Causes Of Parkinson's
What causes Parkinson's?
The simple answer to what causes Parkinsons is that we still don't know. There are leading theories and a lot of research focusing on these theories but we still don't have, with certainty, identification to what's causing Parkinsons disease.
What happens to the substantia nigra in persons who have Parkinson's?
In somebody with Parkinson's disease, the brain cells, the neurons, and the substantia nigra are actually being depleted, they are being lost. If you look at the normal brain, you can see the substantia nigra without any kind of special preparation or staining because it is dark it is pigmented. And if you look at the brain of somebody who has Parkinson's disease that dark area, that pigmented area, is less conspicuous, it is not so dark. It is not so easily visible. Again, if you look at that section with a microscope, you can see that the brain cells are actually reduced in number and in their place is the brain's equivalent of scar formation. There is what is called “gliosis” after this brain cells have been injured and die.
What role do genetics play in acquiring Parkinson's?
For the majority of cases of Parkinsons disease, they don't clearly run in families, in any kind of predictable fashion that we usually think about diseases that run in families. Increasingly, there are genes that are identified that may place people at risk for developing Parkinsons disease. To have that gene alone doesn't mean necessarily that somebody will get Parkinsons disease but it may enable them, under certain circumstances, to develop Parkinsons disease. One is called Parkin, P-A-R-K-I-N, which is found more often in younger people with Parkinsons disease, but also people who are of the typical age to get Parkinsons disease. They have other names, like PINK, not referring to the color, but they are acronyms of biochemical disorders. There's something else called LRRK, too, again referring to some enzymes that are influenced by this disease process.
What role do toxins or illicit drugs play in causing Parkinson's?
We're not sure yet of the role of toxins in Parkinson's disease. There was a clue in the '80s that environmental toxins may be contributing to some people getting Parkinson's disease. This clue was arrived at in kind of a peculiar way, in that some people who were abusing drugs, mostly in the San Francisco area, unintentionally injected themselves with a toxin called "MPTP". In a small percentage of these people who were exposed to "MPTP", they very abruptly, suddenly became severely Parkinsonian, or stiff and slow, to the point of immobility. But this concept--the idea that there was a toxin that very specifically injured this part of the brain, the "substantia niagra", revived this idea-- put a lot of emphasis on this idea that there may be other things in the environment that some of us are unusually sensitive to, that could be injuring the brain in a very specific way, leading to Parkinson's disease. There may be pesticides, or herbicides that we're putting into the environment that some people--not all, but some people are having brain injury, or changes as a consequence of exposure to these things. This is an active area of research currently--not yet settled, we don't yet know if such things exist, but it is being investigated agressively now.
What diseases or physical conditions can cause Parkinson's?
There are other things that can look like Parkinsons disease, but not really cause Parkinsons disease by our definition of having those specific brain changes present. Other disorders - there's something called normal pressure hydrocephalus which we think comes as a completely different entity, but it looks like Parkinsons disease sometimes. People who have multiple small strokes may look as though they have Parkinsons disease, but there's no other process that we know of that creates identical changes in the brain, as does Parkinsons disease.
What role do viruses and bacteria play in Parkinson's?
Brain infections in channelled do not have a role in as we know so far in creed the Parkinson's disease. Decades ago, in the last century there was an epidemic of influenza with some people get encephalitis and some of those people did developed Parkinson's in that look kind of life Parkinson's disease but today we do not think that brain infections are the cause of what we called Parkinson's disease.
What role does race play in Parkinson's?
It does appear that some races are more susceptible to getting Parkinson's Disease and this may reflect some of these genetic variations among races of the things that we discussed about the possibility of certain genes making it easier for certain people to get Parkinson's Disease. It is found worldwide. The disease is found worldwide. It may be found a bit more commonly in some locations than others but the influence of race still is being investigated as how it contributes to Parkinson's Disease.
What is a 'parkinsonian personality'?
There has been discussion in our meetings and also in the literature about so-called premorbid Parkinson's Personality, meaning personality changes or personality types that reflect the brain changes of Parkinson's Disease before the motor symptoms, things like tremor, become evident. This personality type was described as being a reliable person, a steady person, somebody who is not a risk taker, not a gambler, not the sort of an "out-there" type of person, somebody who did their job and did it well and did it reliably. More recently, this concept is less accepted as being valid. It's not clear that people with Parkinson's Disease, either at any time before the motor symptoms appear or after they do, have any kind of specific personality characteristics. It does, though, raise this interesting question about the early brain changes in Parkinson's Disease. We suspect that Parkinson's Disease is happening five, ten, or maybe even more years before the actual motor symptoms show up. There are other clues that people may be developing Parkinson's Disease. None of them reliable ... I want to emphasis that ... that none of these things predict, with certainty, that someone will be getting Parkinson's Disease, but early changes may include the impaired sense of smell or a sleep disturbance called REM Sleep Behavior Disorder. These things may be, in retrospect, when somebody has Parkinson's Disease, looking back, we've identified that people may be having these things before the other, more classic, symptoms are evident.
