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Biology 202
2003 First Web Paper
On Serendip

Bradykinesia

Laurel Jackson

Perception is an intangible part of every being. It cannot be explained, defined, or nailed down the way that most scientists would like. In some ways, perception can be taught-a person's circumstance and background would cause him or her to perceive a situation in a particular way. In other ways, perception is unpredictable and ever changing. Even here, attempting to describe the indescribable, there are flaws in the last two sentences because they are based on the writer's perceptions of perception. It is too subjective for a "scientific" definition. What does it mean for a person suffering from bradykinesia? If the individual understands the condition, she will realize that the perceptions she has are not always correct. She may perceive herself to be making a fist, or spreading her fingers, but in fact she may not have accomplished this. (1) A blind and deaf person may have perceptions about the world around her. Most likely, her only correct perceptions are those perceptions about herself such as: "I am moving my arm," or "I am swinging my legs." The external stimuli are ineffective in this person, whereas a person with bradykinesia can only react completely and at a normal speed to external stimuli. Because of damage to signal pathways, the internal stimuli are ineffectively activated. (1)

Bradykinesia is a Greek term that means "slow movement", and it is one of the constituents of Parkinson's disease (2), although it is also associated with other diseases. For patients suffering from Parkinson's disease, it is usually the most tiring and frustrating of the associated conditions. Small muscle movement is one of the first affected areas of the body. Therefore, a common test is to ask the patient to tap her finger. Normal individuals tap their fingers at 4 or 5 Hz, someone afflicted with bradykinesia can usually manage only up to 1 Hz.(3) There is no cure for bradykinesia. Certain surgeries may help decrease the condition. Hope remains for the future while researchers continue to explore different possibilities, examining causes and treatments that will lead to a cure and to more clues about Parkinson's disease, Huntington's disease, and other conditions with which bradykinesia is associated. (4)

Not only does bradykinesia affect the speed of movement, the person's ability to complete a motion suffers. While walking, the arms no longer swing, but remain lax at the person's sides. (2) If a person suffering from bradykinesia is asked to make a fist without looking, he or she can tell that their movements are slow. The individual does not, however, realize that she never makes a complete fist. The fingers may be only slightly bent. Slowness of movement, by itself, is not bradykinesia. It can be associated with depression, stroke, or any kind of brain injury. The motion may be slow, but it is complete. The shuffling stride of a Parkinsonian and the monotonous voice are examples of bradykinesia-not only is the person moving the feet and legs slowly, they are unable to make a full stride. (1) Bradykinesia is a motion disorder and a perception disorder. A therapy treating both aspects has yet to be found.

Most cases of bradykinesia do not affect the entire body, but it is possible for the whole body to be afflicted. In severe cases, patients have a noticeable, unnatural stillness. While seated, they make no movements the way normal individuals move, such as crossing and uncrossing legs, crossing and uncrossing arms, shifting the angle of their head, or tapping their fingers. Bradykinesia in the face can lead to what is called "mask face" because of the constant lack of expression. Loss of voice volume and lack of intonation are common occurrences in those with bradykinesia.(4)

Since the most obvious symptoms of bradykinesia can apply to other diseases, and there are several causes for the condition, it is important that all bases are checked, including a thorough family history, drug use, and any pre-existing conditions must be considered. MRI generally rules out stroke and tumor. Sometimes a lumbar puncture is taken to measure the presence of metabolites and neurotransmitters in order to rule out metabolic disorders such as dopa-responsive dystonia. Drugs such as calcium-channel blockers, neuroleptics, and serotonin-reuptake inhibitors can be causes of bradykinesia. (4) Other causes include dementia, depression, dementia, drug-induced parkinsonism, and repeated head trauma.(5)

The problem of bradykinesia lies in the internal connections and stimuli within the nervous system. It is not a behavior that can be overcome with training. When there is an interruption of the signal pathway in the nervous system, the brain has an amazing ability to reroute the signal, creating a new pathway. The new pathway, however, does not accomplish effectively the task of carrying the signal. It takes a much longer time, and thus the translation of the signal into motion is much slower than before. Bradykinesia is reduced in patients who undergo therapies that attempt to restore the signal pathway by dealing with the interruption.(2) Even during such treatments, however, the patient may experience what is called the "freezing phenomenon" in Parkinson's disease. The entire body becomes frozen, and the person is literally trapped within her own body, unable to help herself. Although the specifics are not known, it is suspected that the freezing comes when there is a dopamine deficiency in a specific portion of the nervous system called the substantia nigra. Since people who suffer from bradykinesia respond better to external stimuli than internal stimuli, triggering an internal stimulus with an external one can end the "freezing phenomenon" control over their bodies.(6)

One of the identifiable chemical imbalances in people suffering from Parkinson's disease is the depletion of dopamine levels within specific regions of the brain. The treatment, therefore, is L-dopa, a precursor of dopamine, which is designed to convert to dopamine within the brain, compensating for the dopamine losses.(4) This type of medication does much to slow the progression of the disease, but it has little affect on bradykinesia. Surgeries are also used to alleviate the symptoms of Parkinson's disease. The two main surgeries performed are the thalamotomy and the pallidotomy. Of these, only the pallidotomy affects bradykinesia. The surgery involves placing a heat lesion, in the globus pallidus internus, that is commissioned to correct the abnormal amount of discharged nerve cells located in that area of the brain. This treatment was in existence before the introduction of L-dopa in the 1960s. L-dopa became overwhelmingly popular, but because of occasional drastic side effects, not all Parkinson's disease patients can take the medication. Furthermore, there seemed to be little long-term success of L-dopa. Despite this, it continues to be one of the main treatments for Parkinson's disease.(7)

As long as there is creativity and variation of perception, research will continue to explore and probe further into the hows and whys of diseases such as Parkinson's. While research on the larger diseases continues, new information on the symptomatic conditions will surface and help to explain the large and small pictures. Presently, much research is taking place. Neurotrophic proteins are being researched as ways to protect nerve cells from deteriorating. Neuroprotective agents such as naturally occurring enzymes are being investigated in their relationship to the deactivation of so-called free radicals. Explorations continue in neural tissue transplantation and genetic engineering.(8) The possibilities that research suggests are exciting. It holds the promise that future generations will only dig deeper, learn more, and question more. Bradykinesia is part of every day life for some. Others have never heard of it. Perhaps someday research will reveal something exciting that may lead to more information that will lead to effective treatment and better understanding of the functions within the brain.

References

1)Curing Parkinson's disease in our lifetime

2)Parkinson's disease caregiver website

3)Awakenings: the Internet focus on Parkinson's disease

4)We Move

5)General Practice Notebook

6)Freezing Phenomenon in Parkinson's disease

7)Neuroscience Clinic

8)Holistic Medicine


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