Parkinson's Disease

What Is Parkinson's Disease?

Parkinson’s disease (PD), or simply Parkinson’s, is a chronic degenerative movement disorder that causes problems with balance and control of movement.

Parkinson’s disease is one of the most common movement disorders, affecting around one percent of people over the age of 60 worldwide. Around four percent of Parkinson’s cases in the United States occur in individuals younger than age 50 years. Studies suggest that PD affects men more than women.

Parkinson’s Disease Symptoms

The most obvious symptoms of Parkinson’s involve the gradual loss of muscle control. Over time, people with Parkinson’s have trouble producing smooth, coordinated movements and may instead have:

• Slowed movements (bradykinesia): People must present with this symptom for a diagnosis of PD. People with this condition have difficulty maintaining normal movement speed or initiating (starting) a movement.
• Balance difficulties: People with Parkinson’s take shorter steps and drag their feet while walking, increasing fall risk. Falls may occur frequently due to impaired balance.
• Rigid muscles: Over time, the muscles tighten and become difficult to move, making movement slow and possibly painful. During movement, muscle stiffness may be constant (lead-pipe rigidity) or come and go (cogwheel rigidity).
• Postural impairments: As movement becomes more difficult and muscles become stiff, people with PD develop a hunched or stooped posture.
• Problems controlling facial muscles (hypomimia): The facial expressions of people with Parkinson’s change very little or not at all. Lack of facial muscle control may cause drooling and less blinking leading to eye dryness.
• Small handwriting (micrographia): Decreased hand muscle control may cause changes in handwriting. Handwriting for a person with PD may become cramped, smaller, and hard to read.
• Resting tremor: An uncontrolled rhythmic shaking often affects the hands or fingers when at rest. The pill-rolling tremor is a common resting tremor that occurs when the thumb and index finger rub back and forth together.

Parkinson’s disease may also cause symptoms that are unrelated to movement. These symptoms may appear even before movement-related symptoms begin:

• Depression
• Loss of sense of smell (anosmia)
• Parkinson’s-related dementia: Symptoms may present as difficulties with thinking, remembering, or focusing.
• Problems with sleeping: These sleep disturbances may involve restless legs syndrome, rapid eye movement (REM) sleep behavior disorder, and periodic limb movement disorder (PLMD).
• Autonomic nervous system symptoms: These symptoms affect processes in the body that happen without your control. People with PD may experience loss of bowel and bladder control, sexual dysfunction, and blood pressure that drops rapidly after standing (orthostatic hypotension).

What Causes Parkinson’s Disease?

In Parkinson’s, nerve cells in the brain become damaged and die off over time. These affected nerve cells are responsible for producing dopamine, a chemical messenger (neurotransmitter) needed for smooth coordination of movement. As dopamine levels in the brain decrease, problems with balance and movement increase.

Most cases of Parkinson’s disease are “idiopathic” or of unknown causes. Experts think that many cases of PD develop when the body has problems using or breaking down a protein called alpha-synuclein (α-synuclein).

When α-synuclein folds incorrectly into an abnormal shape, the body can't use or remove the abnormal protein properly. This abnormal form of α-synuclein builds up into clumps of cells called Lewy bodies in certain tissues, especially nerve cells in the brain.

Many factors may contribute to the development of Parkinson’s, including:

• Environmental exposures: Exposure to toxins or environmental factors, such as pesticides, may increase the risk for developing Parkinson’s.
• Genetics: Around 10 to 15 percent of PD cases run in families, meaning that children can inherit specific genes that cause Parkinson’s from their parents. Researchers have identified more than 20 genes associated with Parkinson’s disease. Thirteen of these genes cause early-onset PD that begins at a younger age than usual.

Evaluating and Treating Parkinson’s Disease

Many conditions have symptoms that mimic Parkinson’s disease symptoms (atypical parkinsonism syndromes). It’s important to see a neurologist who specializes in movement disorders to get an accurate diagnosis.

Learn more about diagnosing Parkinson’s disease

The Parkinson’s disease clinic at Penn Medicine offers all available treatment options, ranging from newer medications to high-tech surgical techniques.

Learn more about Parkinson’s disease treatment

Leading-Edge Research

Our clinicians and research scientists strive to improve available treatments through Parkinson’s research and clinical trials. Our Parkinson’s disease clinic is nationally recognized as a center for high-impact research and learning.

Parkinson’s Disease Support

Living with Parkinson’s disease is challenging. We strive to provide you with the resources you need to live life to the fullest. The Penn Movement Disorders Center and the Dan Aaron Center for Parkinson’s Disease Rehabilitation organize and sponsor the following resources:

• Exercise programs
• Support groups
• Palliative care support during advanced disease stages
• Yearly educational conferences related to PD

Make an Appointment

Please call 800-789-7366 or make an appointment.

Penn Programs & Services for Parkinson's Disease