The early symptoms of a rare form of Alzheimer's disease, known as Posterior Cortical Atrophy, presents problems for people in seeing and making sense of the world. The disease starts in the visual cortex at the back of the brain. Its impact is devastating and its progression is aggressive. Doug Banks, who is 58 and has PCA, likens it to looking through a shattered mirror. He talks to Peter White about the other ways it affects his life. Alzheimer's Research UK's chief medical officer David Reynolds tells us what's happening to Doug's brain. College student and young actor Ellie Wallwork has had her big break. She is to play the lead guest role in Sunday's episode of Dr Who. She tells Peter White how she got the part and where acting fits into her future aspirations. Presenter: Peter White Producer: Lee Kumutat