What is Parkinson’s disease? 

Parkinson’s disease is an age-related progressive degenerative disorderthat affects the nervous system, meaning it causes parts of your brain to deteriorate. These nerve cells die or become impaired, losing the ability to produce an important chemical called dopamine. As this nerve area deteriorates, you lose the abilities those areas once controlled.

When your brain sends activation signals that tell your muscles to move, it fine-tunes your movements using cells that require dopamine. That’s why lack of dopamine causes the slowed movements and tremors symptoms of Parkinson's disease, such as shaking, stiffness, and difficulty with balance and coordination.  Experts estimate that it affects at least 1% of people over age 60 worldwide.

What causes Parkinson’s disease?

The cause of Parkinson's disease is unknown, but several factors appear to play a role, including:

• Genes.

• Environmental triggers.

• Damage from brain injuries

• The presence of Lewy bodies.

• Alpha-synuclein found within Lewy bodies.

Risk factors

Risk factors for Parkinson's disease include:

• Age

• Heredity

• Sex

• Exposure to toxins

What are the symptoms?

The best-known symptoms of Parkinson's disease involve loss of muscle control.

Motor-related symptoms

• Motor symptoms, which means movement-related symptoms of Parkinson’s disease include the following:

• Slowed movements (bradykinesia).

• Tremor while muscles are at rest.

• Rigidity or stiffness.

• Unstable posture or walking gait.

• Additional motor symptoms can include:

• Blinking less often than usual. Reduced control of facial muscles.

• Cramped or small handwriting. Known as micrographia, this happens because of muscle control problems.

• Drooling. Another symptom that happens because of loss of facial muscle control.

• Mask-like facial expression. Known as hypomimia, this means facial expressions is very little or not at all.

• Trouble swallowing (dysphagia). Reduced throat muscle control. It increases the risk of problems like pneumonia or choking.

• Unusually soft speaking voice (hypophonia). This happens because of reduced muscle control in the throat and chest.

Non-motor symptoms

Non-motor symptoms (with the potential early warning symptoms in bold) include:

• Autonomic nervous system symptoms. These include orthostatic hypotension (low blood pressure when standing up), constipation and gastrointestinal problems, urinary incontinence and sexual dysfunctions.

• Depression.

• Loss of sense of smell (anosmia).

• Sleep problems such as periodic limb movement disorder (PLMD), rapid eye movement (REM) behavior disorder and restless legs syndrome.

• Trouble thinking and focusing (Parkinson’s-related dementia).

Stages of Parkinson’s disease

Symptoms start slowly. The first symptom may be a barely noticeable tremor in just one hand. Tremors are common, but the disorder may also cause stiffness or slowing of movement. In the early stages of Parkinson's disease, your face may show little or no expression. Your arms may not swing when you walk. Your speech may become soft or slurred. Parkinson's disease symptoms worsen as your condition progresses over time.

• Part 1: Non-motor aspects of experiences of daily living. This section deals with non-motor (non-movement) symptoms like dementia, depression, anxiety and other mental ability- and mental health-related issues

• Part 2: Motor aspects of experiences of daily living. This section covers the effects on movement-related tasks and abilities. It includes your ability to speak, eat, chew and swallow, dress and bathe yourself if you have tremors and more.

• Part 3: Motor examination. The criteria measure effects based on how you speak, facial expressions, stiffness and rigidity, walking gait and speed, balance, movement speed, tremors, etc.

• Part 4: Motor complications. That includes both the amount of time you have certain symptoms each day, and whether or not those symptoms affect how you spend your time.

How is it diagnosed?

• Blood tests.

• Computerized tomography (CT) scan.

• Genetic testing.

• Magnetic resonance imaging (MRI).

• Positron emission tomography (PET) scan.