Diagnosis

There is no test available to conclusively diagnose Parkinson’s disease. The diagnosis is made by a skilled neurologist with a detailed history, description of the symptoms, and physical examination. Your doctor will order blood work, imaging, and additional tests, primarily to rule out other diseases or conditions.

History
People with Parkinson’s disease develop progressive symptoms like difficulty with walking, balance, tremor, muscle stiffness, rigidity, and cramps. They also experience slowness and incoordination of movement and difficulty performing routine task like brushing teeth, combing hair, or feeding oneself. They may have loss of automatic movement like blinking, smiling, and swinging of arms when walking. The early signs may be subtle like clumsiness, mild tremor in a finger or one hand, or decreased volume of voice. The early signs may be difficult to distinguish from the normal aging process. In the beginning, symptoms may be dismissed as they may be inconsistent and fluctuate from day to day. If the diagnosis is still not clear after history, physical examination, and imaging, your doctor may decide to give you a trial of medication to see if it helps with you symptoms.

Physical examination
On physical examination, muscle strength is usually normal as is sensation or feeling. The tremor may be visible at rest and may appear like “pill-rolling.”  When the neurologist examines the muscles, they may be difficult to passively move and even feel rigid or like a “clasp-knife.” The appearance of the face may be “mask-like” with a lack of expression. Other signs on physical examination like decreased volume of voice or mumbling speech, decreased blinking, and writing with small letters may all indicate Parkinson’s disease.

Diagnostic tests
Blood test:  There are no specific blood tests to diagnose Parkinson’s disease.

MRI and CT scans:  Although your doctor may order an MRI (magnetic resonance imaging) or CT scan (Computer Axial Tomography), there are no diagnostic findings specific for Parkinson’s disease. Usually these imaging tests are used to rule out other causes of the clinical symptoms. These tests demonstrate the brain anatomy like taking a picture of the brain, but they do not tell us whether the neurons are working or not.

SPECT (single photon emission computed tomography) and PET (positron emission tomography) scans:  These newer types of imaging demonstrate metabolism of chemicals in the brain. The images represent increased or decreased areas of activity in the brain. They are not widely available for general use. They are available usually at large medical centers and are still considered experimental.

Stages
The following stages describe the natural course of Parkinson’s disease. It is important to note that a given individual may not have all the symptoms in each stage or clearly progress through the stages below:

Stage 0: Symptoms are very mild and may not be experienced often.
Stage 1: Symptoms begin to affect one side of the body, and the person and his family and friends have noticed symptoms.
Stage 2: Symptoms have progressed to involve both sides of the body, and the person reports difficulty with certain tasks. At this point walking and posture are affected.
Stage 3: Symptoms at this point include difficulty with walking and limited ability to move. The person has made some changes to work and/or personal activity.
Stage 4: Symptoms at this point are “advanced” and the person may not be able to live independently since he or she needs assistance with certain tasks. The patient can still walk, but at times this may be very difficult.
Stage 5: The final stage of Parkinson’s disease involves severe limitations on all mobility and self-care. Persons at this stage are unable to walk and require 24hour assistance with all tasks.