Parkinson's Disease



Parkinson disease (PD) is a progressive movement disorder. PD is characterized by:

  • Slowing down of movements—bradykinesia
  • Tremor at rest
  • Muscle rigidity
  • Loss of reflexes that maintain posture and equilibrium
Part of the Brain Affected by PD—Yellow Section
Substansia Nigra
Copyright © Nucleus Medical Media, Inc.


PD is caused by a loss of certain nerve cells in the brain. The loss of these cells causes a decrease in the amount of a brain chemical called dopamine. Low dopamine levels cause PD symptoms.

The brain cells may be lost because of genetic defects, the environment, or some combination of the two. A small amount of people with PD have an early-onset form. This type is caused by an inherited gene defect.

Risk Factors

PD is more common in men and in people aged 50 years and older. Other factors that increase your chance of PD include:

  • Family members with PD
  • Nonsmokers
  • Exposure to toxins, such as insecticides, carbon monoxide , or manganese
  • Certain medications, such as antipsychotics, antiseizures, antiemetics, or cardiovascular medications
  • Certain health conditions, such as:
    • Polio
    • High cholesterol
    • Melanoma
    • Hydrocephalus
    • Brain tumors
    • Stroke
    • Encephalitis
    • Meningitis
    • HIV infection
  • IV drug use



PD is a progressive disease. Symptoms begin mildly and worsen over time.

PD may cause:

  • Problems with dexterity
  • Difficulty with activities of daily living
  • Fatigue
  • Stiffness and rigidity of muscles, usually beginning on one side of the body
  • Tremors are present at rest, improve with movement, and are absent during sleep
  • Slowness of purposeful movements
  • Neuropsychiatric symptoms, such as:
    • Depression
    • Anxiety
    • Dementia
    • Hallucinations
  • Difficulty and shuffling when walking
  • Poor balance
  • Tendency to fall
  • Loss of smell
  • Sleep problems
  • Flat, monotonous voice
  • Stuttering
  • Trouble speaking (often speaking with a low volume)
  • Increasingly mask-like face, with little variation in expression
  • Drooling and excessive salivation
  • Shaky, spidery, or small handwriting
  • Seborrhea (a skin problem that causes a red rash and white scales)
  • Trouble chewing and swallowing
  • Urinary symptoms (frequency and urgency)
  • Bowel movement symptoms (straining, constipation)


You will be asked about your symptoms and medical history. A physical exam will be done. There are no tests to definitively diagnose PD. The doctor will ask many questions. This will help to rule out other causes of your symptoms.

Tests to rule out other conditions may include:

  • Blood tests
  • Urine tests

Imaging tests evaluate internal bodily structures. This can be done with:

  • MRI scan
  • CT scan
  • A specialized type of SPECT scan (DaTSCAN)



Currently, there are no treatments to cure PD. There are also no proven treatments to slow or stop its progression. Some medications may help to improve symptoms. Over time, the side effects of the medication may become troublesome. The medications may also lose their effectiveness.


Medications that may be used to treat PD include:

  • Levodopa-carbidopa
  • Dopamine agonists
  • Monoamine oxidase inhibitors
  • Anticholinergics
  • COMT inhibitors
  • Antivirals

Depression or hallucinations may also occur with PD and its treatment. Medications may be prescribed to attempt to treat these conditions. The drugs may include:

  • Selective serotonin reuptake inhibitors (SSRIs)
  • Tricyclic antidepressants
  • Antipsychotics

Hip fractures are common in those with PD. Bisphosphonates are medications that may help reduce this risk.

Constipation, drooling, and lightheadedness when standing are common and may improve with medications or other treatments.


Different brain operations are available, and many more are being researched including:

  • Deep brain stimulation (DBS)—implanting a device to stimulate certain parts of the brain; can decrease tremor and rigidity
  • Thalamotomy and pallidotomy—destroying certain areas of the brain to improve tremor when medication does not work (not as common as deep brain stimulation)
  • Nerve-cell transplants (research only)—to increase amount of dopamine made in the brain

Physical Therapy

Therapy can improve muscle tone, strength, and balance. It includes exercises and stretches. There is also evidence that alternative therapies, such as tai chi, yoga, or dance, may be beneficial.

Psychological Support

Consider joining a support group with other people with PD. It will help to learn how others are learning to live with the challenges of PD.

Cognitive Training

Cognitive training works on aspects of the brain that control certain functions so they can be performed better in daily life. Activities are meant to promote and increase brain fitness through learning or exercises. It works best in conjunction with other healthy lifestyle habits. Some people with Parkinson's disease have seen improvements in reasoning, problem solving, processing speed, and working memory.


There are no current guidelines to prevent PD.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.

a (PD; Paralysis Agitans; Shaking Palsy)


National Parkinson Foundation 

Parkinson's Disease Foundation 


Health Canada 

Parkinson Society Canada 


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