Symptoms of Parkinson’s Disease
Dopamine is an excitatory neurotransmitter that increases the flow of information and messages to various parts of the brain. In Parkinson’s disease, the death of the dopaminergic cells in the substantia nigra causes dopamine levels to decline. When this occurs, these messages are no longer sent properly and fail to reach their destination, causing most of the symptoms associated with Parkinson’s disease.
Dopamine plays a key role in many mental and physical functions. The progressive, incremental destruction of the dopaminergic neurons (the body’s main source of dopamine) drives the symptoms commonly associated with Parkinson’s disease, including:
- Voluntary movement
- Sexual gratification
- The experience of pleasure
Initial symptoms of primary Parkinson’s disease typically develop slowly and randomly over time as dopamine levels decline. Symptoms associated with Parkinson’s disease can be quite varied due to dopamine’s wide range of effects in the body.
Generally, symptoms associated with Parkinson’s disease are separated into Motor Symptoms and Non-Motor Symptoms.
Motor Symptoms and Parkinson’s
The basal ganglia helps control coordination and movement. The death of these dopaminergic cells causes a loss of coordination and voluntary movement over time. Typically, this manifests as the onset of a slight tremor, usually in the hand, which increases in intensity and frequency over time. However, roughly 30% of people with Parkinson’s disease do not develop a tremor.
In addition to a tremor, people with Parkinson’s often experience muscle rigidity and cramping that can be quite severe. This can make normally simple tasks, such as getting out of bed or buttoning a shirt very difficult if not impossible to do; this can be incredibly frustrating for a person dealing with Parkinson’s disease. Once more, as Parkinson’s disease progresses it will cause slowness of movements and often results in balance problems, dramatically increasing the risk of falling and fracture.
Many people with Parkinson’s disease report frequent episodes of “freezing” as the disease progresses. “Freezing” is usually described as the sudden onset of not being able to move, and is experienced by some as a feeling as if their feet are stuck to the floor. These freezing episodes are temporary and usually last from a few seconds to a few minutes.
The loss of the dopaminergic neurons associated with Parkinson’s disease causes a dramatic decrease in dopamine in the body. As stated early, dopamine has far-reaching effects in the body and the progressive loss of dopamine can cause many non-motor symptoms, including depression, anxiety, hallucinations, excessive sleepiness, intense/frightening dreams, difficulty concentrating, constipation and/or incontinence, difficulty swallowing, inability to control saliva , pain (that can at times be severe) and dizziness. Of particular concern, dementia and cognitive decline affect up to 75-80% of people with Parkinson’s disease as the disease progresses.