Analysis of movement quality in preterm infants

Is it possible to predict the infant's neurodevelopmental outcome at 14 months of age by means of a single preterm assessment of General Movements?

BACKGROUND

It continues to be a challenge for clinicians to identify preterm infants likely to experience subsequent neurodevelopmental deficits. The Test of Infant Motor Performance (TIMP) and the assessment of spontaneous general movements (GMs) are the only reliable diagnostic and predictive tools for the functionality of the developing nervous system, if applied before term.

AIM

To determine to what extent singular preterm assessments of motor performance can predict the neurodevelopmental outcome in 14-month olds.

METHODS

Thirty-seven preterm infants born <34weeks gestational age were recruited for the study at the NICU of the São Lucas University Hospital, Porto Alegre, RS, Brazil. At 34weeks, their GMs were assessed; and the Test of Infant Motor Performance (TIMP) was applied. A prospective design was used to examine (A) the association between the GM assessment and the TIMP; and (B) the relation between GMs or the TIMP and the developmental status at 14months, assessed by means of Alberta Infant Motor Scales (AIMS) and the Pediatric Evaluation of Disability Inventory (PEDI).

RESULTS

Nineteen infants (41%) had abnormal GMs; only one scored within the TIMP average range. Hence, GMs and TIMP were not related. Children with cramped-synchronized GMs at 34weeks preterm had a lower AIMS centile rank than those with poor repertoire or normal GMs. There was a marginal association between cramped-synchronized GMs and a lower PEDI mobility score.

CONCLUSIONS

A single preterm GM assessment is only fairly to moderately associated with the 14-month motor development. The TIMP is not suitable as a complementary assessment tool at such a young age.

Functional magnetic resonance imaging of the sensorimotor system in preterm infants

OBJECTIVE

Preterm birth at <32 weeks' gestational age has a specific predilection for periventricular white matter injury. Early prediction of concomitant motor sequelae is a fundamental clinical issue. Recently, functional MRI was introduced as a noninvasive method for investigating the functional integrity of the neonatal brain. We aimed at implementing a unilateral passive forearm extension/flexion functional MRI paradigm in a routine clinical MRI setup to allow noninvasive mapping of the sensorimotor system in preterm infants and to relate the functional data to structural and behavioral data.

PATIENTS AND METHODS

Eight patients (median gestational age: 26.5 weeks; median birth weight: 885 g) were included. The functional MRI was performed at term-equivalent age (median: 39 weeks' postconceptional age) under chloral hydrate (50 mg/kg) sedation. In 5 of 8 patients, functional MRI data acquisition was successful. This resulted in 10 functional data sets (5 for passive stimulation of each forearm).

RESULTS

Unilateral stimulation was associated with mainly bilateral activation of the primary sensorimotor cortex (n = 7 of 10 data sets), the prevailing hemodynamic response being a negative blood oxygenation level-dependent signal. Positive blood oxygenation level-dependent response or failure to activate the sensorimotor cortex (n = 3 of 10 data sets) were seen in those patients with aberrant structural/behavioral indices.

CONCLUSIONS

Our data show the feasibility of passive unilateral sensorimotor stimulation during neonatal clinical MRI protocols. The bilateral activation pattern observed at this age is compatible with a bilaterally distributed sensorimotor system. Our data validate initial accounts for a raised incidence of negative blood oxygenation level-dependent responses in the primary sensorimotor cortex at this developmental stage. The negative blood oxygenation level-dependent response is likely to reflect a reduction of the oxy/deoxy-hemoglobin ratio during a maturational stage characterized by rapid formation of synapses, yet ineffective processing. Positive blood oxygenation level-dependent responses or failure to activate the sensorimotor cortex may be an early indicator of abnormal development and will have to be followed up carefully.

Movement, imaging and neurobehavioral assessment as predictors of cerebral palsy in preterm infants

OBJECTIVE

To study the relative efficacy of three early predictors of cerebral palsy.

METHOD

One Hundred and thirty infants with birth weight <1500 g were recruited. Video recordings of spontaneous general movements were made at 36 and 52 weeks postconceptional age. Magnetic resonance imaging and the neurobehavioral assessment of the preterm infant were done at 36 weeks postconceptional age. Follow-up neurological examination and Bayley assessments were made at 18 months corrected age to make early identification of cerebral palsy.

RESULTS

Magnetic resonance imaging gave the best specificity and accuracy of 91 and 84% respectively. General movements at 52 weeks showed an improved specificity and accuracy over performance at 36 weeks postconceptional age. The negative predictive value for all methods tested was between 90 and 97%. Combining the results of magnetic resonance imaging and the neurobehavioral assessment improved the sensitivity of prediction to 80%, suggesting that a holistic approach to early detection of cerebral lesions is preferable to a single test.

CONCLUSIONS

The majority of infants who appeared to behave within normal limits and exhibit normal brain structure in the newborn period were classified as neurologically intact at follow-up.

Does a detailed assessment of poor repertoire general movements help to identify those infants who will develop normally?

BACKGROUND

The assessment of the quality of general movements (GMs) in young infants is a reliable and valid diagnostic tool for detecting brain dysfunction early in life. Poor repertoire GMs are the most frequently observed abnormal GMs during the preterm, term and early postterm period. However, their predictive value for the neurological outcome is low.

AIM

To find out whether a detailed scoring of poor repertoire GMs might lead to a better prediction of the neurological outcome.

SUBJECTS

We studied 18 preterm infants who were repeatedly videoed from birth to 22 weeks postterm age, including several recordings assessed as poor repertoire GMs. At 8 to 10 years, six children were neurologically normal, six had mild neurological abnormalities, and the remaining six were classified as cerebral palsy.

STUDY DESIGN

Each GM globally assessed as poor repertoire was scored in details according to several aspects of neck and trunk, arm and leg movements applying Prechtl's optimality concept.

RESULTS

By and large, the detailed score of poor repertoire GMs was not related to the neurological outcome.

CONCLUSION

For the clinical application of the GM assessment, it remains important to assess the fidgety movements of those infants with poor repertoire GM trajectories in order to predict their outcome.

The General Movements in children with Down syndrome

OBJECTIVE

Aim of our study was to describe the character of General Movements (GMs) in children with Down Syndrome (DS).

MATERIAL AND METHODS

GMs of 23 children with DS and of 30 healthy full-term infants were assessed from birth to 6th month corrected age. A qualitative and a semi-quantitative evaluation of GMs were achieved for each child. Data were graphically displayed to obtain growth curves of motor optimality scores.

RESULTS

GMs in children with DS are characterised by low-low/moderate speed, large-large/moderate amplitude, partially creating impression of fluency, smoothness and complexity, abrupt beginning and end, few other concurrent gross movements. During the 6 months, all children showed an improvement of qualitative and semi-quantitative evaluation, but it was possible to observe great heterogeneity among children in the evolutionary course. GMs evaluation of children with no known motor problems was normal, showing only slight and transient abnormalities at first months.

CONCLUSION

GMs character of children with DS could be related to central nervous system and peripheral abnormalities characterizing this syndrome. The evaluation of GMs in children with DS could be an early marker of motor impairment and help in early management decisions making.