Parkinson's disease: Q and A

Q. What is Parkinson’s disease?

A. Parkinson’s disease is a degenerative disease of the nervous system that causes disturbances in initiating, controlling and co-ordinating movement. Parkinson’s disease is progressive, which means that the symptoms gradually become worse over time and eventually cause disabilities.

Q. Who is affected by Parkinson’s disease?

A. Parkinson’s disease generally affects older people — the average age at the time of diagnosis is 57 years. Of the more than 30,000 Australians who have Parkinson’s disease, only 5-10 per cent are diagnosed before the age of 40 years. Parkinson’s disease is slightly more common in men than in women.

Q. What causes the movement problems?

A. The movement problems are due to degeneration of certain nerve cells in the middle part of the brain. These nerve cells normally produce a substance known as dopamine — a neurotransmitter (chemical messenger) that is responsible for smooth and controlled body movements. A shortage of dopamine, as seen in people with Parkinson’s disease, causes symptoms such as tremor, stiffness and slow movements.

The quantities of other neurotransmitters (noradrenaline and serotonin) in the brain are also altered, but these changes are not as significant as the reduction in dopamine.

Q. Is Parkinson’s disease inherited?

A. The exact cause of Parkinson’s disease is still uncertain, but it is thought to be related to a combination of genetic and environmental factors.

If you have a family member with early-onset Parkinson’s disease (onset before 50 years of age), then you may have an increased risk of developing the disease at a younger age. But if you have a family member who was diagnosed with Parkinson’s later in life, your risk is no higher than anyone else’s.

Q. What are the symptoms?

A. There are 4 main symptoms that doctors typically associate with Parkinson’s disease.

• Bradykinesia (slowed movements or lack of movement). Voluntary movements become slow or difficult to initiate, and automatic movements, such as swinging your arms while walking or gesturing with your hands while talking, may also be reduced. Your friends and family may have also noticed that your facial expressions are less pronounced. Bradykinesia is probably the most disabling symptom, and means that simple tasks, such as dressing and eating, take much longer and are harder to perform.

• Tremor (involuntary trembling or shaking). The tremor associated with Parkinson’s disease occurs when muscles are at rest, and can become worse when you are tired or emotionally stressed. It improves with active movement, and usually disappears altogether while you are asleep. The tremor most often starts in one hand (often described as a ‘pill-rolling tremor’), and may progress to affect the other hand and the arms and legs.
• Rigidity (muscle stiffness). Rigidity is often not noticed by people with early Parkinson’s disease, but it can be detected by your doctor during an examination. Rigidity could be the cause of some of your aches and pains, and the common complaint of ‘freezing’, where your muscles may feel so stiff that they cannot move — this usually occurs when trying to stand up or start walking.
• Problems with posture and gait. Many people with Parkinson’s disease have a flexed or stooped posture, where they appear to be leaning forward. Your pattern of walking (gait) may also be affected, causing you to shuffle or unintentionally quicken your steps and break into a run to avoid falling. You may also have difficulty changing direction or stopping walking.

While only one side of your body may be affected at first, both sides are usually affected over time. It’s important to remember that Parkinson’s disease affects different people in different ways — you may experience some or all of the typical symptoms and the disease may progress slowly or quickly.

Q. Other than difficulties with movement, are there any other physical symptoms?

A. Other problems associated with Parkinson’s disease include:

• sensory symptoms (such as pain, numbness, tingling, itch, coldness and loss of sense of smell), which occur in up to 40 per cent of people with the disease;
• tiredness not relieved by resting (which, if it leads to inactivity, can make tremor and other symptoms worse);
• sleep problems (including difficulty falling asleep, restless sleep and nightmares), which affect about 70 per cent of people;
• constipation, which is due to the digestive tract slowing down and decreased mobility; and
• urinary incontinence or retention (difficulty urinating).

Constipation (which can be severe), urinary problems and sleep problems can be made worse by some of the medications used to treat Parkinson’s disease.

Q. Are memory and thinking affected as well?

A. Some degree of impaired memory and thinking can be a problem, most often affecting people who have had the disease for at least 10 years. About 20 per cent of people with Parkinson’s disease have severe loss of mental capacity, while about half have minor problems with memory and reasoning.

Depression also affects about half of all people with Parkinson’s disease. Depression may develop as a reaction to the diagnosis or physical disabilities, but is more likely to be part of the disease process itself.

Q. What is the outlook for people with Parkinson’s disease?

A. Most people can continue to work full time and lead relatively normal lives for many years after being diagnosed. The disease does not affect your life expectancy, and your age at diagnosis does not seem to have any effect on your long-term outlook. However, due to the progressive nature of the disease, many people do eventually become disabled.

Q. What is Parkinsonism?

A. Some medications (for example, antipsychotic medications); diseases (encephalitis, and other degenerative neurological diseases); head injuries (especially the repeated head injury that occurs in boxing); and toxins can cause similar signs and symptoms to Parkinson’s disease. This set of signs and symptoms is known as Parkinsonism.

Parkinsonism that is caused by medications is usually reversible once the medication is stopped.

Q. How is Parkinson’s disease diagnosed?

A. There is no specific test for Parkinson’s disease. Your doctor may suspect it based on your symptoms and physical examination findings. Usually, there needs to be at least 2 of the 4 major symptoms to make the diagnosis. Your doctor may perform some tests to rule out other diseases that may be causing your symptoms.

An improvement in symptoms after starting medication used to treat Parkinson’s disease helps to confirm the diagnosis.

Q. Can Parkinson’s disease be cured?

A. Unfortunately, there is no cure for Parkinson’s disease. However, it is possible to control (or at least improve) the symptoms with medications and lifestyle adjustments, and surgery can be beneficial for some people.

Q. What lifestyle adjustments can I make to help improve my symptoms?

A. Although there are medications which are very effective for treating the symptoms of Parkinson’s disease, the effects of these medications usually diminish with time. For this reason, your doctor may recommend some lifestyle changes before starting you on medication.

Regular exercise can help you to maintain flexibility and mobility. It also improves posture, balance, strength, agility and even mood. A moderate level of exercise is best — try walking, swimming, or dancing. Always remember to ask your doctor about an appropriate fitness programme before you start.

Loss of appetite and subsequent weight loss (and even malnutrition) can occur as a result of depression or a decreased sense of smell. Try to maintain a healthy and nutritious diet, with plenty of fibre to prevent constipation. Your doctor may need to prescribe an antidepressant medication if depression is contributing to poor appetite and weight loss.

Q. How can I stop Parkinson’s disease affecting my everyday life?

A. The problems with movement do affect everyday life, but with the help of health professionals you should be able to make adjustments to your daily routine and alterations around your home to help keep you active and independent.

• Speech can become monotonous and soft, and some people stutter if they have difficulty articulating words. A speech therapist can suggest verbalisation exercises and tongue movements to help you to speak louder and enunciate more clearly.
  
• As the disease progresses, you may find that eating becomes difficult due to problems with chewing and swallowing. A speech therapist may also be able to help with these problems.
• You may find walking difficult, especially taking the first step. A physiotherapist can give you exercises to strengthen your muscles and improve flexibility, as well as tips on how to improve posture, balance and mobility. Installing railings in the bathroom and hallways or using a walking aid can also help, and removing rugs from your home can prevent tripping.
• There is footwear available that can help improve gait and balance problems, and clothes with fastenings that should be easy to manage (for example, using Velcro instead of buttons, zippers or laces).
• Your handwriting can become small, shaky, and eventually illegible due to the combination of tremor, rigidity and bradykinesia. Using a large-body pen or pencil or a felt-tip pen may help.

Q. Can Parkinson’s disease affect my sex life?

A. Reduced libido and impotence can result from physical and/or psychological factors of Parkinson’s disease. In addition, some of the medications used to treat the symptoms of Parkinson’s disease can cause sexual dysfunction in men, and vaginal dryness in women. Fatigue can make matters worse. It may help to try having sex in the morning after taking your medication. Medications such as sildenafil (Viagra) may help men with erectile difficulties, and vaginal lubricants may be of help to women.

Q. What are the different types of medications used to treat Parkinson’s disease?

A. Because the symptoms of Parkinson’s disease are caused by a lack of dopamine in the brain, most drug treatments — so-called ‘antiparkinsonian medications’ — are aimed at replacing dopamine or acting like dopamine. (Treatment with dopamine itself does not help, because dopamine taken by mouth cannot enter the brain.)

Levodopa, also known as L-dopa, is the most effective medication available, improving symptoms in more than 80 per cent of people within 6-8 weeks. Levodopa is converted into dopamine by nerve cells in the brain. To prevent it from being converted to dopamine before it reaches your brain, it needs to be given in combination with another medication (carbidopa or benserazide). These combination medications are called Sinemet and Madopar, respectively.

Other medications available for the treatment of Parkinson’s disease include dopamine agonists, anticholinergics, COMT inhibitors, selegiline and amantadine. Although these medications are generally not as effective as levodopa, they do benefit some people. They are especially useful if levodopa is causing intolerable side effects or isn’t controlling symptoms on its own. These medicines are increasingly being used as initial therapy to control relatively mild symptoms, especially in younger patients.

If you are depressed, your doctor may also prescribe antidepressants to relieve symptoms and improve your quality of life.

Q. Are there any problems associated with using levodopa in the long term?

A. The use of medications means that most people with Parkinson’s disease can expect many years of active living. Unfortunately, the initial positive response to levodopa does not always last — its effects often become unpredictable, and various side effects start to appear after about 5 years of treatment. The 3 main side effects associated with long-term levodopa therapy are dyskinesias, the ‘on-off effect’ and the ‘wearing-off effect’.

Dyskinesias are involuntary twitching and jerking movements of the head, face and limbs. These uncontrolled movements are the most common adverse effect of prolonged levodopa therapy. Taking a lower dose of levodopa or combining levodopa with another antiparkinsonian medication — a dopamine agonist — may improve the problem of dyskinesia.

The ‘on-off’ effect is where periods of impaired movement abruptly alternate with periods of improved mobility. You can change from being fairly mobile to severely impaired within seconds. Taking lower, more frequent doses of levodopa or controlled-release levodopa (a preparation that releases levodopa slowly over 4-6 hours) can control these effects at first, but after about 15-20 years, they become even harder to suppress. Because dietary protein can interfere with the absorption of levodopa, reducing the amount of protein in your diet may also help prevent these fluctuations in mobility.

The ‘wearing-off’ effect, or end-of-dose failure, refers to a decrease in the length of time that each dose of levodopa controls symptoms. Taking smaller, more frequent doses of levodopa or using a dopamine agonist (medications that activate dopamine receptors) may help this problem. Taking a controlled-release preparation may help prevent the wearing-off effect from happening during the night.

More than half of people who use levodopa will experience these side effects. Your doctor will need to review your medications frequently to assess their effectiveness and side effects. Adjusting the timing and amount of medication you take, as well as the combination of different medications, will ensure that your treatment is optimal.

Summary of medication actions and side effects

Parkinson's disease medications
Medication	Use	Side effects
Levodopa preparations Levodopa plus carbidopa (brand name Sinemet); levodopa plus benserazide (brand name Madopar)	Levodopa can be used to treat all of the major symptoms of Parkinson’s disease. It is especially effective for controlling bradykinesia and rigidity. Tremor is also improved, although to a lesser extent.	Possible side effects include: nausea and vomiting; constipation; hallucinations; mental confusion; sleep disturbances; episodes of low blood pressure; drowsiness; and flushing. After long-term treatment — usually about 5 years — involuntary movements (dyskinesias), a decrease in the amount of time that each dose is effective (the wearing-off effect), and fluctuations in mobility (the on-off effect) may appear.
Dopamine agonists (for example, bromocriptine, pramipexole, pergolide, cabergoline)	Dopamine agonists mimic the actions of dopamine in the brain. They treat all symptoms of Parkinson’s disease, but are generally less effective than levodopa. Taking a dopamine agonist with, or instead of, levodopa during the early years of treatment may delay the development of dyskinesias (one of the side effects of levodopa). Dopamine agonists and levodopa can complement each other, and the combination can reduce the on-off effect.	Possible side effects include: nausea; low blood pressure when standing; hallucinations; confusion; and nightmares. Dopamine agonists are less likely to cause dyskinesias than levodopa. Hallucinations and sleepiness are more common with dopamine agonists than with levodopa. Pergolide has been withdrawn from the market in the USA because of links to heart valve damage.
Anticholinergics (for example, benztropine, benzhexol, biperiden)	Anticholinergic medications block the effect of acetylcholine, one of the other neurotransmitters in your brain. This helps to restore the acetylcholine-dopamine balance. Anticholinergics can improve tremor and may improve rigidity, but they have no effect on bradykinesia.	Possible side effects include: dry mouth; constipation; blurred vision; disorientation; memory impairment; drowsiness; dizziness; and difficulty urinating (urinary retention). Confusion is most pronounced in older people.
COMT inhibitors (entacapone — brand name Comtan)	COMT inhibitors, as the name suggests, inhibit an enzyme called catechol-O-methyltransferase (COMT), which breaks down dopamine and levodopa in the body. By delaying the breakdown of dopamine and levodopa, they increase the amount of levodopa entering your brain, prolonging its effects. COMT inhibitors can be taken in combination with levodopa to treat advanced disease. They increase mobility and can help improve the wearing-off effect.	Possible side effects include: dyskinesias; dry mouth; nausea; diarrhoea; and abdominal pain.
Selegiline (brand name Selgene or Eldepryl)	Selegiline inhibits an enzyme in the brain (monoamine oxidase B) that metabolises dopamine. It can improve symptoms by delaying the breakdown of any naturally-occurring dopamine as well as dopamine formed from levodopa. Selegiline can be used to treat early Parkinson's disease, or used in combination with levodopa to treat advanced disease. Selegiline can enhance the effects of levodopa and improve the on-off effect. Beneficial effects, which are modest, often wane within a year.	Possible side effects include: dry mouth; nausea; sleep problems; and dizziness.
Amantadine (brand name Symmetrel)	Amantadine is thought to work by stimulating the release of dopamine. It is usually used in combination with levodopa to treat advanced disease. Amantadine is moderately effective for treating all symptoms, but benefits are often short-lived. It can reduce the intensity of dyskinesias induced by levodopa.	Possible side effects include: swollen hands and feet; and a purple-coloured skin rash. Rarer side effects include dizziness, dry mouth, nausea, urinary retention, and incontinence. Psychological problems, such as depression and anxiety, are more common in older people.

Q. Is surgery beneficial for people with Parkinson’s disease?

A. Neurosurgery is generally reserved for people who have erratic and disabling responses to prolonged levodopa therapy. Options include procedures known as pallidotomy, thalamotomy and deep brain stimulation. These procedures are generally only available in large, specialist centres.

Thalamotomy involves destroying a small amount of tissue in the part of your brain known as the thalamus, and is only effective for treating tremor. It is usually only considered if tremor is severe and not responding to medications. Due to the risks associated with performing this operation on both sides of the brain, it can only be used to treat tremor on one side of the body.

Pallidotomy, which involves destroying overactive cells in a region of the brain called the globus pallidus, is generally reserved for people with advanced disease that is not controlled by medications. It can treat the dyskinesias that result from long-term levodopa therapy, and allow continued use of levodopa. Unfortunately, only 5-10 per cent of people with Parkinson’s disease who suffer from dyskinesias are suitable candidates for this type of surgery.

Pallidotomy may also improve tremors, rigidity, bradykinesia, and the on-off effect, but the benefits may not last, and this type of surgery does have risks.

Deep brain stimulation is a relatively new treatment, where electrodes are inserted in the parts of the brain that control smooth motor control. These electrodes are connected to a pacemaker-style device that is implanted under the skin near your collarbone. The main difference between deep brain stimulation and traditional surgery is that you are able to activate and control the device, which sends tiny bursts of electricity to your brain to help control tremor and dyskinesias. For people taking levodopa, it can help stabilise medication fluctuations. Rigidity and bradykinesia can also improve with this treatment. Unfortunately, this procedure is not helpful for people who have not responded to levodopa, and is not suitable for people with dementia.

Q. Is there any research into new treatments?

A. Embryonic stem cell transplantation is one of a number of potential treatments for Parkinson’s disease that are currently being investigated. Embryonic stem cells have the potential to develop into any type of human cell, and researchers believe that they can direct stem cells to develop into dopamine-producing nerve cells. These cells could then be transplanted into the brains of people with Parkinson’s disease, as a replacement for their lost nerve cells.

Scientists derive cells from embryos that are about 4-5 days old for this type of research. The embryos have been fertilised in vitro, that is, in a laboratory, rather than inside a woman’s body. Because there is a limited supply of these stem cells available for research, it could take many years to determine whether this procedure will help people with Parkinson’s disease. There are also significant ethical issues associated with the use of tissue from embryos, because extracting the stem cells results in the embryo being destroyed.

With continued research, improved treatment options and even a cure for Parkinson’s disease may not be too far away.

 

myDr, 2005
© Copyright: myDr, UBM Medica Australia, 2000-2010. All rights reserved.

Last Reviewed: 15 January 2009