Parkinson’s disease is a condition in which parts of the brain become progressively damaged over many years.1
Parkinson’s disease is caused by a loss of nerve cells in part of the brain called the substantia nigra. This leads to a reduction in a chemical called dopamine in the brain.1,2
Dopamine plays a vital role in regulating the movement of the body. A reduction in dopamine is responsible for many of the symptoms of Parkinson’s disease.
Exactly what causes the loss of nerve cells is unclear. Most experts think that a combination of genetic and environmental factors is responsible.
Types of Symptoms
Parkinson’s disease is a slowly progressing neurodegenerative disorder, causing impaired motor function with slow movements, tremor and gait and balance disturbances. Various non-motor symptoms are common and include disturbed autonomic function with orthostatic hypotension, constipation and urinary disturbances, sleep disorders and neuropsychiatric symptoms.4
Onset is insidious with peak age of onset at 55-65 years. It commonly presents with impairment of dexterity or, less commonly, with a slight dragging of one foot. A fixed facial expression is characteristic with infrequent blinking. There may also be saliva drooling from the mouth, often due to impaired swallowing, and a quiet voice.4
The three main symptoms of Parkinson’s disease affect physical movement:3
- tremor – shaking, which usually begins in the hand or arm and is more likely to occur when the limb is relaxed and resting
- slowness of movement (bradykinesia) – where physical movements are much slower than normal, which can make everyday tasks difficult and can result in a distinctive slow, shuffling walk with very small steps
- muscle stiffness (rigidity) – stiffness and tension in the muscles, which can make it difficult to move around and make facial expressions, and can result in painful muscle cramps (dystonia)
Risk Factors 1,4
- Increasing prevalence with age, and slightly more common in men.
- Another recognised factor includes pesticide exposure.
- Small-scale studies have suggested that patients born in the spring have a higher incidence of Parkinson’s disease.