How Is Parkinson's Disease Diagnosed?

How is Parkinson's disease diagnosed? There are no specific tests, but a diagnosis involves a neurological exam by a doctor and a review of your symptoms.

Parkinson's disease (PD) is a chronic, degenerative neurological disorder that affects movement. Although it’s not rare — about one in 100 people over age 60 have the disease, according to the Michael J. Fox Foundation for Parkinson’s Research — diagnosing Parkinson’s disease isn’t always easy.

There are several reasons for this. The National Institute on Aging notes about five to 10 percent of people with Parkinson's have early-onset disease, which begins before the age of 50. And younger people, and sometimes their doctors, initially may not consider a disease associated with older age as the cause of sometimes vague, early signs of Parkinson’s disease.

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What’s more, how Parkinson’s disease is diagnosed doesn’t rely on a specific test because none exists, so far. Instead, doctors use a variety of tests, a medical history, and other strategies to conclude if a person has Parkinson’s.

How is Parkinson’s disease diagnosed?

Common symptoms of Parkinson's disease, such as a resting tremor and balance problems, appear gradually and increase over time. Those physical sensations are often trigger people to make an appointment with their doctor. In fact, the Parkinson’s Foundation notes that an internist or family physician often diagnoses someone with Parkinson’s disease.

Doctors use neurological and physical exams, along with a medical history and an assessment of symptoms, to conclude whether a person has Parkinson’s disease. For a Parkinson’s disease diagnosis, two of the four main symptoms of PD must be present over time, the Parkinson’s Foundation points out:

Shaking or tremor

Slowness of movement (bradykinesia)

Stiffness or rigidity of limbs or trunk

Postural instability

In addition, because how Parkinson’s disease is diagnosed can be problematic and doctors want to make sure they are not missing another possible cause of symptoms, brain scans or laboratory tests may be needed to rule out other diseases, the National Institute of Neurological Disorders and Stroke explains.

Frequently, the doctor will also prescribe medications known to reduce Parkinson’s disease symptoms. If a patient has a good response to the drugs, it’s further evidence PD is the correct diagnosis, according to the Michael J. Fox Foundation for Parkinson’s Research.

Getting a second opinion on a Parkinson’s disease diagnosis

Many people diagnosed with Parkinson’s disease seek a second opinion from a neurologist with experience and specific training in diagnosing, assessing, and treating Parkinson’s disease. Or, if you believe you may have symptoms of PD and have not found a diagnosis yet, consulting a specialist may be a good idea.

Doctors who are untrained in diagnosing Parkinson’s disease may miss subtle symptoms when they are mild, and even skilled neurologists sometimes make mistakes. Because there are no diagnostic blood tests or brain scans for Parkinson’s, about 25 percent of Parkinson’s disease diagnoses are incorrect, the Michael J. Fox Foundation for Parkinson’s Research points out.

A neurologist familiar with Parkinson’s disease will understand a patient seeking additional confirmation of a PD diagnosis. A second opinion can bring peace of mind when it confirms you are on the right track to getting appropriate treatment for your disease.

Advances in how Parkinson’s disease is diagnosed

Many neurologists who are movement disorder specialists use an imagining technique called DaTscan as part of their diagnostic work-up for Parkinson’s disease.

DaTscan, which is approved by the Food and Drug Administration, creates detailed pictures of the dopamine system in your brain (a lack of dopamine is linked to Parkinson’s symptoms). Although the high-tech scan alone can’t diagnose Parkinson’s disease, it provides an innovative way to help confirm diagnoses of movement disorders such as Parkinson’s disease.

“DaTscan may be an important new imaging agent for physicians in differentiating diseases such as Parkinson's disease from essential tremor," said Mark Stacy, MD, a neurologist at the Medical University of South Carolina. "Understanding exactly what you are dealing with is important in selecting the appropriate treatments for patients with movement disorders."

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