It's a staggering number. More than 1 million Americans are living with Parkinson's disease.
Right now, doctors diagnose it by conducting a physical exam that's often unreliable.
But, that's about to change.
William Hill used to be a professional welterweight fighter. Today, he's fighting a different yet powerful opponent, Parkinson's disease.
Debora Bergstrom is also battling the condition that causes tremors, balance problems and speech issues. The mom of three was diagnosed four years ago by a neurologist. "She told me to stand up, walk," Bergstrom said. "She rotated my arms and hands, and she said, 'Yes, you have Parkinson's.'"
But, many people wait years before getting that diagnosis. Doctors physically examine patients for the tell-tale symptoms to formulate their conclusion. However, their observations aren't always accurate. 40 percent of Parkinson's patients are undiagnosed, and at least 10 percent who are diagnosed don't really have it.
Dr. Louise Thomson says a new imaging test called DAT-scan is giving doctors a glimpse inside the Parkinson's brain. First, doctors inject patients with a tracer. Then, they scan the brain for dopamine, a chemical that Parkinson's patients lack.
Thomson says the test can tell doctors if the patient has Parkinson's or just a tremor disorder, which is treated differently. "This is a game changer," she said. "It's going to lead to earlier diagnosis and clearer diagnosis for patients with tremor."
An earlier diagnosis means patients can start treatments sooner, potentially slowing symptom development of this devastating disease.
For William and Debora, every symptom-free day matters. Now, doctors are one step closer to figuring that out.
DAT-scan is the first FDA approved diagnostic imaging test for the assessment of movement disorders such as Parkinson's.
But, there is some debate about its effectiveness.
Some doctors say a negative test doesn't provide enough evidence to rule out Parkinson's completely, and they believe the cost of the scan is much more expensive than a consultation and follow-ups with a movement disorders expert.