Most of us will know, or have known, a loved one with dementia. As memory slips away, it can take with it language, knowledge and even selfhood. But something beautiful can still remain, writes Noga Arikha.

The experience of dementia is sadly common. According to the WHO, around 55 million people worldwide are living with it now – and those are the known cases. In the UK, there are over 600,000 registered patients. The numbers increase as the population ages: even though dementia isn’t necessarily associated with old age, the statistical likelihood of developing it increases hugely as one gets older. Dementia is an illness, or rather, a family of illnesses, all of which have in common the destruction of neurons by way of the dysfunction of proteins that make them up. This physiological causality is certain, even though its complexity is such that it is not yet understood enough for any of the many treatments that have been researched and tried to stop the damage as the proteins go rogue.