Patients with neurological conditions (TBI, Stroke, Cerebral Palsy, etc) may require specific orthoses to help achieve goals and assist in support of the resulting abnormal or increased muscle tone. These orthoses are designed to maintain muscle and soft tissue length and prevent joint contracture.
When working on these orthoses it’s important to know the following terms:
Hypertonicity or increased muscle tone is an increase in the normal muscle tension regardless of movement. Hypertonicity can lead to soft tissue contractures, muscle and tendon shortening and joint deformities. In someone who exhibits increased tone, the resistance you feel is independent of the speed at which you try to move the body part.
Increased flexor tone in the upper extremity presents as elbow flexion, forearm pronation, or wrist flexion and fingers curled into a fist.
Spasticity is a velocity-dependent increase in muscle tone in response to passive movement. For example, in an individual with spasticity, pulling the forearm away from the upper arm will be harder the faster you try to move it. Spasticity restricts active and passive motion in the agonist muscles.
Contractures and soft tissue shortening are often the end result of movement restrictions (spasticity, flexor tone, hypertonicity).
The Modified Ashworth Scale
The Modified Ashworth Scale is a way to grade the resistance of each joint during passive soft tissue stretching and is used as a measure of spasticity.
Resting Hand Orthosis
A resting hand orthosis typically positions the wrist in 20-30° of extension, the MCP joint in flexion of 35-45°, and the PIP and DIP joints in slight flexion and thumb in extension and 45° palmar abduction.
Anti-Deformity Position Orthosis
An anti-deformity position orthosis typically positions the wrist in 30-40° of extension, MCP joint flexion of 70-90°, fingers extended and thumb 40-45° degrees palmar abduction with IP in full extension. The above positioning may not be possible for individual clients. So it is ok to strive for the best positioning possible to achieve the stated goals of the orthotic intervention. It’s also important to note that the term “anti-spasticity orthosis” is a misnomer as the orthosis does not prevent spasticity. It simply manages contractures caused by spasticity.
Therapists must consider the following components of an intervention plan for management of the neurologically involved upper extremity:
- Promote muscle activity to avoid muscle atrophy
- Maintain elasticity of soft tissue through stretching
- Prevent joint contractures and tissue shortening- typically done with the use of orthoses
Not all clients with spasticity/increased muscle tone present in the exact same manner and not everyone requires an orthosis. It is our responsibility to set individual client goals and assist clients with abnormal or increased muscle tone. When identifying the components of an intervention plan, we must consider each client individually and consider the most appropriate orthosis in each case.
- Katalinic, O. M., Harvey, L. A., & Herbert, R. D. (2011). Effectiveness of stretch for the treatment and prevention of contractures in people with neurological conditions: a systematic review. Physical therapy, 91(1), 11-24.
- Bavikatte, G., Bavikatte, T. G. G., & Gaber, T. (2009). Approach to spasticity in General practice Approach to spasticity in General practice. British Journal of Medical Practitioners, 2(3).
- Kilbride, C., Hoffman, K., Tuckey, J., Baird, T., Marston, L., & De Souza, L. (2013). Contemporary splinting practice in the UK for adults with neurological dysfunction: A cross-sectional survey. International Journal of Therapy and Rehabilitation, 20(11), 559.