Ryuta Kawashima is used to children pointing at him on the street. They often shout "Kawashima Devil!" It's the price the neuroscientist pays for being the famous face of a lucrative series of brain puzzles that he developed for Nintendo.
Kawashima appears in the videos as a disembodied, floating head with horns and a bright red face, asking "devilishly" hard maths and memory questions. Millions of games have been sold, earning him royalties of over $30m. But, he says, his games are more than just a fun way to learn: they could, in fact, provide a revolutionary new way to treat dementia.
The 54-year-old refused to keep the money he made from the brain puzzle series, ploughing much of it into a research centre in Japan's Tohoku University, attached to the Institute of Development, Aging and Cancer. Kawashima's 40-strong team of young scientists spends their days working on ways to train our working memory and stimulate the prefrontal cortex, the area of the brain that deals with problem-solving and personality. Brain exercises have been shown to expand the cortex of healthy young people, he says, "So why not the old?"
That question animates a remarkable new documentary on Kawashima's work. In 'Do You Know What My Name Is?' pensioners with severe dementia at a care home in the US state of Cleveland, Ohio, are seen recovering the use of their memories after using a six-month programme of learning therapy he designed. Some are almost literally brought back to life, transformed from depressed, hollow shells slipping inexorably toward death back into sociable, happy people.
"We neuroscientists knew that brain plasticity exists in young subjects. The new point is that we now know it exists even in the brains of dementia sufferers," Kawashima explains.
He says stimulating the frontal cortex clearly improves memory and brainpower: "We found that the best candidate for training working memory in people with dementia is reading aloud and performing simple arithmetic." Kawashima claims his own tests show an improvement in up to six out of 10 dementia sufferers, and he thinks that this can be bettered.
Dementia, a catch-all term for symptoms that include loss of memory and cognitive function, afflicts about 800,0000 people in the UK, according to the Alzheimer's Society. The symptoms are progressive , robbing victims of memory , confidence, personality and, eventually, life as they slowly fade away. The condition costs the UK economy an estimated £23bn a year, says the Society. With the number of sufferers expected to treble worldwide from 36 million to 115 million by 2050, according to the World Health Organization, scientists are now turning to non-drug treatment.