This sounds like a joke, but it’s hard science. Video interview with researchers at link.
Doesn’t sound like hard science. The distance is going to depend quite a lot on stray air currents in the room.
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That will probably be an issue for implementing the test in other venues but I’m sure the researchers were smart enough to take this into consideration. You might want to read the whole article.
It seems to me that there would be all sorts of confounds with a test like this. Never mind air currents, what if someone had a bit of snot lodged in one nostril but not the other? Does the test work the same for left handed as for right handed people, I wonder, or is it reversed? (Given the complications of left-handedness, one might expect it to be reversed in some but not others.) Also, at least going by the article at your link, it seems as though they have absolutely no idea why the nostrils actually should be differentially affected by Alzheimer’s, which makes it all a bit dubious.
There’s a “smell identification test” for Alzheimer’s. People are asked to identify about a dozen common scents, and while it’s not definitive (only a brain biopsy is), it’s apparently quite accurate.
This, of course, only works for people who still have their sense of smell.
You don’t have to know why a correlation exists to prove that it exists.
Doesn’t each nostril go to a different hemisphere of the brain, like your eyes and ears? I believe it’s well known that Alzheimer’s is correlated with problems in the corpus callosum.
The article DOES indicate that this is in the early stages of testing but I think you have to admit that this seems to be a very promising test for a disease that is notoriously difficult to diagnose in the early stages. Or would you prefer to just ignore this and have doctors continue to bumble along, never knowing who has mild cognitive impairment vs early stage Alzheimer’s?
Also, what the hell is meant by
?
Under the circumstances, how on Earth is anything, whether it be peanut butter, or rose oil, or gasoline, or whatever, going to be detected other than via the olfactory nerve? Maybe there really is a good reason why peanut butter is the ideal test odorant, but the explanation given seems like gobbledegook, and makes me suspicious about the whole thing.
No, I don’t think it sounds “very promising”. That is my point. It would be nice if it works, and it may be worth following up further, but I will be surprised if it really pans out. If it is real, possibly the most significant aspect of it is not the ‘test’, but the discovery (if it is one) that Alzheimer’s differentially affects the left and right parts of the olfactory system.
This looks to me like a typical bit of bad science journalism (og knows, there is plenty of it about), reporting prematurely on a half-baked scientific idea.
I just did some looking online and it appears possible there’s some science behind this statement. Many substances have mixed odors and as a result, the nerve signals for smelling these substances travel along several different nerve paths simultaneously. You think you’re smelling one smell but you’re actually smelling a combination of different smells and your brain reassembles all of them into a single smell.
Pure odorants are the term for substances where the nerve signals for the smell passes along a single nervous path. In a test like this, where they’re looking to see how quickly the substance is detected, they’d want a single nerve path so there’s no confusion.
True, but if you have an explanation for it, that makes it a lot more plausible that it is a real effect, rather than the spurious result of some statistical artifact or experimental error.
Yeah, but none of that explains why the left and right nostrils would be differentially affected in a systematic way. There is an olfactory bulb (where olfactory information gets processed) on each side of the brain, and AFAIK the lesions causing Alzheimer’s symptoms occur at pretty much random places throughout the brain.
I’m sure they will take your expert opinion under advisement.
Well ok, “pure odorant” may mean something (though peanut butter? that is a ‘basic’ odor? really?:eek:) but why is such purity relevant to testing which nostril is more affected? Is it just the peanut-butter-smell dedicated fibres in the olfactory nerve that are differentially affected on either side?
Yours too, darling.
What about people (like me) that just have a very crappy sense of smell?
I suppose, but you know that a lot of scientific discovery has occurred when unexpected correlations were observed, and only much later were explanations found.
As Isaac Asimov said, “The most exciting phrase to hear in science, the one that heralds new discoveries, is not ‘Eureka!’ but ‘That’s funny…’”
It’s not explained well in the article, but I suspect they’re referring to things that don’t stimulate the receptors in the nasal cavity innervated by the trigeminal nerve. These receptors respond to what is sometimes called “pungency”: things like chili peppers, mustard, and horseradish, all of which can also stimulate true odor receptors innervated by the olfactory nerve. I believe the cold receptors that respond to menthol and give peppermint a cool perception are also innervated by the trigeminal nerve. Something like mustard that stimulates both pathways could well muck up the results, so they chose to use one of the many substances that stimulates only the true odor receptors innervated only by the olfactory nerve. That is not the same as saying that there is one and only one type of odor receptor that responds to the odor of PB and nothing else. At least that’s my reading of what they’re trying to say.
Apparently (from what I found) different odors trigger different parts of the brain’s olfactory area. So a mixed scent might trigger a response in different areas. A pure odorant, like peanut butter, would presumably only trigger one area. This may be the basis for why there’s a difference in the response of the right and left nostrils.
You’re right, I should have read the whole article. But when I did, I didn’t see anything in the article that fixes this question.
Though, it’s a pleasant article more or less advertising the school, it’s not a scientific paper. As pleasant articles go it seems competent enough.
This would be in the category of medical research, not for example fluid dynamics research. If holding things different distances from the nose is already an established test method with various problems worked out and good practices well known, it’s probably fine. But if the cleverness of a simple smelling distance test is novel here, I wonder how room air currents get accounted for. No doubt we all have the experience of people near one another, one of whom smells something strongly while the other doesn’t.