Thanks for your question!
Doctors rely on several methods to diagnose Parkinson's disease. Since
a number of conditions, such as Alzheimer's or stroke, may present
motor-control symptoms similar to those of Parkinson's disease,
doctors must first become familiar with a patient's medical history,
medication use and/or known medical conditions. It's also necessary to
investigate the possibility of exposure to toxins, which can cause
Parkinson's-like symptoms. At this stage, doctors also commonly
perform an assessment of physical/motor symptoms, watching a patient
turn, walk or rise from a chair for signs of muscle weakness/rigidity.
After this initial assessment, doctors may order more tests, such as
CAT scans or MRIs, to rule out the possibility of conditions like
brain tumor or palsy. A neurologist generally performs this sort of
In the early stages of Parkinson's, the diagnosis is based almost
entirely on symptoms. It's difficult to diagnose, and there's a margin
of early diagnostic error ranging from 8 to 35 percent. Doctors will
generally monitor symptoms over time to confirm the diagnosis. The
physical symptoms of advanced Parkinson's are usually prominent and
unmistakable, and diagnosis is confirmed by physical tests and a
Unfortunately, there is currently no blood or neurological test to
reliably detect the presence of Parkinson's disease. The only
near-perfect diagnostic method is performing a brain biopsy to look
for the presence of Lewy bodies, abnormal brain structures which are
highly indicative of Parkinson's. However, brain biopsies aren't often
used in the evaluation of patients with Parkinson-type symptoms.
It's hoped that simple blood or brain imaging tests can be used in the
near future to detect early-stage Parkinson's; as with any disease,
the earlier it's caught the better the prognosis. For now, diagnosis
often comes down to a doctor's judgment call.
Some resources for you:
Reviewed or recommended web sites for Parkinson's disease
The Parkinson's Institute
What will confirm the diagnosis of Parkinson's disease?
I used the following search to find your answer:
"diagnosing parkinson's disease"
All the best!