Diagnosing Parkinson's: Not So Straightforward

What is Parkinson’s Disease ?
The Mayo Clinic defines Parkinson’s Disease (PD) as a progressive disorder of the nervous system that affects movement. Symptoms include tremors, slowed movement, rigid muscles, impaired posture and balance, loss of automatic movements, speech changes and writing changes. The “simple” cause of these symptoms is the loss and death of neurons, however what is causing the death of neurons is a question scientists have been trying to figure out for decades.
What really causes the symptoms?
To put it into simple words researchers have been able to “pin point” the cause of PD to dysfunctional protein kinases. Protein kinases are enzymes found within the brain and they work by adding phosphate groups to other enzymes with specific functions. By adding a phosphate group kinases cause the other enzyme to either do their job or cause them to stop doing their job. I put quotations around “pin point” because there are a MANY protein kinases within the brain and some have very strong links to PD while others not so much and it seems like new kinases are being linked to PD left and right. To complicate things further these kinases can have VERY different functions in the brain. Most commonly, dysfunctional kinases that are linked to PD deal with oxidative stress, inflammation and autophagy in the brain. Autophagy is a normal process where cells essentially clean up old and used up proteins.
How do we diagnose it now?
With so many kinases linked to PD doctors cannot just look at the levels of some protein in the brain and say with certainty a patient has the disease. Currently the only approved way of diagnosing PD is by looking at symptoms and ruling out other diseases that could cause similar symptoms to PD. I found on the Mayo clinic website that if doctors suspect a patient has PD they can administer a drug used to treat PD and if improvement of symptoms follows that patient most likely has PD.
Are there other ways to diagnose PD?
I found two articles that described some interesting new ways to potentially diagnose PD. The first was about Oxford University researchers that used a new MRI approach called resting-state fMRI. This technique looks at the strength or connectivity of brain networks. The researchers focused on the basal ganglia a part of the brain known to be affected by PD. Using this technique researchers were able to get a correct diagnosis 85% of the time. The second article I found on BBC news told the story of a woman who claimed she could diagnose PD by smell. A researcher got wind of this and put her to the test. Using 6 PD patients and 6 control subjects, people without PD, the researchers had each subject wear a shirt all day and then kept them for testing. They had the woman smell each shirt and she got 11 out of 12 correct. There was one control subject that the woman was sure had PD however the patient claimed to not have PD and doctors did not diagnose this either. However, 8 months later that subject was diagnosed with PD! Meaning this woman was actually 12 for 12!
These novel ways of diagnosing PD are not used widespread what so ever but, could potentially be in the future.