Parkinson's Disease: Causes, Progression, and Treatments

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  • 0:47 What Is Parkinson's Disease?
  • 1:16 Why Does Parkinson's…
  • 3:42 Clinical Signs,…
  • 4:20 Treatment of…
  • 5:29 Putting It All Together
  • 6:28 Lesson Summary
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Lesson Transcript
Instructor: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

This lesson will cover Parkinson's disease. It will inform you of what it is, what symptoms it causes, whom it affects most, why it occurs, and what treatment options exist. We'll explore everything from Lewy bodies to the substantia nigra.

A Condition that Can Affect the Greatest

Diseases are unfortunately not picky. Humans tend to be afraid of more obviously scary things during their life, like getting hit by a car or eaten by a lion. But it's the things that occur within us as opposed to outside us that are the deadliest to us.

That's because it doesn't matter if you're rich and famous like Michael J. Fox or poor. It doesn't matter if you're history's greatest boxer like Muhammad Ali or someone who doesn't even know how to form a fist with their hand. The disease we're going to talk about can affect those famous figures and plenty more without any prejudice.

What Is Parkinson's Disease?

This disease is called Parkinson's disease and is a disease that is a degenerative condition affecting the nervous system, resulting in the diminishment of mobility and cognition in people affected by it. This disease, or something very similar to it, has been described in texts dating back to the ancient times. It's a disease that begins in mid to late life, usually after the age of 50 and seems to affect more men than women.

Why Does Parkinson's Disease Occur?

The exact cause of Parkinson's disease is not fully understood. We know that genetic factors seem to play a role. For example, people who have family members affected with this condition may be more predisposed to being affected by it during their lifetime. However, environmental factors, such as toxin exposures, have been in one way, shape, or form linked to the increased risk of developing Parkinson's.

Regardless of whether those latter points are really true or not, we do know some of what actually occurs in Parkinson's disease that causes the signs and symptoms typically associated with it. Some of things we know about are called Lewy bodies; these are aggregations of proteins inside of nerve cells in a person affected with Parkinson's disease that can be seen only after an autopsy is performed on a person and samples of brain tissue are looked at under the microscope. What we don't know is if these are a cause or a result of this disease.

However, the end result of Parkinson's will be the impairment or death of nerve cells in a place called the substantia nigra. This is a region in the midbrain that is important for movement and learning. The name sounds weird, but it actually means 'black substance' in Latin. That's because some parts of this area appear darker than others owing to high levels of a subtype of melanin called neuromelanin. I'm sure you've heard of this substance before, as another subtype of it, called eumelanin, darkens a person's skin.

Besides melanin, this area of the brain also produces dopamine. Dopamine is a neurotransmitter involved in everything from movement to pleasure. If the cells in the substantia nigra die, the amount of dopamine decreases. Since dopamine is important for smooth muscle movement in the body and its amounts decrease in this disease, the brain cannot communicate with the muscles nearly as effectively as before, causing some of the typical symptoms associated with this disease.

In a very basic sense, you can liken the dopamine to a volume button on a remote control. If you decrease the volume, you will decrease the sound coming out of the TV, which means you won't be able to hear it as well. Well, if you decrease the amount of dopamine being produced by your substantia nigra, your muscles won't be able to hear your brain properly.

Clinical Signs, Symptoms, and Diagnostics

This will then lead to the four major symptoms of Parkinson's disease:

  • Muscle tremors
  • Rigidity of the body or limbs
  • Abnormal coordination and balance
  • Slowness of movement, more technically called bradykinesia
  • And, in later stages of the disease, mental, emotional, and cognitive changes may occur as well.

There are no tests that can diagnose Parkinson's disease. However, after ruling out other causes of such signs, looking at a person's signs and symptoms, as well as by performing a neurological exam, a physician will be able to diagnose this disease.

Treatment of Parkinson's Disease

There is also no cure for this disease, but certain medications may be given to help control the symptoms. Most of these drugs either mimic, become, or increase the level of dopamine in the brain directly or indirectly. One famous class of the latter is a drug that you may have heard of since it's also used to treat depression called MAO B inhibitors. This is a class of drugs that prevents the breakdown of dopamine by inactivating an enzyme, called MAO B, involved in breaking down dopamine.

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