Muscle Rigidity After Stroke

Muscle rigidity, or hypertonia, occurs when there is too much muscle tone and the arms or legs become stiff and difficult to move. Muscle tone is determined by signals that travel from the brain to the nerves letting the muscles know when they need to contract.

When the regions in the brain or spinal cord responsible for controlling these signals are damaged, muscle rigidity occurs.

Hypertonia can occur for many reasons, including stroke, brain tumor, brain trauma, Parkinson's disease, multiple sclerosis, neurodevelopmental abnormalities (such as cerebral palsy) or toxins that affect the brain.

How Muscle Rigidity Affects Stroke Patients

Muscle rigidity often limits the movement of the joints, making it difficult for limbs to move normally.

It can affect different parts of the body. If it affects the legs, the person’s gait becomes stiff and causes problems maintaining a sense of balance, resulting in falls.

Severe cases can cause joints to become set in place, or “frozen,” also known as joint contracture.

Hypertonia is sometimes referred to as spasticity, however, spasticity is a specific type of hypertonia where muscle spasms are increased by movement. Patients with spasticity tend to have exaggerated reflex responses.

In rigidity, another type of hypertonia, the muscles have the same level of stiffness, independent of the degree of movement. Rigidity typically occurs in diseases that involve the basal ganglia region of the brain, such as Parkinson disease.

Exercise

While muscle rigidity makes movement more difficult, exercise can help people with hypertonia to preserve as much movement as possible and improve the quality of life.

Rehabilitative treatment and physical therapy focusing on a range of motion exercises and active stretching exercises can help to improve hypertonia. Occupational therapy can also help patients regain and maintain activities of daily living and quality of life.

Medications

Oral medication, focal injections, and physical therapy are prescribed to help reduce the symptoms of hypertonia and improve active and passive functioning.

Muscle relaxing drugs such as diazepam, dantrolene, and baclofen may be prescribed as an oral medication, although baclofen may also be administered as an injection into the cerebrospinal fluid through a pump.

Botulinum toxin, or Botox, is also used to relieve hypertonia in specific regions because its effects are localized and do not impact the whole body.

Electric Stimulation for Rigidity

For several years, neuromuscular electric stimulation (NMES) has been used to treat stroke patients with muscular rigidity. The treatment involves the use of a device that uses electrodes to transmit an electrical impulse to the skin over selected muscle groups. The NMES, a therapeutic device designed for home use, causes muscles to contract as a form of exercise or physical therapy.

A 2015 meta-analysis of 29 studies found NMES treatment reduced spasticity and increased range of motion compared to a control group. The study authors concluded the treatment should be included along with other modalities to help patients with muscle rigidity.