I have come to learn that our family is not unique in its inability to get each other's names right, but for a long time I thought we were. So frequently was I called Greg, or Greg-Mike, or Derek-Greg-Mike, or even Rusty-Mike (Rusty being a ginger tom cat we had in England) that I began saying:

'I'm Gr-mike, dad.' Then, pointing at Greg, 'And he's M-greg.' It's a strange phenomenon.

I remember when Rachel brought her fiancé Daniel around for Sunday lunch. We were all sitting at the dining table, and either Greg or I was messing around with something on our plate.

'Daniel! Stop playing with your food,' shouted dad.

Daniel nearly died of a heart attack on the spot.

'Oh, sorry. I meant M-greg,' said dad in a much softer voice. By now, whichever of us had been messing around had stopped. Dad was now lost for words, and concluded weakly, 'Gr-mike, just get on and eat your lunch.'

Greg and I grinned at everyone else, and Daniel took a few deep breaths.

Having my name mixed up with those of the family pets was particularly embarrassing when I had friends in the house to hear it. I think I simply got used to this family foible and came out of it better able to handle future manglings of my name.

Mum is now sometimes, though not always, quite stumped if you ask her her name. She can remember neither part of it on her bad days. When we were looking at the brain scans on Thursday I decided to capitalise on the fact that she was preoccupied with her name, printed on each scan. I pointed to dad's name.

'See that?' I said.

'Oh, yes,' mum nodded.

'How do you explain that, mum? He and you have the same surname.'

What followed was one of the most amazing pieces of confabulation and surreal incoherence I have ever heard from mum. Even at the time I wished I'd had a tape recorder. I'll attempt to recreate it here:

'Oh well. Yes! I had a... and the um...you know, both of them. We got a thing, all together. And a, and a church. The babies, all the babies. And my dad. We did going-going, all the. He said... and I did. And that was just what we did.'

I figured out that what she was talking about was getting married, going along with the change of name, and so on. She was quite animated, moving her hands and shrugging.

'So, what you're saying is that you're married?' I offered. As clear as anything she replied:

'Oh, people have been saying that for a long time.'

I had to laugh at how serious she looked. Dad was listening intently, and I had to keep his eye through this exchange so that he didn't interrupt. This is the big issue for him, of course.

'And then you had four children together,' I said to mum.

'Did I?' she asked.

'Yes, and I'm one of them.'

Are you?' she asked delightedly.

'Yes.'

'Oh, that's lovely,' she beamed, and patted me on the arm.