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Stiff-person syndrome

Stiff-person syndrome is a rare, progressive neurological disorder. Symptoms may include:

  • Stiff muscles in the trunk (torso), arms, and legs
  • Greater sensitivity to noise, touch, and emotional distress, which can set off muscle spasms

Over time people with stiff-person syndrome may develop hunched over postures. Some people may be too disabled to walk or move. Many fall frequently because they do not have the normal reflexes to catch themselves. This can lead to serious injuries. People with stiff-person syndrome may be afraid to leave the house because street noises, such as the sound of a car horn, can trigger spasms and falls.

Who is more likely to get stiff-person syndrome?

  • Stiff-person syndrome affects twice as many females as males.
  • It is frequently associated with other autoimmune diseases such as type-I diabetes, thyroiditis, vitiligo, and pernicious anemia.
  • Scientists don't yet understand what causes stiff-person syndrome, but research indicates that it is the result of an autoimmune response gone awry in the brain and spinal cord.

How is stiff-person syndrome diagnosed and treated?

Diagnosing stiff-person syndrome. Stiff-person syndrome is often misdiagnosed as Parkinson disease, multiple sclerosis, fibromyalgia, psychosomatic illness, or anxiety and phobia. A definitive diagnosis can be made with a blood test that measures the level of glutamic acid decarboxylase (GAD) antibodies.

Most people with stiff-person syndrome have elevated (higher) levels of GAD antibodies. Antibody titers are important for the diagnosis of stiff-person syndrome. A titer is a laboratory test that measures the presence and amount of antibodies in blood. Elevated GAD titers, up to 10 times above normal, also are seen in diabetes but in stiff-person syndrome the titers are very high (at least 10 times above the range seen in diabetes) or are present in the spinal fluid.

Treating stiff-person syndrome. With appropriate treatment, stiff-person syndrome symptoms may be kept under control. Several symptoms improve with oral diazepam (an anti-anxiety and muscle relaxant drug) or with drugs that alleviate muscle spasms, such as baclofen or gabapentin.

A study funded by the National Institute of Neurological Disorders and Stroke (NINDS) showed that intravenous immunoglobulin (IVIg) treatment is effective in reducing stiffness, sensitivity to noise, touch, and stress and for improving gait and balance for people with stiff-person syndrome. IVIg contains immunoglobulins (natural antibodies produced by the immune system) derived from thousands of healthy donors.

How can I or my loved one help improve care for people with stiff-person syndrome?

Consider participating in a clinical trial so clinicians and scientists can learn more about stiff-person syndrome 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 stiff-person syndrome at

Where can I find more information about stiff-person syndrome?

The following organization may have resources that can help:

Genetic and Rare Diseases (GARD)

Content source: Accessed June 29, 2023.

The information in this document is for general educational purposes only. It is not intended to substitute for personalized professional advice. Although the information was obtained from sources believed to be reliable, MedLink, its representatives, and the providers of the information do not guarantee its accuracy and disclaim responsibility for adverse consequences resulting from its use. For further information, consult a physician and the organization referred to herein.

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