brain, spinal cord, and nerve disorders
Parkinson Disease (PD)
Introduction
Parkinson disease is a slowly progressive degenerative disorder of specific areas of the brain. It is characterized by tremor when muscles are at rest (resting tremor), increased muscle tone (stiffness, or rigidity), slowness of voluntary movements, and difficulty maintaining balance (postural instability). In many people, thinking becomes impaired, or dementia develops. Parkinson disease results from degeneration in the part of the brain that helps coordinate movements. Often, the most obvious symptom is a tremor that occurs when muscles are relaxed. Muscles become stiff, movements become slow and uncoordinated, and balance is easily lost. Doctors base the diagnosis on symptoms. General measures (such as simplifying daily tasks), drugs (such aslevodopapluscarbidopa), and sometimes surgery can help, but the disease is progressive, eventually causing severe disability and immobility. (See also Overview of Movement Disorders .) Parkinson disease is the second most common degenerative disorder of the central nervous system after Alzheimer disease. It affects About 1 of 250 people older than 40 About 1 of 100 people age 65 or older About 1 of 10 people age 80 or older Parkinson disease commonly begins between the ages of 50 and 79. Rarely, it occurs in children or adolescents. Parkinsonism None 