An elderly couple live in a Paris flat that is cluttered with books and memories. He’s a historian and film theorist writing a book about the links between cinema and dreams. She’s a retired psychoanalyst who suffers from Alzheimer’s. Gaspar Noé’s drama “Vortex” explores ageing and what it means to lose your memory, little by little. Noé uses the split-screen technique throughout the film, enabling us to watch two characters who are in different places at the same time. It shows how two people struggling with the ageing process and illness can become out of sync. With a slew of controversial w…