Parkinson's Disease

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is Parkinson’s disease?

Parkinson’s disease is a neurodegenerative disease. It damages nerve cells in the brain that are responsible for smooth, controlled and coordinated body movements. With time, Parkinson’s disease becomes a seriously disabling disorder. It progressively impairs and destroys a person’s ability to move normally and function independently.

Parkinson’s disease is caused by loss or damage to brain cells that produce dopamine—a brain chemical that transmits nerve impulses. Lack of dopamine disturbs nerve messages from the brain. This results in typical symptoms of Parkinson’s disease, such as trembling or tremor of the hands and feet. Symptoms most often begin in late middle age or older, but can occur earlier in life in rare cases. Curiously, people who smoke cigarettes are less likely to develop Parkinson’s disease.

There is no cure for Parkinson’s disease. However, ongoing research into its progression and treatment is leading to therapies that can slow advancement of the disease and control symptoms.

Symptoms of Parkinson’s disease eventually make it difficult to carry out activities of daily living, such as bathing and dressing. Other complications include dementia and depression. Seek prompt medical care if you have symptoms of Parkinson’s disease, such as trembling of the hands and problems with motor skills and balance. Early diagnosis and treatment can help slow progression of the disease, minimize symptoms, and improve your quality of life.

What are the symptoms of Parkinson’s disease?

The way in which the symptoms of Parkinson’s disease develop varies among individuals. Symptoms usually begin in people older than 50, but they can occur earlier in life in rare cases. In general, symptoms of Parkinson’s disease begin subtly and advance slowly.

Early symptoms of Parkinson’s disease

Early symptoms of Parkinson’s disease include:

  • Depression
  • Feeling shaky
  • Tremors, such as trembling in the hands, arms, legs and face
  • Unusually soft speech

Symptoms as Parkinson’s disease progresses

As symptoms progress they eventually affect a variety of skills and body functions such as:

  • Balance and gait (walking pattern, postural instability)
  • Blood pressure
  • Digestion
  • Emotion
  • Motor skills and movement
  • Posture
  • Speech

Later symptoms of Parkinson’s disease

Later symptoms of Parkinson’s disease include:

  • Akinesia (difficulty beginning or maintaining muscle movements)
  • Blank stare
  • Bradykinesia (a type of slowness of movement)
  • Constipation and urination difficulties
  • Difficulty speaking, chewing and swallowing
  • Impaired balance and coordination
  • Leg discomfort, such as cramps or burning
  • Muscle rigidity, especially in the arms, legs and trunk
  • Shuffling walk and stooped posture, as if hurrying forward to keep balance

Serious symptoms that might indicate a life-threatening condition

Life-threatening complications of Parkinson’s disease include pneumonia and choking, which is caused by difficulties with chewing and swallowing. Seek immediate medical care (call 911) if you, or someone you are with, have any of these symptoms:

  • Change in alertness or level of consciousness, such as passing out, lethargy or unresponsiveness
  • Choking or coughing
  • Gasping
  • Grabbing at the throat
  • High fever (higher than 101°F)
  • Inability to speak

What are the stages of Parkinson’s disease?

While Parkinson’s disease can affect people differently, it generally progresses in stages. These stages represent the typical progression of the disease. There are five stages of Parkinson’s disease:

  • Stage 1: Mild symptoms occur, but do not interfere with daily living. Tremor and movement symptoms only affect one side of the body. You may notice slight changes in posture, walking, and facial expressions.
  • Stage 2: Symptoms occur on both sides of the body. Daily living becomes harder, with tasks taking longer than normal. Problems with posture and walking become more obvious. People in this stage can still have a lot of independence.
  • Stage 3: Loss of balance and slowness of movements are the main symptoms of this mid-stage. Falls become a concern and daily living is challenging. However, independent living is still possible in this stage.
  • Stage 4: Symptoms become severe and limit daily living. Help with activities, such as dressing and eating, is necessary. Walking usually requires a walker and living alone is not possible.
  • Stage 5: Advanced symptoms, such as leg stiffness, make it impossible to stand or walk. A wheelchair is necessary when the person is out of bed. The person needs full-time nursing care and may experience mental symptoms, such as hallucinations.

The most common tool for staging Parkinson’s disease is the Unified Parkinson Disease Rating Scale (UPDRS). The UPDRS measures the severity and progression of the disease. It uses markers such as behavior, mood, motor function, and activities of daily living. Higher scores indicate declining function and advanced disease.

What causes Parkinson’s disease?

Parkinson’s disease is caused by the loss of dopamine-producing nerve cells in the brain. Normal cells transmit messages that control muscle movement to the motor nerves in the spinal cord. The loss of dopamine results in impaired nerve transmission and muscle movement that is characteristic of Parkinson’s disease.

The underlying cause of the loss of these nerve cells is not known, although theories about the cause include a combination of genetics and exposure to environmental toxins. In some cases, Parkinson’s disease is inherited, but most cases occur sporadically in families without a history of the disease.

The specific combination of factors that lead to Parkinson’s disease differ between people. In some cases, the underlying cause(s) may lean more towards genetics, such as people who have a family history of Parkinson’s; in others, exposure to a toxin or something else may have a greater influence than genetics on development of the disease.


In some cases, people can develop a group of symptoms that are very similar to those of Parkinson’s disease. This is called parkinsonism. Treatment focuses first on managing the underlying problem that generated the symptoms, then on symptom relief.

Parkinsonism can be caused by:

  • Carbon monoxide poisoning
  • Encephalitis (inflammation of the brain due to a viral or bacterial infection)
  • Head or neck injury, especially repeated head injuries, such as from boxing
  • Stroke and certain other neurological conditions

What are the risk factors for Parkinson’s disease?

A number of factors increase the risk of developing Parkinson’s disease (PD) or parkinsonism, but not all people with risk factors will get the condition. Risk factors include:

  • Advanced age or late middle age (older than 50 years)
  • Encephalitis (inflammation of the brain due to a viral or bacterial infection)
  • Exposure to certain toxins, such as pesticides and herbicides
  • Family history of Parkinson’s disease—you are two times more likely to develop PD if you have a parent or sibling with PD
  • Male biological sex—50% more males than females get PD
  • Mutations in certain genes
  • Stroke and certain other neurological conditions
  • Use of medications associated with the onset of secondary parkinsonism, such as antipsychotics and metoclopramide, which is used to treat nausea and gastroesophageal reflux disease

Reducing your risk of Parkinson’s disease and parkinsonism

Parkinson’s disease is not preventable, but you may be able to lower your risk of developing parkinsonism by:

  • Avoiding exposure to pesticides and herbicides and following the manufacturer’s instructions for their use
  • Using carbon monoxide detectors
  • Using recommended protective head and neck gear when performing dangerous activities or contact sports

How do you prevent Parkinson’s disease?

The exact cause of Parkinson’s disease is not known, so there are no proven methods of preventing it. Neurologists are actively studying the disease to learn more about its causes and risk factors. You may be able to lower your risk of developing PD or parkinsonism by:

  • Avoiding exposure to pesticides and herbicides and following the manufacturer’s instructions for their use

  • Exercising regularly—aerobic exercise is associated with a lower rate of Parkinson’s disease and Alzheimer’s disease

  • Using carbon monoxide detectors

  • Using recommended protective head and neck gear when performing dangerous activities or contact sports

Caffeine, nicotine and Parkinson’s disease risk

Many studies have confirmed the link between dietary caffeine consumption and decreased risk of PD. Scientists are actively studying how caffeine and other substances in coffee and tea lower a person’s risk of PD. More recent studies show that increased coffee intake is associated with a lower risk of PD in people with certain genetic backgrounds, namely a mutation in the LRRK2 gene. There is more to learn about the neuroprotective substances in coffee and tea. In the meantime, drinking coffee and tea in moderation is low risk and may have positive effects on the brain.

The risk of developing Parkinson’s disease is lower in smokers vs. nonsmokers. From several studies, it is not clear that nicotine, one of the active components in tobacco, is neuroprotective. Another theory is that people who develop PD are less likely to smoke or become addicted to nicotine. In any case, current research may lead to new treatments based on the relationship between smoking and Parkinson’s disease.

How do doctors diagnose Parkinson’s Disease?

There is no specific test to diagnose Parkinson’s disease. Instead, it is a clinical diagnosis, meaning doctors rely on symptoms and a detailed medical history. This makes it challenging to diagnose because early signs and symptoms often look like other conditions and can mimic the effects of aging. As a result, it can take time—sometimes years—to arrive at a definitive diagnosis. Seeing a neurologist with expertise in movement disorders is beneficial. This specialist will evaluate you over time.

Your doctor will likely start with some questions about your symptoms including:

  • What symptoms are you experiencing?
  • When did you first notice your symptoms?
  • Are your symptoms constant or sporadic?
  • What, if anything, seems to make your symptoms better or worse?

Your doctor will also perform a physical exam and ask you to walk. The exam will focus on your posture, coordination and movement. Your doctor is looking for at least two of the following symptoms:

  • Balance problems
  • Stiffness or rigidity in your arms and legs
  • Tremor in your hands and arms at rest or when you extend your arms

Your doctor will also want to know about any other physical symptoms, such as constipation, and mental symptoms, such as depression.

After the physical exam, your doctor may recommend testing, such as blood tests and imaging exams. In some cases, doctors may order special brain scans including:

  • PET (positron emission tomography) scan, which can show how your brain functions and uses sugar
  • DaTscan (dopamine transporter) scan, which can show brain cells that do not have enough dopamine

None of these tests can diagnose Parkinson’s disease, but they can help rule out other conditions. To confirm a Parkinson’s disease diagnosis, your doctor may prescribe a trial of levodopa. Levodopa replaces dopamine in the brain. If your symptoms improve while you are taking the medicine, there is more confidence in the diagnosis.

Because it can be so hard to diagnose Parkinson’s disease, seeking a second opinion may give you more information and answers.

How is Parkinson’s disease treated?

Currently, there is no cure for Parkinson’s disease. However, early recognition and a multifaceted treatment plan can help. The goals of treatment are to slow the progression, minimize your symptoms, and enhance your quality of life. Treatment options include medications, physical therapy, and possibly surgery.

Medications to treat Parkinson’s disease

Medications for Parkinson’s disease help increase dopamine or decrease acetylcholine in the brain. This can minimize trembling and other symptoms. Medications include:

  • Amantadine (Symmetrel), which is an antiviral drug that also has positive effects on jerky movements
  • Anticholinergic medications, including benztropine mesylate (Cogentin) and trihexyphenidyl (Artane), which help reduce trembling temporarily in some cases
  • COMT inhibitors, including entacapone (Comtan) and tolcapone (Tasmar), which make levodopa and carbidopa more effective
  • Dopamine agonists, including pramipexole (Mirapex), ropinirole (Requip) and the patch rotigotine (Neupro), which are medications that have some of the same actions as dopamine
  • Istradefylline (Nourianz), an add-on treatment for people already taking levodopa/carbidopa. Nourianz, an adenosine receptor antagonist, may improve symptoms during "off" episodes, when levodopa/carbidopa are not working well to control symptoms
  • Levodopa, either alone or in combination with carbidopa. Levodopa is a chemical that is converted to dopamine in the brain. Carbidopa helps prevent the breakdown of levodopa, allowing more of it to reach the brain. Levodopa often becomes less effective after several years of treatment. It comes as a regular tablet (Sinemet), an extended-release tablet (Rytary), an orally disintegrating tablet (Parcopa), and an intestinal infusion (Duopa).
  • MAO-B inhibitors, including rasagiline (Azilect), safinamide (Xadago), and selegiline (Eldepryl, Zelapar), which allow dopamine to have a longer-lasting effect on the brain

Surgery and procedures to treat Parkinson’s disease

Surgery may be an option for some people with severe symptoms or symptoms that do not improve with drug treatment. Surgical option include:

  • Deep brain stimulation involves placing special electrical wires in the brain to stimulate the brain in a way that controls tremors.
  • Pallidotomy involves making scars in an area of the brain called the globus pallidus, which is overactive in Parkinson’s disease. This procedure can improve tremor and stiffness.
  • Thalamotomy involves destroying an area in the thalamus gland in the brain to improve hand or arm tremors.

Parkinson’s disease may also be treated with physical therapy and nonconventional treatments:

  • Physical therapy and occupational therapy to improve muscle strength, maintain balance and coordination, and reduce the likelihood of falling
  • Stem cell transplants to regenerate nerve cells may be an option in some cases

Hundreds of clinical trials for experimental therapies for Parkinson's disease are underway in the United States and internationally. Ask your doctor if a clinical trial is an option for you.

Lifestyle and alternative treatments

Lifestyle habits can help people with Parkinson’s disease live a better life and even improve symptoms. Try these strategies:

  • Eat a balanced diet with high-fiber foods and drink plenty of water throughout the day. This can help ease constipation. Working with a dietitian may be an option.
  • Exercise to maintain strength, flexibility and balance. This can include such activities as swimming or walking, along with mind-body programs like yoga and Tai Chi. A physical therapist can help you develop an exercise plan that is safe for you.
  • Practice healthy sleep hygiene by keeping a regular sleep schedule. Get activity during the day, sleep in a dark room, and wind down and avoid screens before bed.
  • Prevent falls by not carrying anything when you walk and not wearing shoes with rubber or gripping soles, which can catch especially when shuffling and cause tripping. Stand with your feet shoulder-width apart and change positions slowly.
  • Schedule an in-home consultation with a home health provider. This professional can make your home safer and more accessible, which helps maintain your independence.
  • Use visualization if you become frozen. Picture something in front of you and imagine stepping over it. Someone could also place their foot in front of you if you need something tangible. But do not let someone pull on you, as this could make the episode worse or cause a fall.
  • Walk consciously by swinging your arms from front to back and lifting your feet off the ground. Also, focus on walking evenly, avoid pivoting (make a U-turn instead), and do not lean, which can throw off your balance. Focus only on walking and do not look around or do anything else. Consider using a walking stick or cane.

Alternative treatments may also be beneficial including:

  • Alexander technique, which focuses on posture, balance, and mindfully using your muscles
  • Massage therapy, which may help improve stiffness
  • Meditation, which can reduce stress and even improve pain
  • Pet therapy, which boosts mood and may help keep you active

What are the potential complications of Parkinson’s disease?

Complications of Parkinson’s disease seriously affect the ability to function in everyday life and can be life-threatening in some cases. You can slow the progression of symptoms and reduce the risk of some serious complications of Parkinson’s disease, such as falls, by following the treatment plan you and your healthcare professional design specifically for you.

Complications of Parkinson’s disease include:

  • Adverse effects of treatment
  • Choking
  • Dementia
  • Emotional isolation
  • Falls
  • Inability to communicate
  • Problems with memory and thinking
  • Severe depression

Does Parkinson’s disease shorten life expectancy?

Parkinson’s disease itself is not fatal, but it can cause life-threatening complications. Studies suggest that the life expectancy for people with the disease is essentially the same as the general population. A typical person with the disease can expect to live 1 to 2 years less than someone without the disease.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Sep 24
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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