What Is Parkinson's Disease?

Written by: Juliette Daly | Last reviewed: November 2021 | Last updated: September 2022

Parkinson’s disease (PD) is a type of movement disorder. It is a chronic (long-term) condition that slowly worsens over time.1,2

PD causes symptoms that impact a person’s ability to move. These symptoms may include tremor, stiffness, and difficulty walking and balancing.1,2

What causes it?

In PD, the brain cells (neurons) that make dopamine stop working or die. Dopamine is a chemical messenger. That means it helps parts of the brain communicate. It has an important role in the part of the brain that regulates movements. The loss of dopamine in the brain causes the movement symptoms of PD.1,3

The exact cause of PD is not known. Scientists believe it may result from a combination of genetic and environmental factors. PD is more common in men, but researchers do not know exactly why. Age is also a risk factor for PD. Most people who are diagnosed are older than 60.1,3

What are the symptoms?

PD is classified as a movement disorder. It is the most common form of parkinsonism, a group of conditions that are noted by 4 typical symptoms:1,3

  • Tremor at rest, such as a slight tremor in a hand or foot
  • Rigidity (stiffness) of limbs, neck, or shoulders
  • Impaired balance when standing up (postural instability), which can contribute to falls
  • Slowness of movement or gradual loss of spontaneous movement (bradykinesia)

Other symptoms of PD may include:1,3

  • Changes in handwriting
  • Stooped posture
  • Soft voice
  • Problems swallowing
  • Constipation
  • Difficulty sleeping
  • Drooling
  • Low blood pressure
  • Problems controlling urine
  • Cognitive changes
  • Hallucinations/delusions
  • Depression or anxiety
  • Loss of smell

Symptoms of PD are generally mild at the beginning. The most common early symptoms are difficulty standing after sitting, stiffness in the limbs, or moving more slowly.1,3

As the condition progresses, more classic and obvious movement symptoms may appear. However, everyone’s experience with PD is unique. Not everyone will have the same symptoms or the same disease progression.1,3

How is it diagnosed?

Diagnosing PD can be difficult because there is no 1 specific test for it. The diagnosis is typically based on medical history, a physical exam, and answers to specific questions. The physical exam will look for signs of PD like tremor or rigidity. Your doctor may use imaging or lab tests to help support a diagnosis of PD and rule out other diseases.1,2

If you think you have PD, it is best to see a neurologist, preferably a movement disorder specialist. This will be the person most qualified to recognize the signs of PD and provide an accurate diagnosis.1,3

How is it treated?

There is no known cure for PD at this time. However, there are many treatment options to help maintain quality of life. The goal of PD treatment is to control symptoms as best as possible.1,2

Treatments for PD may include medicines that promote dopamine signaling, such as levodopa. Levodopa is the most common drug used to treat PD. It works by increasing levels of dopamine in the brain. Other drugs may include those that stimulate dopamine receptors (dopamine agonists). Your doctor may use these drugs along with levodopa to better control symptoms.1,3

There are also some surgical options like deep brain stimulation (DBS). This requires surgery to implant a probe in the brain. The probe uses electrical impulses to modify the activity of the neurons in the brain that control movement.1,2

These treatments can often manage or improve motor symptoms. However, more research is needed to find treatments that stop the progression of the disease or treatments that help alleviate non-motor symptoms.3

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