Degenerative Nerve Disease: Symptoms

Instructor: Amanda Robb

Amanda holds a Masters in Science from Tufts Medical School in Cellular and Molecular Physiology. She has taught high school Biology and Physics for 8 years.

Here, we'll learn about general symptoms of degenerative nerve diseases as well as symptoms of some common examples: Alzheimer's Disease, Parkinson's Disease, and multiple sclerosis.

What Is Degenerative Nerve Disease?

Imagine an air traffic control tower. The people inside are responsible for directing hundreds of flights at busy airports everyday. They have to ensure the planes get to the right gate on time, and incoming planes have a clear path. They regulate what goes where in the airport and when.

Now imagine if some of the equipment stopped working, or if a few key employees called out sick. The job would become a lot harder, signals may get crossed and flight paths might collide. The airport surely wouldn't be working at full capacity.

Now, let's translate this analogy to science. Your brain is an awful lot like the control tower. It's an organ that's involved in regulating everything in your body, from movement to thoughts and emotions. Your brain talks to your body like the control tower talks to all the planes, except instead of radios your body uses nerves, or neurons, to communicate between the body and brain.

Together, the nerves, brain and spinal cord make up your nervous system. To degenerate means to break down, so in degenerative nerve diseases tissue of the nervous system breaks down and stops working.

Human nervous system
nervous system

General Symptoms

As you can imagine, this wreaks havoc on all aspects of the body. Since the brain is responsible for all movement, thought, and emotion, these patients usually start to experience memory loss and some decreased control of movement, or motor function. Depending on the type of degenerative disease, other symptoms can result such as problems managing emotions and sleep.

Eventually, without treatment, organ systems will begin to fail without instruction from the brain, and the patient will die. Since there are a variety of degenerative nerve diseases, let's look at a few common examples: Alzheimer's Disease, Parkinson's Disease, and multiple sclerosis.

Alzheimer's Disease

Alzheimer's Disease is a type of dementia where memory is affected first, and then followed by an inability to carry out daily activities. People with this disease often find themselves forgetting small things at first, but soon the disease can advance to forgetting how to read or write, and other muscle memory tasks as simple as brushing their teeth or tying their shoes.

Eventually they forget family members entirely, and may exhibit erratic behavior, wandering away from home and not understanding how to return. Eventually these patients need care from a specialized facility where they can be fully monitored. There is no cure for Alzheimer's Disease and medications only slow the process, but will not prevent symptoms.

Brain before and after Alzheimers Disease, or AD
Alzheimers Disease brain

Parkinson's Disease

Parkinson's Disease affects a specific part of the brain called the 'substantia nigra', which contain neurons involved in movement. In the disease, those neurons are damaged or die, which prevents the release of a chemical called dopamine. This chemical is what neurons use to talk to each other. Therefore, during Parkinson's Disease, neurons that are involved in movement and use this chemical and thus stop working.

Areas and functions of the brain affected by dopamine
dopamine pathways

Thus, the first symptoms to appear are often small tremors, or shaking of the hands. As the disease progresses, people have trouble walking and experience stiffness, or rigidity in their body. They may not be able to speak eventually, due to muscle problems in the jaw and face. They also may experience some memory loss and emotional disorders, but not to the same magnitude as Alzheimer's Disease. The symptoms are mainly muscular.

Multiple Sclerosis

Multiple sclerosis (MS) is a disorder that affects neurons carrying messages between the brain and the body. Normally, neurons are cased in a substance called myelin that helps them send messages faster. In this disease, the body's immune system actually attacks the myelin, which starts to break apart, and the messages no longer can be sent in a timely manner. Think about myelin like insulation on a wire in your house. The plastic insulation keeps the electricity in the wire and helps it flow where it needs to go.

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