What Is Parkinson’s Disease?

Parkinson’s disease is a progressive neurological disorder that affects motor function, causing tremors, slow and interrupted movements (bradykinesia), and rigidity. While the exact causes of this condition are unknown, people over 60 and those assigned male at birth are more likely to develop it. Overall, Parkinson’s disease is the second most common neurodegenerative disorder, affecting 2 to 3% of adults ages 65 or older.

Though Parkinson’s disease is not fatal, it can severely impact your quality of life, with symptoms worsening over time. Over time, it can affect cognitive ability and sleep and lead to dementia, among other issues. Researchers have not yet found a cure for Parkinson’s.

Parkinson’s treatment depends on the individual case and focuses on easing the severity and progression of symptoms. Medications, additional therapies, and lifestyle changes help make living with Parkinson’s disease easier.

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Types of Parkinson’s Disease

Parkinson’s disease is often broken down into different types based on the causes of symptoms. 

Idiopathic Parkinson’s Disease

The majority of Parkinson’s disease cases are idiopathic, meaning there’s no identified cause for the onset of symptoms. You’re considered to have this type if you develop cardinal signs of the condition, such as tremors and bradykinesia, in absence of any other condition, environmental exposure, genetic predisposition, or medication usage. This type is seen in those who are older than 60.

Early-Onset Parkinson’s Disease

In early-onset Parkinson’s disease, the symptoms of the disease set in when people are younger, with 55 often serving as the cut-off age. This subtype is rarer—only 5 to 10% of patients experience symptoms before age 50—and it’s characterized by slower onset, preserved cognitive ability, and a higher rate of motor effects in response to levodopa treatment (medications used to manage symptoms).

Familial Parkinson’s Disease

Some rare forms of Parkinson’s disease are familial, meaning that they’re passed from parent to child. Researchers have identified about 20 specific gene mutations known to cause symptoms. These mutations, which may also account for some early onset cases, directly account for 5 to 10% of cases and may also influence overall susceptibility to the disease.

Parkinson’s Disease Symptoms

Symptoms of Parkinson's disease can be somewhat variable. There are four cardinal symptoms, plus a multitude of potential motor and non-motor symptoms.

Cardinal Signs

Parkinson’s disease primarily affects motor function and the ability to coordinate movements. It’s considered to have four cardinal signs, which are used to define the condition:

  • Tremor: Uncontrollable trembling is a common feature of Parkinson’s disease. Tremor occurs while the limbs are at rest, typically worsening over time. 
  • Bradykinesia: Defined as slow or interrupted movements, bradykinesia is present at the onset of about 80% of cases. This causes weakness, lack of coordination, and a lessened ability to control movements. 
  • Rigidity: Rigidity is characterized by stiffness and tension leading to pain and discomfort. It is seen in anywhere from 75 to 90% of those with Parkinson’s disease. Rigidity can affect any part of the body but often affects one side more than the other.
  • Postural instability: More often present at later stages of the disease, an inability to maintain a normal, erect posture is another cardinal sign of the condition. This causes a feeling of imbalance and increases the risk of falls.  

Other Motor Symptoms

Parkinson’s disease can cause a range of other motor symptoms. These secondary symptoms affect different parts of the body and include:

  • Speech impairments and inability to articulate words
  • Inability or difficulty with chewing (dysphagia)
  • Excessive drooling
  • Blurred vision
  • Impaired ability to gaze upwards or to move eyes
  • Stooped or angled posture 
  • A shuffling gait (way of walking), characterized by short, awkward steps
  • Festination, or speeding up when making repetitive movements
  • Freezing, or stopping suddenly when making repetitive movements

Non-Motor Symptoms

Alongside the effects of motor function are several other types of symptoms. Some of these emerge before the onset of the cardinal symptoms. These non-motor signs include:

  • Impacted cognition and dementia, such as concentration and memory problems
  • Hallucinations and psychosis
  • Mood disorders, especially depression and anxiety
  • Sleep disorders
  • Autonomic symptoms, such as dizziness, constipation, or inability to control urination and erectile dysfunction
  • Fatigue and daytime sleepiness
  • Olfactory dysfunction, or a loss of smelling and tasting ability
  • Pain
  • Dermatitis or other skin disorders 

What Causes Parkinson’s Disease?

The major symptoms of Parkinson’s disease arise due to the degeneration of neurons (brain cells) in the substantia nigra of the basal ganglia of the brain. This region primarily regulates movements. Neurons in this area produce dopamine, an important neurotransmitter (brain chemical). The symptoms occur as dopamine levels—as well as the levels of another neurotransmitter, norepinephrine—drop.

Researchers are still unsure as to the exact causes of this degeneration in the substantia nigra. Genetic factors play a central role in a small number of cases and they may influence susceptibility to the condition. Exposure to toxins in the environment may also play an important role. It’s currently believed that Parkinson’s disease arises due to a combination of genetic and environmental factors.

What are better understood are risk factors for developing this condition. These include:

  • Age: Being older than 65 greatly increases the risk of developing Parkinson’s disease, with approximately 75% of cases seen in this population.
  • Sex: People assigned male at birth are at a higher risk, and are a little less than 1.5 times more likely to develop the condition.
  • Genetics: As noted, certain genes have been identified as influential, with some forms of the disease being directly caused by heredity. A family history of the condition is considered to be a risk factor for Parkinson’s disease.
  • Environmental exposure: Since Parkinson’s has been linked to exposure to certain toxins in the environment, the risk of developing it is higher if you live in rural or farming areas, areas with high air pollution, have high dietary iron, and reduced levels of vitamin D from diet or sun exposure. 

How Is Parkinson’s Disease Diagnosed?

There’s no singular test for Parkinson’s disease, so healthcare providers primarily rely on a combination of medical history and symptom assessment to diagnose the condition. When taking your medical history, they’ll ask about any medications you’re taking, your history of symptoms or other diseases, any family history of the condition, and any potential environmental exposure to toxins. 

To assess the presence and severity of motor symptoms, a neurological exam is needed. This may include:

  • Repetitive movement tests: Your ability to perform certain tasks, such as opening and closing a hand or tapping your toes, is assessed.
  • Spontaneous movements: The healthcare provider will seek irregular movements while you’re sitting, standing, or walking
  • Tremor assessments: You’ll be observed for any resting tremors while staying still and being asked to focus on specific tasks.
  • Rigidity assessment: The healthcare provider will check the amount of resistance they feel when pushing on a limb near a joint.
  • Gait assessment: You’ll be observed while walking down a hallway for any irregularities with gait.
  • Pull test: While standing, the healthcare provider pulls you from behind to assess your ability to maintain balance. 

On top of that, additional tests or imaging may be needed to rule out other neurological conditions or potential causes of the symptoms. These include:

  • Magnetic resonance imaging (MRI): This is used to assess for other neurological conditions that may cause symptoms. MRI relies on magnetic fields and computer-generated radio waves to generate images of the brain.
  • DaTScan: Used to distinguish Parkinson’s from other neurological diseases, a radioactive material is injected into the blood to assist with MRI or X-ray imaging.
  • Positron emission tomography (PET) scan: Similar to DaTScan, a small amount of radioactive material assists in imaging, allowing providers to determine dopamine levels in the brain.
  • Olfactory (smell) tests: Loss of your sense of smell is a supportive sign of Parkinson’s disease and can be used to rule out other neurological conditions. 

In addition, you may undergo genetic testing if hereditary Parkinson’s disease is suspected.

Treatments for Parkinson’s Disease 

There is no outright cure for Parkinson’s disease, so the goals of treatment are to reduce the severity and impact of the symptoms. This typically involves a combination of medications, additional therapies, and making certain lifestyle adjustments. Generally, the specific course of treatment is individualized and depends on the case.

Prescription Medications

The primary approach to Parkinson’s disease involves taking medications that stimulate dopamine production. These medications help replace the lack of dopamine in the brain and control symptoms. These include:

  • Levodopa-carbidopa: Available as Sinemet or Rytary, courses of levodopa-carbidopa represent the first-line medication approach to Parkinson’s disease. 
  • Non-ergot dopamine agonists: This is a class of drugs that includes pramipexole (Mirapex), ropinirole (Requip), and transdermal rotigotine.
  • Monoamine oxidase type B (MAO B) inhibitors: Including Zelapar (selegiline), Azilect (rasagiline), and (Xadago) safinamide may be indicated for milder cases. 
  • Amantadine: Often indicated alongside Sinemet or Rytary, Gocovri (amantadine) can assist with symptoms as other therapies wear off.
  • Anticholinergic drugs: Anticholinergics, such as Artane (trihexyphenidyl) and Cogentin (benztropine), are indicated especially for people with early-onset Parkinson’s disease and may not be appropriate for older adults. 

Deep Brain Stimulation

Deep brain stimulation is a therapy typically reserved for severe cases of Parkinson’s disease or cases where medications aren’t yielding desired results. 

Using surgery, a neurologist (a doctor specializing in conditions of the brain and spinal cord) implants electrodes into the subthalamic nucleus of the brain, near the substantia nigra. These electrodes are connected to a device in the chest. This device transmits mild electrical shocks to stimulate parts of the brain affected by Parkinson’s disease.

Physical Therapy

Alongside medical treatment, working with a physical therapist can help promote motor coordination and reduce symptoms. Physical therapy approaches may include developing aerobic exercise and resistance training routines as well as working to improve gait. Additionally, task-specific training (such as practicing holding a pencil) may be used to help with fine coordination and limb function. Balance training can help with postural instability.

For cases where speech ability is affected, you may undergo speech therapy. This work focuses on addressing articulation problems as well as the breathy, hoarse, or very quiet voice that can result from the Parkinson’s.

Lifestyle Changes

To further assist in therapy, certain lifestyle changes may be recommended, including:

  • Adjusting diet to include more vitamins, minerals, fiber, and antioxidants and avoiding processed foods, sugars, and excess carbohydrates.
  • Yoga and stretching can help improve mobility and ease the stress associated with the condition.
  • Meditation or other means of stress management, such as taking baths, can also assist in therapy.  
  • Massage therapy can help reduce rigidity and associated muscle tension.

How to Prevent Parkinson’s Disease

Since the exact causes of Parkinson’s disease are unknown, there are no known means of preventing this condition. However, some research has shown that adopting some lifestyle changes may help slow the progression of the disease. There’s evidence that getting regular aerobic exercise—in which heart rate is increased—can help slow the onset of motor symptoms.

Though the evidence is less robust, dietary adjustments may also be helpful. Studies have found that the Mediterranean diet, which is high in fresh vegetables and fruits, unsaturated fats, and nuts, may slow the progression of Parkinson’s. In addition, increasing caffeine and reducing dairy and alcohol intake may also help slow progression.

Comorbid Conditions

There are several health issues that you’re more likely to have if you have Parkinson’s disease. Here’s a quick breakdown of these comorbid conditions: 

  • Diabetes: Diabetes is characterized by the body’s inability to digest sugars. It is linked with a number of neurological diseases, including Parkinson’s disease. Further research is needed on the connection between these two conditions.
  • Anemia: Anemia is characterized by an insufficient level of red blood cells and low levels of iron. Though the exact link is unclear, a 2016 study found that people who are anemic are more likely to develop Parkinson’s.
  • Dementia: Dementia—characterized by cognitive and memory difficulties that impact daily living—has been found to impact up to 90% of people with Parkinson’s disease. It also can be a sign of an advanced case.
  • Depression: Considered a non-motor symptom as well as a potential risk factor, depression frequently co-occurs with Parkinson’s. This has been linked to the impact of living with a chronic condition as well as physiological processes associated with Parkinson’s disease.
  • Hypertension: High blood pressure, or hypertension, is also frequently associated with Parkinson’s disease. Studies have found between 29.4% and 34% of people with Parkinson’s experience hypertension.
  • Stroke: Stroke is a potentially fatal blood circulation disruption of the brain. Researchers have found being diagnosed with Parkinson’s disease increases the risk of subsequent diagnosis of stroke as well as its severity.

Living With Parkinson’s Disease 

Since it’s chronic and irreversible, Parkinson’s disease significantly impacts your quality of life. While this condition isn’t fatal on its own, the mortality of patients is three times higher than those living without it due to associated conditions. Most people with Parkinson’s become disabled within 10 years of diagnosis. Over time, the condition significantly impacts the ability to live independently.

That said, there are strategies that can help you cope with the condition, including:

  • Seeking assistance and social support from family and friends and getting help with essential tasks. 
  • Seeking out support groups or online communities that can provide useful information and emotional assistance.
  • Looking for information from and supporting patient advocacy organizations, such as the American Parkinson Disease Association, among others.

A Quick Review

Parkinson’s disease is a progressive, incurable neurodegenerative disease that severely impacts motor function, causing tremors and other difficulties with movement. Researchers are unsure as to the exact causes of this condition. Risk factors include older age, assigned-male sex, genetics, and exposure to environmental toxins. Treatments focus on easing symptoms and include medications, physical therapy, and making lifestyle changes.  

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