Parkinson's disease is a motor system disorder that is caused by a loss of the brain cells that produce dopamine, a neurotransmitter responsible for many brain functions including cognition, movement and mood. Parkinson's disease is a chronic disease that worsens over time. The cause of Parkinson's disease is unknown and although there are treatment options to alleviate symptoms, there is no cure. Those affected with Parkinson's disease may experience different effects, which vary from person to person. There are four primary effects of Parkinson's disease. In order to be diagnosed with the disease, at least one of the four main effects must be present, according to the Parkinson's Disease Foundation.
Resting Tremor
The first effect is a resting tremor. A resting tremor is a small tremor that occurs while the muscles are not moving, or are at rest. The severity of the tremor diminishes with movement. Initially, the resting tremor is most often seen in the hand or foot on one side of the body. Sometimes a slight tremor will be visible in the face or jaw. As the disease progresses, the tremor can encompass the whole body, causing all limbs to become affected. The resting tremor causes further complications by decreasing fine motor skills, such as writing or the ability to button a shirt.
Bradykinesia
Bradykinesia, or slow movement, is another primary effect of Parkinson's disease. In addition to slow movement, someone affected by bradykinesia may experience difficulty with movements, incomplete movements or interrupted movements. Because of difficulty associated with moving, people with Parkinson's disease often become immobile, according to the Merck Manuals Online Medical Library. Facial muscles can also be affected by bradykinesia, which results in little to no facial expressions or reactions.
Rigidity
Muscle stiffness and inflexibility are also primary motor effects associated with Parkinson's disease. This inflexibility is known as rigidity. In healthy individuals, muscles contract during movement and relax when at rest. In those affected with rigidity, muscles never reach a stage of relaxation and are constantly contracted, according to the Parkinson's Disease Foundation. This causes a decrease in range of motion.
Impaired Balance
As Parkinson's disease progresses, problems with balance arise. Those affected have difficulty maintaining a straight posture or turning around. Impaired balance can cause stumbling while walking and an increased number of falls. A combination of bradykinesia and impaired balanced can result in an inability to reach the arms and hands in front of the body to break the fall, according to the Merck Manuals Online Medical Library.
