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Parkinson's Disease Factsheet

What is Parkinson’s Disease (PD)?

PD is a progressive, degenerative neurological disease which affects the control of body movements. Meaning that as the disease progresses; body movements such as walking and talking are affected.1

How is it caused?

PD develops when the nerve cells or neurons in the brain which produce dopamine become impaired or die. Dopamine is a neurotransmitter, responsible for transmitting impulses between the nerve cells in the brain to control body movements.1

Decreased levels of dopamine, damage this chemical pathway resulting in abnormal nerve patterns in the brain which in turn causes impaired body movements. Research has pointed to a reduction of 60-80% of dopamine in the brain occurring in PD patients before symptoms appear. Exact causal factors for the reduction of dopamine are unknown. However research suggests that certain genes and environmental factors may play a role in disease progression.1

How common is Parkinson’s Disease (PD)?

It is estimated that 1 in 500 people develop PD which equates to 127,000 people in the UK.2PD is more prevalent in adults over the age of 50 however it can occur in younger people with recent figures highlighting that 1 in 20 PD patients in the UK are under the age of 40.2

What are the symptoms?

PD symptoms will vary according to each individual as will the rate of disease progression. The main symptoms are divided into two categories: motor symptoms and non-motor symptoms. Motor symptoms will include the following:2

  • Tremor – this is the sudden involuntary movement of the hand, foot or jaw lasting for a few seconds. PD tremors are most obvious when the affected body part is at rest and can start on one side of the body and may progress to the next as the disease develops. Tremors often disappear during sleep or improve with intentional movement1
  • Rigidity – this involves resistance to movement and is one of the most common symptoms of PD. Rigidity becomes apparent when the arm is moved by another person and it will only move in short or jerk-like movements1
  • Bradykinesia – this involves the slowing down of spontaneous and automatic movements preventing the individual living with PD to perform routine movements such as washing or dressing1
  • Postural instability – this involves impaired balance which can lead to falls and may result in stooped posture causing the shoulders to droop and head to become bowed1

Non-motor symptoms (NMS) of PD include:3

  • Pain
  • Depression
  • ConstipationSleep disturbance
  • Difficulty in swallowing (dysphagia)
  • Sweating

NMS are a major cause of disability for people with Parkinson’s and their carers.3,4Studies have revealed that between 31% and 65% of people with Parkinson’s experience NMS which can go unreported to healthcare professionals, because people are either embarrassed or unaware that the symptoms are linked to Parkinson's disease.5However, in many cases NMS are treatable.5

How is Parkinson’s Disease (PD) diagnosed?

Diagnosis by a physician will involve a series of clinical observations to assess the presence of motor symptoms using diagnostic criteria according to the UK Brain Bank criteria.6A combination of neurological examinations including computed tomography (CT) or magnetic resonance imaging (MRI) scans will be conducted to help identify the presence of structural lesions that may cause or contribute towards tremors associated with PD.6

However such tests cannot provide an accurate diagnosis as sometimes brain scans for PD patients can appear normal.1Blood tests may also be conducted to rule out other diseases which may result in PD-like symptoms. In general, correct diagnosis of PD will be a gradual procedure due to the patients’ medical history, age and symptoms.

Is Parkinson’s Disease (PD) treatable?

There is no cure for PD but there are a number of available treatments which help to alleviate symptoms. People living with PD may also opt for surgery depending on their symptoms or consult therapists to help manage day-to-day activities which the disease may impact on.

Treatment can be prescribed to manage either motor symptoms or non-motor symptoms. Clinical treatments prescribed to manage the onset of motor symptoms are categorised into different drug classes according to the mode of action. Treatment will either:1

  • Increase the level of dopamine in the brain,
  • Mimic dopamine activity in the brain (drugs referred to as dopamine agonists)
  • Inhibit dopamine breakdown (drugs referred to MAO-B and COMT inhibitors)

Treatment for non-motor symptoms associated with PD such as anxiety and depression can be also prescribed by a physician. These can include anti-depressants or benzodiazepines for anxiety.1

How does Parkinson’s Disease affect daily life?

PD is a chronic disease. It is not intrinsically fatal and life expectancy of people living with the disease is similar to those who do not live with it. Symptoms are gradual and in some cases can take up to 20 years to appear.1Disease progression can and often leads to impaired cognitive function and increases depressive symptomology.7As a result Parkinson’s can be disabling for the individual living with it and can make routine tasks such as walking, dressing or washing difficult to conduct on a daily basis.1

References

1. National Institute of Neurological Disorders and Stroke http://www.ninds.nih.gov/disorders/parkinsons_disease/detail_parkinsons_disease.htm (accessed June 2012)

2. Parkinson’s UK http://www.parkinsons.org.uk/about-parkinsons/what-is-parkinsons.aspx (accessed June 2012)

3. Chaudhuri et al. Parkinson’s disease: The non-motor issues. Parkinsonism and Related Disorders.2011; 17: 717-723

4. Martinez-Martin et al. Prevalence of nonmotor symptoms in Parkinson's disease in an international setting; study using nonmotor symptoms questionnaire in 545 patients. Movement Disorders. 2007; 22(11): 1623-1629

5. Chaudhuri R et al. The non-declaration of nonmotor symptoms of Parkinson's disease to health care professionals: An international study using the nonmotor symptoms questionnaire. Movement Disorders. 2010; 25: 704–709

6. Grosset D G et al. Diagnosis and pharmacological management of Parkinson’s disease: summary of SIGN guidelines. BMJ 2010; 340:b5614: 1-10.

7. Hobson et al. Measuring the impact of Parkinson’s disease with the Parkinson’s Disease Quality of life questionnaire. Age and Ageing 1999; 28: 341-346.

Sep 2012 - UK/12NE0077