By Liz Seegert 

Parkinson’s disease (PD) is a progressive disease of the nervous system that primarily affects older adults. It typically begins after age 50. The disease can be very hard to live with because it severely restricts mobility, making daily activities increasingly difficult. Many people will eventually require 24/7 nursing home care. While effective treatments exist to relieve some symptoms, there is no cure.

The National Institute of Neurological Disorders and Stroke (NINDS) estimates that Parkinson’s affects about two percent of those over age 65. The prevalence of PD rises with age, and by 2030 further projections suggest that more than one million people in the U.S. will be living with this progressive neurological disorder. The cause of PD is still not fully known and researchers are still working to identify potential biomarkers. Fifty to 80 percent of those with the disease eventually develop Parkinson’s disease dementia. The average time from onset of Parkinson’s to developing dementia is about 10 years, according to NINDS.

Approximately 60,000 people in the United States are diagnosed each year; some 10 million people worldwide currently live with the disease. Most people first develop Parkinson’s around age 60, but the Parkinson’s Foundation estimates some 10 to 15 percent of those affected have early-onset Parkinson’s (monogenetic), which begins before the age of 50, as this Idaho Statesman story reported. Actor Michael J. Fox and the late boxer Muhammed Ali are among those who first developed early-onset Parkinson’s. Researchers believe this form of the disease is inherited and possibly linked to specific gene mutations. Having a first-degree relative with Parkinson’s disease increases the risk of developing the disease.

Parkinson’s affects the nerve cells in the brain that produce dopamine, in a specific area of the brain called the substantia nigra. While this occurs in both genders, the disease affects about 50 percent more men than women, according to the National Institutes of Health. PD also affects non-dopamine cells in the brain, contributing to the non-movement symptoms. These symptoms may begin even before the movement problems or emerge in advanced PD. Non-motor symptoms are receiving increasing attention because they impair quality of life and are not adequately treated using existing therapies.

Ongoing exposure to certain toxins or environmental factors, such as herbicides and pesticides, may slightly increase one’s risk of Parkinson’s disease. The Mayo Clinic calls the risk relatively small, although researchers continue to investigate potential links between environment factors and Parkinson’s.

Symptoms

No two people experience Parkinson’s the same way, but some commonalities exist. Symptoms start gradually, sometimes with a barely noticeable tremor in just one hand, according to the Mayo Clinic. Very early signs are often subtle. These include loss of sense of smell, chronic constipation or a sleep disorder known as REM behavior disorder (physically acting out dreams at night). If detected and treated early, further deterioration may be prevented or slowed, according to the Parkinson’s Foundation.

In addition to tremors, people with PD experience:

• Bradykinesia, which is marked by reduced arm swing, hesitation in initiating movement, shrinking handwriting, monotonous speech and reduced blink rate. This condition, which all Parkinson’s patients experience, can make simple tasks difficult and time-consuming.
• Increased difficulty with walking or getting out of a chair.
• Increasing limb rigidity leading to pain and limit range of motion.
• Gait and balance problems. Posture may become stooped, or patients struggle with balance, increasing the risk of falls.
• Chewing, swallowing and eating difficulties, which can lead to drooling, choking and nutritional problems.
• Urination problems. Parkinson’s disease may cause bladder problems, such as being unable to control urine or having difficulty urinating.
• Cognitive problems (Parkinson’s dementia). This usually occurs in the later stages of the disease. Many people with Parkinson’s dementia develop plaques and tangles — the hallmark brain changes linked to Alzheimer’s disease, according to researchers from the Alzheimer’s Association.
• Sleep problems, including frequent nighttime waking, waking up early or falling asleep during the day.
• Depression, anxiety, fear or loss of motivation are common, especially in the early stages of the disease.
• Blood pressure changes, which can lead to dizziness or lightheadedness, due to a sudden drop in blood pressure (orthostatic hypotension).

Fatigue is also common among those with this disease. Many people with Parkinson’s disease lose energy and experience fatigue, especially later in the day. The cause isn’t always known.

Treatment

There is no standard treatment for Parkinson’s disease. Treatment is individualized based on specific symptoms. It can include medication and surgical therapy, along with lifestyle modifications, such as increasing rest and exercise.

Levodopa (L-dopa) is the mainstay of drug therapy treatment for PD. Levodopa is a chemical precursor of dopamine. The drug is transported to the brain and then transformed into dopamine, according to the Parkinson’s disease clinic at UC San Francisco, It can dramatically reverse symptoms of PD for several years in many people. However, the drug does not slow the underlying neurodegeneration and becomes less effective as PD progresses. It also causes side effects, including uncontrolled movements called dyskinesias, nausea, and “on-off” fluctuations in symptom control. It’s sometimes given in combination with carbidopa to help control nausea.

Several additional drugs are now available to complement levodopa therapy, but none significantly slows the underlying neurodegeneration. This article in Parkinson’s News Today provides a good summary of currently effective therapies for both motor and non-motor symptoms.

The Parkinson’s Foundation estimates that medication costs upwards of $2,500 each year in the United States. Surgery can easily top $100K per individual.

The Michael J. Fox Foundation has this list of medications currently used to treat Parkinson’s disease and others that were recently approved.

Surgery is sometimes recommended to regulate certain regions of the brain and improve symptoms. Deep brain stimulation (DBS) improves symptoms of PD by electrically stimulating brain cells in movement control areas of the brain through chronically implanted electrodes. It’s been used in Parkinson’s patients for 25 years, but also has side effects and risks, as U.S. News highlights. This article in The Tennessean walks readers through the procedure.

Now researchers are looking at how to conduct DBS remotely, according to Harvard University. Other studies are exploring how patients can adapt DBS to self-manage their symptoms.

Experts

• Michael D. Fox, M.D., associate director, Deep Brain Stimulation Program, Beth Israel Deaconess Hospital, Boston; also an assistant professor of neurology at Harvard Medical School; 617-667-0307. Contact: Jennifer Kritz. senior director of communications, 617-667-7301, jkritz@bidmc.harvard.edu.
• Jeanne F. Loring, Ph.D., professor of developmental neurobiology and director of The Center For Regenerative Medicine at Scripps Research Institute, La Jolla, Calif; 858-784-7767.
• Stanley Fahn, M.D. founder and past president of the World Parkinson Coalition, professor of neurology and director emeritus of the Center for Parkinson’s Disease and Other Movement Disorders at Columbia University; 212-305-5277.
• Julie K. Andersen, Ph.D., professor, Buck Institute for Aging Research, Novato, Calif. Contact: Mary Redwine, administrative lab coordinator, MRedwine@buckinstitute.org, 415-209-2237.

Resources

• The Parkinson’s Foundation has designated 45 medical centers around the world as Centers of Excellence, including 31 in the United States.
• There is no national registry for Parkinson’s diagnosis. However, several states, including Utah, Nebraska, Washington and California have statewide reporting mandates.
• This list of clinical trials of potential Parkinson’s therapies from the NINDS can help you take a deeper dive into specific treatment-related research. You can filter the data by age group, trial status, study type and other criteria.
• This blog by Simon Stott, a researcher at the University of Cambridge, U.K., provides consumer-friendly insight into current Parkinson’s research.
• The VA has six Parkinson’s Disease Research, Education, and Clinical Centers (PADRECCs), part of their Centers of Excellence for Parkinson’s disease.
• You may want to read this powerful essay from reporter Benjamin Stecher on his own journey with Parkinson’s disease. Check out the list of meaningful quotes from experts at the end of the piece.