The diagnosis of Parkinson’s disease is currently mostly based on motor symptoms assessed during clinical tests. The most distinguished symptom is bradykinesia (slowness of movement) and the patient usually has one or more of the following symptoms: muscle stiffness, resting tremor or balance impairment. Further tests can then confirm the diagnosis and rule out diseases in which the symptoms resemble those of Parkinson’s disease.

In many cases, a brain scan is performed in order to check whether the dopamine-producing neurons in the midbrain are affected. This so-called SPECT-scan is performed by administering a radioactive tracer (that can make the dopamine-producing neurons visible on the scan) to the patient. If these neurons are healthy and in abundance, a red colour in the regions of the striatum and basal ganglia will be visible on the scan. If the patient has Parkinson’s disease, there will be less red and more blue colour seen on the scan. 

The biggest problem in the current diagnosis procedure is that a diagnosis is only possible after the patient experiences motor symptoms. At that point, most of the dopamine-producing neurons have already degenerated. New methods that can allow us to diagnose Parkinson’s disease at an early stage or even give risk estimations would enable us to tackle the disease sooner with neuroprotective treatment options.