What a rare form of dementia reveals about how we construct the world outside

Posterior cortical atrophy (PCA), also known as Benson’s syndrome, is a rare form of dementia in which the brain’s spatial reasoning, visual processing and spelling and calculating functions deteriorate. In the vast majority of cases, the condition is caused by Alzheimer’s disease. Because the symptoms frequently manifest before declines in memory and cognitive skills, PCA means that people who have it are very much aware that something has gone awry with their perceptions – they reach out again and again to pick up a coffee cup they see but can’t grasp, or watch as the words in their newspaper begin to move and mutate. This short film from the British animator Simon Ball guides viewers through the strange and unsettling experience of PCA from the perspective of six individuals with the condition. In addition to offering an empathic window on the day-to-day difficulties of living with the disorder, the film also provides insight into how we all construct our worlds from within.