Parkinson's disease is a movement disorder of the nervous system that worsens over time. The nervous system is a network of nerve cells that controls many parts of the body, including movement.

Symptoms start slowly. The first symptom may be a barely noticeable tremor in just one hand or sometimes a foot or the jaw. Tremor is common in Parkinson's disease. But the disorder also may cause stiffness, slowing of movement and trouble with balance that raises the risk of falls.

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. Symptoms get worse over time.

Although Parkinson's disease can't be cured, medicines may help symptoms get better. Sometimes a healthcare professional may suggest surgery to help control parts of the brain. This surgery may help lessen symptoms.

Parkinson's disease symptoms can be different for everyone. Early symptoms may be mild, and you may not even notice them. Symptoms often begin on one side of the body, then affect both sides. Symptoms are usually worse on one side than the other. Some Parkinson's disease symptoms are similar to those of other disorders.

Parkinson's symptoms may include:

• Tremor. This rhythmic shaking usually begins in the hands or fingers. Sometimes tremor begins in the foot or jaw. 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 or when you're under stress. You may notice that you shake less when you're doing some sort of task or moving around.
• Slowed movement, also called bradykinesia. Parkinson's disease may slow your movement, making simple tasks more difficult. It may be hard to get out of a chair, shower or get dressed. You may have less expression in your face. It may be hard to blink.
• Rigid muscles. You may have stiff muscles in any part of your body. Your muscles may feel tense and painful, and your arm movements may be short and jerky.
• Poor posture and balance. Your posture may become stooped. You may fall or have balance problems.
• Loss of automatic movements. You may be less able to make certain movements that you typically do without thinking, 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 flat or monotone, without typical speech patterns.
• Writing changes. You may have trouble writing, and your writing may appear cramped and small.
• Nonmotor symptoms. These may include depression, anxiety, constipation and sleep problems. They also may include acting out dreams, needing to urinate often, trouble smelling, problems with thinking and memory, and feeling very tired.

When to see a doctor

See a healthcare professional if you have any symptoms of Parkinson's disease. This will help diagnose your condition and rule out other causes.

In Parkinson's disease, nerve cells in the brain called neurons slowly break down or die. Many Parkinson's disease symptoms are caused by a loss of neurons that produce a chemical messenger in the brain. This messenger is called dopamine.

Decreased dopamine leads to irregular brain activity. This causes movement problems and other symptoms of Parkinson's disease. People with Parkinson's disease also lose a chemical messenger called norepinephrine that controls many body functions, such as blood pressure.

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

• Genes. Specific genetic changes are linked to Parkinson's disease. But these are rare unless many family members have had Parkinson's disease.
• Environmental factors. Exposure to certain toxins or other environmental factors may increase the risk of later Parkinson's disease. One example is MPTP, a substance that can be found in illegal drugs and is sometimes sold illegally as "synthetic heroin." Other examples include pesticides and well water used for drinking. But no environmental factor has proved to be a cause.

Many changes happen in the brains of people with Parkinson's disease. Researchers are studying why the changes happen and the roles they play. These changes include:

• The presence of Lewy bodies. Clumps of proteins in the brain are associated with Parkinson's disease. These are called Lewy bodies, and researchers believe these proteins hold an important clue to the cause of Parkinson's disease.
• Alpha-synuclein found within Lewy bodies. Alpha-synuclein is a protein found in all Lewy bodies. It occurs in a clumped form that cells can't break down. This is currently an important focus among Parkinson's disease researchers. Alpha-synuclein has been found in the spinal fluid of people who later have Parkinson's disease.
• Altered mitochondria. Mitochondria are powerhouse compartments inside cells that create most of the body's energy. Changes to mitochondria can cause cell damage. These changes have been found in the brains of people with Parkinson's disease.

Risk factors for Parkinson's disease include:

• Age. The risk of Parkinson's disease increases with age. Usually, it starts around age 50 or older. The average age of onset is around age 70. Parkinson's disease can occur in younger adults, but it is rare. When people younger than age 50 have the disease, it's known as early-onset Parkinson's disease.
• Genetics. Having one or more first-degree relatives, such as parents or siblings, with Parkinson's disease increases your risk. Your risks are still small unless you have many blood relatives with the condition.
• Male 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.

People with Parkinson's disease may have other complications that may be treatable. These may include:

• Trouble thinking clearly. Parkinson's disease can affect people's memory, language and reasoning skills. The disease also can lead to dementia or other conditions that affect thinking. These complications usually happen later in Parkinson's disease, and medicines usually have only a modest benefit in managing these symptoms.
• Emotional changes and depression. Some people may feel irritable and concerned early in the course of Parkinson's disease. They also may have depression and anxiety. Medicines and other treatment can help with these changes.
• Trouble swallowing and chewing. Late-stage Parkinson's disease affects the muscles in the mouth. This causes trouble swallowing and chewing, which can lead to not getting enough nutrients in your diet. If food or saliva collects in the mouth, it can cause choking or drooling.

• Sleep problems and sleep disorders. You may wake up often during the night, have nightmares and fall asleep during the day.

  Another symptom may be rapid eye movement sleep behavior disorder. This involves acting out your dreams. Medicines and other therapies may help your sleep get better.

Other symptoms that can occur include:

• Bladder problems. You may have problems such as urgency.
• Constipation. You may have a hard time passing stool. You may pass stool fewer than three times a week.
• Blood pressure changes. You may feel dizzy or lightheaded or even faint when you stand up due to a sudden drop in blood pressure. This also is called orthostatic hypotension.
• Loss of smell. You may fully or partially lose your sense of smell.
• Tiredness. You may feel very tired and lack energy, especially late in the day.
• Pain. You may have pain or cramps in your muscles and joints.
• Sexual symptoms. You may have a decrease in sexual desire or performance.

Because the cause of Parkinson's disease is not known, there are no proven ways to prevent it. Research shows that some factors may help protect against it. But scientists don't know for sure. These factors include:

• Exercise. Aerobic exercise has been linked to a lower risk of Parkinson's disease.
• Caffeine. Some studies show a link between drinking caffeinated beverages such as coffee and green tea and a lower risk of Parkinson's disease.
• Medicines. Some medicines, such as ibuprofen and statins, have been linked to a lower risk of the disease.

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.

It can take time to diagnose Parkinson's disease. Healthcare 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.

Your healthcare team may order some of these tests and procedures:

• Physical and neurological exam. This includes taking your medical history and doing a neurological exam that tests your thinking and mental abilities, senses, coordination, and reflexes.
• Blood and lab tests. These are used to rule out other conditions that may be causing your symptoms.
• Imaging tests, such as an MRI, brain ultrasound and PET scan. These are used to rule out other conditions. They are not very helpful in diagnosing Parkinson's disease.
• A specific single-photon emission computerized tomography (SPECT) scan called a dopamine transporter (DAT) scan. This can help support the suspicion that you have Parkinson's disease and help identify different types of tremor. But it is your symptoms and the results of your neurological exam that determine your diagnosis. Most people do not require a DAT scan.
• Genetic testing. This tests for gene changes if there is a known family history of Parkinson's disease or if you have early-onset disease.
• A short, low-dose treatment of medicines. You may be given medicines used to treat Parkinson's disease to see if you get better. If your symptoms show significant improvement, this may help confirm your diagnosis. You must be given a sufficient dose to show the benefit, as getting low doses for a day or two isn't reliable.
• Follow-up appointments. Regular appointments with neurologists trained in movement disorders may be needed over time to confirm a diagnosis.

• Alpha-synuclein test. This test, also called an alpha-synuclein seed amplification assay, detects Parkinson's disease before symptoms begin. Alpha-synuclein clumps are a hallmark sign of Parkinson's disease. Healthcare professionals can test for this condition in the skin or spinal fluid.

  Alpha-synuclein is found in Lewy bodies. It forms clumps that the body can't break down. The clumps spread and damage brain cells.

  In a 2023 study, researchers tested the spinal fluid of more than 1,000 people to look for clumps of the protein alpha-synuclein. 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 breakthrough 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.

Prevent falls

The following tips may help:

• Don't rush.
• Don't do too many things at once.
• Use handrails.
• Use night-lights.
• Don't use throw rugs or rolling chairs and keep cords out of the way.
• Learn new turning and walking techniques, including landing on your heel first. Also, stand tall and look straight ahead rather than down at your feet when you walk. If you start shuffling, stop. Check your posture and make sure you're standing up straight.
• Use a walker or cane if your healthcare professional recommends it.

Daily living activities

These healthcare professionals can help with daily tasks:

• Occupational therapist. An occupational therapist can show you ways to help with activities such as dressing, bathing and cooking.
• Speech therapist. A speech therapist may be able to help with swallowing and speech problems.

Supportive therapies may help ease some of the symptoms of Parkinson's disease, such as pain, fatigue and depression. When combined with your medical treatments, they may improve your quality of life. These include:

• Massage. Massage therapy can reduce muscle tension and promote relaxation. This therapy 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.
• Yoga. In yoga, gentle stretching movements and poses may increase 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.
• Relaxation techniques. These practices help lower blood pressure and heart rate and improve muscle tone.
• Self-hypnosis. This method helps you learn to relax when prompted by your own phrase or suggestion.

Living with any chronic illness can be hard, and it's common 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. Talk with your healthcare team if you have feelings of sadness or hopelessness that don't go away.

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 Parkinson's disease symptoms started. Focus on the present and try to maintain a positive attitude.

To learn about support groups in your community, talk with your healthcare 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 with 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 your family healthcare 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.

What you can do

• Write down any symptoms you have, including any that may seem unrelated to the reason for your 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 hard 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 can 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 get worse?
• 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 healthcare 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 having 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?