WHO Fact Sheet No 152 April 1997

PARKINSON'S DISEASE

Parkinson's disease has existed since biblical times, but it was only in the 19th century that it was clinically recognized. Because the prevalence of Parkinson's disease increases with age, the shorter life expectancy in previous centuries probably meant that it was not as noticeable as it is today.

The condition was first established as a clinical entity in 1817 by a London doctor, James Parkinson (1755 - 1824), in his Essay on the Shaking Palsy, or "paralysis agitans" as he called it in Latin. Later, in the 1860's, the French neurologist Pierre Marie Charcot (1853 - 1940) called the condition "Parkinson's disease". Today, a hundred and eighty years after it was first published, Parkinson's essay continues to be recognised throughout the world as the classic description of this condition.

• Parkinson's disease is a progressive neuro-degenerative disorder which affects movement or the control of movement, including speech and "body language". A number of conditions may mimic Parkinson's disease and are properly termed "Parkinsonism".
• Prevalence: There are few reliable data of global prevalence or morbidity of Parkinson's disease, but it is known to affect all ethnic groups. The overall prevalence of Parkinson's disease in Europe, for example, is estimated to be 1.6 per 100 in persons over 65 years of age. In 1990, worldwide there were an estimated 4 million people suffering from the disease. It should be emphasised that more than one in ten sufferers are diagnosed before the age of 50.
• Cause: The cause of Parkinson's disease is unknown. What is known is that it results from a deficiency of the chemical messenger dopamine, which is produced by the brain and influences the initiation, planning and execution of movements. The symptoms of Parkinson's disease appear when about 80% of dopamine is lost. An individual's ability to produce smooth controlled movements is affected by this.
• Symptoms: The expression of Parkinson's disease varies enormously and no two people will have exactly the same symptoms. The three main symptoms, which are used as a basis for diagnosis, are tremor, rigidity and bradykinesia.
• Tremor is often the first sign to be noticed, although it is estimated that about 25% of people with Parkinson's disease do not have a tremor. The tremor usually occurs at rest and lessens with voluntary movements. It is commonly experienced in the hands and arms, often on one side, but may affect any part of the body.
• Rigidity results from a sustained increase in muscle contraction and may cause muscle pain and stiffness. Clinically it may be felt as an intermittent ('cog-wheel') or sustained ('lead pipe') resistance to movement when passively putting a limb through its range of movement.
• Bradykinesia means slowness or poverty of movement. In an unaffected person, automatic movements occur involuntarily and subconsciously. People with Parkinson's disease experience an increasing poverty of such spontaneous activity. This accounts for symptoms such as the stooped posture, drooling of saliva and a shuffling gait.
• Loss of communication skills is particularly common. Speech often becomes soft, mumbling and monotonous in tone. There is often reduced facial expression, resulting in a typical 'mask-like face' and limited body language. Many people also have problems with their handwriting, which becomes small and cramped, making it very difficult to read.

Parkinson's disease is complicated by several factors: the progression is highly variable; the degree of disability can fluctuate dramatically, sometimes over the course of a single hour; and each person will experience Parkinson's differently.

• The communication problems can seriously affect the social and emotional life of both the person with Parkinson's and his or her family. Research has shown that the loss of non-verbal skills has a negative impact on people's perception of an individual's abilities. Because of reduced body language people are often erroneously labelled unintelligent, unco-operative and difficult.
• Although some people in the later stages may become mentally confused or demented, most retain their intellectual facilities while living in a body which is becoming increasingly disabled. This, in itself, can contribute to the boredom, social isolation and depression commonly experienced by sufferers.

Like many other neurological illnesses, Parkinson's disease is chronic, progressive and, at the moment, incurable. The main treatment for it is drug therapy, although surgical techniques are also used.

• Drug treatment does not cure Parkinson's. Its main objective is to restore the deficiency of dopamine. Two kinds of drugs are used: those able to cross the blood-brain barrier and be converted into dopamine by the brain; and those able to effectively stimulate the dopamine receptors of the brain.
• Drug therapy is complicated by side effects which often occur as a result of long-term use of anti-Parkinsonian medication. These side effects can be as disabling as the condition itself. One of the most distressing side effects is the 'on-off' syndrome, or disabling fluctuations in ability. This side effect is greatly misunderstood by many physicians who often label a person who is 'off' as 'difficult' or 'unco-operative'.
• Other side effects of drug therapy include nausea and vomiting, confusion hallucinations and involuntary movements. As the disease progresses, drug management often involves a careful balancing act between controlling the symptoms and minimising the side effects.
• There is great interest in the use of surgical techniques to treat Parkinson's disease. One such technique -- stereotactic surgery -- involves inserting delicate instruments through a specially created small hole in the skull, and using instruments to operate on parts of the brain which are involved in the control of movement. It was relatively common form of treatment before the advent of drugs after which it largely fell into disuse. Research is also continuing into the use of foetal brain tissue implants, but as yet the results are inconclusive.

Management of Parkinson's Disease

Because of the individual, complex nature of Parkinson's disease, management requires a holistic approach which takes account of the whole of the affected person's life.

• Accurate diagnosis: Good management of the disease starts with an accurate diagnosis, which can be made by a doctor with specialist knowledge of Parkinson's disease, usually a neurologist or a geriatrician.
• The diagnosis of Parkinson's disease is often a shattering experience both for those diagnosed and their families. It needs to be given in a sensitive way so as to allow people time and space to come to terms with the diagnosis, and encourage them to seek further information and advice as they need it.
• Referral to a specialist benefits the patient in many ways. One of the most obvious is the enhanced knowledge that a specialist will have of drug and surgical treatments available to help treat Parkinson's disease. The specialist will also have experience in dealing with the side effects which might occur and will respect the individuality of each patient.
• Individual approach: There is no optimum drug treatment for Parkinson's disease. Each person must be prescribed a specific regimen to suit his or her particular needs, both in terms of timing and dose. This will often involve a 'cocktail' of different drugs available to ensure the best possible effects for the patient. It is important to note again that drug treatment does not cure Parkinson's and so the disease continues to progress under treatment. As the disease progresses, the individual regimen needs to be reviewed and, when necessary, modified.
• Multidisciplinary support: Early access to a multidisciplinary team is essential. Multidisciplinary assessment can be made of the person's abilities, potential difficulties can be identified and coping mechanisms put into place before problems start. The multi-disciplinary team may include physicians, dieticians, chiropodists, counsellors, psychologists, specialist nurses and volunteers. Continuity of care, particularly with the involvement of so many different professionals, is very important.
• Involving the patient and carer in the management of the condition entails listening to them and valuing their experiences. It means not making assumptions or choices for them. All too often, the experiences of the patient and carer (his or her immediate family members, relatives, friends, etc.) are ignored or treated with suspicion.
• The role of the carer should be recognised and valued, and their own needs acknowledged and addressed. Many carers receive no training, guidance or instruction on how to cope with someone who has Parkinson's disease. They need general information and practical advice. Most importantly, they need emotional support.
• Carers' lives are greatly affected and their needs may be just as important as those of the person with Parkinson's disease. Carers may experience a whole range of feelings: guilt, anger, resentment, fear and bereavement. Because of the demands of caring, and the communication problems experienced by people with Parkinson's disease, many carers become socially isolated and depressed.
• People with Parkinson's disease and their carers have a great deal to contribute to our knowledge and understanding. They can do this by participating in research, education and many other initiatives relating to Parkinson's disease. They also have a tremendous role to play in supporting and helping one another.
• Involving National Voluntary Organisations: In some countries self-help groups have emerged and provide valuable information and support for the people and their families living with this cruel illness.

International response

Because of the ageing of the world population, the importance of Parkinson's disease as a public health issue is expected to increase. The World Health Organization (WHO) deals with global aspects of control of the disease within the framework of the WHO Global Initiative on Neurology and Public Health.

• The emphasis in WHO's efforts is placed on the promotion of epidemiological studies and health statistics; assessment of cost benefits and health needs; the organization of services; and on raising public and professional awareness of Parkinson's disease.
• WHO is developing close collaboration with national health services, international and regional medical associations, such as the European Parkinson's Disease Association, as well as with other interested parties.
• A WHO working group on Parkinson's disease will meet in May 1997 to develop guidelines for the WHO-led international efforts to control the disease.

For further information, contact WHO's Office of Public Information, Geneva. Telephone (41 22) 791 2584. Fax (41 22) 791 4858. E-Mail: inf@who.int

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