What Is Parkinson's Disease?

Parkinson's disease (PD) is a neurodegenerative disease caused by degeneration (dysfunction and death) of dopamine-producing cells in the brain. Parkinson's disease affects people of all ages, but the likelihood of developing PD increases with age. More than a million people in the United States have the disease, including 1 percent of people over the age of 60.  

Symptoms of Parkinson’s Disease

PD can include motor and nonmotor symptoms:

Motor Symptoms

• Tremor
• Slowness of movement (bradykinesia)
• Stiffness (rigidity)
• Stooped, shuffling gait
• Decreased arm swing when walking
• Lack of facial expression
• Slowed activities of daily living
• Impaired balance

Nonmotor Symptoms

• Diminished sense of smell
• Low voice volume
• Sleep disturbance
• Depression
• Constipation
• Drooling
• Urinary frequency/urgency
• Male erectile dysfunction

Diagnosis

There is no specific test or marker for PD. Most often the disease is diagnosed by symptoms and a careful neurological examination and depends on the presence of at least two of the three major signs: Tremor at rest, rigidity and bradykinesia, as well as the absence of a secondary cause.

In some cases, imaging such as a fluorodopa positron emission tomography (PET) scan can to help confirm the diagnosis.

Treatment

Although no treatment has been definitively shown to stop or slow disease progression, there is effective treatment for the symptoms of the disease. Medical and surgical treatments are available. Other approaches include physical therapy and exercise.

Medical treatment

The following classes of drugs are used to treat the motor symptoms of PD:

• Levodopa-carbidopa (Sinemet)
• MAO inhibitors: Selegiline (Eldepryl, Zelapar), rasagiline (Azilect)
• COMT inhibitors: Entacapone (Comtan), tolcapone (Tasmar)
• Dopamine agonists: Pramipexole (Mirapex), ropinirole (Requip), cabergoline (not approved in the U.S.), apomorphine (Apokryn), and others
• Anticholinergics: Trihexyphenidyl (Artane), benztropine (Cogentin)
• Amantadine (Symmetrel)

Surgical treatment

Surgical treatments, such as deep brain stimulation (DBS), are used for more advanced patients whose symptoms can no longer be adequately managed with medications. A good surgical candidate is someone who responds well to dopaminergic therapy, has motor complications (off periods and dyskinesias), and is otherwise healthy.

Deep brain stimulation uses implanted electrodes to stimulate a specific target in the brain. The electrical stimulation interferes with the abnormal activity, creating the same effect as a lesion.

Learn more about Parkinson's disease services at Duke.