Ann Romney is considered one of likely Republican presidential nominee Mitt Romney's greatest assets on the campaign trail. But will her multiple sclerosis affect how active she can be in backing her husband?

Romney, 63, was diagnosed with multiple sclerosis in 1998, when she was 49 years old. She recounted how she had a scary flare-up of the disease's symptoms during the Super Tuesday primary contests last month.

What happens is that I start to almost lose my words, I can't think, I can't get words out, Romney told Nancy O'Dell of Entertainment Tonight. I start to stumble a little bit and so those things were happening and I thought, 'Uh oh, big trouble.'

Video of the interview can be viewed by scrolling further down in this article.

Romney is often called Mitt's secret weapon because of her likability, whereas Mitt is seen as a little stiff and has difficulty connecting with voters.

Multiple sclerosis is a disease where the immune system attacks nerves in the brain and spinal cord and affects vision, muscle coordination, strength, sensation and other bodily functions, according to the Mayo Clinic. MS is usually diagnosed in individuals between 20 and 40 years old, with MS more likely to develop in women than men.

Ann Romney said getting enough sleep is key to keeping her MS symptoms at bay and horseback riding is therapeutic for the former first lady of Massachusetts.

So you can expect Ann Romney to hit the campaign trail hard for her husband despite her disease, providing she takes the steps to limit symptoms of her condition.

For people that have MS, there are certain rules that we've got to follow, she said. One is go to bed on time, don't have stress in your life, eat balanced meals every day and, of course, being on the campaign trail none of those things work. And it's been a hard thing for me to balance. If I feel myself getting a little off balanced, a little unusually fatigued I'm like, 'See you later!'

During the Super Tuesday contests, Ann Romney was alongside her husband in five states and a dozen campaign stops -- a grueling endeavor just by itself.

That tough schedule could have caused the flare-up in her symptoms.

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, Dr. Fred Lubin, director of the Corinne Goldsmith Dickinson Center for MS at Mount Sinai Medical Center told ABC News.