkeurige observatie van de spontane motoriek maar ook de alertheid en gedragsregulatie van het prematuur geboren kind zijn prognostisch van grote betekenis. De manier en vooral de kwaliteit waarmee het kind reageert op diverse uitgelokte stimuli zijn een aanwijzing voor zijn latere functioneren. Vroege opsporing van stoornissen in de motoriek geven ons de mogelijkheid om eventueel te intervenieren in een periode waarin het goed mogelijk is de ontwikkeling te beinvloeden. Een goed gestructureerde follow-up van kinderen met een verhoogd risico is daarom noodzakelijk. In dit artikel worden de verschillende motorische tests kort besproken. Vroegtijdige interventie kan corrigerend, ondersteunend en preventief werken in een poging deviaties van de motoriek te voorkomen of te miniseren.SummaryThe motor behavior of the young infant should be regarded as a reflexion or representation of the nervous system. Close observation of spontaneous movements and also the reaction to elicited movements can give the experienced examiner an impression of the well being and neurological functioning of the infant.The assessment and study of motor development is a sensitive parameter to identify infants at risk for developmental deviances. Well regulated and structured follow-up of preterm infants is essential for early recognition and intervention. In this paper different assessments, tests and screening methods used in the Netherlands are discussed and early intervention techniques are presented.SamenvattingHet motorisch gedrag van het jonge kind kan worden gezien als een afspiegeling van zijn neurologisch functioneren. Nauwkeurige observatie van de spontane motoriek maar ook de alertheid en gedragsregulatie van het prematuur geboren kind zijn prognostisch van grote betekenis. De manier en vooral de kwaliteit waarmee het kind reageert op diverse uitgelokte stimuli zijn een aanwijzing voor zijn latere functioneren. Vroege opsporing van stoornissen in de motoriek geven ons de mogelijkheid om eventueel te interveniëren in een periode waarin het goed mogelijk is de ontwikkeling te beïnvloeden. Een goed gestructureerde follow-up van kinderen met een verhoogd risico is daarom noodzakelijk. In dit artikel worden de verschillende motorische tests kort besproken. Vroegtijdige interventie kan corrigerend, ondersteunend en preventief werken in een poging deviaties van de motoriek te voorkomen of te miniseren.