Parkinson's Disease

Parkinson’s disease is a chronic condition, which means it is lifelong (until a cure is found). It is not infectious or contagious. You cannot give it to or catch it from someone through contact.

  Parkinson’s disease occurs when the cells in a part of the brain called the substantia nigra begin to fail and die off. These cells produce a chemical called dopamine, which helps the brain control movement and coordination in the body. As less dopamine is supplied to the brain, the motor symptoms that are characteristic of Parkinson’s disease, such as tremor and slowness of movement, begin to appear.

PD affects different people in different ways. For instance, although most people associate shaking or “tremor” with Parkinson’s disease, some people may not experience this symptom.

Most people are diagnosed around the age of 60, but Parkinson’s disease has been increasingly diagnosed in people 40 years old and younger. This is called Young-Onset Parkinson's disease.   Young-Onset Parkinson’s disease is very similar to Parkinson’s disease in older patients; however, it is more likely to cause cramping, aching, or awkward posturing of a part of the body. In addition, people with Young-Onset Parkinson’s disease are less likely to experience dementia than those who are diagnosed later in life.

Causes

What causes Parkinson’s disease? Many possible causes, from dental fillings to well water, have been suggested, but these have not been proven and appear to have very little evidence to back them up. Researchers have found certain inherited genes that some people with Parkinson’s disease carry. However, in most cases, PD is not directly inherited from a family member. For many people with Parkinson’s disease, there is no known cause. It is generally believed that the disease is a result of a combination of both genetic and environmental causes.

Slightly more men are diagnosed with PD than women—for every 3 men there are 2 women with the disease —but it affects people of every race and ethnic background, from all parts of the world.

Diagnosis

In order to diagnose Parkinson’s disease, physicians rely on office exams, a person’s medical history, and the patient’s and/or family member’s description of symptoms. Symptoms begin to appear gradually, over many years. At first they can be mistaken for simple nerve pain, muscle strain, or stress-related “twitches”—or just the normal aging process. Since many of the main symptoms of Parkinson’s disease, such as balance problems and stiffness, are eventually experienced by most people as they get older, it is sometimes difficult for doctors to tell PD apart from the normal aging process in some older patients. However, neurologists can usually make an accurate diagnosis of Parkinson’s disease by taking a careful look at the clues, including clinical and laboratory findings, the rate at which symptoms are progressing, and when symptoms first started to appear.

A neurologist may also perform several tests, including an MRI (magnetic resonance imaging) or CAT (Computer Axial Tomography) scan, in order to rule out other diseases that have “Parkinson’s-like” symptoms.

SPECT (Single Photon Emission Computed Tomography) and PET (Positron Emission Tomography) are other tools that create images of the brain. The use of such tools to diagnose Parkinson’s disease is still experimental at this point.

If there is still doubt about the diagnosis after performing these tests, a doctor may give you a drug used to treat Parkinson’s disease. If your symptoms improve when the medication is administered, it’s likely that the condition is Parkinson’s.

Symptoms

There are 4 main symptoms of Parkinson’s disease. All of these symptoms involve the loss of dopamine in the brain, which affects the ability of the body to move in a controlled way. Since Parkinson’s disease affects everyone differently, not everyone who is diagnosed will necessarily experience all of the major symptoms. Also, some symptoms may appear earlier in some people or may affect one person more than another. The important thing to remember is that these symptoms can often be managed with the use of medication.

In addition, physical and occupational therapy, as well as lifestyle changes such as eating a nutritious diet and exercising (with permission from your doctor or other health care provider), can help to improve functioning in the activities of daily life.

The 4 main symptoms of Parkinson’s disease are described below:

Tremor

In most people with Parkinson’s disease, the first symptom experienced is tremor. This typically occurs in the hands but sometimes occurs in the feet or jaw. It is a rhythmic, uncontrolled movement that can make it difficult to hold a teacup or spoon steadily, or to perform other delicate tasks such as tying shoelaces or buttoning a shirt or coat. Tremor often decreases or even disappears when muscles contract for more strenuous movement, such as throwing a ball or swinging a golf club. At first, the tremor may affect just one side of the body but eventually affects both sides.

An example of a very common Parkinson’s disease-related tremor involves the back-and-forth motion of the thumb and forefinger. This movement makes it seem as though an invisible pill is being rolled between the fingers. This is sometimes referred to as the “pill-rolling” tremor.

Muscle Rigidity (Stiffness)

With normal movement, some muscles contract while the opposing muscles relax. However, in Parkinson’s disease, muscles become rigid when they should be relaxed. This makes stretching the legs and arms difficult and uncomfortable. When muscle rigidity occurs, it causes the person to perform short, interrupted movements. These awkward, jerky movements are called “cogwheel” rigidity because they appear similar to way the cogs on a wheel move.

Muscle rigidity (stiffness) can affect handwriting, making it too small to read. It may also cause some people with Parkinson’s disease seem as though they have a “mask-like” expression on their face. This may obviously have negative social implications, as the person may appear to react inappropriately during common social exchanges. However, people with this symptom may not be aware of how they appear to others. It should therefore be discussed delicately by others if it is brought up, to help avoid feelings of embarrassment.

Slowness of Movement

People with Parkinson’s disease may experience slowness of movement, which can affect them in several different ways. They may experience a loss of spontaneous movement, difficulty starting movements, or the sudden stopping of ongoing movement. As a result, routine activities such as washing or dressing may take longer to complete and become frustratingly slow.

Slowness of movement can also affect the muscles in the throat and mouth. This may lead to slurring or other changes in speech and difficulty with swallowing. However, speech and swallowing difficulties do not usually tend to appear until the later stages of the disease. If you are having problems with speech or swallowing, ask your doctor to refer you to a speech or occupational therapist.

Balance and Coordination Problems (Postural Instability)

Balance and coordination problems are typically among the last symptoms of Parkinson’s to appear, sometimes 10 years or more after the onset of the disease.

Postural instability may occur because the postural reflexes, which are located deep inside the brain, have been impaired by Parkinson’s disease. In addition to problems with balance and coordination, postural instability may also lead to slumped posture, or forward or backward leaning posture.

Loss of balance can make people with Parkinson’s unsteady on their feet and precautions should be taken around the house and when going out to prevent serious falls. Please see tips for Avoiding Trips and Falls for suggestions about dealing with this problem.

Other Symptoms

The 4 primary symptoms of Parkinson’s disease—tremor, stiffness, slow movement, and balance and coordination problems—can make daily activities hard to perform. Things one used to take for granted—such as walking, dressing, eating, and bathing—now represent obstacles. In addition, people with Parkinson’s disease may also experience several “secondary” symptoms that may include³ :

• Loss of smell. This is believed to be an early warning sign of Parkinson’s disease. It has been suggested that a “smell test” could be an effective way to diagnose the disease early on.
• Muscle pain. This may be among the first symptoms of Parkinson’s disease. Pain can occur in the shoulders, arms, calves, or neck. Other related symptoms include numbness, heat, coldness, cramping, aching, and tingling in the hands and/or feet.
• Speech problems. These may include a gradual “softening” of the voice until words are barely audible. Slurring, drooling, and difficulty swallowing may also result from the rigidity and slowness of movement caused by PD. 
• Cramped, small handwriting. This may be a gradual result of the combination of slow movement and muscle rigidity symptoms.
• Facial “Masking” (lack of expression). The combination of rigidity and slow facial muscles can make it difficult to blink or smile.

Depression

Depression and anxiety are conditions that are linked to changes in brain chemistry, and they seem to be especially common for people with Parkinson’s disease. It’s been estimated that as many as 90% of the people diagnosed with PD suffer from depression at some point