Sometimes known as pseudoparkinsonism, arteriosclerotic parkinsonism involves damage to brain vessels due to multiple small strokes. Tremors are rare in this type of parkinsonism, while dementia (the loss of mental skills and abilities) is common. Antiparkinsonian drugs are of little help to people with this form of parkinsonism.
Some toxins, such as manganese dust, carbon disulfide, cyanide, and carbon monoxide, can also cause parkinsonism. A chemical known as MPTP (1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine) causes a permanent form of parkinsonism that closely resembles Parkinson's disease. Investigators discovered this reaction in the 1980s when heroin addicts in California who had taken an illicit street drug contaminated with MPTP began to develop severe parkinsonism. This discovery, which demonstrated that a toxic substance could damage the brain and produce parkinsonian symptoms, caused a dramatic breakthrough in Parkinson's research. For the first time, scientists were able to simulate Parkinson's disease in animals and conduct studies to increase understanding of the disease.
Parkinsonism-Dementia Complex of Guam
This form of parkinsonism occurs among the Chamorro populations of Guam and the Mariana Islands, and may be accompanied by a disease resembling amyotrophic lateral sclerosis (also known as ALS or Lou Gehrig's disease). The course of the disease is rapid, with death typically occurring within five years. Some investigators suspect an environmental cause, perhaps the use of flour from the highly toxic seed of the cycad plant. This flour was a dietary staple for many years when rice and other food supplies were unavailable in this region, particularly during World War II. Other studies, however, refute this link.
Parkinsonism Accompanying Other Conditions
Parkinsonian symptoms may also appear in people with other, clearly distinct neurological disorders, such as: