What is stiff-person syndrome? Celine Dion sings live for the first time at 2024 Paris Olympics since revealing diagnosis

Celine Dion took to the stage for the first time since revealing her stiff-person syndrome diagnosis in September 2022. Wearing a white gown, with the rain beating down and the Eiffel Tower in the background, the 56-year-old sang Edith Piaf’s “L’Hymne à L'amour.” It marked a triumphant and dramatic return for Dion, something she vowed to do earlier this year when she said her illness would not take anything from her. “I’m going to go back onstage, even if I have to crawl. Even if I have to talk with my hands, I will. I will,” she told "Today" in June. “I am Celine Dion, because today my voice will be heard for the first time, not just because I have to, or because I need to. It’s because I want to and I miss it.”

Here’s what to know about stiff-person syndrome, and how it affects the lives of people like Dion.

What is stiff-person syndrome?

Stiff-person syndrome — often called SPS — is a rare autoimmune disorder, meaning that infection-fighting cells in the body mistakenly attack healthy tissues. In the case of SPS, these off-target cells attack the neurological system and deplete its supply of a chemical messenger, called gamma-aminobutyric acid, or GABA, which signals muscles when to relax.

Typically, muscles work in opposing pairs. “When you contract a muscle, the opposite muscle — say, the tricep, when the bicep contracts — relaxes,” says Dr. Marinos Dalakas, a Thomas Jefferson University neurologist who specializes in stiff-person syndrome. “Otherwise, all of us would be stiff.” For people with SPS, that’s exactly what happens, sporadically, causing stiffness in the legs, arms and torso, as well as muscle spasms.

What are the symptoms?

Like many autoimmune diseases, SPS exists on a spectrum and, as a result, symptoms can look quite different in different people, Dr. Scott Newsome, head of the Johns Hopkins Stiff Person Syndrome Center, tells Yahoo Life. The most common form of the disease “typically will present with insidious stiffness in the legs more than the torso,” and some people may have arm stiffness, Newsome says. Symptoms usually appear in middle age, but can strike elderly people and even children.

This stiffness, as well as muscle spasms, can last anywhere from minutes to hours. “Spasms can be prompted by triggers including good or bad stress, hot or cold weather or tactile stimuli,” Newsome adds. Less commonly, someone’s first symptoms might be blurry vision, a wobbly walking gait or a general sense of wobbliness.

As the condition progresses, stiffness may become more widespread and persistent. And stiffness can cause people to become unsteady on their feet, leading not only to falls, but a fear of falling and avoidance of independent activities, experts say. “Anxiety is part of the disease,” says Newsome. “People can have a lot of falls related to balance issues or mobility problems if they have severe spasms. That can lead to people not going outside of their houses.”

Can stiff-person syndrome be fatal?

No, at least not directly, says Newsome. Many people with SPS eventually may need to use a cane, walker or scooter to get around as their stiffness and spasms progress. But the spasms themselves aren’t fatal. However, falls resulting from stiffness can lead to deadly brain injuries. Some people with SPS also develop swallowing issues that put them at risk for inhaling something that could cause a life-threatening lung infection.

There’s no reason to think the disease itself shortens life expectancy, however, Newsome says that some treatments for stiff-person syndrome could cut life short because they suppress the overactive immune system, which can make someone more vulnerable to infections.

How is it treated?

There is no cure for SPS. However, immunotherapy can be used to quiet the overactivity of the immune system. These “are the types of treatments that I feel have the potential greatest impact on preventing progression,” says Newsome. “They don’t reverse time,” he says, and they don’t always work, especially if the disease is diagnosed relatively late. A number of other medications — including anti-seizure drugs, Botox, muscle relaxers like tizanidine and anti-anxiety or sedative medications like Valium — are used to reduce stiffness on a day-to-day basis, according to the Stiff Person Syndrome Research Foundation.

Physical therapy, massage, yoga and therapy or medication to manage anxiety and depression are also important to helping someone with SPS maintain their quality of life, says Newsome. “Using a multi-pronged approach can help patients the most,” he adds.

How rare is stiff-person syndrome?

If you’ve felt stiffness from time to time, it’s very unlikely that you have the disease, Newsome says. Most research suggests that between one and two people out of every million have the condition (though Newsome says recent research suggests it could be considerably higher). Its causes are unknown, as is the reason that it afflicts women more often than men (as is the case with other autoimmune disorders).

Newsome and Dalakas both believe that SPS is at once under- and overdiagnosed. They say it’s often mistaken for another autoimmune neurological disorder, multiple sclerosis, but note that public awareness of SPS is also growing, meaning that more people think they could have it.

Occasional stiffness alone isn’t enough to suggest someone has SPS, but “if there’s a consistency, and you’re noticing worsening of symptoms, you should go and get it looked at,” says Newsome. “That said, most people who have symptoms in common with SPS will not have SPS.”

This article was originally published on June 11, 2024, and has been updated.