The Centers for Disease Control and Prevention (CDC) notes that, as of 2004, Parkinson's disease was the 14th most common cause of death in America. Parkinson's is due to decreased levels of dopamine in the part of the brain called the substantia nigra. Dopamine is a neurotransmitter, a chemical substance that is sent by the nerves. To have normal, balanced movement, dopamine and acetylcholine (another neurotransmitter) must be in balance. In Parkinson's, this is no longer the case.
Bradykinesia
This term describes slow movements. People with Parkinson's usually have a hard time starting to move. And, once they are able to move, they move very slowly. They walk with what is termed a "festinating gait." They walk slowly, in little steps, with their legs wide apart from each other. As time goes by, their movements are not only slow, but also they are usually less (called hypokinesia).
Rigidity
Parkinson's disease causes very rigid movements. According to the Merck Manuals, David Eidelberg, M.D., Professor of Neurology and Neurosurgery at the NYU School of Medicine, says this rigid movement is referred to as "cogwheel rigidity." During a physical exam, when a physician bends a patient's arm, the muscles may get very jerky, acting like the cogs in an old-fashioned wheel.
Resting Tremor
The typical tremor of Parkinson's is a tremor when the person's limb is only "at rest." The tremor is not seen while the person is moving the limb. In "Current Medical Diagnosis & Treatment," Michael Aminoff, M.D., and Maxine Papadakis, M.D., write that there are four to six tremors every second. And, this resting tremor seems to get worse during periods of stress. For people who have this tremor, it will usually be in one limb, at first. If they do have it in more than one, it is usually in the arm and leg that are on the same side. But, after several months or years, they may develop a resting tremor in all four limbs.
Postural Instability
Dr. Eidelberg explains that this phrase refers to all the instability that Parkinson's causes, whether in movement or when just trying to stand still. People with Parkinson's may fall a lot. The disease affects their reflexes, causing them to fall backward and forward, even though they may try to briefly walk faster to prevent from falling down. They walk without moving their arms, have a hard time making turns and, even, have a hard time stopping.
References
- CDC: Deaths, Percent of Total Deaths, and Death Rates for the 15 Leading Causes of Death
- "Current Medical Diagnosis & Treatment 2009"; Stephen McPhee, M.D. and Maxine Papadakis, M.D.; 2009
- Merck Manuals: Parkinson's Disease
