Spastic cocontraction in Hemiparesis. Effects of Botulinum Toxin

I really don't care about their use of botox. But they did come up with an objective way to measure spasticity.  Which needs to be utilized when testing spasticity protocols, the manual testing of when your muscle 'catches' has got to stop.
http://onlinelibrary.wiley.com/doi/10.1002/mus.23427/abstract

Abstract

Introduction:

In this study of spastic hemiparesis we evaluated cocontraction during sustained agonist/antagonist efforts, before and after botulinum toxin (BoNT) injection in one agonist.

Methods:

Nineteen hemiparetic subjects performed maximal isometric elbow flexion/extension efforts with the elbow at 100° (extensors stretched). Using flexor and extensor surface electromyography we calculated Agonist Recruitment/Cocontraction Indices from the 500ms peak voluntary agonist recruitment, before and one month after onabotulinumtoxinA injection (160U) into biceps brachii.

Results:

Before injection, Agonist Recruitment and Cocontraction Indices were higher in extensors than flexors (resp. 0.74±0.15 vs 0.59±0.10, p<0.01; 0.43±0.25 vs 0.25±0.13, p<0.05). Biceps injection decreased extensor cocontraction index (-35%, p<0.05) while increasing flexor agonist recruitment and cocontraction indices.

Discussion:

In spastic hemiparesis, stretch may facilitate agonist recruitment and spastic cocontraction. In the non-injected antagonist, cocontraction may be reduced by enhanced reciprocal inhibition from a more relaxed and therefore stretched agonist or through decreased recurrent inhibition from the injected muscle.