In 1906, the German psychiatrist and neurologist Dr Alois Alzheimer first identified the illness that would become known as Alzheimer's disease.

His discovery was based on the case of a 51-year-old woman, Auguste Deter, who had suddenly begun to exhibit irrational behaviour and memory loss.

He treated her at a psychiatric hospital in Frankfurt and kept detailed notes of their conversations and examined her brain after her death.

But Alzheimer's original case file on Auguste Deter was lost for almost a century, until it was discovered by Prof. Dr Konrad Maurer in the archives of the Goethe University Hospital in Frankfurt.

Prof. Maurer talks to Witness about his discovery and Dr Alzheimer's breakthrough case.

Witness is a World Service programme of the stories of our times told by the people who were there.