Which Cognitive Enhancers Really Work?

[Guest guest]

The below article concludes that on current evidence exercise is

clearly the best method for increasing useful everyday cognitive

functioning. And in the future we may even have exercise regimes that

are specifically targeted at enhancing cognitive function.

Which Cognitive Enhancers Really Work: Brain Training, Drugs,

Vitamins, Meditation or Exercise?

http://www.spring.org.uk/2008/06/which-cognitive-enhancers-really-

work.php

Although wisdom may come with age, our brains don't get any faster.

Many areas of cognitive function decline over time: attention wavers,

processing speed decreases, memory starts to crumble.

All kinds of methods for fighting back against this brain-wide slow-

down have been suggested. There is training with computer programs,

popping pills, taking nutritional supplements, meditating or even

getting some more exercise.

Some want to ward off the scourge of a rapidly ageing population:

dementia. Others are looking for competitive advantage against

younger, faster brains.

So: what to choose? These methods, along with many others, are often

presented as though they're all roughly equivalent, but this isn't

true. The scientific evidence currently available is much stronger

for some of these options than others.

This post examines what the research currently tells us about each

method for cognitive enhancement and delivers a verdict on each.

1. Brain training

Computer programs that promise to improve cognitive function have

become all the rage in recent years, mostly on the back of the

success of Nintendo's 'Brain Age' game. Many other companies have now

jumped on the bandwagon and the market for brain fitness software

reached $225 million in the US in 2007 according to a report from

SharpBrains.

But what about the science behind the hype?

Certainly cognitive training has been shown to be effective in a few

randomised controlled trials, but the evidence is still quite

limited. The first large study in older adults without dementia

failed to find an improvement in daily functioning from the training,

but it did slow decline. Also, this study's method has been

criticised.

Other studies have found benefits for specific groups such as

children with attention deficit hyperactivity disorder (ADHD) and

dyslexia. Whether advantages gained by these groups might be

effective for others is a matter for debate.

The real challenge for brain training is showing that practising one

type of mental skill transfers over into other real-life benefits.

Doing puzzles like Sudoku or completing crosswords probably only

improves your performance on those specific tasks.

One new study, though, does suggest that training working memory can

increase fluid intelligence - what we use to solve problems which

don't rely on things we already know. The study, recently published

in The Proceedings of the National Academy of Sciences, found that

gains in fluid intelligence were proportional to the amount of

working memory training completed.

Unfortunately this is still early-stage exploratory research and many

are not convinced that the actual products available on the market

are beneficial. Aamodt, the editor in chief of Nature

Neuroscience and Sam Wang, a Princeton University molecular biologist

explain in the New York Times:

" In the United States, consumers are expected to spend $80 million

this year on brain exercise products, up from $2 million in 2005.

Advertising for these products often emphasizes the claim that they

are designed by scientists or based on scientific research. To be

charitable, we might call them inspired by science -- not to be

confused with actually proven by science. "

It's telling that the best-selling brain training software -

Nintendo's 'Brain Age' - has the lowest level of clinical validation

according to a market report from Sharp Brains.

Verdict: Evidence for the benefits of cognitive training for everyday

functioning is still very limited. Brain training software currently

available is mostly 'inspired by science' rather than based on it.

Treat marketers' claims with extreme scepticism. Side-effects are

probably limited to repetitive strain injury and a depleted wallet.

2. Drugs

Until recently the main chemical cognitive enhancer most people used

was caffeine. But there are a whole batch of new drugs that could

challenge caffeine's dominance as the safe stimulant of choice. Of

these, two well-known for their 'off-label' use are Modafinil (also

known as Provigil) and Ritalin..........

Verdict: Amongst the chemical cognitive enhancers Modafinil is

currently fashionable for grown-ups. But is it really that much

better than caffeine? This study and this study suggest that in

warding off sleep Modafinil is no more effective than caffeine - and

caffeine is legal and readily available. Probably better to stick to

tea or coffee.

3. Nutritional supplements

There are all kinds of claims for the abilities of nutritional

supplements to enhance cognition. For example, vitamin B6 has been

found to enhance memory (but far from conclusively) and there are

many other claims being made by marketers for vitamins E, B12,

folate, neurosteroids and so on.

However, in reviewing the research the Academy of Medical Sciences

points out that most of the studies are few, far between and small in

scope.

Verdict: Unproven, but probably not dangerous as long as you're not

exceeding the recommended daily allowances. On the downside

supplements can be costly.

4. Meditation...........

Verdict: Meditation still has to be considered unproven as a

cognitive enhancer but it probably won't do you any harm, plus it's

free.

5. Exercise

Whether you're old or young, fit or even suffering from a

neurodegenerative disorder, aerobic exercise has been found to be

beneficial for cognitive health. Randomised controlled trials, along

with reviews of many of these trials (such as this one in

Neuromolecular Medicine), have shown that exercise improves cognitive

function across the board. It has also been found to be particularly

good at enhancing executive control processes (e.g. planning and

working memory).

Exercise is also thought to encourage the growth of new brain cells.

In the past scientists always thought that neurogenesis - growing new

brain cells - was impossible in humans. New studies, though, have

shown that we can grow new brain cells.

Research reviewed in Neuromolecular Medicine suggests physical

exercise can promote neurogenesis in the hippocampus - an area of the

brain thought to be important in memory and learning.

Verdict: The evidence for exercise boosting cognitive function is

head-and-shoulders above that for brain training, drugs, nutritional

supplements and meditation. Scientifically, on the current evidence,

exercise is the best way to enhance your cognitive function. And as

for its side-effects: yes there is the chance of an injury but

exercise can also reduce weight, lower the chance of dementia,

improve mood and lead to a longer life-span. Damn those side-effects!

The results are in (for now)

Even though exercise is the current winner for enhancing cognition,

this might change in the future. Maybe better drugs for enhancing

brain function will be developed - possibly en route to improved

treatments for conditions like Alzheimer's. Or maybe studies on

nutritional supplements, brain training software or particular forms

of meditation may provide firmer evidence.

Maybe.

On current evidence exercise is clearly the best method for

increasing useful everyday cognitive functioning. And in the future

we may even have exercise regimes that are specifically targeted at

enhancing cognitive function.

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Carruthers

Wakefield, UK