A Comparative Study on the Neural and Mechanical Properties of Spastic Medial Gastrocnemius Muscle before and after Twelve Months of Illness in Patients with Stroke

Stroke is the most important cause of disability in adult people. Spasticity is a common motor disorder that develops secondary to upper motor neuron lesions such as stroke. Spasticity can cause changes in skeletal muscle, and affects both the neural and mechanical properties of skeletal muscles. The aim of this study was to compare neural and mechanical properties of spastic muscle between two groups of patients with stroke based on the duration of disease. In this study, 45 patients with stroke were divided into two groups of less and more than twelve months of stroke onset. Clinical assessment including muscle tone, achilles deep tendon reflex, and range of motion of ankle joint were measured using Modified Ashworth Scale, hammer, and goniometer, respectively. Neural properties, including H-reflex latency and Hmax/Mmax ratio, were acquired with electromyography (EMG) machine, and mechanical properties, including fascicle length, pennation angle, and muscle thickness in the spastic medial gastrocnemius muscle, were evaluated using ultrasonography instrument. To compare between two groups, we used t-test. Except for the duration of the disease (P < 0.001), there were not any significant differences in others parameters between the two groups. The results of this study showed that there was no significant difference in neural and mechanical parameters between the patients with stroke before and after 12 months of onset.