It may not sound much like medicine, but playing a computer game could cut your risk of dementia by 25 per cent, a new study found.
The game, Double Decision, is designed to improve the brain’s processing speed – which controls how quickly we take in and react to information. This is a skill that tends to slow with age, but is also a key marker for cognitive decline that can indicate an increased risk of dementia.
In the game, a vehicle flashes up on screen for a split second while a road sign appears at the edge, surrounded by distracting images. The player has to identify both.
It was developed in the 1990s by US researchers to improve processing speed in older drivers: a 2010 study involving 908 drivers and published in the Journal of the American Geriatrics Society found just ten hours of practice using Double Decision cut their crash rate in half over the next six years.
In a landmark new study, almost 3,000 participants aged over 65 were split into three groups, each training a different brain skill – memory, reasoning or processing speed (i.e. playing Double Decision). All three groups trained for around an hour, twice a week, for five to six weeks. About half of each group then had four booster sessions 11 and 35 months later.
Researchers analysed participants’ medical records 20 years after the brain training ended.
The findings, recently published in the journal Alzheimer’s & Dementia, show those in the Double Decision group with booster sessions were 25 per cent less likely to have been diagnosed with dementia than any other group.
The game, Double Decision, is designed to improve the brain’s processing speed – which controls how quickly we take in and react to information. This is a skill that tends to slow with age, but is also a key marker for cognitive decline
Professor Marilyn Albert, director of the Alzheimer’s Disease Research Center at Johns Hopkins Medicine in the US, who led the study, says one reason the speed training worked so well is that the game got harder as a player improved.
Images appeared and vanished faster – and more distracting signs were added, so the brain was always being stretched. Meanwhile, the groups doing memory tasks (involving remembering items on a list) and reasoning (interpreting patterns in order to make predictions of what comes next) did not adapt and get harder.
D ouble Decision, says Professor Albert, helped boost ‘brain plasticity’ i.e. its ability to rewire itself in response to experience and learning.
‘This can strengthen existing connections between brain cells, create new ones and thicken myelin – the fatty coating around nerve fibres that helps messages travel quickly through the brain.
‘The result is faster, more accurate neural processing and strengthened brain networks that resist the effects of developing dementia,’ she says.
Speed training specifically may also help preserve acetylcholine, a chemical messenger crucial for attention, learning and memory that drops sharply in the early stages of Alzheimer’s, she says.
Previous research, published in JMIR Serious Games in 2025, using specialised brain scans found that speed-training boosted acetylcholine activity in areas responsible for memory and attention – reversing the equivalent of roughly a decade of age-related decline.
Everyone experiences dementia differently. Use this checklist to help you make a note of your symptoms before you talk to your GP.
However, other experts stress that these benefits are not necessarily unique to Double Decision (which is free on the BrainHQ app, available on App Store for iPhone or Google Play for Android).
‘Any form of activity that challenges the brain can help make it more resilient to dementia,’ says Barbara Sahakian, a professor of clinical neuropsychology at the University of Cambridge.
Indeed, she was involved in research, published in 2017, for a game called Wizard – where players have to recall where patterns appeared on screen, with the game becoming harder as they improve. It’s designed to target the hippocampus, the brain memory area that is hit earliest by Alzheimer’s.
P atients with early cognitive decline (a precursor to Alzheimer’s) who played for eight hours over four weeks boosted their memory scores by around 40 per cent and made a third fewer errors, reported the International Journal of Neuropsychopharmacology.
Another brain-boosting game is Decoder, also developed by Professor Sahakian, which is said to train the brain’s frontal-parietal network – the area responsible for focus and problem-solving – by asking players to decode number sequences against the clock.
A 2019 study of healthy young adults found those who played it for eight hours over a month showed significantly improved attention and concentration.
And Lumosity, made up of dozens of short games targeting memory, attention and processing speed, was studied in 2015. Adults who used it for ten weeks improved more on standard cognitive tests than a control group doing crosswords. (However, in 2016, the firm behind Lumosity agreed to pay $2 million (£1.6 million) to settle US regulatory claims it had misled customers by suggesting its games could delay cognitive decline.)
All of these brain-boosting games are available to download on App Store or Google Play for free, or require a small subscription.
Gill Livingston, a professor of psychiatry of older people at University College London, says all brain-training games could be part of a broader approach to brain health, alongside hearing and eyesight checks, blood pressure control, exercise and social activity – but are not a standalone fix. ‘It is the same verdict for all of them – they should be used as part of a strategy for a healthier brain.’
As for the latest research, she notes that only 105 of the 512 originally assigned to play Double Decision completed the booster sessions – a relatively small number, which makes it hard to rule out that those who stuck with it were simply more health conscious which might also have lowered their dementia risk.
