Parkinson's disease (also known as Parkinson disease or PD) is a degenerative disorder of the central nervous system that often impairs the sufferer's motor skills, speech, and other functions.
''Tremor'' normally has a frequency between 4 and 6 Hz (cycles per second) and is the most apparent and well-known symptom.
Festination: Mood problem Prevalence Depression 58% Apathy 54% Anxiety 49%
Parkinson's Disease causes neuropsychiatric disturbances, which include mainly cognition, mood and behavior problems and can be as disabling as motor symptoms. Deficits include:
- Slowed reaction time; both voluntary and involuntary motor responses are significantly slowed.
- Executive dysfunction, characterized by difficulties in: differential allocation of attention, impulse control, set shifting, prioritizing, evaluating the salience of ambient data, interpreting social cues, and subjective time awareness. This complex is present to some degree in most Parkinson's patients; it may progress to:
- Short term memory loss; procedural memory is more impaired than declarative memory. Prompting elicits improved recall.
- Non-motor causes of speech/language disturbance in both expressive and receptive language: these include decreased verbal fluency and cognitive disturbance especially related to comprehension of emotional content of speech and of facial expression.
Apathy
Urinary incontinence A factor in this is the appearance of Lewy bodies and Lewy neurites even before these affect the functioning of the substantia nigra in the neurons in the enteric nervous system that control gut functions.
According to some sources, Parkinsons disease is slightly less prevalent in the African community. The average crude prevalence is estimated at being from 120-180 out of 100,000 among the caucasian (white) community. For the Parsi community in Mumbai, India the rate is approximately double.
Neuro-ophthalmologicalPD is related to different ophthalmological abnormalities produced by the neurological changes. There is also recent evidence that a common gene defect contributes susceptibility to both Parkinson's Disease and Alzheimer's Disease.
ToxinsOne theory holds that many or even most cases of the disease may result from the combination of a genetically determined vulnerability to environmental toxins along with exposure to those toxins. This hypothesis is consistent with the fact that Parkinson's disease is not distributed homogeneously throughout the population; its incidence varies geographically. However, it is not consistent with the fact that the first appearance of the syndrome predates the first synthesis of the compounds often attributed to causing Parkinson's disease. The toxins most strongly suspected at present are certain pesticides and transition-series metals such as manganese or iron, especially those that generate reactive oxygen species, and/or bind to neuromelanin, as originally suggested by G.C. Cotzias.
In the Cancer Prevention Study II Nutrition Cohort, a longitudinal investigation, individuals who were exposed to pesticides had a 70% higher incidence of PD than individuals who were not exposed.
Numerous studies have found an increase in PD in persons who consume rural well water; researchers theorize that water consumption is a proxy measure of pesticide exposure. In agreement with this hypothesis are studies which have found a dose-dependent increase in PD in persons exposed to agricultural chemicals.
The tragedy of a group of drug addicts in California in the early 1980s who consumed a contaminated and illicitly produced batch of the synthetic opiate MPPP brought to light MPTP (pro-toxin N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) as a specific cause of Parkinson symptoms. This made it possible to develop the first animal model for Parkinson's. MPTP's toxicity likely comes from the generation of reactive oxygen species through tyrosine hydroxylation. The book ''The Case of the Frozen Addicts'' by William Langston (Vintage, New York, June 25, 1996) documents this tragedy and describes the first attempts at fetal brain tissue transplants to treat PD.
Other toxin-based models employ PCBs, paraquat (a herbicide) in combination with maneb (a fungicide), rotenone (an insecticide), and specific organochlorine pesticides including dieldrin and lindane. Rotenone is an inhibitor of complex 1 of the electron transport chain. It easily crosses membranes due to its extremely hydrophobic properties and, therefore, does not rely on the dopamine transporter to enter into the cytoplasm.
Head TraumaPast episodes of head trauma are reported more frequently by individuals with Parkinson's disease than by others in the population.
A recent methodologically strong retrospective study who found a similar risk of 3.8, with increasing risk associated with more severe injury and hospitalization. However, a 2008 study has shown that the head trauma is actually a result of early symptoms of clumsiness associated with Parkinson's causes individuals, and not the cause of disease.