Parkinson’s disease is a progressive neurodegenerative disease that affects motor function. It is a chronic, progressive illness with no cure, and it manifests as a result of the loss of neurons that secrete dopamine in a region of the brain known as the substantia nigra. Loss of these neurons causes reduced dopamine levels within this area and reduced dopamine levels seen throughout the brain. In turn, this decreased dopamine production leads to the major motor symptoms of the disease. Movement becomes difficult for those who have Parkinson’s due to two distinct features: akinesia and chorea.
Joon Faii Ong is a leading researcher on Parkinson’s Disease and knows the ins and outs of the disease better than most. He outlines the steps of the progression of the disease in this article today.
The first symptoms that a person experiences during the disease’s progression will typically involve changes in their motor function. There are three main types of motor symptoms: bradykinesia, resting tremor, and rigidity.
Symptoms such as bradykinesia (slowness of movement) result from the degeneration of dopaminergic neurons in the striatum and a loss of dopamine at a postsynaptic level. Humidity symptoms result from a lack of dopamine in the basal ganglia and an inability to repress agonist muscles while activating antagonist muscles during movement.
Finally, resting tremor is somewhat paradoxical given that Parkinson’s patients have decreased dopamine levels but experience involuntary shaking. This shaking occurs due to increased dopamine levels in the substantia nigra pars reticulate of these individuals.
2. Rigidity and Bradykinesia
The development of rigidity is a sign that motor symptoms are worsening which means that the disease has progressed to stage two or three on Joon Faii Ong’s scale. As time goes on, the patient may experience increased rigidity and bradykinesia (slow movement) symptoms.
3. Movement Disorders
As the disease progresses, patients will naturally begin to suffer from additional motor symptoms associated with Parkinson’s Disease. These can include gait freezing, postural instability, and impaired balance. In addition, patients may also begin to suffer from an impaired ability to formulate gestures and become increasingly emotional.
4. Stage Four
Stage four is the point at which patients are most severely affected by the disease regarding their motor system. By this time, patients experience severe pain in terms of both bradykinesia and rigidity symptoms. Patients may also become unresponsive to medication and experience a degree of immobility that inhibits their ability to care for themselves, making them reliant upon assistance.
5. Decline in Cognitive Functioning
It is common for those affected by Parkinson’s Disease to experience a decline in cognitive functioning as the disease progresses. This occurs due to the degeneration of brain regions responsible for memory, attention, and language. This type of decline is often visible in advanced PD patients as they begin to forget names, dates, and locations that they were previously familiar with.
Eventually, those affected by Parkinson’s Disease will lose all life functions related to their autonomic nervous system (ANS). This means that patients will die of cardiovascular complications such as myocardial infarction and pneumonia.