Parkinson's disease is a brain disorder that usually occurs in men and women over 65 years of age. According to the National Parkinson's Foundation, about 15 percent of new cases occur in people under 50 years of age. Parkinson's disease affects the nerve cells in an area of the brain called the substantia nigra. These cells become damaged and lose their function or die. Under normal circumstances, the nerve cells produce a chemical called dopamine, which functions in movement and coordination. When there is a lack of dopamine, the clinical features of Parkinson's disease become evident. They include slowness of movement, tremor, rigidity and imbalance.
Slowness of Movement
Slowness of movement, also known as bradykinesia, is a sign of Parkinson's disease. Movement is slower than normal, but there may also be a hesitation between the intended movement and the completion of the movement. This symptom progresses over time and is not reversible. A decline is seen in the ability to move the hands and perform repetitive tasks, such as finger tapping. According to "Pharmacotherapy: A Pathophysiologic Approach," freezing, or movements that stop and start again, is another common characteristic. It occurs more often when walking in a crowd or through a narrow doorway.
Tremor
Tremor, or shakiness, is a very common characteristic of Parkinson's disease. It is usually present in the hands and can involve the jaw or legs. Like bradykinesia, this characteristic progresses gradually over time. Medical intervention delays the progression of the signs but is not able to reverse it. Furthermore, medication should not be discontinued to avoid a quick progression of the disease. In some individuals, tremor occurs more like an internal vibration but never develops outwardly.
Rigidity and Imbalance
Parkinson's disease causes rigidity in the body and muscles. It is described as increased muscular resistance in range of motion. Rigidity may lead to problems in balance. According to "Pharmacotherapy: A Pathophysiologic Approach," "postural instability is one of the most disabling problems of parkinsonism." Individuals will have a disturbance in the manner in which they respond to changes in motion and balance. Festinating gait, or quick short steps, and a flexed postured may also be seen in people with Parkinson's disease. Like the other characteristics of Parkinson's disease, these will gradually progress and are irreversible.
References
- "Pharmacotherapy: A Pathophysiologic Approach"; Joseph T. DiPiro, Rovert L. Talbert, et al; 2008
- National Parkinson Foundation: About Parkinson's Disease
