Parkinson’s disease is neurodegenerative, the second most common disorder of this type after Alzheimer’s disease.
Within your body, nerves transmit information to and from the brain or spinal cord, which affects muscles and organs. Neurodegeneration means that your nerves are not functioning normally. Parkinson’s disease is a progressive and unending movement disorder.
What Are the Symptoms of Parkinson’s Disease?
Common motor symptoms include:
- Tremors or shaking in hands, arms, legs, jaw, and face
- Rigidity or stiffness of limbs and trunk
- Slowness of movement
- Difficulties with balance, speech, and coordination
There are also non-motor symptoms which may develop years before the onset of motor problems, which may include:
- Cognitive impairment
- Poor sense of smell
- REM sleep behavior disorder (dream-enacting behavior)
Disease warning signs, such as tremors, loss of grip strength, and gait disruption, begin gradually and typically worsen over time. Symptoms and their progression may vary. Parkinson’s disease cannot be cured, but treatments and drugs can help control it.
What Causes Parkinson’s Disease?
The exact cause of Parkinson’s disease is unknown. Most people diagnosed with Parkinson’s have a late-onset form of the disease, which does not have a clear genetic cause. Early-onset Parkinson’s, defined as beginning before age 50, accounts for 2% to 10% of cases. This form may have a genetic cause.
Parkinson’s disease likely results from both genetic and environmental factors, and interactions among these factors. A full understanding of Parkinson’s risk requires integrated efforts to study both genetic and environmental factors.
Environmental toxicants could cause stress and damage to cells, triggering inflammation in the brainstem. These exposures could impair mitochondria, the structures within cells responsible for producing energy, and accelerate aging in the brain. Toxicant exposure may also trigger widespread accumulation of a misfolded version of protein called alpha-synuclein, which is toxic to nerve cells and a hallmark of Parkinson’s disease.
Studies have shown that the symptoms of Parkinson’s usually appear when 50%
or more of the dopamine neurons in the midbrain are lost. It progresses slowly as small clusters of neurons in the middle of the brain die. The gradual loss of these neurons results in reduction of a chemical called dopamine, which is responsible for transmitting messages to parts of the brain that coordinate muscle movement.