Is an instrumented spasticity assessment an improvement over clinical spasticity scales in assessing and predicting the response to integrated Botulinum Toxin-A treatment in children with Cerebral Palsy?
Archives of Physical Medicine and Rehabilitation vol:95 issue:3 pages:515-523
To compare (a) responsiveness and (b) predictive ability of clinical and instrumented spasticity assessments after Botulinum-Toxin-A (BTX) treatment combined with casting in the medial hamstrings (MEH) in children with spastic cerebral palsy (CP).
Prospective cohort study
31 children (40 MEH muscles) with CP, consecutive sample, requiring BTX injections.
Clinical and instrumented and spasticity assessments before and 53±14 days after BTX.
Main outcome measures:
Clinical spasticity scales included the Modified Ashworth Scale and the Modified Tardieu Scale. The instrumented spasticity assessment integrated biomechanical (position and torque) and electrophysiological (surface electromyography-sEMG) signals during manually-performed low- and high-velocity passive stretches of the MEH. Signals were compared between both stretch velocities and examined pre- and post-BTX. Responsiveness of clinical and instrumented assessments was compared by percentage exact agreement. Prediction ability was assessed with a logistic regression and the area under the Receiver Operating Characteristic (ROC) curves of the baseline parameters of responders versus non-responders.
Both clinical and instrumented parameters improved post-BTX (p≤0.005), though showed a low percentage exact agreement. The baseline Modified Tardieu Scale was the only clinical scale predictive for response (area under ROC curve=0.7). For the instrumented assessment, baseline values of root mean square (RMS) EMG and of torque were better predictors for a positive response (area under ROC curve=0.82). RMS-EMG remained an important predictor in the logistic regression.
The instrumented spasticity assessment showed higher responsiveness than the clinical scales. The amount of RMS-EMG is considered a promising parameter to predict treatment response.