October 22, 2007
Educated People Develop Dementia Later But More Rapidly
Any thoughts on the mechanism behind this?
BRONX, NY – People with more years of education lose their memory faster than those with less education in the years prior to a diagnosis of dementia, according to a study by researchers at Albert Einstein College of Medicine of Yeshiva University, published in the October 23rd issue of the medical journal Neurology.
The study included 117 people who developed dementia out of an original cohort of 488. The researchers, led by Charles B. Hall, Ph.D., associate professor of epidemiology and population health at Einstein, followed study participants for an average of six years using annual cognitive tests. Study participants ranged in formal education levels of less than three years of elementary school to individuals with postgraduate education.
The study found for each additional year of formal education, the rapid accelerated memory decline associated with oncoming dementia was delayed by approximately two and one half months. However, once that accelerated decline commenced, the people with more education saw their rate of cognitive decline accelerate 4 percent faster for each additional year of education. The latter portion of this finding corroborates previous research, which had shown that people with more education had more rapid memory loss after diagnosis of dementia.
Maybe the smarter people can lose more neurons before they show symptoms of decay. Then their disease is more developed when they finally start showing symptoms and by then they are on a steeper later part of the declining slope.
I really want rejuvenation therapies for my brain. I'm so not looking forward to the intellectual decline of old age. But I'm hopeful that the accelerating pace of biotechnological advance will provide solutions before most of us become demented.
Perhaps the study isn't all that it might be. They are measuring a disease that isn't all that easy to measure. And with a rather small sample. And it doesn't seem to have been a double blind study. (might have been though).
I'll assume it is correct.
Well educated people have spent years training their brain to pass tests. They probably develops a switching ability which selects an alternative network when an existing one isn't functioning well. And the switching ability would be able to maintain itself by exactly the same method.
Networks failures are taking place but the superior switching is negating them in the educated brain. Over years the switch sends problems to fewer networks because so many have already failed. Less and less of the brain is working but things appear normal.
But finally the switching ability will fail to correct itself. Then decline is rapid because the malfunctioning switch sends out problems willy-nilly, most go to already failed networks but a few get to one of the networks still working.
In contrast, the person who has never possessed much switching ability will decline gradually as networks fail over the years and and switching doesn't cover it up.
I was thinking that more educated brains have a greater number of neuron connections. This means that dementia takes longer to show because old, damaged paths to complete activities have alternative routes. However, when the network degrades bellow a minimum number of neurons, a larger number of connections vanish with each dying neuron and so performance degrades faster.
Perhaps the mechanism described in this link: http://www.windsofchange.net/archives/009812.php provides a clue. Random elimination of nodes in a scaled network has little effect. But attack the most important "hubs" and the network can collapse quickly. If the structure of more educated brains differs from those of less educated ones in this way, it is a possibility.
I'm looking forward to dementia. I'll only need one CD, book, and DVD.
"I'm looking forward to dementia. I'll only need one CD, book, and DVD.'
But you won't know that.
I can think of several ways the brain might organize to explain these results. Engineers might refer to network nodes as Bill W. does. The comment from OneEyedMan is akin to the first comment from me - the damage just doesn't show for a longer time but the brain must relies more on each good neuron as time passes.
It could be even simpler - the educated brain computes several times and uses the majority answer. This is like math students comparing their homework. The wrong answer is more readily detected and discarded.
The less educated brain computes only once and uses that answer. This person will display (to a tester) the wrong answer more often at an early age.
The more educated person just discards wrong answers much longer. But eventually wrong answers outweigh correct ones and decline seems very fast.
I suspect educated folk have a lot of adaptive tricks to conceal their cognitive impairment. I have a bunch now, and I'm only middle aged.
The tricks work for quite a while, but when they fail the true deficit becomes apparent.
I'm personally skeptical that the dementing process is much affected by education. I think the associated disability is more affected than the underlying physiology.