Rarity Again (Neurologists)

As we know, though some deny it, the prevalence of spinocerebellar ataxia (SCA) is upwards of 5 per 100,000, or about 16,100 in the U.S. in 2015. Consider this:

  • There are about 16,366 neurologists in the U.S.—about 5.1 per 100,000
  • (There are about 915,000 doctors in the U.S.—about 280 per 100,000)

https://www.aan.com/PressRoom/home/PressRelease/1178
https://www.kff.org/other/state-indicator/total-active-physicians/

The prevalence of neurologists is nearly identical to that of SCA! What a coincidence! If you have SCA, neurologists are just as rare as you are. Also consider this:

  • Only ten cities in the U.S. have more than a million people (i.e., each with more than 50 neurologists and more than 50 people with SCA).
  • Only 300 cities in the U.S. have more than 100,000 people (i.e., each with more than 5 neurologists and more than 5 people with SCA).
  • Those 300 cities total about 90.5 million people, or 29% of the whole country.

https://en.wikipedia.org/wiki/List_of_United_States_cities_by_population

If there are five neurologists in your area, there are probably five people with various types of SCA, as well. One extreme would be if all five ataxians see the same neurologist and four neurologists see no ataxians. The other extreme would be if each neurologist sees one ataxian. The ratio being one-to-one is such that for every neurologist who sees more than one ataxian, there’s a neurologist not seeing any ataxians.

Deniers of sane prevalence

Let’s consider the mythologically high SCA prevalence of 150,000 in the U.S. That number is currently about nine times the number of neurologists in the U.S. It fallaciously means that for every five neurologists in your area, there are about 45 people with SCA. With a ratio like that, you would expect every neurologist to be inundated with the full spectrum of ataxians. Hanging onto these warped numbers only warps your perspective and your expectations.

Don’t call me Ishmael

I don’t think it’s fair to harp on neurologists for knowing little—on average—about ataxia. There are thousands of other rare diseases that both ataxians and neurologists have never come across.

And the ataxia specialist? It’s highly unlikely that any reasonable neurologist would limit themselves entirely to seeing only ataxia patients. They will at least specialize in other movement disorders such as Parkinson’s disease or other triplet repeat diseases such as Huntington’s disease. And if they do choose a few neurological diseases to specialize in, such as ataxia, there are still thousands that they’re excluding.

A neurologist will be largely defined by their range of experience. If they treat patients, as opposed to (e.g.) doing research, they will be largely defined by the issues that people bring to them. If a neurologist sets up shop and is never visited by someone with ataxia but is visited by people with Parkinson’s disease, Alzheimer’s disease, migraine headaches, etc., that’s the range of experience that will eventually define them. If twenty years down the line, one person shows up with ataxia, the disease won’t be familiar to them. There’s no surprise there.

I want to emphasize my situation and perspective: I have SCA3, and that means it’s hereditary. Not only have I had first-hand experience with my mother going from non-symptomatic to death, I know my family’s medical history going back to about 1808. There’s no real mystery about what’s happening to me, except for the details, especially of how it will end. I am not questing for a diagnosis, as many non-SCA ataxians are. All I need is a neurologist who is smart, considerate, who listens, and who is on my side, especially as I transition to not being able to speak.

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