Ann Romney's struggles with multiple sclerosis kept her away from her husband's campaign shortly before Super Tuesday.
The wife of the presumptive GOP's presidential nominee, Mitt Romney, told "Entertainment Tonight" about a "health scare" she had in the days leading up to the marathon day of primaries in March.
"I was quite fatigued, and I knew I couldn't quit. I didn't tell anybody I was tired," Romney said.
As she continued her work on the campaign, she said her symptoms worsened.
"You know, what happens with me is that I start to almost lose my words. I almost can't think. I can't get my words out. I start to stumble a little bit and so those things were happening and I thought, 'Uh oh, big trouble.'"
Experts say Romney's experience with MS is fairly common for the majority of people who deal with the symptoms of the disease, which is characterized by variable, often unpredictable symptoms.
Multiple sclerosis is an autoimmune disorder in which the body's immune system attacks the protective covering, called the myelin sheath, surrounding nerves in the brain and spinal cord.
When the nerves in these key structures are damaged, the impulses controlling basic functions like movement and cognition become distorted, producing a wide range of symptoms, some minor and some severe.
"MS is the most variable of serious neurologic diseases," said Dr. Fred Lublin, director of the Corinne Goldsmith Dickinson Center for MS at Mount Sinai Medical Center. "It can be very, very mild, to the point where some people don't know they have it, and it can be very debilitating for others. And everything in between."
Romney's experience with MS has become a central part of her husband's presidential campaign. The Romneys often discuss her 1998 diagnosis at age 49, and how she dealt with the disease while raising her five sons. Experts say a number of things about Romney's current schedule and role in the campaign may have aggravated her symptoms, producing the effects she described.
"Those who have MS have some underlying damage to the nervous system. If their system is off -- if they get overheated or stressed a lot or unusually tired -- the symptoms may manifest themselves" by making the transmission of impulses along the already-frayed neurons even worse, Lublin said.
According to the National Multiple Sclerosis Society, about 400,000 Americans and 2.1 million people worldwide live with MS. Most experience a range of symptoms that can come and go, but for some, the disease worsens progressively and becomes physically disabling. Romney herself has said she once feared that she would be confined to a wheelchair and would not be able to cook or care for her family.
MS is chronic, and there is no cure. But experts say the treatments for MS have vastly improved since the 1990s. The U.S. Food and Drug Administration has approved eight medications, half approved in the last five years. The drugs work to block the immune system's attacks on the brain and prevent relapses of the disease.
The drugs have been fairly successful in treating people like Romney, said Tim Coetzee, chief research officer at the National Multiple Sclerosis Society.
"The unmet need is tackling the need of people with more progressive, debilitating forms of the disease," he said.