WHAT IS PARKINSON’S DISEASE?

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WHAT IS PARKINSON’S DISEASE?

Is everyone at risk for the development of Parkinson’s?   Who is affected by this neurological disorder? How is it diagnosed?   What are the treatments available?   Is there a cure for Parkinson’s?

I am very well aware of the effects that Parkinson’s has not only the patient, but on the family   as a whole.   My mother was diagnosed with Parkinson’s about 15 years ago, when she had mild tremors which got worse over time.   She became a candidate for Deep Brain Stimulation (DBS) surgery which was successful and controlled the tremors, plus daily medication. Some of the side effects of Parkinson’s that mom dealt with was the worsening of her beautiful handwriting and her speech. There were times it was so difficult to understand what mom was saying, but with patience and understanding you could figure out what she was saying. There are other side effects that have to be dealt with as well. Not every patient with Parkinson’s is eligible for this type of treatment and surgery. It is not easy on the caregiver or the family to see a loved one deteriorate, but it must be dealt with.   Unfortunately, for our family mom passed away a few months ago, but I know that she is more at peace now, and can relax.

Parkinson’s disease (PD) is a neurodegenerative brain disorder that progresses slowly in most people. What this means is that individuals with PD will be living with PD for twenty years or more from the time of diagnosis. While Parkinson’s disease itself is not fatal, the Center for Disease Control rated complications from the disease as the 14th top cause of death in the United States. There is currently no cure for Parkinson’s; however, your doctors will be focused and dedicated to finding treatments that help control the symptoms of PD and have a good quality of life.

Normally, there are brain cells (neurons) in the human brain that produce dopamine. These neurons concentrate in a particular area of the brain, called the substantia nigra. Dopamine is a chemical that relays messages between the substantia nigra and other parts of the brain to control movements of the human body. Dopamine helps humans to have smooth coordinated muscle movements. When approximately 60 to 80% of the dopamine-producing cells are damaged, and do not produce enough dopamine, the motor symptoms of Parkinson’s disease appear. This process of impairment of brain cells is called neurodegeneration.  Early in the course of the disease, the most obvious symptoms are movement-related; these include shaking, tremors, rigidity, slowness of movement and difficulty with walking and gait. Later, thinking and behavioral problems may arise, with dementia commonly occurring in the advanced stages of the disease, whereas depression is the most common psychiatric symptom. Other symptoms include sensory, sleep and emotional problems. Parkinson’s disease is more common in older people, with most cases occurring after the age of 50.

The main motor symptoms are collectively called parkinsonism, or a “parkinsonian syndrome”. Parkinson’s disease is often defined as a parkinsonian syndrome that is idiopathic (having no known cause), although some atypical cases have a genetic origin. Many risk and protective factors have been investigated: the clearest evidence is for an increased risk of PD in people exposed to certain pesticides and a reduced risk in tobacco smokers. The pathology of the disease is characterized by the accumulation of a protein called alpha-synuclein into inclusions called Lewy bodies in neurons, and from insufficient formation and activity of dopamine produced in certain neurons within parts of the midbrain. Lewy bodies are the pathological hallmark of the idiopathic disorder, and the distribution of the Lewy bodies throughout the Parkinsonian brain varies from one individual to another. The anatomical distribution of the Lewy bodies is often directly related to the expression and degree of the clinical symptoms of each individual. Diagnosis of typical cases is mainly based on symptoms, with tests such as neuroimaging being used for confirmation.

Modern treatments are effective at managing the early motor symptoms of the disease, mainly through the use of levodopa and dopamine agonists. As the disease progresses and dopaminergic neurons continue to be lost, these drugs eventually become ineffective at treating the symptoms and at the same time produce a complication called dyskinesia, marked by involuntary writhing movements. Diet and some forms of rehabilitation have shown some effectiveness at alleviating symptoms. Surgery and deep brain stimulation have been used to reduce motor symptoms as a last resort in severe cases where drugs are ineffective. Research directions include investigations into new animal models of the disease and of the potential usefulness of gene therapy, stem cell transplants and neuro-protective agents. Medications to treat non-movement-related symptoms of PD, such as sleep disturbances and emotional problems, also exist.

The disease is named after the English doctor James Parkinson, who published the first detailed description in An Essay on the Shaking Palsy in 1817. Several major organizations promote research and improvement of quality of life of those with the disease and their families. Public awareness campaigns include Parkinson’s disease day (April 11th) and the use of a red tulip as the symbol of the disease. People with parkinsonism who have increased the public’s awareness of the condition include actor Michael J. Fox, Olympic cyclist Davis Phinney, and professional boxer Muhammad Ali. Parkinson’s not only affects humans, but other primates as well, which have often been used in researching the disease and testing approaches to its treatment.

The term parkinsonism is used for a motor syndrome whose main symptoms are tremor at rest, stiffness, slowing of movement and postural instability. Parkinsonian syndromes can be divided into four subtypes according to their origin: primary or idiopathic, secondary or acquired, hereditary parkinsonism, and parkionson plus syndromes or multiple system degeneration. Parkinson’s disease is the most common form of parkinsonism and is usually defined as “primary” parkinsonism, meaning parkinsonism with no external identifiable cause. In recent years several genes that are directly related to some cases of Parkinson’s disease have been discovered. As much as this conflicts with the definition of Parkinson’s disease as an idiopathic illness, genetic parkinsonism disorders with a similar clinical course to PD are generally included under the Parkinson’s disease label. The terms “familial Parkinson’s disease” and “sporadic Parkinson’s disease” can be used to differentiate genetic from truly idiopathic forms of the disease.

Usually classified as a movement disorder, PD also gives rise to several non-motor types of symptoms such as sensory deficits, cognitive difficulties or sleep problems. Parkinson plus diseases are primary parkinsonisms which present additional features. They include multiple system atrophy, progressive supra-nuclear palsy, corti-co-basal degeneration and dementia with Lewy bodies.

Postural instability is typical in the late stages of the disease, leading to impaired balance and frequent falls, and secondarily to bone fractures. Instability is often absent in the initial stages, especially in younger people. Up to 40% may experience falls and around 10% may have falls weekly, with number of falls being related to the severity of PD. Other recognized motor signs and symptoms include gait and posture disturbances such as rapid shuffling steps and a forward-flexed posture when walking, speech and swallowing disturbances including voice disorders, mask-like face expressions or small hand writing, although the range of possible motor problems that can appear is large.

Parkinson’s disease in most people is idiopathic (having no specific known cause). However, a small proportion of cases can be attributed to known genetic factors. Other factors have been associated with the risk of developing PD, but no causal relationships have been proven.   A number of environmental factors have been associated with an increased risk of Parkinson’s including: pesticide exposure, head injuries, and living in the country or farming. Rural environments and the drinking of well water may be risks as they are indirect measures of exposure to pesticides.   Implicated agents include insecticides, primarily chlorpyrifos and organochlorides and pesticides, such as rotenone or paraquat, and herbicides, such as Agent Orange.   Heavy meals exposure has been proposed to be a risk factor; however, studies on the issue have been inconclusive.

A physician will diagnose Parkinson’s disease from the medical history and a neurological examination. There is no lab test that will clearly identify the disease, but brain scans are sometimes used to rule out disorders that could give rise to similar symptoms. People may be given levodopa and resulting relief of motor impairment tends to confirm diagnosis. The finding of Lewy bodies in the midbrain on autopsy is usually considered proof that the person had Parkinson’s disease. The progress of the illness over time may reveal it is not Parkinson’s disease, and some authorities recommend that the diagnosis be periodically reviewed

There is some evidence that speech or mobility problems can improve with rehabilitation, although studies are scarce and of low quality. Regular physical exercise with or without physiotherapy can be beneficial to maintain and improve mobility, flexibility, strength, gait speed, and quality of life. However, when an exercise program is performed under the supervision of a physiotherapist, there are more improvements in motor symptoms, mental and emotional functions, daily living activities, and quality of life compared to a self-supervised exercise program at home. As for gait and addressing the challenges associated with the disease such as hypokinesia (slowness of movement), shuffling and decreased arm swing; physiotherapists have a variety of strategies to improve functional mobility and safety. Areas of interest with respect to gait during rehabilitation programs focus on but are not limited to improving gait speed, base of support, stride length, trunk and arm swing movement. Strategies include utilizing assistive equipment (pole walking and treadmill walking), verbal cueing (manual, visual and auditory), exercises (marching and PNF patterns) and altering environments (surfaces, inputs, open vs. closed). Strengthening exercises have shown improvements in strength and motor function for people with primary muscular weakness and weakness related to inactivity with mild to moderate Parkinson’s disease. However, reports show a significant interaction between strength and the time the medications was taken. Therefore, it is recommended that people with PD should perform exercises 45 minutes to one hour after medications, when they are at their best. Also, due to the forward flexed posture, and respiratory dysfunctions in advanced Parkinson’s disease, deep diaphragmatic breathing exercises are beneficial in improving chest wall mobility and vital capacity.   Other patients prefer less invasive forms of therapy like tai chi.

There is no cure for Parkinson’s disease, but medications, surgery and multidisciplinary management can provide relief from the symptoms.

The U.S. Food and Drug Administration approved deep brain stimulation, which is also used to treat depression, to reduce symptoms in Parkinson’s patients. Electrodes are implanted into the brain and connected to a small device, (similar to a pacemaker) that emits programmed pulses to help control movement.   Deep brain stimulation (DBS) is the most commonly used surgical treatment. It involves the implantation of a medical device called a brain pacemaker, which sends electrical impulses to specific parts of the brain. DBS is recommended for people who have PD with motor fluctuations and tremor inadequately controlled by medication, or to those who are intolerant to medication, as long as they do not have severe neuropsychiatric problems.

Kathy Kiefer

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