Article

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.
CI - Copyright (c) 2014 Elsevier B.V. All rights reserved.

Langue : ANGLAIS