I hope I'm not stepping on Janie's post, I'm always grateful to her for keeping the home fires lit, but this article caught my eye as it were and I thought I'd put up, in large part because it lets me talk about what's ailing me (and maybe some of you?)
https://www.sciencealert.com/your-vision-can-predict-dementia-12-years-before-diagnosis-study-finds
Our research was based on 8,623 healthy people in Norfolk, England, who were followed up for many years. By the end of the study, 537 participants had developed dementia, so we could see what factors might have preceded this diagnosis.
At the start of the study, we asked participants to take a visual sensitivity test. For the test, they had to press a button as soon as they saw a triangle forming in a field of moving dots. People who would develop dementia were much slower to see this triangle on the screen than people who would remain without dementia.
So why might that be?
Visual issues may be an early indicator of cognitive decline as the toxic amyloid plaques associated with Alzheimer's disease may first affect areas of the brain associated with vision, with parts of the brain associated with memory becoming damaged as the disease progresses. So vision tests may find deficits before memory tests do.
I can't help but feel like there is a correlation/causation problem here. Couldn't it be that loss of visual acuity itself be a factor in Alzheimer's? The assumption is that the amyloid plaques are affecting visual acuity, which is taken as a sign, but it could be that if your eyes get worse, that might be the/a causative factor?
Cause as you get old, your vision certainly gets worse. This link has a useful list and it seems to me that rather than thinking that Alzheimer's is screwing up your eyes, it might be the other way around. Or at least enough to not make pronouncements about plaques and inhibitory controls.
I tend to think this cause I can feel that my worsening eyesight as well as my experiences with my vision suggest that the vision causes problems for memory.
I was the first kid to get glasses in my elementary school. My 2nd grade teacher told my mom at the end of the year conference that she thought I needed glasses because I was doing poorly on math tests not because my calculations were wrong but because I was writing down the wrong starting numbers. My mom thought that was crazy until one day during summer vacation, one of our neighbors, an officer in the Air Force, was coming to our house and I told my mom that the plumber was coming.
I got glasses and, in an experience common to people like me, it was astonishing because it was the first time I could see individual leaves on the tree. Another interesting thing was that my memories, for the most part, start when I got glasses. I can't do it now, but well into my 40's, I could remember everyone in my elementary school classes. Back then, glasses took you off the sports track, at least for contact sports like football. I did judo as a kid, and while not being able to see very well can help you with balance and being able to react, I was unable to visually learn, which seems to be a really important way for me. I got to be even more of a book worm, and could often remember where on the page a particular passage was.
Fast forward to language learning, I thought I was quite good at languages, doing French, Latin and Greek at uni and then going to Japan. I don't want to spend too much time in the weeds, but after 5 years in Japan, my Japanese was ok and I worked pretty hard on reading. It was just as the computer revolution was starting and I purchased a Fujitsu Oasys word processor because Japanese on the computer was rather tortured. I went to grad school and got interested in endangered languages, so took Thai, imagining I could do fieldwork in Thai. With grad school, I didn't do any Japanese reading, but when I got a job at Hokkaido University, I unboxed the stuff I had sent from Japan to rebox it to send back to Japan (Some of you may know this drill) and I came about my Fujitsu Oasys word processor. I plugged it in, opened it up and was greeted with a 3 page essay that I had written. I could remember typing it out, where I was sitting, a whole wealth of details, but I couldn't read what I had written. I could figure out characters, and piece it together, but I might have just been typing the Japanese equivalent of Redrum.
Getting back to Japan, I had a job with a fixed term and after three years, I again packed up my stuff to ship down to Southern Japan. At that time, I found my Thai notebooks and this time, it was even worse. I couldn't make heads or tails out of stuff that I had written. It made me realize that a lot of my language ability was tied up in roman letters. If I had gone with Vietnamese, I probably would have been a lot better off.
Fast forward to about 10 years ago when I had to have emergency surgery for a detached retina. It wasn't because of a punch or a car crash, apparently, the vitreous (the clear fluid that fills your eye) turns to a more gelatin like consistency and in shrinking, it can pull the retina from the back of the eye. I had the surgery, but afterwards, I found that I had lost about 10 or 20 meters off my vision in terms of recognizing faces. This wouldn't be a big deal, but before the operation, I could recognize someone who was my student and in the time that it would take to close the distance between us, I could dredge up their name. Losing that distance meant that I had less time to figure out who it was and would often draw a blank. In the past ten years, I can tell that this inability has impinged on me remembering student names and placing them in context.
Now, my father had alzheimer's, but his was probably because he was a college boxer (strangely enough, his eyesight was probably as bad as mine, but he still boxed) So I don't think these holes in my memory are because of some genetic disposition towards alzheimers, it is more having an increasing number of holes in my knowledge base and therefore, lose ground because of losing the context.
There is an interesting cultural aspect to this. Asians are known for having poor eyesight, and it is not just an ignorant trope from Breakfast at Tiffany's, but an actual issue for East Asian countries. I like this podcast, which I started watching because of the insights into TSMC, which is building two factories near me, and this episode about the issues with myopia in China and what they are doing to deal with it
https://www.youtube.com/watch?v=3YWbR8K0jT4&t=42s
While the push to deal with myopia in China is more because of the ocular health, but I wonder if people like me will decline more quickly because of this. At any rate, talk about your eyes or whatever else ails you.
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