Dorothee Zuleger, MOT, OTR/L, DRS
Thursday, November 21st, 2019
Following a stroke, abnormal muscle tone is a common complication. A single muscle or a muscle group may become completely paralyzed. This is known as hypotonic or flaccid or a muscle may increase in muscle tone. This is known as hypertonic or spastic. This abnormal tone usually occurs in the side of the body opposite to the side of the brain lesion.
Weakness or loss of movement in a limb are usually immediately apparent following a stroke and often contribute to decrease in active and passive range of motion. A decrease in range of motion can lead to joint contractures and soft tissue shortening. For example when the hand is closing into a fist.
Abnormal muscle tone also affects the ability to perform voluntary movements. An example we often see after a stroke is a stroke survivor lifting the entire shoulder toward the ear to elevate the affected arm when reaching forward or getting dressed. Some of the shoulder muscles are now more active, whereas others are much weaker now. This abnormal tone and movement often affects all activities of daily living.
Neurologist Vladimar Janda suggests that muscle imbalances and movement impairments follow predictable movement patterns, especially following an upper motor neuron lesion such as a stroke. The predictable movement patterns include tight flexor muscles and weak extensor muscles. After a stroke, muscle tone often starts to increase slowly, continues to increases, then, with time and treatment tone can decrease again. These predictable changes in movement and tone are described in the Brunnstrom Stages of Recovery.
During stroke recovery, it is important to prevent the overactive muscle from getting to tight and the soft tissue from shortening. Regular stretching, weightbearing, and splinting can be beneficial and help to maintain a good position of the affected limb. Other treatments such as Botox injections or oral medications can also help to decrease the abnormal tone and movement patterns. Moving the weakened muscle voluntarily or with use of electrical stimulation will help prevent muscle atrophy.
The goal of a skilled clinician is to assist a person return to a normal movement pattern by activating and strengthening the weaker muscles and turning off or inhibiting the spastic muscles. For example, in order for a person to get their arm through a shirt, the clinician may perform weightbearing to relax the biceps and the use electrical stimulation on the triceps. Thus making getting dressed easier and more successful.