SUN CITY, Ariz. -- For Drs. Charles Adler and Thomas Beach, one of the most difficult parts of diagnosing Parkinson's disease is that they could be wrong.
"There is no test, so we don't have any way of looking at making a diagnosis while someone is alive," said Adler, a neurologist with the Mayo Clinic in Scottsdale.
But Adler and Beach, a senior scientist at the Banner Sun Health Research Institute, are reporting strides in developing the first diagnostic test to detect Parkinson's, a devastating and chronic neurological disorder.
A study they conducted through the Mayo Clinic and Banner Health found that examining a portion of a person's saliva gland may allow doctors to diagnose the disease.
They will present the study in March at the American Academy of Neurology's annual meeting.
Should this lead to a diagnostic test, Adler said he is pretty confident it will be able to change the course of the disease.
"Patients often undergo invasive treatment, and people who don't have Parkinson's don't respond well," Adler said. "Being able to tell people, ‘Yes, you do have Parkinson's,' would make it much easier."
Diagnosis has for years occurred through a sometimes inaccurate examination of symptoms such as tremors, slowness of movement and muscle stiffness. Doctors have only found definitive answers through autopsies.
"That's a big problem for clinical trials (of treatments or cures)," Beach said. "If you're testing people with new drugs and only half actually have Parkinson's disease, then right away you're up against a problem."
Adler said only 80 to 85 percent of patients autopsied actually had Parkinson's, so a tissue test would guarantee diagnosis and lower chances of degeneration.
Beth Lee, 62, started showing symptoms of Parkinson's almost nine years ago. She said she struggled turning her car keys, drawing circles and performing simple tasks, but having Parkinson's never crossed her mind until she met with a specialist.
"I looked at him like he had 10 heads and said, ‘I have what?'" Lee said.
If she had the option of a diagnostic test, Lee said she could have saved the three years of degeneration it took to find out she had Parkinson's.
Adler and Beach's study tested tissue biopsies of 15 patients who showed symptoms of Parkinson's for at least five years and responded to medications.
Of the 15 patients, 11 had enough tissue to examine. Of those 11, nine tested positive for the Parkinson's protein.
Adler isn't just professionally invested in this study. He has worked for nearly 30 years to improve the treatment and diagnosis of Parkinson's, from which his grandfather suffered.
Some steps remain before a diagnostic test could be prepared for clinical use. Adler said the recent study and past autopsy results show the test's success with advanced Parkinson's patients, or those who have had the disease for at least five years.
But Beach said the team now needs to study the test's accuracy on early Parkinson's patients.
Tom Viviano, co-director of the American Parkinson's Disease Association's Arizona chapter, said the test could be helpful if a treatment or cure for the disease is discovered.
"This can become a way to routinely test for Parkinson's," he said.