Identification of the neural component of torque during manually-applied spasticity assessments in children with cerebral palsy

L. Bar-On, K. Desloovere, G. Molenaers, J. Harlaar, T. Kindt, E. Aertbelien

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28 Citations (Scopus)


Clinical assessment of spasticity is compromised by the difficulty to distinguish neural from non-neural components of increased joint torque. Quantifying the contributions of each of these components is crucial to optimize the selection of anti-spasticity treatments such as botulinum toxin (BTX). The aim of this study was to compare different biomechanical parameters that quantify the neural contribution to ankle joint torque measured during manually-applied passive stretches to the gastrocsoleus in children with spastic cerebral palsy (CP). The gastrocsoleus of 53 children with CP (10.9. ±. 3.7. y; females n= 14; bilateral/unilateral involvement n= 28/25; Gross Motor Functional Classification Score I-IV) and 10 age-matched typically developing (TD) children were assessed using a manually-applied, instrumented spasticity assessment. Joint angle characteristics, root mean square electromyography and joint torque were simultaneously recorded during passive stretches at increasing velocities. From the CP cohort, 10 muscles were re-assessed for between-session reliability and 19 muscles were re-assessed 6 weeks post-BTX. A parameter related to mechanical work, containing both neural and non-neural components, was compared to newly developed parameters that were based on the modeling of passive stiffness and viscosity. The difference between modeled and measured response provided a quantification of the neural component. Both types of parameters were reliable (ICC. >. 0.95) and distinguished TD from spastic muscles (p<. 0.001). However, only the newly developed parameters significantly decreased post-BTX (p= 0.012). Identifying the neural and non-neural contributions to increased joint torque allows for the development of individually tailored tone management. © 2014 Elsevier B.V.
Original languageEnglish
Pages (from-to)346-351
JournalGait and Posture
Issue number3
Publication statusPublished - 2014

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