HOUSTON -

Every three to six months, Martin and GayLynn Bullock load up the car and make the nine-hour drive from Sweetwater, Okla. to Houston. Once they hit the Bayou City, the pair goes to Baylor College of Medicine to be, as GayLynn puts it, poked, prodded, cut and shot all in the name of science.

The Bullocks are part of a landmark study searching for the biomarker of Parkinson's disease.

Dr. Joseph Jankovick told Local 2 they are the key to developing a test for the progressive neurological disorder.

"Biomarker is a substance or some kind of chemical or blood test or imaging test that allows us to identify individuals that have Parkinson's disease or those at risk for Parkinson's disease, and by following these biomarkers, we can track the progression of the disease," Jankovick said.

Being able to watch the progression of the disease will help with targeting therapies and learning more about Parkinson's disease. The real goal of the study, though, is to identify the biomarker so it can be used as a diagnostic test for people who do not even exhibit the symptoms.

An avid golfer and handyman, Martin first realized something was wrong when his writing started to look worse and worse.

"[My signature] became like a doctor's -- almost unrecognizable," said Martin. "I would get the first letter, and then the rest would go to pot."

When it began affecting his golf swing and ability to hammer a nail, Martin searched for answers. The result was a Parkinson's diagnosis based solely on the symptoms.

"That is kind of sad to watch, but he has a very good attitude," said GayLynn. "Both of us have a very good sense of humor, so we try to be funny about it."

With that good attitude and hearty sense of humor, Martin looked for a way to make his diagnosis matter. What he found was a casting call at the Michael J. Fox Foundation for the biomarker study.

"Somebody ought to get some good out of it down the line," said Martin.

Baylor College of Medicine is one of 14 studies in the United States being funded by the Fox Foundation. They collect blood samples, take MRIs and collect spinal fluid to not only search for the biomarker but to monitor the progress of the disease.

Martin's wife has even gotten in on the action by joining the control group of the study. People without the disease go through the same tests, including the spinal taps. GayLynn told Local 2 that is the toughest part.

"Oh my gosh, it was so bad but I just looked at the poster of Michael J. Fox they had hanging on the wall and told myself, 'Come on,'" said GayLynn.

If the research leads to tests or even treatment, it may not be anything Martin is able to use in his battle, but the pair said that's not why they come back every few months.

"If they can find these markers like they say when someone is young that might have a propensity towards that, that would be great," said GayLynn.