June 2011

Increased Muscle Belly and Tendon Stiffness in Patients with Parkinson’s Disease, as Measured by Myotonometry

Authors: Jarosław Marusiak, Anna Jaskólska, Sławomir Budrewicz, Magdalena Koszewicz, Artur Jaskólski

Affiliations: Department of Kinesiology, Faculty of Physiotherapy, University School of Physical Education, Wroclaw, Poland

Journal: Movement Disorders - September 2011, Volume 26, Issue 11, Pages 2119-2122 (DOI: 10.1002/mds.23841)

Based on Davis’s law, greater tonus of the muscle belly in individuals with Parkinson’s disease can create greater tension in the tendon, leading to structural adjustment and an increase in tendon stiffness. Our study aimed to separately assess passive stiffness in the muscle belly and tendon in medicated patients with Parkinson’s disease, using myotonometry.

We tested 12 patients with Parkinson’s disease and 12 healthy matched controls. Passive stiffness of muscle belly and tendon was estimated by myotonometry, electromyography, and mechanomyography in relaxed biceps and triceps brachii muscles.

Compared with controls, patients with Parkinson’s disease had higher stiffness in the muscle belly and tendon of the biceps brachii and in the tendon of the triceps brachii. In patients with Parkinson’s disease, there was a positive correlation between muscle belly stiffness and parkinsonian rigidity in the biceps brachii.

Patients with Parkinson’s disease have higher passive stiffness of the muscle belly and tendon than healthy matched controls.