Memory loss is a frequent concern and half of people above the age of 40 years think that their memory is worsening. This may be due to normal ageing and mild deterioration in the brain’s function. Sometimes, it may be due to a disease of the brain that stops it working as it should, such as a stroke or epilepsy. On other occasions, it may be due to dementia, which is more rapid memory loss than expected with decline in other aspects of thinking and behaviour too.