Parkinson is a progressive neurodegenerative disease of unknown cause that produces a malfunction of basal ganglia and other movement centers of the brain that is characterized by the trial of tremor, bradykinesia and rigidity. There are other syndromes that can look like Parkinson that also cause cognitive disorders and have been classified as Parkinson plus syndromes.
In a normal brain, dopamine (inhibitory) and acetylcholine (excitatory) levels have a very tight equilibrium. When dopamine levels are reduced, the excitatory activity predominates and causes abnormal movements which translate into the 4 to 6 Hz tremor we see.
A loss of about 80% of the neurons (brain cells) of the "substantia nigra" that produce dopamine leads to the symptoms of Parkinson.
Rigidity results from the contracting of agonist and antagonist muscles at the same time.
When seen through the microscope the substantia nigra has "Lewy bodies" that characterize this disease from an histological point of view.
Bradykinesia: slowness in movement because of delayed transmission signals from the brain to the muscles.
Tremors: Shakiness often occurs in the hands. It is seen at rest and it disappears with movement.
Rigidity: Stiffness that produces muscle pain that increase during movement.
Poor Balance: the loss of reflexes that help posture can cause falls and walking problems.
Parkinson's Gait: Head down, no arm swing, body leans forward (remember our last Pope?).
Symptoms that are related to disautomy
Loss of sphincter control
Problems with handwriting
What is a Parkinson plus syndrome?
When Parkinson symptoms are associated with memory loss, cognitive disorders, dementia, orthostatic hypotension, etc.
This Parkinson plus syndromes can include Multiple Systems Atrophy, Shy Drager disease, and other parkinsonisms.