Benefits of brain training for dementia uncertain
"Forget popping pills – the best way to boost your brainpower is a crossword or sudoku," the Mail Online website states. The website reports that fish oils and ginkgo supplements won’t prevent cognitive decline, but that brain training games might.
The story is based on a well-conducted review of previous research that looked at prevention of cognitive decline. Researchers found 32 relevant studies investigating the use of different treatments, including drug treatments, supplements, physical activity and cognitive exercises, for preventing cognitive decline.
Interestingly, there was no firm evidence that pharmacological treatments (such as cholinesterase inhibitors and vitamin pills) were of any benefit for preventing cognitive decline. In fact, the available research suggested that certain treatments, such as hormonal therapies, may worsen memory.
The researchers also found inconsistent evidence for the supposed benefits of physical activity for preventing cognitive problems.
However, they did find some evidence (from three studies) that brain training exercises could help prevent cognitive decline. It is important to note that none of the research looked at sudoku or crosswords and that the ‘brain training’ involved was of a more intensive and long-lasting nature.
The bad news is that most things that have been tried to prevent cognitive decline don’t appear to work (or are even harmful), while the probable benefits of cognitive training are also uncertain. However, further research into ways to improve or maintain cognitive function may well change this view.
Where did the story come from?
This was a systematic review that looked at a total of 32 randomised controlled trials (RCTs) that studied treatments for cognitive decline. It was carried out by researchers from the Divisions of Geriatric Medicine and General Internal Medicine at the University of Toronto. No competing interests or sources of financial support were reported.
The study was published in the peer-reviewed Journal of the Canadian Medical Association.
The Mail Online’s reporting generally represented this research well. However, the headline that you should "forget popping pills – the best way to boost your brainpower is a crossword or sudoku" is misleading. The studies included in the review did not use puzzles of this nature. They instead used cognitive exercises that were described by the researchers as “labour and resource intensive” – less laid back than completing a crossword puzzle or sudoku grid.
What’s more, there are currently no pills you can “pop” to “boost your brainpower”.
What kind of research was this?
The researchers say that, as the population as a whole is ageing, it is becoming increasingly important to find ways of preventing or limiting cognitive decline in healthy older adults. In this review they looked at evidence on how effective drug treatments and non-pharmacological interventions might be.
Because this was a well-conducted systematic review we can be fairly sure that the researchers identified all available RCTs that have evaluated the effectiveness of different interventions for preventing cognitive decline. However, the quality of the individual studies is likely to vary, which limits the strength of any conclusions that can be made.
What did the research involve?
The researchers searched four literature databases up to October 2011 using search terms such as ‘cognitive decline’, ‘dementia’ and ‘mild cognitive impairment’ to find relevant RCTs. They defined these as RCTs looking at pharmacological or non-pharmacological interventions in people aged 65 years or older who had normal cognition or mild cognitive impairment at the start of the study.
Studies were eligible if they looked at the effect of the intervention on any form of cognitive decline, including the development of mild cognitive impairment (if the person had normal cognition at study start), worsening cognitive function on cognitive testing, or progression to dementia. The focus of their review, however, was on people with normal cognition at study start.
A total of 5,205 articles were initially identified but, when reviewed, only 32 were eligible for inclusion. The researchers assessed the quality of these studies using valid criteria.
What were the basic results?
The researchers found 26 studies on pharmacological interventions for cognitive problems. These were:
- Three studies on cholinesterase inhibitors and NMDA (N-methyl-D-aspartate) receptor antagonists, which included 89 people and lasted between three and 15 months. These drugs are sometimes used to treat people with neurodegenerative disorders, such as Alzheimer's disease. From these studies they found no evidence of an overall effect on memory.
- Thirteen studies on various hormonal therapies. Seven studies were on oestrogen therapies and included a total of 10,792 women. These studies lasted between two weeks and five years. These studies overall showed that oestrogen treatments actually worsened memory. Three studies were on testosterone therapies. These studies lasted between three months and three years and included 144 men. These studies provided inconsistent evidence of any effect of testosterone on memory. Three studies were on DHEA (a synthetically produced version of a natural hormone produced by the adrenal glands). These studies lasted between six weeks and one year and included 317 people. These studies provided inconsistent evidence of any effect of DHEA on memory.
- Two studies on ginkgo (a type of herb found in China), including 348 people and lasting between six weeks and 3.5 years. These studies provided no evidence of any effect on memory.
- Four studies of vitamins and fatty acids, including 6,779 people and lasting between four weeks and 9.6 years. These studies provided no evidence of any effect on memory.
- Four studies of miscellaneous pharmacological interventions (including various anti-inflammatories and heart drugs), including 7,530 people and lasting between four weeks and 3.7 years. These studies provided inconsistent evidence of an effect on memory.
The following studies of non-pharmacological interventions were identified:
- Three studies on physical exercise, including 244 people and lasting between six months and one year. These studies provided inconsistent evidence on exercise.
- Three studies on cognitive training (mental exercises), including 3,321 people and lasting between three weeks and five years. These studies showed significant improvements in auditory memory (processing spoken information) and attention.
How did the researchers interpret the results?
The researchers concluded that there is no consistent evidence that any pharmacological treatment is beneficial in preventing cognitive decline in healthy older adults. Furthermore, studies investigating oestrogen therapies have suggested that these treatments may actually cause a decline in memory.
They also said that there is weak evidence to suggest that physical activity can have an effect in preventing cognitive decline and that formal cognitive training exercises may have some potential benefit in preventing cognitive decline.
Conclusion
As the researchers say, there are various products on the market that claim to prevent cognitive decline. These range from physical and mental activities to prescription and non-prescription medications.
However, as the researchers mention, the evidence supporting the benefits of these interventions can be limited, and studies into these types of intervention are often of poor quality.
This review usefully clarifies what scientific evidence is available for these interventions, and what this evidence shows.
Researchers found no firm evidence that any pharmacological interventions would be of benefit in preventing cognitive decline. In fact, certain treatments including oestrogen therapies may even worsen memory.
Looking at exercise, there was evidence from one study on resistance training that this may improve memory, but in a study of resistance and balance training and another of aerobic exercise there was no effect. However, three studies on cognitive training or mental exercises did suggest that these may be beneficial.
The studies in the review used labour- and resource-intensive cognitive training exercises. They did not assess more readily available puzzles such as crosswords or sudoku, as the headlines suggest. The studies in question appear to involve the level of cognition and memory equivalent to learning a foreign language, rather than simply filling out a crossword. So the headline that the “best way to boost your brainpower is a crossword or sudoku” is not accurate.
This may have been extrapolated from the suggestion by the researchers that further research is needed to address the potential impact of more readily accessible puzzles, such as crosswords.
While this research shows the state of the current evidence on the effects of treatments to prevent cognitive decline in older people, uncertainties remain. Further, high-quality evidence may well change our understanding of what can and cannot help prevent cognitive decline.
