Parkinson’s Disease

What Is Parkinson’s Disease?

Parkinson’s disease (PD) is a neurodegenerative disorder that primarily affects movement.

In people with PD, brain cells develop Lewy bodies, which are pathological aggregates in the midbrain causing dysfunction or death of the nerve cells. Cells in this part of the brainstem, particularly in the substantia nigra, stop producing the neurotransmitter dopamine, which inhibits the muscles from functioning voluntarily and stopping involuntary movements.

More than 10 million people living with Parkinson’s worldwide.

PD is characterized by four primary symptoms (tremors, rigidity, bradykinesia, and postural instability), but as the disease progresses, it can also affect cognitive functioning and emotional well-being.

What Is The Difference Between Parkinson’s Disease and Parkinsonism?

Parkinsonism is an umbrella term that refers to neurological disorders that cause movement problems. In addition to Parkinson’s disease, Parkinsonism includes:

• Drug-Induced Parkinsonism
• Progressive Supranuclear Palsy (PSP)
• Multiple System Atrophy (MSA)
• Vascular Parkinsonism
• Dementia with Lewy Bodies (DLB)
• Corticobasal Degeneration (CBD)

What Are The Symptoms Of Parkinson’s?

There are four primary symptoms of Parkinson’s disease including:

• Tremors: Tremors are uncontrollable shaking or rhythmic movements. They usually start in the hands but can also affect the jaw or feet.
• Rigidity: In rigidity, muscle stiffness, or resistance to movement, your muscles remain constantly contracted and tense.
• Slow movement (bradykinesia): The symptoms of bradykinesia can be frustrating because the slowing of your movement means it takes longer to do things and get places.
• Postural instability: Parkinson’s can cause postural instability and balance issues. Extra care must be taken to avoid tripping and falling.

Other symptoms that may present in PD include:

• Pain can contribute to loss of function in those with PD. The pain may result from the rigidity associated with the disease that causes muscle cramps, especially in the legs and toes.
• Parkinson’s can also be associated with dystonia—sustained muscle contractions that cause forced or twisted positions caused by fluctuations in the body’s level of dopamine.
• Mood may be affected as Parkinson’s progresses, with depression, pessimism, and insecurity surfacing.
• The effects of Parkinson’s on the mouth may lead to speech and swallowing challenges.
• Bladder and bowel problems can occur due to improper autonomic nervous system functioning.

The 5 Stages Of Parkinson’s Disease

The Hoehn and Yahr scale defines five stages of PD based on clinical disability or what can and cannot be performed in terms of activities of daily living.

Stage One: Tremor and other movement symptoms occur on one side of the body only. Changes in posture, walking, and facial expressions occur.

Stage Two: Symptoms start getting worse. Tremor, rigidity, and other movement symptoms affect both sides of the body or the midline (such as the neck and the trunk).

Stage Three: Considered mid-stage, loss of balance (such as unsteadiness as the person turns or when they are pushed from standing) is the hallmark.

Stage Four: The person needs significant help with daily living activities and cannot live alone.

Stage Five: Stiffness in the legs may make it impossible to stand or walk.

The Hoehn and Yahr stages 1 and 2 represent early-stage, 2 and 3 mid-stage, and 4 and 5 advanced-stage Parkinson’s.

What Causes Parkinson’s?

While no single factor has been identified as the cause of PD, research suggests that factors like age, genetics, brain health, and gut health may be risk factors.

Brain and Gut Health

Growing evidence strongly suggests a significant association between the gut microbiome and PD. Biochemical studies suggest the effect of abnormal aggregation of α-synuclein and spreading of pathology between the gut, brainstem, and higher brain regions. At a cellular level, abnormal mitochondrial, lysosomal, and endosomal function can be identified. Recent work has also highlighted maladaptive immune and inflammatory responses, possibly triggered in the gut, that accelerate the pathogenesis of Parkinson’s disease.

Medical research indicates that inflammation in the nervous system and the rest of the body contributes to worsening symptoms, which means paying attention to digestion and diet is important.

Clinical studies have also contributed to the growing body of evidence by recognizing gut symptoms in the early stages of PD may serve as important indicators for earlier diagnosis and improved overall management.

Genetics

People with one or more close relatives who have PD have an increased risk of developing the disease themselves. An estimated 15-25% of people with PD have a known relative with the disease. Some cases of the disease can be traced to specific genetic mutations.

Ellen Sidransky, a clinical geneticist and pediatrician at the National Institutes of Health, won the 2024 Breakthrough Prize in Life Sciences for her discovery of a common genetic risk factor for Parkinson’s disease. Sidransky discovered that mutations in the gene GBA1 encode an enzyme that breaks down fatty substances in the lysosomes of cells and is a genetic risk factor for Parkinson’s.

Age

PD is often considered an age-related condition, with only 4% of people diagnosed under the age of 50. For the majority, symptoms start showing up around age 70, and the incidence rises significantly with older age.

Gender

Men are 1.5 times more likely to have Parkinson’s.

Environmental Factors

There is also evidence to suggest that environmental factors can lead to heightened PD risk. Studies show an increased risk of PD in people who live in rural areas with increased pesticide use.

How Is Parkinson’s Diagnosed?

You will get a diagnosis of Parkinson’s disease when your doctors notice the symptoms of Parkinson’s. The primary care physician will do a medical history and a number of movement and activities of daily living tests. There is no blood test or brain scan that will definitively give a diagnosis of Parkinson’s.

Currently, the diagnosis of Parkinson’s disease is based on a thorough medical history, a neurological examination, observation of activities of daily living, and sometimes a genetic test.

Laboratory tests and brain scans are used to rule out other disorders. However, brain scans of people with PD usually appear “normal” or “unremarkable.”

Scientists have now developed a test called the alpha-synuclein seed amplification assay. This test detects misfolded alpha-synuclein protein in the fluid surrounding the brain, making earlier diagnosis possible.

How Common Is This Condition?

After Alzheimer’s disease, Parkinson’s disease is the most common neurodegenerative disorder, with nearly one million people in the U.S. living with Parkinson’s. Doctors expect to be treating 1.2 million people with Parkinson’s by 2030, and every year, roughly 90,000 people in the U.S. are diagnosed with this disease.

According to the Parkinson’s Foundation’s Prevalence Project, the combined direct and indirect cost of Parkinson’s, including treatment, social security payments and lost income, is estimated to be nearly $52 billion per year in the U.S. alone.

How Is Parkinson’s Disease Treated? Is There A Cure?

There is no cure for PD, but research is ongoing, and medications or surgery can often provide substantial improvement with motor (muscle movement) symptoms.

Common treatments for PD include physical, occupational, and speech therapy; integrative manual therapy; antidepressants; and botulinum toxin (Botox) for dystonia.

A recent study noted the benefit of physical activity on the symptoms of Parkinson’s for all populations, focusing on encouraging underrepresented groups. Regular exercise and particularly big movements can be very helpful in improving symptoms. Findings of a systematic medical research review suggest that all exercise categories can be prescribed to improve balance and mobility, while combined exercises, strength, and specific activities improve both motor and non-motor outcomes, and aerobic exercise and sensorimotor activities improve motor outcomes. A regular daily exercise program has many benefits and is vital for maintaining muscle tone, strength, and flexibility.

The most beneficial treatment protocols are designed with the individual in mind and looking at what will increase your quality of life.

What Medications And Treatments Are Used?

Treatment with the drug levodopa, or L-dopa (the precursor to dopamine), can cause remarkable improvements, particularly in the early stages. This is why early diagnosis is best. The following are some of the other drugs effective in decreasing PD symptoms:

• Dopamine does not easily pass through the blood-brain barrier, which is a protective lining of cells inside blood vessels that regulate the transport of oxygen, glucose, and other substances in the brain. Drugs, like levodopa-carbidopa increase the level of dopamine in the brain. These dopamine precursors cross the blood-brain barrier and are then changed into dopamine.
• Anticholinergic drugs interfere with the production or uptake of the neurotransmitter acetylcholine in the body and can be effective in reducing tremors.
• Antidepressants help control the non-motor symptoms of the disease.
• MAO-B inhibitors cause dopamine to accumulate in surviving nerve cells and reduce the symptoms of PD. These medications include selegiline and rasagiline.
• COMT stands for catechol-O-methyltransferase and is another enzyme that breaks down dopamine. The COMT inhibitor drugs (entacapone, opicapone, and tolcapone) prolong the effects of levodopa by preventing the breakdown of dopamine.
• Amantadine is an antiviral drug that can help reduce symptoms of PD and levodopa-induced dyskinesia, but its effectiveness wears off in up to half of the people taking it.
• Anticholinergic drugs, which include trihexyphenidyl, benztropine, and ethopropazine, decrease the activity of the neurotransmitter acetylcholine and can be particularly effective for tremors associated with PD.

The most common treatment for Parkinson’s is a combination of levodopa-carbidopa drugs. Dopamine agonists (helpers) mimic the role of dopamine in the brain. They are somewhat less effective than levodopa but work for longer periods. Dopamine agonist drugs include apomorphine, pramipexole, ropinirole, and rotigotine.

What Complications or Side Effects are Possible With Treatments?

Potential side effects of levodopa and dopamine agonists include:

• Nausea and vomiting
• Low blood pressure
• Restlessness
• Drowsiness or sudden sleep
• Hallucinations and psychosis
• Confusion
• Involuntary movements (mild to severe twisting and writhing)
• Edema (swelling due to excess fluid in body tissues)
• Nightmares
• Behavioral addictions, such as gambling, hypersexuality, or shopping

Sleep issues are also common in Parkinson’s. Sometimes it is difficult to stay asleep. Restless sleep, nightmares, emotional dreams, and drowsiness during the day are common. The medications used to treat PD may contribute to sleep issues.

The drugs may also cause hallucinations, delusions, and other psychotic symptoms. Typically, when you are asleep, your muscles don’t engage, so when you have a particularly vivid dream, where you are jumping or running, it is all happening in your mind, but your body is still. Some Parkinson’s medications cause the muscles to engage so that instead of being still your body is moving and kicking as you dream. This is called “REM behavior disorder.”

The medications used to treat Parkinson’s may also contribute to orthostatic hypotension (hypo means low, and tension refers to blood pressure). Orthostatic hypotension is a sudden drop in blood pressure when you stand up from a lying down or seated position. This may cause dizziness, lightheadedness, and loss of balance or fainting.

What Can I Expect If I Have Parkinson’s Disease?

If you have Parkinson’s or are at risk of developing this condition, the progression can be slow, and quality of life can be maintained with drug treatments, surgery, exercise, and physical therapies.

Talk with your doctor today if you are noticing symptoms associated with Parkinson’s disease.