More than 100 years after the German physician Alois Alzheimer first identified the illness that bears his name, scientific study has advanced but diagnosis still offers almost unmitigated gloom for patients and their carers alike.

As populations around the world age, so does the impact of the disease. One estimate by specialists at Johns Hopkins University suggested that as many as 27m people are living with Alzheimer’s disease around the world, of which more than two-fifths require a high degree of care equivalent to that provided in a nursing home.