What Is Parkinson’s Disease?

What Is Parkinson’s Disease?

Parkinson’s disease is a progressive neurodegenerative disorder that damages neurons (nerve cells) in the substantia nigra (SN), an area of the brain that helps control movement, and other areas of the brain. These neurons produce dopamine, a neurotransmitter in the brain that acts as a messenger between parts of the brain and the nervous system. Dopamine helps control body movements, memory, and other functions. As a result of the loss of neurons, dopamine in the brain decreases, and movement and other body functions are affected.

People who develop Parkinson’s disease are typically 60 or older, and the risk increases with age. However, it is not rare for younger adults to develop Parkinson’s disease. Symptoms of Parkinson’s disease include muscle stiffness and slow movement. Parkinson’s disease starts with mild symptoms, which get worse over time. Currently, there is no cure for Parkinson’s disease cannot, but medications can improve the symptoms.

Parkinson’s disease vs. parkinsonism

Parkinsonism is a term used to describe the symptoms of tremors, muscle rigidity, and slowness of movement typical Parkinson’s disease and other conditions. Parkinson’s disease is the most common type of parkinsonism, but other conditions have similar symptoms.

Other medical conditions that can cause parkinsonism include:

  • Essential tremor (ET)
  • Normal pressure hydrocephalus (NPH)
  • Lewy body dementia (LBD)
  • Multiple system atrophy (MSA)
  • Corticobasal syndrome
  • Progressive supranuclear palsy


Signs & Symptoms of Parkinson's Disease


Symptoms of Parkinson’s disease begin gradually and get worse as the disease progresses. Signs and symptoms of Parkinson’s disease include:

  • Tremors (although many patients do not experience tremors)
  • Muscle stiffness
  • Slow movement
  • Poor posture
  • Balance and coordination difficulties
  • Speaking difficulties
  • Mental and behavioral changes or conditions, including depression and memory problems

Elderly man eating soup, holding the spoon with one hand and using the other to steady it.

What Causes Parkinson's Disease?


Parkinson’s disease is caused by damage to certain nerve cells (neurons) in the part of the brain called the substantia nigra (SN), which helps control movement and other brain areas. These neurons produce dopamine, and when they become damaged, they produce less dopamine. This loss of dopamine causes atypical activity in the brain, which leads to movement issues and other symptoms.

The cause of Parkinson’s is unknown. It may be related to genetic changes and environmental factors, but the details are unclear, and more research is needed.

Other changes occur in the brains of people with Parkinson’s disease, but it is unclear why they occur. These changes include the presence of Lewy bodies. Lewy bodies are clumps of abnormal protein particles that affect brain parts associated with movement, cognition, behavior, and sleep, leading to Parkinson’s disease or Lewy body dementia.

Risk Factors

Risk Factors

Risk factors for developing Parkinson’s disease include:

  • Age – People who develop Parkinson’s disease are typically 60 years old or older, and the risk increases with age. However, it is not rare for younger adults to also develop Parkinson’s disease.
  • Genetics – There is a small risk that a parent will pass on the disease to a child due to genetic factors.
  • Gender – People who are biologically male are more likely to develop Parkinson’s disease than those who are biologically female.
  • Exposure to toxins – Research suggests that certain herbicides and pesticides may increase the risk of developing Parkinson’s disease. More research is needed.



Some conditions are often associated with Parkinson’s disease. Still, as Parkinson’s disease typically affects older people, some of the issues experienced by people with Parkinson’s disease may not be directly associated with the disease. Some treatments may help with symptoms.

Complications of Parkinson’s disease may include:

  • Cognitive changes – In the later stages of Parkinson’s disease, people may experience cognitive problems (problems thinking, remembering, making decisions, or using judgment) or dementia (which occurs when cognitive impairment becomes severe, impacting personal and professional functioning) as symptoms worsen.
  • Depression and emotional changes – People with Parkinson’s disease may experience depression and anxiety. Treatments for these conditions are available.
  • Chewing and swallowing problems – In the late stages of Parkinson’s disease, chewing and swallowing difficulties may lead to poor nutrition and increase the risk of choking.
  • Sleep problems and sleep disorders – People with Parkinson’s disease often have sleep issues, such as waking up frequently or falling asleep during the day. Medications may help improve sleep.
  • Bladder problems – Frequent and urgent urge to urinate (even when the bladder isn’t full) can occur in people with Parkinson’s disease.
  • Constipation – Some people with Parkinson’s disease have infrequent bowel movements or difficulty passing stool.

Parkinson’s Disease Prevention


Because the cause of Parkinson’s is unknown, there are no proven ways to prevent the disease.

Get Care

Trust NewYork-Presbyterian for Parkinson’s Disease Care

Specialists at NewYork-Presbyterian have training and expertise in treating people with Parkinson’s disease and helping manage related symptoms. Learn more about treatments for Parkinson’s disease available at NewYork-Presbyterian. Contact us to make an appointment.