The long, difficult search for a drug to treat Alzheimer’s and dementia

Dementia is now the commonest cause of death in England and Wales, and although Alzheimer's was first identified more than a century ago, effective treatments have proved elusive. But progress may now be in sight

Related: Sea Hero Quest: the mobile phone game helping fight dementia

Most of us forget names, dates or places from time to time. But Hilary Doxford never did. While the rest of us smile about our common inadequacy, she knew she was experiencing a genuine malfunction of her high-performance brain. "I did have a really good memory and didn't need to write things down," she says. "And I used to be able to multiply two four-digit numbers together almost instantaneously." But one day, she started getting the sums wrong.