Parkinson's disease is a progressive disorder that affects the nervous system and the parts of the body controlled by the nerves. Symptoms start slowly. The first symptom may be a barely noticeable tremor in just one hand. Tremors are common, but the disorder also may cause stiffness or slowing of movement.

In the early stages of Parkinson's disease, your face may show little or no expression. Your arms may not swing when you walk. Your speech may become soft or slurred. Parkinson's disease symptoms worsen as your condition progresses over time.

Although Parkinson's disease can't be cured, medicines might significantly improve your symptoms. Occasionally, a health care professional may suggest surgery to regulate certain regions of your brain and improve your symptoms.

Parkinson's disease symptoms can be different for everyone. Early symptoms may be mild and go unnoticed. Symptoms often begin on one side of the body and usually remain worse on that side, even after symptoms begin to affect the limbs on both sides.

Parkinson's symptoms may include:

• Tremor. Rhythmic shaking, called tremor, usually begins in a limb, often your hand or fingers. You may rub your thumb and forefinger back and forth. This is known as a pill-rolling tremor. Your hand may tremble when it's at rest. The shaking may decrease when you are performing tasks.
• Slowed movement, known as bradykinesia. Over time, Parkinson's disease may slow your movement, making simple tasks difficult and time-consuming. Your steps may become shorter when you walk. It may be difficult to get out of a chair. You may drag or shuffle your feet as you try to walk.
• Rigid muscles. Muscle stiffness may occur in any part of your body. The stiff muscles can be painful and limit your range of motion.
• Impaired posture and balance. Your posture may become stooped. Or you may fall or have balance problems as a result of Parkinson's disease.
• Loss of automatic movements. You may have a decreased ability to perform unconscious movements, including blinking, smiling or swinging your arms when you walk.
• Speech changes. You may speak softly or quickly, slur, or hesitate before talking. Your speech may be more of a monotone rather than have the usual speech patterns.
• Writing changes. It may become hard to write, and your writing may appear small.

When to see a doctor

See a health care professional if you have any of the symptoms associated with Parkinson's disease — not only to diagnose your condition but also to rule out other causes for your symptoms.

In Parkinson's disease, certain nerve cells called neurons in the brain gradually break down or die. Many of the symptoms of Parkinson's are due to a loss of neurons that produce a chemical messenger in your brain called dopamine. When dopamine levels decrease, it causes irregular brain activity, leading to problems with movement and other symptoms of Parkinson's disease.

The cause of Parkinson's disease is unknown, but several factors appear to play a role, including:

• Genes. Researchers have identified specific genetic changes that can cause Parkinson's disease. But these are uncommon except in rare cases with many family members affected by Parkinson's disease.

  However, certain gene variations appear to increase the risk of Parkinson's disease but with a relatively small risk of Parkinson's disease for each of these genetic markers.

• Environmental triggers. Exposure to certain toxins or environmental factors may increase the risk of later Parkinson's disease, but the risk is small.

Researchers also have noted that many changes occur in the brains of people with Parkinson's disease, although it's not clear why these changes occur. These changes include:

• The presence of Lewy bodies. Clumps of specific substances within brain cells are microscopic markers of Parkinson's disease. These are called Lewy bodies, and researchers believe these Lewy bodies hold an important clue to the cause of Parkinson's disease.
• Alpha-synuclein found within Lewy bodies. Although many substances are found within Lewy bodies, scientists believe that an important one is the natural and widespread protein called alpha-synuclein, also called a-synuclein. It's found in all Lewy bodies in a clumped form that cells can't break down. This is currently an important focus among Parkinson's disease researchers. Researchers have found the clumped alpha-synuclein protein in the spinal fluid of people who later develop Parkinson's disease.

Risk factors for Parkinson's disease include:

• Age. Young adults rarely experience Parkinson's disease. It ordinarily begins in middle or late life, and the risk increases with age. People usually develop the disease around age 60 or older. If a young person does have Parkinson's disease, genetic counseling might be helpful in making family planning decisions. Work, social situations and medicine side effects are also different from those of an older person with Parkinson's disease and require special considerations.
• Heredity. Having a close relative with Parkinson's disease increases the chances that you'll develop the disease. However, your risks are still small unless you have many relatives in your family with Parkinson's disease.
• Sex. Men are more likely to develop Parkinson's disease than are women.
• Exposure to toxins. Ongoing exposure to herbicides and pesticides may slightly increase your risk of Parkinson's disease.

Parkinson's disease is often accompanied by these additional problems, which may be treatable:

• Thinking difficulties. You may experience cognitive problems, such as dementia, and thinking difficulties. These usually occur in the later stages of Parkinson's disease. Such cognitive problems aren't usually helped by medicines.

• Depression and emotional changes. You may experience depression, sometimes in the very early stages. Receiving treatment for depression can make it easier to handle the other challenges of Parkinson's disease.

  You also may experience other emotional changes, such as fear, anxiety or loss of motivation. Your health care team may give you medicine to treat these symptoms.

• Swallowing problems. You may develop difficulties with swallowing as your condition progresses. Saliva may accumulate in your mouth due to slowed swallowing, leading to drooling.
• Chewing and eating problems. Late-stage Parkinson's disease affects the muscles in the mouth, making chewing difficult. This can lead to choking and poor nutrition.

• Sleep problems and sleep disorders. People with Parkinson's disease often have sleep problems, including waking up frequently throughout the night, waking up early or falling asleep during the day.

  People also may experience rapid eye movement sleep behavior disorder, which involves acting out dreams. Medicines may improve your sleep.

• Bladder problems. Parkinson's disease may cause bladder problems, including being unable to control urine or having difficulty in urinating.
• Constipation. Many people with Parkinson's disease develop constipation, mainly due to a slower digestive tract.

You may also experience:

• Blood pressure changes. You may feel dizzy or lightheaded when you stand due to a sudden drop in blood pressure (orthostatic hypotension).
• Smell dysfunction. You may experience problems with your sense of smell. You may have trouble identifying certain odors or the difference between odors.
• Fatigue. Many people with Parkinson's disease lose energy and experience fatigue, especially later in the day. The cause isn't always known.
• Pain. Some people with Parkinson's disease experience pain, either in specific areas of their bodies or throughout their bodies.
• Sexual dysfunction. Some people with Parkinson's disease notice a decrease in sexual desire or performance.

Because the cause of Parkinson's is unknown, there are no proven ways to prevent the disease.

Some research has shown that regular aerobic exercise might reduce the risk of Parkinson's disease.

Some other research has shown that people who consume caffeine — which is found in coffee, tea and cola — get Parkinson's disease less often than those who don't drink it. Green tea also is related to a reduced risk of developing Parkinson's disease. However, it is still not known whether caffeine protects against getting Parkinson's or is related in some other way. Currently there is not enough evidence to suggest that drinking caffeinated beverages protects against Parkinson's.

Currently, there isn't a specific test to diagnose Parkinson's disease. A diagnosis is made by a doctor trained in nervous system conditions, known as a neurologist. A diagnosis of Parkinson's is based on your medical history, a review of your symptoms, and a neurological and physical exam.

A member of your health care team may suggest a specific single-photon emission computerized tomography (SPECT) scan called a dopamine transporter (DAT) scan. Although this can help support the suspicion that you have Parkinson's disease, it is your symptoms and results of a neurological exam that ultimately determine the correct diagnosis. Most people do not require a DAT scan.

Your care team may order lab tests, such as blood tests, to rule out other conditions that may be causing your symptoms.

Imaging tests — such as an MRI, ultrasound of the brain and PET scans — also may be used to help rule out other disorders. Imaging tests aren't particularly helpful for diagnosing Parkinson's disease.

In addition to examining you, a member of your health care team may give you carbidopa-levodopa (Rytary, Sinemet, others), a Parkinson's disease medicine. You must be given a sufficient dose to show the benefit, as getting low doses for a day or two isn't reliable. Significant improvement with this medicine will often confirm your diagnosis of Parkinson's disease.

Sometimes it takes time to diagnose Parkinson's disease. Health care professionals may recommend regular follow-up appointments with neurologists trained in movement disorders to evaluate your condition and symptoms over time and diagnose Parkinson's disease.

However, a new test may be on the horizon. Researchers are studying a Parkinson's test that can detect the disease before symptoms begin. The test is called an alpha-synuclein seed amplification assay. In a 2023 study, researchers tested the spinal fluid of more than 1,000 people to look for clumps of the protein alpha-synuclein. Alpha-synuclein is found in Lewy bodies. It forms clumps that the body can't break down. The clumps spread and damage brain cells.

Alpha-synuclein clumps are a hallmark sign of Parkinson's disease. The test accurately identified people with Parkinson's disease 87.7% of the time. The test also was highly sensitive for detecting people at risk of Parkinson's disease.

This study of the alpha-synuclein seed amplification assay was the largest so far. Some researchers say the study may be a game changer for Parkinson's disease diagnosis, research and treatment trials. But larger studies are needed. There's hope among researchers that in the future, the test could be done using blood samples rather than spinal fluid.

Avoiding falls

In the later stages of the disease, you may fall more easily. In fact, you may be thrown off balance by just a small push or bump. The following suggestions may help:

• Make a U-turn instead of pivoting your body over your feet.
• Distribute your weight evenly between both feet, and don't lean.
• Avoid carrying things while you walk.
• Avoid walking backward.

Daily living activities

Daily living activities — such as dressing, eating, bathing and writing — can be difficult for people with Parkinson's disease. An occupational therapist can show you techniques that make daily life easier.

If you are having trouble talking, a speech therapist may be able to help. Many people with Parkinson's disease have speech difficulties such as a slow, weak voice, trouble with consonants, slurred speech, a low voice that has a monotone with little expression, and inappropriate silences. A speech therapist may be able to help with these problems.

Supportive therapies can help ease some of the symptoms and complications of Parkinson's disease, such as pain, fatigue and depression. When performed in combination with your treatments, these therapies might improve your quality of life:

• Massage. Massage therapy can reduce muscle tension and promote relaxation. This therapy, however, is rarely covered by health insurance.

• Tai chi. An ancient form of Chinese exercise, tai chi uses slow, flowing motions that may improve flexibility, balance and muscle strength. Tai chi also may help prevent falls. Several forms of tai chi are tailored for people of any age or physical condition.

  A study showed that tai chi may improve the balance of people with mild to moderate Parkinson's disease more than stretching and resistance training do.

• Yoga. In yoga, gentle stretching movements and poses may increase your flexibility and balance. You may modify most poses to fit your physical abilities.
• Alexander technique. This technique — which focuses on muscle posture, balance and thinking about how you use muscles — may reduce muscle tension and pain.
• Meditation. In meditation, you quietly reflect and focus your mind on an idea or image. Meditation may reduce stress and pain and improve your sense of well-being.
• Pet therapy. Having a dog or cat may increase your flexibility and movement and improve your emotional health.
• Relaxation techniques. These practices help lower your blood pressure, reduce your heart rate and improve muscle tone.

Living with any chronic illness can be difficult, and it's not uncommon to feel angry, depressed or discouraged at times. Parkinson's disease can be profoundly frustrating as walking, talking and even eating become more difficult and time-consuming.

Depression is common in people with Parkinson's disease. But antidepressant medicines can help ease the symptoms of depression, so talk with your health care team if you're feeling persistently sad or hopeless.

Although friends and family can be your best allies, the understanding of people who know what you're going through can be especially helpful. Support groups aren't for everyone. However, for many people with Parkinson's disease and their families, a support group can be a good resource for practical information about Parkinson's disease.

Also, groups offer a place for you to find people who are going through similar situations and can support you.

Trying to maintain some of your usual activities may be helpful. Aim to do as many things as possible that you could do before the onset of Parkinson's disease. Focus on the present and try to maintain a positive attitude.

To learn about support groups in your community, talk to your health care team, a Parkinson's disease social worker or a local public health nurse. Or contact the Parkinson's Foundation or the American Parkinson Disease Association.

You and your family also may benefit from talking to a mental health professional, such as a psychologist or social worker trained in working with people who have chronic conditions.

You're likely to first see a health care professional. You may then be referred to a doctor trained in nervous system disorders, called a neurologist.

Because there's often a lot to discuss, it's a good idea to prepare for your appointment. Here's some information to help you get ready for your appointment.

What you can do

• Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
• Write down key personal information, including any major stresses or recent life changes.
• Make a list of all medicines, vitamins and supplements that you're taking.
• Ask a family member or friend to come with you, if possible. Sometimes it can be difficult to remember all the information provided to you during an appointment. Someone who goes with you may remember something that you missed or forgot.
• Write down questions to ask during your appointment.

Your time with your care team is limited, so preparing a list of questions ahead of time will help you make the most of your time together. For Parkinson's disease, some basic questions to ask include:

• What's the most likely cause of my symptoms?
• Are there other possible causes?
• What kinds of tests do I need? Do these tests require any special preparation?
• How does Parkinson's disease usually progress?
• Will I eventually need long-term care?
• What treatments are available, and which do you recommend for me?
• What types of side effects can I expect from treatment?
• If the treatment doesn't work or stops working, do I have additional options?
• I have other health conditions. How can I best manage these conditions together?
• Are there any brochures or other printed material that I can take home with me? What websites do you recommend?

In addition to the questions that you've prepared to ask your care team, don't hesitate to ask questions that occur to you during your appointment.

What to expect from your doctor

Your health care team is likely to ask you a several questions. Being ready to answer them may reserve time to go over any points you want to spend more time on. You may be asked:

• When did you first begin experiencing symptoms?
• Do you have symptoms all the time, or do they come and go?
• Does anything seem to improve your symptoms?
• Does anything seem to make your symptoms worse?