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:
Slurred or abnormally soft speech
Difficulty chewing or swallowing
Impaired bladder control
Abnormal regulation of body temperature
Cramps, numbness, tingling or pain in the muscles