Parkinson’s disease differs from person to person. Symptoms often start on one side of the body and remain worse on this side, even after both sides become affected.


  • a tremor usually begins in one limb, often in the hand or fingers
  • the tremor may appear during sleep
  • the thumb and forefinger may be rubbing back and forth as a “pill-rolling” motion

Slowed movement

  • smaller steps and dragging feet when walking
  • difficulty doing simple tasks and movements such as getting out of a chair

Rigid muscles

  • Impaired posture and balance

Loss of automatic movements

  • reduced blinking, smiling or swinging arms when walking

Speech changes

  • speech may become softer, quicker, slurred, or hesitant
  • monotonal instead of with inflections

Writing changes

  • difficulty with writing
  • smaller handwriting than before

Causes and Risk Factors

  • In Parkinson’s disease, certain neurons in the brain gradually die off. Many symptoms result from the loss of neurons that produce a chemical messenger called dopamine. Abnormal brain activity can be caused by a low dopamine level. Although the specific cause of Parkinson’s disease is unknown, the following factors are thought to play a role:
    • Certain genetic mutations can cause Parkinson’s disease, but these genes are uncommon except in rare cases where many family members are affected by Parkinson’s disease
    • Certain gene variations may increase the risk, but with a relatively small risk of Parkinson’s disease for each of these genetic markers

    Risk Factors

    • Age
      • Parkinson’s disease typically begins in middle or late life (around 60s), and its risks increase with age
    • Heredity
      • having a close relative with PD can increase the risk
    • Sex
      • men are more likely to develop PD than are women
    • Exposure to toxins
      • ongoing exposure to herbicides and pesticides increases the risk