Stiff-Person Syndrome

Stiff-person syndrome is a rare, progressive neurological disorder. It causes constant painful contractions and spasms of voluntary muscles. This involves particularly the muscles of the back and upper legs.


Researchers suspect that this syndrome may be an autoimmune disorder. Other autoimmune disorders may occur more often in patients with this syndrome. They include:

  • Diabetes.

  • Pernicious anemia. This is a chronic, progressive blood disorder.

  • Inflammation of the thyroid gland (thyroiditis).


Symptoms may occur slowly. They can spread from the back and legs to involve the arms and neck. Symptoms may get worse when the patient is anxious or exposed to sudden motion or noise. Affected muscles may become twisted and contracted. This leads to bone fractures in the most severe cases. Patients may have difficulty making sudden movements. They may have a stiff-legged, unsteady gait. Sleep usually reduces the frequency of contractions. Patients may develop:

  • A hunched posture (kyphosis).

  • A swayback (lordosis).

  • Increased stiffness.


The drug diazepam relaxes the muscles. It provides improvement in most cases. Other drugs may provide some benefit. In some patients, immunomodulatory treatments may be helpful. Intravenous immunoglobulin is an example. Physical and rehabilitation therapy may also be needed.

There is no cure for this syndrome. The long-term outcome for patients with this syndrome is uncertain. Managing the disorder with drug therapy may provide improvement. It may also relieve symptoms.


Research on this syndrome aims to:

  • Enhance scientific understanding of the disorder.

  • Evaluate new therapeutic interventions.