Understanding the Progression of Parkinson's Disease

By Ronald F. Pfeiffer, M.D.

The Big Picture, camera image

When a diagnosis of Parkinson's disease (PD) is made, one of the first things that my patients and their loved ones ask is, "What is going to happen? How is this disease going to progress?" As doctors, we do our best to help people with PD and families to understand the disease and the changes that may occur in the future. 

First, I tell my patients, PD progresses slowly. There is time to prepare for changes because they develop gradually rather than suddenly. 

Second, I believe it is important to let people with PD know that the manner in which the disease develops and progresses varies greatly from person to person. Some people may have trouble with a particular symptom, such as tremor, that another person never will experience at all. This variability applies also to the place at which Parkinson's disease progresses. Some people experience only mild symptoms for many years, and respond well to medications. For others, the disease may progress more quickly. 

Currently it may not be possible to predict how someone's PD will progress or to provide treatments to slow its course, but research shows that the average lifespan of people with PD is only slightly less than people without it. There are many strategies that can help people with PD to manage the disease most effectively over the years and to feel their best. 

Movement Symptoms and Complications

It is likely that what brings someone to the doctor for a suspected PD diagnosis is one of the movement symptoms, such as tremor, slowness or rigidity. Most people initially will experience one of these symptoms on one side of the body and want to know: will those symptoms extend to the opposite side of the body? 

For some people with PD, their symptoms remain confined to one side of the body for a considerable time, but in most people, movement symptoms will progress to the other side of the body, although they are likely to be less severe on the more recently affected side.

Most people with PD eventually will experience some level of movement fluctuations, which are caused by the medications used to treat PD. Studies show that 15 years after PD diagnosis, more than 90 percent of people will be aware of a gradual shortening of the duration of benefit from a dose of levodopa, which is termed “wearing-off” and more than 90 percent of people will be experiencing dyskinesia — that is, involuntary twisting and writhing movements.

These two types of fluctuations occur when people with PD have been treated for some time with levodopa, which is the gold-standard therapy for movement symptoms. “Wearing-off” usually begins, on average, around six years after levodopa was first prescribed, although it may appear much earlier in some persons. For most people, though not all, it is not particularly severe or disabling and wearing-off time occupies less than a quarter of the waking day. The same is true of dyskinesia. More than a decade after starting levodopa therapy, as many as 50 percent of people with PD report that the dyskinesia they are experiencing is not disabling; only 12 percent describe it as severe.

Common Nonmotor Symptoms

In recent years, recognition has grown that the most troubling issues for many people living with PD are nonmotor symptoms, which are features of PD that have little or nothing to do with movement. It is important for people with PD to be aware of these nonmotor symptoms so that they can recognize them and discuss them with their doctor. Effective treatment is often available.

Falls: Falls are an important concern; more than 80 percent of people with PD experience falls within 15 years of diagnosis. Although medications generally do not eliminate the balance impairment that often leads to falls, and falls cannot be completely prevented, measures that will reduce significantly the risk of falling can be undertaken. Physical and occupational therapists can help reduce the risk through such strategies as exercise programs or simple changes in the home.

Orthostatic hypotension (low blood pressure): Some 35 percent of people with PD, within 15 years of diagnosis, will experience orthostatic hypotension (OH), which is a drop in blood pressure that occurs when a p person stands up. For most people, this will mean feeling dizzy and lightheaded when getting up from a chair or out of bed. If OH is severe, it can lead to falls and even to a loss of consciousness. There are a variety of causes for this condition — from PD itself, to the medications used to treat it, to dehydration —  and for each of these there are strategies (including medications) available to treat it.

Bladder and bowel problems: Issues with gastrointestinal and urinary functions are relatively common, with about 40 percent of people with PD experiencing urinary difficulties within 15 years of diagnosis. For many people, this means frequency; for a smaller percentage, it may mean incontinence. Constipation is also common; about 40 percent of people with PD use laxatives on a daily basis by 20 years after diagnosis.

Cognitive changes: The prospect of cognitive change — impairment of memory and other thought s processes — can be of greater concern than anything else for someone who is newly diagnosed with PD. Such changes do occur, but they happen slowly and do not necessarily become severe. Among people who have had PD for 15 years, significant cognitive difficulty has developed in just under 50 percent, but about 35 percent have only mild difficulty and 15 percent have experienced no significant changes. The a changes in thinking and memory that occur with PD are not identical to those of Alzheimer’s disease and often are less severe or disabling.

Hallucinations: The medicines used to treat PD can sometimes cause hallucinations. More rarely, hallucinations appear as part of PD itself. Although about 50 percent of people with PD will experience them within 15 years, medication adjustments can often reduce and sometimes eliminate hallucinations completely.

Living Well with PD

How can a person ensure that his or her PD is managed most effectively? Here are some strategies:

See a specialist: An important step is to see that the person receives care from a neurologist who specializes in PD — ideally a movement disorders specialist. People with PD who live too far from a specialist should consider seeing a knowledgeable general neurologist on a regular basis, and then traveling a longer distance to see a specialist a few times a year.

Build a health care team: Beyond simply seeing their neurologist, people with PD should take advantage of the other health care professionals who can help make their lives easier. Physical therapists can help a person improve strength, balance and flexibility; occupational therapists can suggest ways to make the home environment more accessible and reduce the risk of falls; speech therapists can help a person feel more at ease in social situations.

Take medications on time: People with PD should be sure to take all of the medicines that the doctor prescribes, and to take them on time. This can be difficult to manage if a person is taking medicine every few hours, but PD medications will be most effective at controlling symptoms when they are taken at the times prescribed. If problems with the medications are encountered, discuss this with the treating neurologist so that medication adjustments can be made. For some individuals, deep brain stimulation surgery may be an appropriate treatment approach.

Read and learn about PD: What you do not know, you fear, and what you fear can make life with PD much more difficult to manage. People with PD should be sure to educate themselves by reading, learning, attending support groups — and seeking information from groups like PDF.

Exercise: Exercise can help a person with PD maintain and even improve mobility. Recent studies have shown that people who exercise regularly are more successful in managing their PD. Although all types of exercise (aerobic, resistance, yoga — even boxing!) are helpful, recent studies have suggested that Tai Chi and dance therapy might be particularly beneficial in addressing the balance impairment and other movement difficulties associated with PD. Even more exciting, there is some developing evidence that exercise may actually slow PD progression, although this has not been definitively proven.

Expect the best, plan for the worst: Everyone can benefit from planning ahead for health care and retirement, but for someone with PD, such planning is even more important. For example, many people continue to work after PD has been diagnosed. Although the decision when to tell an employer about PD, or when to stop working, is entirely individual, it may be beneficial to think about this earlier rather than later, in order to arrange for accommodations and to plan a solid financial future.

People with PD should consider discussing issues like driving and long-term care with loved ones before they become immediate issues. Although a diagnosis of PD doesn’t by itself make driving dangerous, PD progression and the medications used to treat PD can result in problems such as slowed reaction time and excessive drowsiness that make driving unsafe. Long-term care needs also become important as PD progresses. Advance planning that takes into account both family support and finances is important to avoid situations in which care decisions must be made on an emergency basis and choices might be limited.

Build connections, expect resilience: In other disease areas, such as cancer, research indicates that one factor in determining why some people fare better than others is “resilience.” Boiled down, resilience comes from the supportive relationships and meaning that we create in our lives. For a person with PD, it can mean finding an enjoyable social group — whether PD-related or not — spending time with family, having a beloved pet, or taking a walk each day. It means striking a healthy balance between the management of PD and maintenance of the important connections and activities that ensure that life isn’t just about the disease.


PD progression is a complex subject that involves the inter-relationship of disease pathology, symptoms and treatments. In looking at disease progression, it is natural to primarily focus attention on the process of improving treatments, but it also is important to focus on “life progression” as a whole — how people with PD can take an active role in managing their PD in the context of living happy and successful lives.

Dr. Pfeiffer is Professor and Vice Chair, Department of Neurology and Director, Division of Neurodegenerative Diseases at the University of Tennessee Health Science Center in Memphis, TN. 

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