HEALTH ZONE – Parkinson’s Disease Introduction
What is Parkinson’s Disease?
Parkinson’s Disease is a neurological condition which causes day to day problems with movement. Sufferers may find they have a tremor at rest, have difficulty starting activity (e.g. walking), slowed thought, or low mood. In the past 50 years there have been great advances in the treatments available for Parkinson’s and the disease has moved from being regarded as a debilitating untreatable illness to a very manageable chronic condition thanks to advances in medicine.
The “shaking palsy” was first described by the British Dr. James Parkinson in 1917. However the causes underlying Parkinson’s were not understood until the 1960’s and the first effective treatment, L-dopa, only came into widespread clinical use in 1967.
Relative to other neurological diseases, Parkinson’s is quite common, developing in about 100-200/100,000 people per year, or about 2% of all people aged over 60. Parkinson’s disease is not considered a terminal illness and many patients live a normal life span. However, studies have shown a slightly increased risk of death amongst Parkinson’s sufferers as a whole, particularly amongst those who also have dementia or depression.
The underlying cause of the disease is damage to a part of the brain called the substantia nigra. These cells produce a neurotransmitter called dopamine which acts as a chemical messenger in the brain. Many systems in the body work in antagonistic pairs; for instance you have bicep muscle to bend your arm and tricep muscle to straighten it. Neurotransmitters often work in a similar way. In this case, another messenger called acetylcholine works like the bicep, causing muscles to contract, whilst dopamine causes them to relax. When these two neurotransmitters are in balance with one another, you have normal control of your muscles. However in Parkinson’s disease there’s a slow loss of dopamine in the brain, which means the balance swings in favour of the acetylcholine, causing muscle contraction known as “spasticity”.
The vast majority of cases are ‘sporadic’, which means the disease appears out of the blue, typically affecting adults between the age of 55 and 60. However younger patients do exist, although cases younger than 30 are very rare. About 15% of cases have a family history of the disease, but there is not a clear pattern of “autosomally dominant” inheritence. In other words, unlike diseases like Familial MND or Huntington’s Disease, the child of a Parkinson’s disease patient is only very slightly more likely to develop the disease in the future. It is more likely that genes are recessive, or have a weak “penetrance”; in other words they may only give a predisposition towards the disease rather than guaranteeing that an individual will definitely get it.
Additional signs of Parkinson’s Disease may include:
Small cramped handwriting
Lack of arm movement on affected side
Decreased facial expression
Lowered voice volume
Depression or anxiety
“Freezing,” being stuck in place when initiating a step or entering a doorway
Slight foot drag on affected side
Increase in dandruff or oily skin
Less frequent blinking
What causes Parkinson’s?
At this point it is uncertain what causes Parkinson’s Disease. Often, by the time physical symptoms manifest themselves, 60-80% substantia nigra cells have been destroyed. As a result, very little is known about the early phases of the disease. Most physicians and researchers believe that Parkinson’s arises out of a combination of genetic and environmental factors.
Who is at risk for Parkinson’s?
As many as 1.5 million Americans alone are afflicted with Parkinson’s, more than multiple sclerosis or muscular dystrophy combined. Generally, men and women are at equal risk for developing Parkinson’s. However, individuals over the age of 50 are considered to be at a higher risk. There is also a subset of Parkinson’s, called Young Onset Parkinson’s that affects those under the age 50, sometimes as early as 30 years of age.
Some research is pointing to certain lifestyle risk factors that may have an effect on whether someone will develop Parkinson’s. A disproportionate number of Parkinson’s cases are found in people who either live or grew up in rural areas. Factors in this area that are being explored are exposure to pesticides, heavy metals and whether well water was the primary source of drinking water. Interestingly, smoking and caffeine have been shown in some studies to have protective effects against Parkinson’s.
Drug treatment revolves around replacing lost supplies of dopamine in the brain. Dopamine precursors (such as L-dopa) are chemical compounds that provide the ingredients for the brain to make more dopamine naturally. Brand names include Sinemet and Madopar. Whilst these can be very effective for relieving symptoms, unfortunately they become less effective over time and can lead to side effects such as uncontrollable movements (known as “dyskinesias”). Another group of drugs stop the short term breakdown of existing dopamine in the brain as it gets used up (called COMT and MAO-B inhibitors). Brand names include Entacapone, Tolcapone, Stalevo, Rasagiline, and Selegiline. These drugs are often used more frequently in people who have only been diagnosed recently and can be used to help the “wearing off” effect of L-dopa. However there can be side effects including nausea, headaches, and possibly hallucinations in some cases. Finally, another class of drugs called the dopamine agonists act as direct mimics of naturally occurring dopamine. Brand names include Cabergoline, Ropinirole, Pramipexole, and Pergolide. Like L-dopa, these drugs are quite effective at reducing the core symptoms of Parkinson’s disease, although there may be side effects including hallucinations and changes in blood pressure; careful monitoring is required.
Whilst these drugs help Parkinson’s sufferers lead a more normal life their regime can be very complicated and many people end up taking dozens of tablets a day. Missing one can lead to an unpleasant “off” period during which they find it hard to move or initiate action. When the drugs have been prescribed correctly and spaced out properly, the levels of dopamine can be controlled well. However it is generally acknowledged that following a drug plan to the letter is difficult and at worst impossible. New advances include “controlled release” tablets such as Sinemet CR which act over a longer time period. For instance taking a CR tablet last thing at night can avoid having an “off” period first thing in the morning. Other technologies include injection pumps so that drugs are delivered directly into the body at a constant rate without having to remember a complex tablet regime. Advances on the horizon may include transdermal patches (much like the “Nicorette” patch to quit smoking) which provide a slow steady release of a drug without the inconvenience of tablets. Some patients may be eligible for a surgical procedure called deep brain stimulation (DBS). This works by electrically “jamming” the signal from the thalamus which tell the muscles to contract. For some patients it can be very successful in causing significant reduction in symptoms. However it is not for everyone, not without risks, and there may be a range of side effects which are currently being explored.
Physiotherapy is important for maintaining joint mobility and may include strategies to prevent falls. Occupational therapists may prescribe splints, eating aids, walkers, and wheelchairs to assist with mobility. Speech and language therapists may advise on swallowing techniques, assisted cough, and may prescribe alternative speech devices such as a Litewriter or laptop computer. Other drugs used in the treatment of symptoms include baclofen for spasticity, anti-depressants for anxiety and depression, and in some cases opiates for pain management.
Other sources of support
People with Parkinson’s disease and their families need support from a number of places. The family itself is an important source of emotional and spiritual support, and are also likely to give a lot of their time in assisting the patient with daily care. More so than for other neurological conditions, it is important that employers recognise areas that may be difficult for someone with Parkinson’s; for instance attending early morning meetings or tasks requiring fine motor skills.
In the UK the main additional source of support comes from a registered charity, the Parkinson’s Disease Society. They have an information telephone hotline, train medical professionals, provide information leaflets for patients and doctors, fund research, pay for specialist nurses, raise awareness, campaign for more resources, and fund a network of regional support groups. In the USA, there are several organisations including the American Parkinson Disease Association,
Research into Parkinson’s Disease
There is a wealth of research going on into Parkinson’s Disease, far too much to list here! To get the most up to date information try subscribing to www.pubcrawler.ie. This is an automated service which will deliver the results of customised queries straight to your inbox as often as you require. In the long term, future developments are likely to include improved techniques for deep brain stimulation, novel ways of getting dopamine replacement drugs into the brain, and might include stem cell therapy to replace and repair cells that have already been damaged by the disease.
How you can help
If you’ve read this information sheet and are interested in doing more there are several places you can go. The Institute of Psychiatry in South London, UK, always requires healthy participants for research projects, some of which are investigating Parkinson’s or other brain disease. You can register for their participant database, “PsychPop” To find out more about your local Parkinson’s Disease association go to the website for the European Parkinsons’ Disease Association . You might like to consider joining a local association branch as a volunteer or making a donation to research. There will be a cure for Parkinson’s, but it is hard to say how long it will take. That length of time is however affected by three big factors: money for research, time for care, and awareness for the public. If you can contribute in any way you’ll be helping us in the fight.
This information has been supplied to the BioTrax Volunteer Support Group in the interests of greater awareness and support of research volunteers by James Connolly – Research Specialist of the Parkinson’s Disease and Movement Disorders Center. University of Pennsylvania
Dr.Paul Wicks at the MRC centre for Neurodegeneration research. From the Institute of Psychiatry
Medical research studies may be conducted and are carefully designed to answer specific medical questions while protecting participants� safety. Well conducted medical trials are the fastest and safest way to find improved treatments and preventions for diseases. Clinical trials or interventional trials determine whether experimental preventions, treatments, or new ways of using known therapies are safe and effective under controlled conditions. Observational or natural history studies examine health issues and disease development in groups of people or populations. For more information on current medical trials or to register on the BioTrax database, view the study section atwww.biotrax.com .
Why not E-Mail this Health Zone News Letter to a friend who may benefit or print copies to give to your support groups or friends ? Click on the buttons below.