There are also secondary forms of PD caused by drugs that interfere with the brain's metabolism of dopamine, and prolonged use of these drugs can produce PD symptoms. PD usually begins with a hand tremor on one side of the body. Resting tremors may eventually be accompanied by slowness and stiffness on the same side. As symptoms progress, patients tend to notice limitations on the other side of the body, almost always less severe than the primary side. Due to fine motor deficits, finger and hand movements requiring skilled coordination may become slow and difficult.
Some patients notice a slight foot drag on the affected side or a feeling of walking in quicksand.
The voice can become softer and raspier. Many individuals with PD experience gait and balance problems, difficulty navigating doorways and narrow passages, stutter-steps, and precarious balance on turning. Many PD symptoms can be controlled with medications. Low-dose Sinemet is commonly started when the patient experiences enough inconvenience or incapacity from PD symptoms to interfere with his or her ability to carry out normal activities. Maximal results are obtained the first few years on this medication, although most patients continue to get benefit for many years.