Pure Pedantry

This is the question that I get all the time in family gatherings. Well, maybe not in those words. Usually it is phrased as “How can I not get Alzheimer’s? Because that would be a bummer…for me…”

People are concerned about the issue of cognitive decline with aging — both with pathological decline such as Alzheimer’s disease and your normal “I can’t find my keys” declines. Numerous popular remedies exist that purport to improve your chances of staying with it longer, such as doing crossword puzzles or running ten miles a day for your entire life.

In the late 90s, the National Institute on Aging initiated what is called the ACTIVE trial (Advanced Cognitive Training for Independent and Vital Elderly) to evaluate whether mental training — analogous to crosswords — could improve age-related declines in cognitive function and quality of life. We know that declines in cognitive function do eventually lead to declines in quality of life. It was hypothesized that if we give seniors repeated training in cognitive tasks we could not only delay the cognitive declines but also the quality of life declines.

The results of this study were published last month here in JAMA.

In the study about 3,000 seniors agreed to participate. They were broken up into four groups. First, there was a control group who was just followed over the course of five years. The three other groups each received a different kind of mental training for about 10 to 18 hours. Here is the descriptions of the three types of training:

Each of the 3 training interventions was designed to narrowly target a specific cognitive ability — memory, reasoning, or speed of processing — and included no overlap with the functional outcomes in this study. Memory training involved teaching mnemonic strategies (organization, visualization, association) for remembering verbal material (eg, word lists, texts). Reasoning training involved teaching strategies for finding the pattern in a letter or word series (eg, a c e g i . . . ) and identifying the next item in the series. Speed of processing training involved visual search and divided attention (identifying an object on a computer screen at increasingly brief exposures followed by dividing attention between 2 search tasks). Each training intervention was 10 sessions. Only 10% of the 60- to 75-minute training sessions focused on applying these strategies to solving everyday problems (eg, mnemonic strategies to remember a grocery list; reasoning strategies to understand the pattern in a bus schedule). (Emphasis mine.)

Then the participants were followed over five years, evaluating them for both performance on cognitive tasks and self-evaluation for what are called instrumental activities of daily living (IADL). IADL correlate with overall health outcome and quality of life — whether you can stay out of the nursing home, whether you get hurt, etc. There was also evaluation for performance-based (not self-assessed) measures of IADL, most of which were tests like “can you remember the grocery list”, etc.

Some of the cohort from the training groups also received what is called booster training during the study. Booster training resembled the original cognitive training and was intended to give them a cognitive tune-up during the study.

The results were as follows:

  • Cognitive training for all the different groups was maintained during the three year interval. If you were trained on memory tasks, for instance, at the end of the 5 year study you were statistically more likely to perform better on memory tasks. The effect sizes were not huge. For memory and reasoning training, the effect sizes were about .25. For speed training, the effect size was larger at about .75. (For a description of what effect sizes are read the beginning of this post.)
  • However, cognitive training did not result in improved quality of life according to either self reported or performance-based measures. Both measures are of IADL as stated early. Here is a chart of the self-reported IADL:

    i-b5a6c37d4e7b0a5c4f3edc185691799d-iadl.jpg

    As you can see across the study there is a decline in IADL — read ability to maintain quality of life. Most of this decline is in the later years of the study, consistent with other studies. Important for this study, the decline is irrelevant to whether the individual received mental training. (The only statistically significant improvement that the researchers saw was for a performance-based measure for the speed trained cohort. However, this effect size was small, and it was only for those who also received booster training.)

What can we take away from this?

Cognitive training is effective at improving the cognitive skills of seniors. However, it does not appear that cognitive training translates into improved quality of life or resilience to cognitive aging. There could be several reasons for this:

  • First, we know that cognitive decline only slowly translates into declines in quality of life. It takes time before the problems really manifest. It could be that the reverse is also true: mental training only slowly translates into improvement.
  • Second, the researchers — by selection bias — may have a cohort of people who were relatively resistant to aging effects at the start. This would result in a ceiling effect — the people who are resistant aren’t going to get much better.
  • Third — and this is what I think it is — the effects of cognitive training are minimal when employed late in people’s lives. Let me expound on this idea a little bit…

    Researchers have speculated for many years that we have what is called a cognitive Reserve. Cognitive Reserve means that people who have been using their brains a lot have a lot more left to lose. This additional reserve masks the effects of aging and of dementia like Alzheimer’s. There are several markers that we use for cognitive reserve — the best is education. Numerous studies have shown that individuals with greater education are resistant to Alzheimer’s.

    But cognitive reserve means that people have been participating in activities requiring heavy mental lifting for decades. They went on to achieve graduate degrees, they learned foriegn languages, and they did crosswords from the age of seven — not the age of seventy.

    To suggest that cognitive training late in life will protect from aging-related declines is missing the point. You shouldn’t start late in life. This needs to be a lifelong activity for it to work. It needs to be lifelong to generate a cognitive reserve. This view is supported by the relatively tiny improvements the researchers observe in this study.

    More information on cognitive reserve can be found in this review.

The last bit that I want to say…

I do not want to suggest that people who have cognitive-related declines are somehow to blame. Overwhelming evidence points at two risk factors for cognitive aging and dementia: age and genetics. Neither of these are things you have control over.

Also, I do not want to suggest that you shouldn’t do any difficult thinking — that it won’t help. It does not appear that it will help huge amounts if you start late, but if you start early the results could be very different. The meaning of this study to me is that good health is a lifetime commitment.

NPR covered this paper this morning with an interview.

Comments

  1. #1 Mr. Me
    January 4, 2007

    Numerous studies have shown that individuals with greater education are resistant to Alzheimer’s.

    Has the effect education been shown to be any greater than IQ?

  2. #2 JW Tan
    January 4, 2007

    Some studies recommend learning a new language to stave off Alzheimers. I believe there is also evidence that multilingual people are less prone to Alzheimers than monolingual people.

  3. #3 Jake Young
    January 4, 2007

    Mr. Me,

    So studies I know have looked at premorbid IQ and related it to Alzheimer’s risk. I am pretty sure that they show a benefit to high premorbid IQ. However, education is a better indicator than IQ. This makes sense if you think about it because it is possible to have a high IQ and not do anything with it.

  4. #4 Michael
    January 4, 2007

    Cognitive reserve is the key. I think learning a language and crosswords are great but you need to make sure you are getting a complete brain work-out in all five cognitive functions. Crossword puzzles only work on certain areas such as language.

    You need a balanced approach with a broad spectrum of challenging activities that cross train all areas with a lot of variety, diversity and complexity.

  5. #5 Craig Helfgott
    January 5, 2007

    There was a recent paper that claimed that some age-related cognitive decline may be associated to certain viral infections over the course of one’s lifetime.

    With that in mind, how do we know that “cognitive reserve” is really working the way we think it is? How do we know that the causation isn’t operating the other way — maybe people who will later have more cognitive decline have difficulty learning earlier in life because the damage has already begun?

    At present, the concept of cognitive reserve is based around the following hypothesis:
    Education gives a greater “cognitive reserve” which later confers protection from cognitive decline.
    It seems to me an equally persuasive model is:
    Less susceptibility to cognitive decline later in life is due to less progressive damage earlier in life which also allows for greater learning ability.

  6. #6 Mr. Me
    January 5, 2007

    pretty sure that they show a benefit to high premorbid IQ. However, education is a better indicator than IQ. This makes sense if you think about it because it is possible to have a high IQ and not do anything with it.

    But is it clear from the data that education and high IQ are more beneficial than just having a high IQ alone, have there been any comparisons between between those with and without higher degrees who are matched for IQ? I am curious if maybe these hypotheses about learning and cognitive reserve are missing the mark because they really proxy for partially innate IQ, that perhaps even without a great deal of learning those with higher IQ are more resistant to Alzheimer’s because of the genetic/early developmental organization of their brains are harder for the disease to effect.

    I’m just worried people who are being sold on these “brain gym” efforts are getting suckered out of their money by manipulation of their intuitions about physical fitness and remuneration for work, that these don’t necessarily apply to the situation of cognitive decline.

  7. #7 Jason Malloy
    January 5, 2007

    The Seattle Longitudinal Study did not show any meaningful cognitive decline until about the 70s – and even this didn’t appear to be a general problem of aging, but confined to those in pathological deterioration.

    Perhaps I’m out of date, but the premise may be flawed.

  8. #8 Alvaro
    January 20, 2007

    Hi Jake,

    I don’t think the article above warrants the conclusion “the effects of cognitive training are minimal when employed late in people’s lives”.

    2 other potential explanations:

    1) The type of mental activity/ cognitive training was not the right one. Research and clinical practice shows that you need to ensure cross-training of a number of functions-the people in the study were doing the equivalent to going to the gym and simply working on their right arm all the time.

    2) The duration of the intervention is pretty surprising. Cognitive training is not a magical pill-it requires practice, and increasing challenge levels. 10 sessions? does someone expect to go to the gym 10 times this month and then be significantly fitter 5 years from now?

    In my opinion, given the type of training intervention, it is nothing short of impressive that there were any results at all.

    A better study would measure the impact of well-designed cross-training programs that ensure novelty, variety and increasing challenge, 2-3 sessions a week 30-40 minutes each for at least 3-4 months or, better, as a regular routine.

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