Parkinson's Disease (PD)

One of the world’s fastest-growing brain disorders, Parkinson’s is a long-term progressive disease affecting movement capabilities. Discover 3 Early Signs of Parkinson’s, 4 Stages & 16 Symptoms. Exciting breakthrough on PD diagnosis. 

Table of Contents

What's Parkinson's Disease?

PD is a progressive neurodegenerative disorder characterized by muscle stiffness, tremors, and general inability to control voluntary movements. Parkinson’s may also affect involuntary/autonomic controls, including swallowing, digesting, heart rate, blood pressure, and urinary continence.

Parkinson's Disease Statistics

Here are the key statistics about PD:

  • Globally, PD affects about 10 million people.
  • About one million people in America are living with Parkinson’s Disease.
  • An additional 60,000 Americans receive a Parkinson’s diagnosis each year. 
  • This disease is more prevalent among people aged 80+, nearly 1,900 people per 100,000.
  • Early-onset is relatively rare. About 4% of people are diagnosed before age 50.
  • Men are 1.5X more likely to develop Parkinson’s than women.

What Causes Parkinson's Disease?

The cause of Parkinson’s is still under investigation. However, research shows that the disease is related to the protein Synuclein.

When normal Synuclein misfolds into toxic shapes, they become misfolded proteins, causing damage to the brain.

Key Early Signs of Parkinson's Disease

Here are some key warning signs of PD, distinct from the more commonly known motor symptoms, including:

  • Constipation (not linked to other known problems)
  • Sleep disorders (mainly associated with REM sleep)
  • Loss of smell and taste

About 60% of people with Parkinson’s symptoms go on to develop the disease within 10 years.

Stages of Parkinson's Disease

There are four major stages.

Prodromal stage

During this early stage, symptoms are atypical of PD motor symptoms, as mentioned above.

However, these initial PD symptoms are also found in other disorders. Therefore using conventional methods, accurate diagnosis at this stage can be challenging.


This phase presents the earliest measurable motor control changes. The person is likely to be the only one noticing these new signs. At this point, the disease can be found in the brainstem.

Early-stage symptoms often overlap with normal brain aging as well as other non-progressive motor disorders. Therefore, molecular testing and biometric detection offer more accurate diagnoses.

In particular, biometric tracking of eye movements, keyboard typing, and vocalization shows promise as early-stage PD indicators.

Thanks to advancements in molecular science, biomarker testing is finally here.

Our SYNTap® Test helps doctors diagnose PD accurately by detecting misfolded Synuclein in cerebrospinal fluid.


Here, the symptoms include more noticeable motor disorders, such as tremors, rigidity, and shuffling.


The advanced stage may show evidence of the disease in the hippocampus and the cerebral cortex. These brain regions control memories as well as thinking and planning, respectively.

Here, the person shows rapidly declining motor symptoms, as well as progressive dementia symptoms.

If dementia and memory loss appear at earlier PD stages, doctors might diagnose Lewy Body Dementia (LBD).

Parkinson's Disease Symptoms

Below is a list of key PD symptoms.

Motor Symptoms

Cramped Handwriting

The person may develop micrographia, aka small handwriting. Therefore, it’s a good idea to regularly take and compare writing samples to detect if the writing is shrinking.


One of the most recognizable signs of Parkinson’s is tremors. Watch for twitching of hands, fingers, or feet. The person will notice this first sign before others do.

As the disease progresses, the shaking could become worse. Others will likely notice the tremors at this point. It’s worth noting that medicine, stress, injuries, and extreme physical work-out can also cause tremors.

Trouble Sleeping

Sleep issues are normal from time to time. However, drastic movements could be an early sign of PD. Here are some examples:

  • Flailing arms
  • Thrashing
  • Kicking
  • Falling out of bed

Moving Difficulty

PD damages brain cells controlling body movement, affecting daily activities. For example:

  • Stiffness in the arms, legs, or even the entire body could lead to movement troubles, usually beginning with the shoulders or hips
  • Bradykinesia or slowed movement
  • Difficulty getting out of a chair
  • Dragging feet
  • Shorter steps when walking
  • Automatic movements, like blinking or smiling, may become more difficult.

Other diseases can cause movement symptoms besides Parkinson’s. Therefore, based on movement symptoms alone, diagnosis can be difficult.  

Voice Changes

The following voice changes can be early signs of Parkinson’s:

  • Speaking faster or softer
  • Increased hesitation before speaking
  • Slurring of words
  • Speaking in monotone instead of with inflection
  • Less dramatic voice changes, such as excessive enunciation, voice pitching lower, or sounding hoarse

Facial Masking

The human face has 43 muscles to help express emotions. The brain controls these muscles via the nervous system. Unfortunately, people living with PD often develop an expressionless face, known as hypomimia or Parkinson’s mask.

Posture Changes

Small posture changes sometimes occur, such as leaning or slouching. Difficulties with coordination and balance may also happen.

Non-Motor Symptoms

Between 80-90% of people living with PD also develop non-motor symptoms. These include fatigue, cognitive decline, and mood changes. Here are a few examples:

Dizziness or Fainting

Severe lightheadedness could cause fainting or blackout. Increased dizziness could be a sign of Parkinson’s.

Loss of Smell

Some patients develop hyposmia (reduced sensitivity to scents) or anosmia (loss of smell). For some people, these are early signs of Parkinson’s. For others, these symptoms don’t develop until years after the traditional motor symptoms emerge.


Some patients also experience gastrointestinal issues, including constipation. It occurs when the disease slows the digestive system’s automatic movements.

Loss of Bladder Control

Parkinson’s can cause bladder problems, leading to urine control difficulty.


Fatigue is a common PD symptom.

Weight Loss

Some people also experience weight loss, which often occurs in the later stages of PD.

Cognitive Changes

People living with advanced PD may experience cognitive decline, including:

  • Difficulty finding the right words
  • Making sound judgments
  • Clear thinking
  • Moodiness
  • Behavior
  • Memory

Mood Disorders

Parkinson’s could bring mood disorders, such as depression, fear, or anxiety. Some patients also experience personality changes, including impulsive behaviors and hypersexuality.

Vision Problems

Parkinson’s could diminish eye movement abilities, such as slow blinking, which leads to dry eyes.

Understanding PD warning signs can help people know when to seek early care. In addition, there is a useful Parkinson’s research/treatment center directory that we created for the community.

What Drives Parkinson's Progression?

PD is driven by an accumulation of alpha-Synuclein aggregates in the brain called Lewy bodies.

What is a Lewy Body?

A Lewy body is composed of misfolded Synuclein plus other cellular proteins and lipids. 

Bottom line: 

Lewy bodies cause cell death.

Parkinson's Biomarker

Misfolded Synuclein is a biomarker for PD.

With Parkinson’s, the initial damage occurs in the substantia nigra region, where high concentrations of the neurotransmitter dopamine are produced. Dopamine helps initiate and control voluntary movements.

The first wave of misfolded proteins corrupts other healthy proteins as the disease progresses, causing widespread misfolding.

During this asymptomatic stage, misfolded Synuclein damages the brain silently. This goes on for years.

Parkinson's Risk Factors

Research shows the following as risk factors.


Approximately 10-15% of people with PD carry genes that may be responsible for the disease. In addition, these individuals may have one or more first-degree family members with PD. Such a family history increases the risk.

Genes that can increase the disease’s probability include SNCA, LRRK2, PARKIN, PINK1, and GBA.

Specifically, for people carrying mutations in the GBA-1 or LRRK2 genes, their risk increases significantly. The action mechanism for these genes is not yet entirely understood. However, both of these genes may be involved in the accumulation of misfolded proteins.

  1. Mutations in GBA-1 cause the accumulation of specific lipids in the brain that trigger Synuclein misfolding.
  2. Mutations in LRRK2 may impair the removal and degradation of misfolded Synuclein in nerve cells.

Both mutations increase the level of Misfolded Synuclein, upping the risk of Parkinson’s.

Traumatic Head Injuries

Athletes who suffer from multiple head injuries have an increased risk of PD. Particularly professional players in basketball, boxing, and football.

Environmental Effects

Both internal and external environmental factors play a role in Parkinson’s risk.

Internal Environment

For some people, the disease originates from toxic bacteria in the gastrointestinal tract. Certain bacterial strains may promote Synuclein misfolding in the gut. The misfolded Synuclein travels via the vagus nerve from the intestines to the brain. People who have had their vagus nerve removed show a decreased risk or delayed onset of Parkinson’s.

External Environment

Long-term exposure to environmental toxins may increase the risk of Parkinson’s. Here are some examples:

  • Insecticides
  • Herbicides
  • Toxic metals such as lead, mercury, barium, zinc, etc.

Is PD an Old Person's Disease?

People in their 70’s experience PD symptoms over 100X more than those in their 40’s. However, the process of brain protein misfolding began in early adulthood. 

During this asymptomatic phase, brain cell damage spreads silently and undetected. Physical symptoms appear many years later. Consider the following:

Check the Appendix

Researchers examined teenage appendectomies and discovered misfolded Synuclein aggregates within. 

This indicates PD develops early in life.

Misfolded Protein Synuclein Athlete
Muhammad Ali Parkinson's Fighter

Repeated Head Traumas

Athletes with multiple head injuries in their 20’s and 30’s have increased risks.

Muhammad Ali is a notable example.

Early Onset

About 5% of people with PD are diagnosed with early-onset. For example, the NBA player, Brian Grant, was diagnosed at age 36.

His organization inspires people living with PD to exercise as part of their treatment plan. 

Web-Diagnosis-PD Early onset

Parkinson’s Disease Diagnosis

Currently, Parkinson’s diagnosis happens after clinical symptoms begin. 

Ironically, PD’s symptoms appear after much of the brain has been irreversibly damaged. Therefore, clinical diagnosis is at a late stage.

It’s no surprise that Parkinson’s looks like a disease of the elderly.

PD Diagnostic Challenges

About 1 in 4 Parkinson’s Disease cases is misdiagnosed initially. So why is accurate diagnosis so challenging?

A major contributing factor is that many symptoms of other movement disorders also look like PD early symptoms:

  • Tremors
  • Stiffness
  • Balance disorders
  • Constipation

In addition, these symptoms overlap with typical aging signs. 

Breakthrough Test For Parkinson's Disease

Thanks to scientific innovation in molecular science, we are proud to offer our breakthrough biomarker test for Parkinson’s Disease to help doctors diagnose it accurately. Learn more about this revolutionary PD test here.

Parkinson’s Treatment Options

People with PD diagnosed at early and intermediate stages tend to respond initially to drugs such as Levodopa and Carbidopa.

Long-term treatment using these drugs can lead to side effects, including nausea, confusion, and involuntary movements. Also, the drugs have diminishing benefits over time.

Deep brain stimulation (DBS) improved voluntary movement in a subset of people living with PD.

So far, there is no cure yet for Parkinson’s. However, studies have shown early preventive care such as exercise, a healthy diet, and positive lifestyle changes can help slow/stop the progression.

Who Gets Parkinson’s?

PD affects men more frequently and severely than women. For instance, about 65% of people with PD are men.

parkinson's affects men more than women

Who Gets Parkinson’s?

PD affects men more frequently and severely than women. For instance, about 65% of people with PD are men.

A Healthy Diet May Help Delay PD Onset

9 dragons tea-healthy foods vitamine-c-vitimine-e

Did you know that a diet rich in vitamins C and E may reduce the risk of Parkinson’s?

A Healthy Diet May Help Delay PD Onset

9 dragons tea-healthy foods vitamine-c-vitimine-e

Parkinson's Frequently Asked Questions

At present, there are no treatments that can restore the neurons or their connections. However, several treatments can substitute for the lost cells temporarily.

Substantia nigra cells produce and release large amounts of dopamine. L-DOPA is a precursor drug converted in the brain to dopamine. Thus, they can restore some lost functions.

In addition, the cells' electrical activity in substantia nigra can be mimicked. This is done by embedding thin wires in the region where signals have been lost.

Short answer - Yes. PD can progress over time to dementia which further complicates the motor symptoms. In addition, some people with PD show early dementia signs when motor symptoms appear. In such cases, dementia associated with PD is difficult to distinguish from Alzheimer's. 

The earliest PD signs are distinct from the typical Parkinson's motor symptoms. These include constipation (not linked to other known problems), sleep disorders (mainly associated with rapid-eye-movement REM sleep), and loss of smell and taste. For individuals with one of these symptoms, about 60% go on to develop PD within 10 years. 

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