Parkinson’s Disease

Parkinson’s disease is a progressive brain disorder that affects movement and many other aspects of daily life. While there is currently no cure, understanding the condition and available treatments can help people manage symptoms and maintain quality of life for many years.

Table of contents

• What is Parkinson’s Disease?
• How Parkinson’s Affects the Brain
• Symptoms of Parkinson’s Disease
• What Causes Parkinson’s Disease?
• Who Gets Parkinson’s Disease?
• How is Parkinson’s Disease Diagnosed?
• Treatment Options
• Living Well with Parkinson’s Disease

What is Parkinson’s Disease?

Parkinson’s disease is a condition where parts of the brain become progressively damaged over many years.^[1] It is called a movement disorder because it mainly affects how a person moves, but it can also cause many other symptoms throughout the body.^[2]

The disease is progressive, which means symptoms slowly worsen over time.^[1] However, the experience of living with Parkinson’s varies greatly from person to person. Some people may have mild symptoms that worsen very slowly but never become severe, while others will develop more serious difficulties with walking, speaking, and thinking.^[16]

Parkinson’s disease is very common overall, ranking second among age-related degenerative brain diseases.^[3] Experts estimate that it affects at least 1% of people over age 60 worldwide.^[3] Nearly 1 million people in the United States and more than 6 million people worldwide are living with this condition.^[5]

How Parkinson’s Affects the Brain

Although many brain areas are affected in Parkinson’s disease, the most common symptoms result from the loss of neurons (nerve cells) in an area near the base of the brain called the substantia nigra.^[1] This paired structure is part of a circuitry deep within the brain that helps control bodily movements and other behaviors.^[16]

The neurons in the substantia nigra produce dopamine, a chemical messenger that transmits signals in the brain to produce smooth, purposeful movement.^[1] When you have Parkinson’s disease, you don’t have enough dopamine, and your brain cannot properly fine-tune movements.^[3] Studies have shown that most people with Parkinson’s have lost 60 to 80% or more of the dopamine-producing cells in the substantia nigra by the time symptoms appear.^[1]

People with Parkinson’s also lose nerve endings that produce norepinephrine, the main chemical messenger to the part of the nervous system that controls many automatic functions of the body, such as pulse and blood pressure.^[1] The loss of norepinephrine might explain several symptoms that are not related to movement, such as fatigue and blood pressure changes.^[1]

The affected brain cells of people with Parkinson’s contain Lewy bodies, which are deposits of the protein alpha-synuclein.^[1] Researchers do not yet know why Lewy bodies form or their exact role in the disease. Some research suggests that the cell’s protein disposal system may fail in people with Parkinson’s, causing proteins to build up to harmful levels and trigger cell death.^[1]

• Brain (substantia nigra)
• Basal ganglia

Symptoms of Parkinson’s Disease

Parkinson’s disease affects different people in different ways. The rate of progression and the particular symptoms differ among individuals.^[1] Symptoms typically begin on one side of the body. However, the disease eventually affects both sides, although symptoms are often less severe on one side than on the other.^[1]

Movement Symptoms

The four primary movement symptoms of Parkinson’s disease are:^[1]

• Tremor (shaking) often begins in a person’s hand, although sometimes the foot or jaw is affected first. The particular tremor associated with Parkinson’s has a rhythmic back-and-forth motion. Often, the tremor causes a person to rub their thumb and forefinger together, which may appear as “pill rolling.” It is most obvious when the hand is at rest or when a person is under stress.^[1]
• Slowed movement, also called bradykinesia. This makes moving and completing simple tasks difficult and time-consuming.^[2] A Parkinson’s disease diagnosis requires that a person has this symptom.^[3]
• Stiffness or rigidity of muscles, which can be painful and affect movement.^[9]
• Trouble with balance and increased risk of falls. People may have difficulty with posture and coordination.^[2]

Other movement-related symptoms may include changes in walking (such as taking smaller steps or shuffling), problems with speech (soft or slurred), very small handwriting, difficulty swallowing, and “freezing” (temporarily unable to move at all).^[6][16]

Non-Movement Symptoms

Parkinson’s disease can also cause a wide range of symptoms that are not related to movement. These include:^[6][7]

• Depression and anxiety
• Sleep problems, including acting out dreams and sleep talking
• Constipation
• Loss of sense of smell
• Memory problems and cognitive impairment
• Fatigue
• Pain and sensory disturbances
• Low blood pressure, especially when going from lying to sitting, or sitting to standing
• Increased saliva production

Non-movement symptoms sometimes appear years ahead of movement symptoms.^[3] Many people with Parkinson’s also develop dementia (problems with thinking and memory) during the course of their disease.^[7]

In the early stages of Parkinson’s disease, the face may show little or no expression, and the arms may not swing when walking.^[2] Early symptoms may be mild and easily overlooked, which is why the condition is often difficult to diagnose in its beginning stages.^[9]

What Causes Parkinson’s Disease?

Parkinson’s disease is caused by a loss of nerve cells in part of the brain called the substantia nigra. This leads to a reduction in dopamine in the brain.^[6] However, exactly what causes the loss of nerve cells is unclear. Most experts think that a combination of genetic and environmental factors is responsible.^[6]

Researchers believe that in most people, Parkinson’s is caused by a combination of environmental and genetic factors.^[5] Some contributing factors include:^[9]

• Ageing
• Genetic changes
• Exposure to toxins such as pesticides or solvents
• Some medicines
• Infections

The cause of Parkinson’s is unknown, but people with a family history of the disease have a higher risk.^[7] While a small percentage of Parkinson’s cases are caused by a single genetic mutation, the large majority are not.^[5] Exposure to air pollution, pesticides, and solvents may increase risk.^[7]

One important thing experts know is that Parkinson’s disease starts well before symptoms surface. Patients typically only notice motor symptoms after 60% to 80% of the substantia nigra neurons are lost or impaired. Those changes may have been happening for a year or two, potentially even longer.^[16]

Who Gets Parkinson’s Disease?

The risk of developing Parkinson’s disease naturally increases with age, and the average age at which it starts is 60 years old.^[3] Most people with Parkinson’s start to develop symptoms when they’re over 50, although some people with the condition first experience symptoms when they’re under 40.^[6]

Men are affected more often than women.^[7] It’s slightly more common in males.^[3]

While Parkinson’s disease is usually age-related, it can happen in adults as young as 20, though this is extremely rare.^[3] About 5% to 10% of people experience onset before the age of 50. Early-onset forms of Parkinson’s are often, but not always, inherited, and some forms have been linked to specific alterations in genes.^[10]

How is Parkinson’s Disease Diagnosed?

Currently, there isn’t a specific test to diagnose Parkinson’s disease.^[11] No blood test, brain scan, or other test can be used to make a definitive diagnosis.^[5] A diagnosis is made by a doctor trained in nervous system conditions, known as a neurologist.^[11]

A diagnosis of Parkinson’s is based on medical history, a review of symptoms, and a neurological and physical exam.^[11] 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 the condition and symptoms over time and diagnose Parkinson’s disease.^[11]

Diagnosing Parkinson’s disease is especially difficult in the early stages, as early symptoms can be unclear and not specific.^[9] Some of these tests and procedures may be ordered:^[11]

• Physical and neurological examination, including taking medical history and testing thinking and mental abilities, senses, coordination, and reflexes
• Blood and lab tests to rule out other conditions that may be causing symptoms
• Imaging tests, such as an MRI, brain ultrasound, and PET scan to rule out other conditions
• A specific scan called a dopamine transporter (DAT) scan to help support the suspicion of Parkinson’s disease
• Genetic testing if there is a known family history of Parkinson’s disease or early-onset disease
• A short, low-dose treatment of medicines used to treat Parkinson’s disease to see if symptoms improve

If you notice shaking, stiff muscles, lack of balance, or slowed muscle movements, you should see your doctor.^[9] Your doctor may refer you to a specialist, such as a neurologist, for more tests.^[9]

Treatment Options

Although there’s currently no cure for Parkinson’s disease, treatments are available to help relieve the symptoms and maintain quality of life for as long as possible.^[12] Most people respond well to treatment and only experience mild to moderate disability, whereas a minority may not respond as well and can, in time, become more severely disabled.^[6]

There is no one-size-fits-all treatment for Parkinson’s. Treatment should be tailored to an individual’s symptoms through a shared decision-making process with healthcare providers.^[15] You may not need any treatment during the early stages of Parkinson’s disease, as symptoms are usually mild. But you may need regular appointments with your specialist so your condition can be monitored.^[12]

Medications

Levodopa is the most potent drug for controlling Parkinson’s symptoms and remains the most effective medicine for improving symptoms, functioning, and quality of life.^[14] Levodopa is absorbed by the nerve cells in the brain and turned into dopamine.^[12] It is usually taken as a tablet or liquid and is often combined with other medication to prevent it from being broken down before reaching the brain and to reduce side effects.^[12]

At first, levodopa can cause a dramatic improvement in symptoms. However, its effects can be less long-lasting over the following years. It is also associated with complications such as the “wearing off” effect and involuntary movements called dyskinesias.^[14]

Other medication options include:^[14]

• Dopamine agonists, which mimic the effects of dopamine
• Monoamine oxidase-B inhibitors, which help prevent the breakdown of dopamine
• COMT (catechol-o-methyl-transferase) inhibitors, which are used with levodopa to extend its effects
• Medications for non-movement symptoms such as constipation, urinary problems, depression, sleep problems, and pain

Supportive Therapies

Several therapies can make living with Parkinson’s disease easier and help manage symptoms on a day-to-day basis:^[12]

• Physiotherapy can work to relieve muscle stiffness and joint pain through movement and exercise, improve walking and flexibility, and increase fitness levels
• Occupational therapy can identify areas of difficulty in everyday life and help work out practical solutions to ensure the home is safe and properly set up
• Speech and language therapy can help improve swallowing difficulties and problems with speech through exercises or assistive technology
• Diet advice from a dietitian may help with specific symptoms such as constipation, low blood pressure, or weight loss

Surgery

Sometimes surgery may be suggested to help control parts of the brain and lessen symptoms.^[2] Deep brain stimulation (DBS) is a surgical procedure that may be an option when medications do not work as well or when people experience side effects such as dyskinesia.^[17]

Deep brain stimulation involves the surgical implantation of a device used to quiet the brain and tone down Parkinson’s symptoms when they are severe.^[16] This surgery may be considered in patients who are levodopa-responsive but whose levodopa-related motor complications cannot be managed adequately with medication adjustments.^[14]

Another surgical option is focused ultrasound, a non-invasive surgical procedure for Parkinson’s motor symptoms or dyskinesia that can’t be controlled with medication. For some people, focused ultrasound may be an alternative to deep brain stimulation surgery.^[17]

Living Well with Parkinson’s Disease

While living with Parkinson’s can be challenging, there are many things people can do to maintain and improve quality of life and live well with the disease.^[4]

Exercise and Physical Activity

Regular exercise is particularly important in helping relieve muscle stiffness, improving mood, and relieving stress.^[12] Exercise can help manage Parkinson’s symptoms, and some early-stage research shows it may help protect the brain.^[17] Consider activities such as walking, stretching, gentle yoga, seated movements, or more vigorous activities like cycling if symptoms are mild.^[12]

Healthy Eating

Maintaining a well-balanced diet is essential because it provides the necessary nutrients to sustain energy levels and support overall health.^[22] Include “brain foods” in meals and snacks, such as nuts, berries, dark leafy greens, and healthy fats like avocado and salmon.^[22] Making dietary changes can help improve some symptoms, such as increasing fiber and fluids to reduce constipation.^[12]

Rest and Sleep

Getting enough rest is key for individuals with Parkinson’s, as the body takes longer to repair itself and brain changes connected to Parkinson’s can disrupt sleep.^[22] Establish a daily sleep and wake time, allowing the body to respond to a rest routine. Relaxation techniques like deep breathing, meditation, or listening to calming music can help manage stress and promote restful sleep.^[22]

Social Connections

Maintaining personal connections with friends and family is essential. Nurturing relationships provides emotional support and a sense of belonging.^[22] Consider joining a support group or an online community specifically for individuals with Parkinson’s. Sharing experiences with others who understand the journey can be incredibly empowering.^[22]

Parkinson’s UK is a main support and research charity that can help if you’re living with the disease and let you know about support groups in your area. You can contact them by calling their free helpline or emailing them.^[6]

Setting Goals

As you begin to build your life after a Parkinson’s diagnosis, setting clear personal goals then acting on them can help you live well.^[18] Focus your energy where it best serves you. Start small with viable, realistic goals and take doable steps toward achievement.^[18]

Working with Your Healthcare Team

A care plan should be agreed with your healthcare team and your family or carers. This will outline the treatments and help you need now and what you’re likely to need in the future, and should be reviewed regularly.^[12] Building a strong care team is essential to managing Parkinson’s effectively.^[19]

Work and Financial Support

Being diagnosed with Parkinson’s does not mean you have to stop working. Many people with the condition keep working for years after their diagnosis.^[24] If you do have to stop work or work part-time, you may be entitled to various types of financial support and benefits.^[24]

Parkinson’s disease does not directly cause people to die, but the condition can place great strain on the body. However, with advances in treatment, most people with Parkinson’s disease now have a normal or near-normal life expectancy.^[6]