Diseases

The disorder is often misdiagnosed as Parkinson's 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 in the blood. People with Stiff-Person syndrome have elevated levels of GAD, an antibody that works against an enzyme involved in the synthesis of an important neurotransmitter in the brain.

People with Stiff-Person syndrome respond to high doses of diazepam and several anti-convulsants, gabapentin and tiagabine. A study funded by the NINDS demonstrated the effectiveness of intravenous immunoglobulin (IVIg) treatment in reducing stiffness and lowering sensitivity to noise, touch, and stress in people with Stiff-Person syndrome.

Stiff-Person syndrome is characterized by fluctuating muscle rigidity in the trunk and limbs and a heightened sensitivity to stimuli such as noise, touch, and emotional distress, which can set off muscle spasms. Abnormal postures, often hunched over and stiffened, are characteristic of the disorder. People with Stiff-Person syndrome can be too disabled to walk or move, or they are afraid to leave the house because street noises, such as the sound of a horn, can trigger spasms and falls.

Stiff-person syndrome (SPS) is a rare neurological disorder with features of an autoimmune disease.

Treatment with IVIg, anti-anxiety drugs, muscle relaxants, anti-convulsants, and pain relievers will improve the symptoms of Stiff-Person syndrome, but will not cure the disorder. Most individuals with Stiff-Person syndrome have frequent falls and because they lack the normal defensive reflexes; injuries can be severe. With appropriate treatment, the symptoms are usually well controlled.

The National Institute of Neurological Disorders and Stroke (NINDS) conducts research related to Stiff-Person syndrome in its laboratories at the National Institutes of Health (NIH), and also supports additional research through grants to major medical institutions across the country. A study using the drug rituximab proved ineffective in treating individuals with the disorder. Current research is focused on understanding the cause of the disease and the role of the anti-GAD antibodies.

Stiff-Person syndrome affects twice as many women as men. It is frequently associated with other autoimmune diseases such as 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.