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Parkinson’s disease is a disorder of the nervous system. It can best be described as a movement disorder. It is progressive, whereby the symptoms worsen over time. It develops gradually, with the first symptoms being barely noticeable. Often this is seen as a slight tremor in just one hand. While tremors are the most widely known symptom of the disease, it can also emerge as stiffness (or rigidity of the muscles) and slowing of movement and speech that becomes soft or slurred. Parkinson’s can also result in non-motor symptoms, such as anxiety, depression, sleep disorders, constipation, and fatigue. The symptoms result from a progressive degeneration of nerve cells in the section of the brain that regulates body movements. 

Parkinson’s disease is seen most often in older people but can also occur in younger adults. It normally begins between the ages of 50 and 65 and is slightly more common in males than females. It is also more prevalent in Caucasians than Asians or African Americans.

There are an estimated ten million people in the world with Parkinson’s disease with about one million residing in the United States.

Despite all the problems associated with Parkinson’s, it typically has very little impact on life expectancy. People with the disease live about as long as people without the disease. It’s also important to note that early treatment can result in people living years that are nearly symptom-free. The rate of the disease’s progression can also vary significantly. For some, symptoms develop slowly over a decade or two.

What are the Symptoms of Parkinson’s Disease?

Parkinson’s disease symptoms can vary between individuals. Sometimes the early signs may not be noticeable. It is common for symptoms to begin on one side of the body before spreading to the other side. Additionally, the symptoms will typically remain worse on the side that first encountered the disease. Parkinson’s symptoms may include the following and may not all be apparent at the outset of the disease:

  • Tremor: One common characteristic of Parkinson’s disease is a tremor, or shaking, of the hand or limb while at rest. It may be exhibited in a back-and-forth rubbing of the person’s thumb and forefinger, known as a pill-rolling tremor. Resting tremors can also take place in the jaw, chin, mouth, or tongue.

  • Rigidity of muscles: More commonly referred to as muscle stiffness, it can occur in limbs or torso. This can limit the person’s range of motion and be painful.

  • Slowed movement (bradykinesia): Parkinson’s disease can result in slowed movement and a person’s ability to move. This may also result in their stride becoming shorter or they may drag their feet as they walk. Other symptoms associated with the bradykinesia of Parkinson’s disease is a reduced facial expression, a decreased eye blinking, and reduced fine motor coordination.

  • Speech changes: Changes in the voice are commonly experienced. The voice may become softer or people may speak in a monotone without the normal variation in volume and emotion. They may have speech problems as a result of Parkinson’s disease. They may also slur their words or hesitate before talking.

  • Loss of automatic movements: Parkinson’s disease may reduce a person’s ability to perform normal unconscious movements, such as swinging their arms as they walk.

  • Impaired posture and balance: Postural instability includes the inability to maintain a steady, upright posture. This can result in the person’s posture becoming stooped or hunched over. This can also lead to unsteady balance or difficulty rising from a seated position.

  • Small Hand Writing: Writing may become difficult. Letter sizes may be reduced, and the words may become crowded on the page.

  • Other symptoms: These include loss of the sense of smell, sleep problems, apathy, depression, anxiety, constipation, cognitive changes, fatigue, hallucinations and/or delusions, and lightheadedness.

What Causes Parkinson’s Disease?

In Parkinson’s disease nerve cells in a very specific region of the brain (substantia nigra) break down or die.  Many of the symptoms associated with Parkinson’s result from the loss of neurons that produce dopamine, which is a neurotransmitter that helps to regulate movement.  Many treatments for Parkinson’s disease work to increase dopamine levels in the brain.

Research into the causes of Parkinson’s disease is also focusing on Lewey bodies and the protein alpha-synuclein, which is found within Lewy bodies.  Lewey bodies are clumps of specific substances within brain cells and are recognized as markers of the disease.  Alpha-synuclein clumps within the Lewey bodies in a form that cells can’t break down. It is believed that the build-up of alpha-synuclein contributes to the cause of Parkinson’s disease.

Researchers also believe that genetic factors may sometimes play a role.  While considered rare, Parkinson’s disease may result from a viral infection or through exposure to environmental toxins like carbon monoxide, pesticides, certain heavy metals or repeated head injuries.  In most cases the cause of the disease is unknown, but researchers commonly believe that the interaction of genetics and environmental factors cause the disease in most people diagnosed.

What Are the Stages of Parkinson’s Disease?

Parkinson’s disease is a progressive illness, and as such, there are typical patterns to this progression.  These are commonly referred to as the stages of the disease.  While there are many symptoms of Parkinson’s, not everyone will encounter all of them.  Additionally, they may not experience them at the same severity or the same order.  The following are generally accepted as the five stages of Parkinson’s.

  • Stage One: In the first stage the symptoms are typically mild and normally do not hinder daily activities.  The symptoms are noticeable on one side of the body and are experienced as tremors or other body movement problems.  The person may also notice changes in posture, walking and facial expressions.

  • Stage Two: In the second stage both sides of the body are affected with symptoms worsening, although on the initial side they are more severe. Walking and poor posture may become more noticeable as the person experiences greater stiffness, tremors, and other movement symptoms.  Additionally, changes in facial expressions or speech difficulties can occur.  People in stage two can typically still live alone but completing daily tasks can be more challenging and time consuming.

  • Stage Three: In stage three, loss of balance, decreased reflexes and slowness of movements mark a notable turning point in the disease.  Falls become more prevalent.  Daily tasks are significantly affected in this stage, but the person can remain independent.

  • Stage Four: In stage four symptoms are much more severe and limiting.  The person may be able to stand without assistance, but movement may require a walker or other type of assistive device. The person is unable to live alone and will need help with daily activities.

  • Stage Five: Stage five is the most advanced and debilitating stage. Advanced stiffness in the legs can also cause freezing upon standing, making it impossible to stand or walk. People in this stage require wheelchairs or are confined to a bed.  Hallucinations, delusions and dementia are common.

It’s also important to note that not all people progress through the disease at the same rate. To some, the disease can progress over 20 years.  For others, the progression is much more rapid.