What is Parkinson’s Disease?

Understanding the Basics of PD

So what exactly is Parkinson’s disease (PD)? Parkinson’s disease is a type of movement disorder that can affect the ability to perform common, daily activities. Although Parkinson’s disease is associated with a wide range of symptoms, there are features of Parkinson’s disease that most people with the condition will experience. These symptoms are typically divided into those that affect movement (motor symptoms) and those that do not (non-motor symptoms).

The most common motor symptoms of Parkinson’s disease are tremor (a form of rhythmic shaking), stiffness or rigidity of the muscles, and slowness of movement (called bradykinesia). A person with Parkinson’s disease may also have trouble with posture, balance, coordination, and walking. Common non-motor symptoms of Parkinson’s Disease include sleep problems, constipation, anxiety, depression, and fatigue, among others.

It is important to note that, although there are common symptoms of PD, they can vary greatly from person to person. Moreover, how these symptoms change over time and whether other symptoms of Parkinson’s disease emerge differ from person to person. Most people who develop the symptoms of Parkinson’s disease do so sometime after the age of 50, but Parkinson’s disease can affect younger persons as well. There are an estimated 1 million Americans living with Parkinson’s disease and more than 10 million people worldwide.

How Parkinson’s Disease Affects the Brain

What makes Parkinson’s disease distinctive from other movement disorders is that cell loss occurs in a very specific region of the brain called the substantia nigra (sub-STAN-she-uh NYE-gruh). The nerve cells, or neurons, in this region actually appear dark under a microscope (substantia nigra is Latin for “black substance”).

Those dark neurons produce a specific type of neurotransmitter (a chemical messenger that allows neurons to communicate) called dopamine. The neurotransmitter dopamine helps to regulate movement. This loss of dopamine is the reason that many treatments for Parkinson’s Disease are intended to increase dopamine levels in the brain.

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Future research will hopefully tell us more about this protein. Learn more about APDA research initiatives here.

In addition to decreases in dopamine and the cells that make dopamine, you might also read or hear about alpha-synuclein (AL-fa-sin-NUKE-lee-un). We do not yet know what this protein does in the healthy brain, but in Parkinson’s disease it clumps up in what are called Lewy (LOO-ee) bodies. Researchers believe that alphasynuclein build-up contributes to the cause of Parkinson’s disease and that it may be possible to develop new treatments based on this idea.