My sister has had Alzheimer's for  2.5 years but we knew that something was wrong long before that: little things like repeating a story and thinking it was the first time.  What is more distressing is that she knows that she has it and even now becomes very upset because she knows that it is incurable.  There is only 19 months difference in age between us and as children we fought and quarrelled together, but as we grew older we would talk on the phone for hours.  I can't do that now which upsets me.

Around 225,000 people develop dementia every year – that's the equivalent to one person every three minutes. This September and October Memory Walks will be taking place across England, Wales and Northern Ireland to raise money for a world without dementia. Arm in arm, step by step and pound by pound, we will get there. Once you donate, Just Giving will send your money directly to the Alzheimer's Society. So it's the most efficient way to raise money – saving time and cutting costs for the charity. Please dig deep and help us walk for a world without dementia.