I called both my brother and sister and gave them the news. Neither of them was really surprised, of course. We'd all had our suspicions. It is hard to know when ordinary forgetfulness evolves into something more ominous, but early in the year we'd seen a sudden change in our father. He had quite suddenly started getting lost for what to do with monthly or quarterly bills. I began to help him write out cheques and address envelopes. Before long I discovered that his files, which had been meticulously maintained for decades, had fallen into chaos. The first signs of disorganisation dated back about two years, and since then his filing had steadily worsened, until it was non-existent. Some of the most recent paperwork had been stuffed among sweaters in the wardrobe, or left on a shelf in the kitchen. What was remarkable was dad's ability to mask his condition. He had always talked a good story about what he could do. The truth was increasingly something different. My brother was the first to suspect that our father was rapidly declining. My sister and I were more easily taken in by his line in chat.

My mother had been different. Speech was one of the first of her skills to be affected. Her problems were therefore more obvious to us. I'll spend some time over the next few months describing the background and development of my mother's condition, while I meanwhile keep a journal about both of them, and how the rest of us are adjusting.

You've got to be fatalistic about Alzheimer's. Although medicine is advancing rapidly, there is really very little hope of things ever improving for people of our parent's generation. It sometimes feels to me like entering a tunnel that has no light at the end of it - it just gets darker. With my mother's steadily deteriorating condition we had had to adjust to a new set of problems every few months. My father had never been very understanding about her condition. Now he was in the same boat we didn't really expect him to gain any insight into it. The first thing Alzheimer's steals from you is insight.