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Postural control deficits have been suggested to be a major component of gait disorders in cerebral palsy (CP). Standing balance was investigated in 23 ambulatory children and adolescents with spastic diplegic CP, ages 5 to 18 years, and compared with values of 92 children without disability, ages 5 to 18 years, while they stood on a force plate with eyes open or eyes closed. The measurements included center of pressure calculations of path length per second, average radial displacement, mean frequency of sway, and Brownian random motion measures of the short-term diffusion coefficient, and the long-term scaling exponent. In the majority of children with CP (14 of 23) all standing balance values were normal. However, approximately one-third of the children with CP (eight of 23) had abnormal values in at least two of the six center of pressure measures. Thus, mean values for path length, average radial displacement, and diffusion coefficient were higher for participants with CP compared with control individuals with eyes open and closed (p<0.05). Mean values for frequency of sway and the long-term scaling exponent were lower for participants with CP compared with control participants (p<0.05). Increased average radial displacement was the most common (nine of 23) postural control deficit. There was no increase in abnormal values with eyes closed compared with eyes open for participants with CP, indicating that most participants with CP had normal dependence on visual feedback to maintain balance. Identification of those children with impaired standing balance can delineate factors that contribute to the patient's gait disorder and help to guide treatment.

SUMMARY Energy expenditure indices (EEI) based on oxygen uptake and heart rate were used to compare the economy of walking at various speeds by normal and cerebral‐palsied children. At low walking speeds, EEI values were high, indicating poor economy. At higher speeds the EEI values decreased until a range of maximum economy was reached. For normal children who were capable of walking beyond this range at higher speeds, the EEI increased again. This pattern was noted for both oxygen‐uptake and heart‐rate indices. Mean EEI values based on oxygen uptake and heart rate for normal children were significantly lower and occurred at faster walking speeds than values for children with cerebral palsy. EEI based on either oxygen uptake or heart rate can be used clinically to provide objective information to help evaluate the influence on gait function of surgical intervention, ambulatory aids or orthotics. RÉSUMÉ Index d'économie énergétique de la marche chez les enfants normaux et IMC Les indices de l'économie énergétique (EEI) basés sur la consommation d'oxygène et le rythme cardiaque ont été utilisés pour comparer l'économie de marche à vitesses variées chez l'enfant normal et IMC. A faible vitesse, les valeurs EEI étaient élevées, indiquant une économie médiocre. A vitesses plus élevées, les valeurs EEI décroissaient jusqu'à un niveau d'économie optimale. Pour les enfants normaux capables de vitesses de marche au delà de cet optimum, l'EEI s'accroissait. Cette distribution était observée aussi bien pour la consommation d'oxygène que le rythme cardiaque. Les valeurs moyennes EEI de consommation d'oxygène et de rythme cardiaque étaient significativement plus basses et apparaissaient à des vitesses plus élevées chez les enfants normaux par rapport aux valeurs des enfants IMC. L'EEI basée sur la consommation d'oxygène ou le rythme cardiaque est bien adaptée à la clinique et peut être utilisée pour fournir des informations objectives aidant à évaluer l'influence des interventions chirurgicales, des aides de marche ou des appareillages sur la fonction de marche. ZUSAMMENFASSUNG Energieumsatzindex beim Laufen bei gesunden Kindern und Kindern mit Cerebralparese Der Energieumsatzindex (EEI), basierend auf Sauerstoffverbrauch und Herzfrequenz, wurde herangezogen, um die Energieausnutzung beim Laufen mit verschiedenen Geschwindigkeiten bei gesunden und cerebralparetischen Kindern zu vergleichen. Bei niedrigen Geschwindigkeiten waren die EEI‐Werte hoch, was für eine schlechte Energieausnutzung sprach. Bei höheren Geschwindigkeiten fielen die EEI‐Werte ab, bis ein Bereich der maximalen Ausnutzung erreicht war. Bei den gesunden Kindern, die in der Lage waren, diesen Bereich mit höheren Geschwindigkeiten zu überschreiten, stieg der EEI an. Dieser Verlauf wurde sowohl für den Sauerstoffverbrauch als auch für die Herzfrequenz festgestellt. Die mittleren EEI‐Werte, basierend auf Sauerstoffverbrauch und Herzfrequenz waren für gesunde Kinder signifikant niedriger und traten bei höheren Geschwindigkeiten auf, als die Werte für die cerebral...

Summary:We performed a histologic and morphometric study of spastic muscle from 10 children with diplegic cerebral palsy, comparing muscle structure with the gait parameters of energy expenditure index and dynamic electromyography. Variations in fiber area within and between fiber types were increased significantly in children with cerebral palsy. In each of the control subjects, the combined coefficient of variation for type-1 and type-2 fiber area was less than 25% and the average was 17%; in the subjects with cerebral palsy, the combined coefficient of variation was more than 25% and the average was 36% (p 5 0.004). The average difference between the mean area of type-1 and type-2 fibers was 26.7 f 18.9% for subjects with cerebral palsy and 4.2 k 2.4% for control subjects (p I 0.004). There was a 67% predominance of one fiber type in the subjects with cerebral palsy compared with a 55% predominance in the control subjects (p 5 0.03). The difference between the total area of type-1 and type-2 fibers was 57% in the subjects with cerebral palsy and 17% in the control subjects (p 5 0.002). There was a significant correlation between the combined coefficient of variation of fiber area and the energy expenditure index (r = 0.77, p 50.03). The difference between the mean area of type-1 and type-2 fibers correlated with prolongation of electromyographic activity (r = 0.69, p $0.05). No abnormalities in fiber ultrastructure were found in the subjects with cerebral palsy. Children with cerebral palsy had abnormal variation in the size of muscle fibers and altered distribution of fiber types. The values for variation in fiber area correlated with the energy expenditure index and with prolongation of electromyographic activity during walking.Skeletal muscle adapts to changes in activity level and to habitual exercise by altering both structure and function (5,7,24). Because children with musculoskeletal disabilitites are less mobile than other children, it is reasonable to assume that at least one adaptation would be atrophy of the muscle fibers.However, children with cerebral palsy routinely experience excessive and prolonged muscle contraction (12,36). The purpose of this investigation was to examine the histochemistry and ultrastructure of spastic muscle from children with cerebral palsy and to evaluate the relationship of the size, type, and distribution of muscle fibers to the energy expenditure index and dynamic electromyographic activity during walking.