Parkinson's Disease

Parkinson's disease (PD) is a disease of the central nervous system. It causes problems with body motions, including:

  • Tremor (shakiness)
  • Rigidity (muscle stiffness)
  • Slowed body movements
  • Unstable posture
  • Difficulty walking

PD develops when certain nerve cells (neurons) in the brain die. These are neurons that produce a chemical called dopamine. Dopamine helps relay messages between areas of the brain that control body movement.

When these neurons die, abnormally low levels of dopamine are produced. This makes it difficult to control muscle tension and muscle movement.

PD usually occurs in middle age. It typically begins around age 60. A small number of patients have early onset PD. They are younger than 40 years old when symptoms begin.

Having a parent or sibling diagnosed with the disease at a younger age increases your risk of getting PD. The same is not true if the affected family member was older when diagnosed.


PD usually begins as a slight tremor or stiffness. It occurs in the arm or leg on one side of the body. The tremor is most obvious at rest. It is regular, typically occurring three to six times per second.

The PD tremor:

  • Usually worsens under stress
  • Improves when the arm or leg is moved voluntarily
  • May disappear entirely during sleep

At first, PD may be evident only as a tremor involving the thumb and index finger. It looks as if the person is manipulating a small object.

As the illness worsens, tremors may become more widespread. They eventually affect limbs on both sides of the body. Handwriting may become small, shaky and eventually illegible.

PD often causes stiffness or rigidity in the arms or legs. In addition, there is a slowing of body movements, called bradykinesia.

Rigidity and bradykinesia can be the most disabling aspects of the disease. They can impair the person's ability to walk. They can make it difficult to perform daily activities. These may include washing, dressing or using utensils.

Problems with unsteady balance and posture may make it hard to sit down in a chair, or to rise from one. Walking is accomplished with small, shuffling steps and a stooped posture.

Bradykinesia can affect the facial muscles. It can decrease spontaneous facial expressions and normal eye blinking.

Other symptoms of PD may include:

  • Depression
  • Anxiety
  • Disturbed sleep
  • Memory loss
  • Slurred or abnormally soft speech
  • Difficulty chewing or swallowing
  • Constipation
  • Impaired bladder control
  • Abnormal regulation of body temperature
  • Sexual dysfunction
  • Cramps, numbness, tingling or pain in the muscles


Your doctor will examine you. He or she will pay extra attention to the neurological examination.

Your doctor will look for symptoms of PD, especially:

  • The classic PD tremor
  • Slowness of movement
  • Rigidity

Gait problems