The Parkinson’s Disease (Idiopathic Parkinson Syndrome) is today one of the most known and most common movement disorders in the world. Parkinson’s usually manifests at a higher age but can also occur within younger people. The disease can occur before the age of 40 too, but this is very rarely. Parkinson’s was first described in the year 1817 by the English physician James Parkinson, after whom the disease was named later. In his time the neurodegenerative disease was known as “Shaking Palsy”.
Parkinson’s is a very complex disease that is characterised by the ongoing reduction of nerve cells in the brain in the so-called Substantia nigra. This reduction of nerve cells is responsible for a deficit of the messenger substance dopamine; due to that deficit the symptoms of Parkinson’s occur.
Until the first symptoms become noticeable, about half of the affected nerve cells are reduced. Parkinson’s is still not curable and the progression of the disease cannot be stopped. But there are therapeutic ways to reduce the severity of the symptoms and to give back some quality of life to the patients.
The cause of Parkinson’s is still not identified. On the one hand it is estimated that genetic reasons play a role, on the other hand environmental influences, like toxins or similar, are discussed within research as possible cause of the Parkinson’s Disease. But for none of these possible reasons was found proof. In Austria there are 20,000 people diagnosed with Parkinson’s1. In Germany are between 250,000-280,000 people suffering from this disease2. In general, men are more often affected than women.
Before the motor symptoms of Parkinson’s become noticeable, patients can show early symptoms, even years before a diagnosis. These early symptoms are mostly non-motor and people tend to not connect them immediately to Parkinson’s. Later on, the missing swinging of an arm while walking can be a first sign of Parkinson’s. Common early symptoms are e.g. smell disorders, sleeping disorders, reduced intestinal activity or also pain that often occurs in the shoulders.
Especially sleeping disorders that affect the REM sleep can be an early symptom of Parkinson’s. A healthy human in the REM sleep lays still and calm, the only movements that are occurring are those of the eyes (REM = rapid eye movement). The REM sleep also is the phase of sleep were humans dream.
Persons who suffer from a REM sleep disorder are not calm during this phase: intense movements, speaking or crying are common; dreams are lived out actively. Persons concerned cannot influence this behaviour. Due to the uncontrolled movements, the REM sleep disorder can be a danger to people concerned themselves and others. In general, people with this kind of sleep disorder have a higher risk of developing a neurodegenerative disease.
Characteristic for the Parkinson’s Disease are the four main symptoms bradykinesia, tremor, rigor and postural instability.
Bradykinesia is the ongoing slowing of movements of Parkinson’s patients. It affects all muscles in the body. Specific movements, parallel motor activities and fine motoric movements are slowed. The bradykinesia often impedes everyday life. Many patients show first signs of bradykinesia already in an early stage of the disease through the so-called micrography: writing becomes smaller and illegible.
With the ongoing of the disease the bradykinesia also increases. The slowing of the movements can go as far as the complete “freezing” of patients while they are walking and cannot move at all anymore. This freezing is called akinesia. Because the bradykinesia affects the face muscles too, patients often have a “mask-like” expression and reduced facial expressions. Also, the voice becomes quieter and incomprehensible.
The bradykinesia starts, like the other main symptoms too, in one half of the body and spreads during the progress of the disease onto the other side. Therefor the comparison of the two halves of the body is important for physicians because differences of movements, gestures and facial expressions become more visible during such comparisons. To receive the diagnosis Parkinson’s Disease at all, the bradykinesia needs to be present, together with one of the other main symptoms. Due the fact that the bradykinesia is the greatest burden for patients, this symptom is the first target for therapeutic treatments.
Tremor is the term for uncontrollable shaking of the muscles. Tremor often affects the hands but can also occur in the arms, the legs, the head or the tongue. The most common tremor form at Parkinson’s is the rest tremor. This type of tremor occurs, when the affected body part is in a rest position, e.g. the hands lay in the lap. As soon as a movement is implemented, the rest tremor disappears.
But not only rest tremor can occur at Parkinson’s, also the postural tremor or the intention tremor can manifest. The postural tremor occurs, when the hands are holding something, e.g. a glass. The intention tremor occurs when an action is implemented, e.g. reaching for a glass.
A patient can develop more than one type of tremor. During the ongoing of the disease a tremor affects about 75% of the patients. Like the other main symptoms, the tremor affects one side of the body in the beginning and spreads later onto the other side.
It depends on the tremor severity how much the shaking impedes patients in their everyday life. If it becomes a burden, it is possible to treat it with medication. A drug therapy can help to reduce the severity of the shaking. Find more about tremor here
Rigor is the term for the increased muscle tone of Parkinson’s patients. The basic tone of muscles is called the rest muscle tone. Parkinson’s patients have a higher rest muscle tone and because of that the rigor occurs. In healthy humans the muscles are working together in a balance: when one muscle is tensed, its counter muscle loosens up.
The muscle tension of Parkinson’s patients is imbalanced: when one muscle is tensed, its counter muscle doesn’t loose up, it also tenses. Because of the higher muscle tone, patients often feel pain similar to muscular tensions. The rigor is also responsible for the ongoing stiffness of all muscles and therefor for the stiffness of the body of Parkinson’s patients.
Due to the stiffness, movements are impeded and, due to the higher rest muscle tone, often exhausting for patients too.
The rigor is also co-responsible for the posture of Parkinson’s patients: during the course of disease the arms, wrists, elbows, trunk and knees bend more and more and the typical Parkinson’s posture becomes visible.
Postural instability is the term for disorders while standing and walking and also patients’ problems with the balance. The postural instability shows in the later course of disease and occurs because the muscle’s compensation movements to unexpected movements are slowed down more and more. Due to that it is much harder for Parkinson’s patients e.g. to catch a fall with a lunge than it would be for someone healthy. Therefor the postural instability is a symptom with major consequences that can lead to serious falls and therefor to injuries. But not only while walking or standing patients report of the effects of postural instability: they feel it sometimes even during sitting and describe the feeling as if they would fall at any moment to one side.
The disorder during walking becomes visible through tiny and unsure steps. The uncertainty is also often enhanced by the anxiety about falling.
The reason for the postural instability has not been found but it is estimated that it develops because of a combination of the other main symptoms. Unlike the other main symptoms, the postural instability cannot be treated with any medication and it cannot be captured objectively.
Parkinson’s is not curable but there are effective therapeutic methods that can help to reduce the severity of the symptoms and give patients back some of their quality of life. To find the best fitting and individually adapted therapy for each patient, it is important to evaluate the symptoms. The course of Parkinson’s is always similar but not exactly the same; just as humans are individuals, the course of disease is individual too.
The first step of Parkinson’s treatment is the drug therapy. The drug that is used the most is Levodopa, shortly L-Dopa. L-Dopa is a precursor of the messenger substance dopamine. Due to the reduction of the nerve cells in the Substantia nigra and the resulting lack of dopamine, the substitution of dopamine is important. This substitution is secured with L-Dopa: as a precursor of dopamine, it transforms into dopamine within the brain and therefor reduces the severity of the symptoms.
Next to L-Dopa, so-called dopamine agonists are used too. These substances have similar effects and imitate the effect of dopamine within the brain.
Another group of substances used for treatment are the COMT-inhibitors. Catechol-O-Methyl-Transferase (=COMT) is an enzyme that plays a role in the depletion of dopamine. COMT-inhibitors are prescribed especially to patients who have bypassed the “honeymoon phase” and L-Dopa has not the effect anymore that it had in the beginning of the disease. The honeymoon phase is the phase during the first years of the disease, where drugs show very good effects on the symptoms. Taken together with L-Dopa, the duration of effect of L-Dopa is prolonged due to the COMT-inhibitors.
Other additional therapeutic steps for Parkinson’s treatment are physiotherapy and ergotherapy. During these therapies, patients work on motion sequences, train their own awareness of their bodies and maintain their mobility.
If neither medication nor other therapies show an effect anymore, the reduction of the symptoms can be gained with Deep Brain Stimulation. The Deep Brain Stimulation is a surgical procedure. During this procedure a trigger is implanted under the skin near the collarbone. The trigger is wired, and the wires are placed into the so-called basal ganglia within the brain during the procedure. Due to that the trigger can give impulses that actively intervene into the brain’s operations.
1 Source: Website of the "Parkinson Selbsthilfe" www.parkinson-sh.at, visited on 06/04/2018
2 Source: Website of the "Parkinson Selbsthilfe Deutschland" www.parkinson-gesellschaft.de, visited on 06/04/2018
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