Hypertonia

Hypertonia is a condition in which there is too much muscle tone. For instance, arms or legs are stiff and hard to move. Muscle tone is controlled by signals that travel from the brain to the nerves and tell the muscle to contract. Hypertonia happens when the regions of the brain or spinal cord that control these signals are damaged. This can occur for many reasons, such as:

• A blow to the head
• Stroke
• Brain tumor
• Toxin that affects the brain

• Neurodegenerative processes such as in multiple sclerosis or Parkinson's disease
• Neurodevelopmental abnormalities such as cerebral palsy

Hypertonia often limits how easily the joints can move. If it affects the legs, walking can become stiff and people may fall because it is hard for the body to react quickly enough to regain balance. If hypertonia is severe, it can cause a joint to become "frozen," which is called a joint contracture.

Spasticity is a term that is often used interchangeably with hypertonia. Spasticity, however, is a type of hypertonia in which muscles spasms are increased by movement. In this type, people usually have exaggerated reflex responses.

Rigidity is another type of hypertonia in which the muscles have the same amount of stiffness separate from the degree of movement. Rigidity usually occurs in diseases such as Parkinson's disease that involve the basal ganglia, a deep region of the brain. To know which type of hypertonia someone has, healthcare providers will ask the individual to relax and then will move the arm or leg at different speeds and in different directions.

Treatment

People with hypertonia should try to keep moving by exercising within their limits and doing physical therapy. There are also a range of treatment options:

• Muscle relaxing drugs such as baclofen, diazepam, and dantrolene may be prescribed to reduce spasticity. All of these drugs can be taken by mouth, but baclofen may also be injected directly into the cerebrospinal fluid through an implanted pump.
• Botulinum toxin is often used to relieve hypertonia in a specific area of the body because its effects are local, not body-wide.
• Drugs that affect the dopamine system such as levodopa/carbidopa, or entacapone, are often used to treat the rigidity associated with Parkinson's disease because dopamine is a chemical in the brain that sends messages between nerve cells.

Outlook

The prognosis for people with hypertonia depends upon how severe it is and the cause. In some cases, such as cerebral palsy, the hypertonia may not change over the course of a lifetime. In other cases, it may worsen along with the underlying disease.

• Mild hypertonia has little or no effect on a person's health.
• Moderate hypertonia can cause falls or joint contractures that can affect a person's health and safety.
• Severe hypertonia can cause immobility, leading bones to become fragile and fracture. It can also lead to infection, bed sores, and pneumonia.

How can I or my loved one help improve care for people with hypertonia?

Consider participating in a clinical trial so clinicians and scientists can learn more about hypertonia and related disorders. Clinical research uses human volunteers to help researchers learn more about a disorder and perhaps find better ways to safely detect, treat, or prevent disease.

All types of volunteers are needed—those who are healthy or may have an illness or disease—of all different ages, sexes, races, and ethnicities to ensure that study results apply to as many people as possible, and that treatments will be safe and effective for everyone who will use them.

For information about participating in clinical research visit NIH Clinical Research Trials and You. Learn about clinical trials currently looking for people with hypertonia at Clinicaltrials.gov.

Where can I find more information about hypertonia?

The following organizations and resources help individuals, families, friends, and caregivers of people living with hypertonia:

Cerebral Palsy Foundation
Phone: 212-520-1686

Christopher and Dana Reeve Foundation
Phone: 973-379-2690 or 800-225-0292

Dystonia Medical Research Foundation
Phone: 312-755-0198

Content source: https://www.ninds.nih.gov/health-information/disorders/hypertonia Accessed June 23, 2023.

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