Parkinson’s disease is a type of brain disorder that causes uncontrolled or unintentional movements. Its effects can extend beyond muscle movements and include issues with balance, difficulties with the bowels, memory problems, and mental health challenges.

The arm of one person crossing over the arm of another person, with both their hands moving. Share on Pinterest
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Parkinson’s disease affects an estimated 8.5 million people worldwide. By 2030, experts believe that roughly 1.2 million Americans will be diagnosed with the condition.

People living with Parkinson’s can experience a variety of potentially disabling symptoms. They range from muscle tremors and stiffness to issues with balance, speaking, bowel movements, and mental health.

Parkinson’s disease is progressive. A person may not notice all the symptoms at first, and symptoms may develop slowly or worsen over time.

This article reviews the various ways that Parkinson’s disease can affect a person’s body.

A diagram showing how various symptoms of Parkinson's disease affect different parts of the body.Share on Pinterest
Diagram showing how various symptoms of Parkinson’s disease affect different parts of the body. Medical Illustration by Bailey Mariner.

Experts consider muscle tremors to be one of the four main symptoms associated with Parkinson’s disease, along with muscle stiffness, slow movement, and balance issues. It is also one of the first symptoms a person may experience.

Tremors, or uncontrolled movements, often affect a person’s:

  • legs
  • head
  • arms
  • hands
  • jaw

Tremors often occur when the muscle is at rest and may stop when the muscles become engaged or when the person is asleep.

Muscle stiffness or rigidity occurs when a person’s muscles stiffen and remain tightened for long periods of time.

It is one of the most common symptoms associated with Parkinson’s disease. An estimated 90% of people with Parkinson’s disease experience muscle stiffness at least once in their lifetime.

People with muscle stiffness may experience difficulties with the following:

  • Everyday tasks: Certain tasks, such as holding a pen or doing up buttons, can become challenging.
  • Facial muscles: Stiffness can affect chewing, swallowing, and making facial expressions (known as “Parkinson’s mask”).
  • Arm swinging: Muscle tightness can lead to changes in arm swing, including reduced motion.
  • General movement: Stiffness can affect general movements, such as getting out of chairs or turning over in bed.
  • Breathing: Stiffness can make a person’s chest muscles weaker, which can lead to breathing problems and chest infections.

Slow movements, known as bradykinesia, are another common symptom of Parkinson’s disease. Bradykinesia can appear in several ways, such as:

  • slowness when initiating movement
  • reduced automatic movements
  • general slowness in walking and other movements

A Parkinson’s diagnosis requires the presence of bradykinesia along with either muscle stiffness or tremors.

Balance is another of the four most common symptoms of Parkinson’s disease.

It can include issues with both balance and coordination, which can lead to difficulties with standing and walking and increase a person’s likelihood of falling.

Coordination issues can also make it difficult to perform daily tasks such as carrying objects or doing up buttons on clothes.

Learn more about problems with balance.

Parkinson’s disease can change how a person speaks. They may have a more monotone affect when speaking, which forms part of a group of speech disorders known as dysarthria. They may also:

  • speak too quickly or too slowly
  • slur their words
  • speak too softly
  • hesitate before speaking
  • trail off at the end of words

Further, a person may experience issues with chewing and swallowing due to muscle stiffness. This can involve symptoms associated with eating and drinking, such as:

A person may also drool due to reduced swallowing. This can lead to a buildup of saliva in the mouth.

A person living with Parkinson’s disease may experience issues with their bowel movements and digestive health in general. Common symptoms include both constipation and nausea.

Experts believe this may be due to two factors. These include slowed muscle responses delaying the swallowing of and digestion of food, and issues with the nerves in the digestive tract.

Depression and anxiety commonly occur in people living with Parkinson’s disease.

According to the Parkinson’s Foundation, an estimated 50% of people will develop some form of depression, and about 40% will develop an anxiety disorder after their Parkinson’s diagnosis.

A person living with Parkinson’s disease may notice issues with their memory. Memory issues may not develop in all people. It can also affect people differently, with mild to severe symptoms.

More severe symptoms may affect a person’s daily life, while mild issues with memory are less likely to cause challenges with work, school, or home life.

Common symptoms of memory or cognitive issues can include:

  • difficulty focusing or concentrating
  • trouble seeing information three-dimensionally (such as following directions)
  • difficulty with problem-solving
  • issues with multitasking

Learn more about short and long-term memory loss.

Researchers are still unclear on the exact cause of Parkinson’s disease. However, there are several theories as to what potentially causes the condition. These include:

  • Impaired or dead nerve cells in the basal ganglia (area of the brain responsible for movement): The cause of death of these neurons is not known.
  • Loss of the nerve endings that produce norepinephrine: This chemical is a messenger for the nervous system, which controls many bodily functions.
  • Lewy bodies in the brain: These are irregular clumps of a protein. Scientists are trying to better understand how these proteins work.
  • Possible genetic or hereditary connections: A few cases can be traced to particular genetic mutations, although most cases are not passed down through families.

Learn more about the different types and causes of Parkinson’s.

Parkinson’s disease does not have a cure. Treatment goals focus on addressing symptoms associated with the condition.

Therapies may include one or more of the following treatments:

Learn more about treatment for Parkinson’s.

Parkinson’s disease progresses slowly. It is not possible for a doctor or other expert to predict how the disease will progress.

In general, a person living with Parkinson’s disease will live the same length as anyone else. However, as the disease progresses, they become less likely to respond well to medications and may experience more life-altering complications, such as:

Parkinson’s disease is a progressive disease associated with several movement-related symptoms. It can also affect thinking, mood, and other issues in the body. A person may not notice symptoms all at once, and symptoms can get worse over time.

Treatments can help with symptoms, but there is no cure for the condition. A person can live a full life but may experience more life threatening or serious complications as the disease progresses.