• Suspect Parkinson's disease if the person has any of the following characteristic features (which, early in the disease, are usually unilateral, but become bilateral as the disease progresses):
• Bradykinesia (slowness of movement) or hypokinesia (poverty of movement) — for example:
• Reduced facial expression, arm swing, or blinking.
• Difficulty with fine movements such as buttoning clothes and opening jars, or small, cramped handwriting.
• Slow, shuffling gait, or difficulty turning in bed.
• Stiffness or rigidity, which may be:
• Lead-pipe rigidity, which describes the constant resistance felt when a limb is passively flexed in the presence of increased tone without tremor, or
• Cogwheel rigidity, which describes the regular intermittent relaxation of tension felt when a limb is passively flexed in the presence of tremor and increased tone.
• Rest tremor, which:
• Improves on moving.
• May appear at the thumb and index finger ('pill-rolling'), the wrist, or the leg.
• Is absent in up to 30% of people at disease onset.
• Parkinson's disease may be confused with other causes of tremor and parkinsonism — see Differential diagnosis.
• If the person is taking a drug known to cause parkinsonism (that is: an antipsychotic; the anti-emetics, metoclopramide and prochlorperazine; or, less commonly, an antidepressant, amiodarone, cinnarizine, lithium, sodium valproate, or a cholinesterase inhibitor), see Differentiating Parkinson's disease from drug-induced parkinsonism.

In depth