Understanding Parkinson’s Disease

For many of us, when we hear “Parkinson’s disease,” we think of how it has affected people we know personally or celebrities who have publicly faced the disease: actors Michael J. Fox and Alan Alda, boxer Muhammad Ali, singers Linda Ronstadt, Ozzy Osbourne, and Neil Diamond, and spiritual leaders Billy Graham and Jesse Jackson.

We’ve witnessed their shaky hands, unsteady gait and softer voices. They are among the nearly 1 million people in the United States living with Parkinson’s disease. It is second only to Alzheimer’s disease as the most common of neurodegenerative diseases, in which nerve cells in the brain and nervous system lose function, leading to disability.

Parkinson’s disease was once rare but is now common and will become more so as the population continues to age and people live longer.

We talked with UNC Health neurologist Nina Browner, MD, to learn more.

What Is Parkinson’s Disease?

Parkinson’s disease causes changes in body movements: tremors, stiffness, slowness, and trouble with balance and speech. Symptoms emerge when brain cells that produce dopamine—the brain chemical that transmits signals between nerve cells—stop working.

“When you don’t have enough dopamine, your body slows down, your muscles tighten up and some people develop tremor,” Dr. Browner says.

Dopamine is associated with feelings of pleasure and reward, and is involved not only with motor functions, but also mood regulation, executive functioning, memory and paying attention, sleep, and digestion and blood flow. That’s why other symptoms of Parkinson’s can include depression, anxiety, apathy, problems with memory or sleep, constipation, excessive sweating, loss of smell, and frequent urination or incontinence.

Quality of Life with Parkinson’s Disease

Parkinson’s symptoms may not progress to an advanced stage for many years.

“People can live well with Parkinson’s disease for 10 to 15 years after they are diagnosed,” Dr. Browner says. “The worst myth—and it’s heart-wrenching—is that people with Parkinson’s will be in a wheelchair within five years. With recent advancement in medications and rehabilitation techniques, people can have many years with a high quality of life after they are diagnosed. We work on encouraging people to live their lives to the fullest.”

Another misconception is that all people with Parkinson’s will eventually have dementia or memory loss similar to people with Alzheimer’s disease. Although Parkinson’s disease can cause cognitive changes, these are typically distinct from those seen in Alzheimer’s, and are characterized by problems with attention, short-term memory and multitasking.

Understanding the Causes of Parkinson’s Disease

No one knows what causes Parkinson’s disease, Dr. Browner says.

“Most likely, it’s a combination of different factors, genetic and environmental,” she says.

Between 15 and 17 percent of people with Parkinson’s disease have particular gene mutations linked to the disease. Environmental factors may include head injury, exposure to pesticides, solvents and polychlorinated biphenyls (PCBs), and where you live—there are clusters of areas where Parkinson’s cases are more common, including in “Rust Belt” states.

The greatest and most common risk factor is age, Dr. Browner says.

More than 95 percent of people with Parkinson’s disease  are diagnosed after age 50, and most are older than 65. Men are more likely than women to develop Parkinson’s disease.

A study released in 2022 shows new cases are increasing 1.5 times more rapidly than previously thought. As many as 90,000 new cases are diagnosed each year, the study estimates. One reason is that the population is aging. Another is better reporting of cases.

Diagnosing Parkinson’s Disease

There may be early signs of Parkinson’s that appear before tremor, balance and other mobility problems set in, Dr. Browner says. These can be subtle and include a decrease in voice volume, lessened sense of smell, vivid dreams, more constipation and smaller handwriting.

“Sometimes one of the first things people notice is a slower reaction time, which could affect their driving,” Dr. Browner says. This doesn’t mean someone who has just been diagnosed with Parkinson’s needs to stop driving immediately, but it’s good to pay attention as symptoms gradually progress, she adds.

“There’s a high suspicion that by the time a doctor sees symptoms in a patient, the Parkinson’s has been around 5 to 10 years,” Dr. Browner says.

Many symptoms of Parkinson’s are common with other diseases and conditions, she says, which makes diagnosing it in the early stages harder.

“We certainly don’t want to tell every patient who has constipation or a poor sense of smell that they might have Parkinson’s,” she says. “At this time, we do not have interventions to lower the risk of Parkinson’s, and there’s a chance they won’t develop the disease. Right now, we look for a combination of movement symptoms to make the diagnosis.”

The latest criteria for considering a Parkinson’s disease diagnosis start with slowness of movement (bradykinesia) and one or more of these symptoms:

  • Shaking or tremor in a limb that occurs while the limb is at rest.
  • Stiff or rigid arms, legs or trunk of the body.
  • Trouble with balance and falling.

A primary care physician is usually the first to detect symptoms. They will often refer a patient to a neurologist for a more definitive diagnosis and treatment. Movement disorder specialists are neurologists with special training in assessing and treating Parkinson’s and other disorders, and they are commonly consulted to provide specialized care for patients.

Treating Parkinson’s Disease

Right now, there is no cure for Parkinson’s disease. And because each patient’s symptoms vary, there’s no single standard treatment. However, doctors commonly start patients on medicines that either help replenish dopamine or mimic the action of dopamine. Patients may take medications to target specific problems, such as to improve movements, mood or sleep.

Because the disease is progressive, patients need to work with their doctors and medical care team to adjust treatment over time.

Exercise, especially when started early in the disease, can help slow down the decline of motor functions, including balance, mobility and ability to do activities of daily living. Exercise can also help ease depression and improve sleep.

Good nutrition is important for overall health, as is building the right care team, Dr. Browner says.

“You want to have a neurologist in your corner—if possible, a movement disorder specialist,” she says. “As your disease progresses, you will need others, too.”

All patients will benefit from occupational, speech or physical therapy, she says. A mental health provider may be helpful to coach you through living with a chronic illness.

Living with Parkinson’s Disease

If you or a loved one is diagnosed with Parkinson’s disease, rely on your care team for guidance and resources.

“The diagnosis affects the whole family,” Dr. Browner says.

Your symptoms may progress slowly and change with time, so it’s important to understand your disease and know what resources are available to you, including locally.

Dr. Browner advises people with Parkinson’s to focus on what they can do, rather than what they can’t, and to stay optimistic whenever possible.

“Research for new treatments is ongoing,” she says, “and we’re always hopeful.”

If you have questions about your health or your risk for chronic diseases, talk to your doctor or find one near you.