Parkinson's disease is a chronic and degenerative disorder of a small part of the brain known as the substantia nigra. This area of the brain sends messages down nerves to the spinal cord to help control the muscles of the body. Messages are passed between brain cells, nerves, and muscles by chemicals called neurotransmitters. Dopamine is the main neurotransmitter that is made in the substantia nigra.
If you have Parkinson’s Disease, a number of cells in the substantia nigra become damaged and die. The cause of this is not known. Over time, more and more cells become damaged and die. As cells are damaged, the amount of dopamine is also reduced. A combination of the reduction of cells and a low level of dopamine in the cells in this part of the brain causes nerve messages to the muscles to become slow and abnormal.
Who suffers with Parkinson's disease?
Parkinson’s Disease mainly develops in people over the age of 50. It becomes more common with increasing age. About 5 in 1000 people in their 60s, and about 20 in 1000 people in their 80s have Parkinson’s. It affects both men and women. Rarely, it develops in people under the age of 50. Parkinson’s is not usually inherited, and it can affect anyone. However, genetic (hereditary) factors may be important in the small number of people who develop the disease before the age of 50.
What are the symptoms like?
The brain cells and nerves affected in Parkinson’s Disease normally help to produce smooth, co-ordinated movements of muscles. Therefore, three common symptoms that gradually develop are:
- Slowness of movement (bradykinesia)
- Stiffness of muscles (rigidity)
- Shaking (tremor)
- Less facial expressions such as smiling or frowning.
- Difficulty with writing (handwriting tends to become smaller).
- Difficulty with balance and posture.
- Speech may become slow and monotonous.
- Swallowing may become troublesome, and saliva may pool in the mouth.
- Tiredness, and aches and pains.
Various other symptoms develop in some cases, mainly as the condition becomes worse. These include:
- Bladder symptoms and sometimes incontinence.
- Hallucinations (seeing things that are not real).
- Sexual difficulties.
- Alterations in your sense of smell.
- Difficulties with sleeping.
- Depression and anxiety.
Does Parkinson's disease cause dementia?
The cells in the brain affected in Parkinson’s are not in the 'thinking' parts of the brain and dementia is not a typical early feature of Parkinson’s. However, if you have Parkinson’s Disease you have an increased risk of developing dementia and about half of people with Parkinson’s develop dementia at some stage.
What are the treatments for Parkinson's disease?
There is no known cure for Parkinson’s Disease, and no known treatment prevents the disease from progressing. However, there are treatments available that can ease symptoms such as drugs, physiotherapy, occupational therapy and speech therapy. Surgery may also be an option for some severe cases.
Which drugs are used to treat Parkinson's disease?
Three types of drugs are commonly used to ease the symptoms of Parkinson's Disease:
Levodopa: This drug has been used for many years. Nearly all people with Parkinson’s Disease notice a good improvement in symptoms after starting Levodopa. The body converts Levodopa to Dopamine. Therefore, the low level of Dopamine in the affected part of the brain increases. Levodopa is always combined with another drug (either Benserazide or Carbidopa) to reduce unwanted side-effects and increase the amount of Levodopa that gets to the brain where it is converted to dopamine.
Dopamine Agonists: Dopamine Agonists are drugs that act on the same receptors in the brain as dopamine. So, in effect, they act like a substitute for dopamine.
There are several types such as Apomorphine, Bromocriptine, Cabergoline, Lisuride, Pergolide, Pramipexole, and Ropinirole) each with different brand names.
Dopamine Agonists are not thought to be as good as Levodopa at easing symptoms in some people. Until recently they have mainly been used as a 'top-up' treatment when the condition progressed and symptoms had not been well controlled with Levodopa alone.
Monoamine oxidase-B inhibitors: These drugs are another alternative to Levodopa for early Parkinson's disease. They include Selegiline and Rasagiline. These drugs work by blocking the effect of a chemical in the brain called monoamine oxidase-B. This chemical is involved in the breakdown of Levodopa and Dopamine.
Various factors influence which drug is advised. For example, your age, severity of symptoms, how well your symptoms respond to treatment, if side-effects develop, other drugs that you may take, etc. Your specialist will advise on the best drug to take for your circumstance.
The dose of the drug that you start with usually needs to be increased over time. In time, combinations of drugs may be required for best control of symptoms. The treatment schemes and doses can vary greatly from person to person. As the disease progresses, the symptoms may not be so well controlled by drugs.
Other therapies for Parkinson's disease
A Specialist Nurse can provide support, information and counselling. A specialist nurse can also monitor response to treatment, and can give advice on how to adjust medication if necessary.
A physiotherapist can advise on posture, walking, and exercises.
An occupational therapist can advise on such things as home adaptations which may ease many tasks.
A Speech and Language Therapist can help if speech or swallowing problems occur.
Surgical techniques are being gradually developed which may help some people who have had Parkinson’s for several years. Surgery does not cure Parkinson’s Disease, but may help to ease symptoms when drugs are not working well. For example, chronic deep brain stimulation is a technique that involves putting a pulse generator (like a heart pacemaker) in the chest wall. Fine cables are tunnelled under the skin to electrodes placed in the brain. The electrodes stimulate the parts of the brain that is affected by Parkinson’s Disease and can help to ease symptoms.