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Stiff Person Syndrome

Stiff Person Syndrome Overview

Stiff person syndrome is a progressive neurological disorder characterized by episodes of muscle stiffness and painful muscle spasms. These spasms may occur randomly or be triggered by stimuli, such as noise, physical touch, or emotional distress. They may involve the entire body or only a specific area. 

Stiff person syndrome has features of an autoimmune disease. Many of the individuals affected have antibodies to glutamic acid decarboxylase (GAD), a protein that is involved in making gamma aminobutyric acid (GABA). GABA is a neurotransmitter that helps control muscle movements. People may develop stiff person syndrome when the immune system mistakenly attacks the nerve cells that produce GAD, leading to a deficiency of GABA in the body. 

elderly hands

Symptoms of Stiff Person Syndrome

Symptoms of stiff person syndrome include:

  • Difficulty walking
  • Falling while walking or standing
  • Hunched posture
  • Recurrent episodes of muscle stiffness (rigidity), particularly in the trunk and limbs
  • Painful muscle spasms that can be prolonged, forceful, and triggered by stimuli

Treatments for Stiff Person Syndrome

Without treatment, muscle spasms and rigidity can progress into challenges with walking and performing other everyday tasks. Medications such as benzodiazepines, which are GABA receptor agonists, can help treat muscle stiffness and episodic spasms. Baclofen, a muscle relaxer, may be prescribed in conjunction with benzodiazepines. 

People with stiff person syndrome may also find relief from conservative therapies such as stretching, heat therapy, aqua therapy, massage therapy, and acupuncture.

Studies have shown that intravenous immunoglobulin may also be an effective treatment for stiff person syndrome, although more research is needed.

Additional Information on Stiff Person Syndrome

How common is stiff person syndrome?

Stiff person syndrome is extremely rare. It affects an estimated 1 in 1 million people. However, some cases of stiff person syndrome may be misdiagnosed as Parkinson’s disease, multiple sclerosis, fibromyalgia, psychosomatic illness, anxiety, or a phobia. 

Who gets stiff person syndrome?

Stiff person syndrome affects twice as many women as men. Most people begin experiencing symptoms between the ages of 30 and 60.

Stiff person syndrome is frequently associated with other autoimmune diseases, such as:

  • Diabetes
  • Pernicious anemia
  • Thyroiditis
  • Vitiligo

How is stiff person syndrome diagnosed?

In addition to conducting a clinical evaluation and taking a detailed medical history, your doctor will likely use the following tests to diagnose stiff person syndrome:

  • Blood test to detect GAD antibodies
  • Electromyography to record the electrical activity of voluntary muscles at rest and during contraction

Additional Information & Resources for Stiff Person Syndrome

National Institute of Neurological Disorders and Stroke
National Organization for Rare Disorders

Group 49
It affects an estimated 1 in 1 million people.
Medically Reviewed by Holly Shill, MD, FAAN on December 9, 2022