Axis Diagnosis for Parkinson's Disease

Parkinson's disease is a progressive neurological disease that primarily affects individuals in late life. The American Psychiatric Association characterizes this disorder as an "Axis III" disorder, a physical medical condition that is relevant to a patient's mental state. Diagnosis of Parkinson's is founded on the observation of key symptoms.

How a Diagnosis Is Made

• There is no definitive test for Parkinson's disease. Therefore, diagnosis relies on medical history and neurological examination. This involves the observation of one or more of the four cardinal signs of disease: tremor, rigidity, bradykinesia and gait disturbance.

Resting Tremor

• Many patients with Parkinson's disease exhibit a resting tremor. This variety of tremor occurs when a person's muscles are relaxed and at rest. It should not be confused with a common essential tremor, or active tremor, which occurs when a person moves.

Rigidity

• Rigidity of the limbs and trunk is another common symptom of Parkinson's disease. Often this manifests as "cogwheel rigidity," when a muscle under tension gives way to pressure in little jerks. In milder cases there is a stiffness of affected areas.

Bradykinesia

• Slowness of movement, called bradykinesia, is very common in Parkinson's patients. This can get progressively worse over time. In some instances muscles may freeze up in the middle of a movement.

Gait Disturbance

• Another cardinal symptom is gait disturbance. This can take the form of postural instability--a shakiness when standing--or loss of balance and impaired coordination. Often you can observe a person affected by Parkinson's disease walking with a stoop or shuffle.