I can’t remember….

by Dr Hugo J Spiers and Dr Jenny Gimpel

Memory is essential for survival. The brain stores all kinds of memories, like the way to ride a bike, what happened yesterday and even the meaning of the word 'memory'. But memories are fragile and when the brain is damaged by an accident or an illness, memories can disappear along with the ability to remember. Could you survive without your memory? Find out how Sarah, an amnesic, copes with her loss and how her brain used to store memory.

I can't remember where I am. I haven't been asleep but it feels like I’m waking from a dream. I’m bleeding, I wonder why? Images of a handbag – a blue one like the kind my mother used to wear - are flashing in my mind, but I’m not sure if the woman on the bus seat next to me really did swing her bag at me. Why would she do that?

I’m standing at a bus stop and I remember ringing the bell for this stop, so I must be in the right place. I think I recognise the shop across the road – it looks like the corner shop I used to work in when I was fifteen - but I can’t remember why I travelled here…

My name is Sarah. The doctors tell me I have a classic case of amnesia. My childhood memories have stayed with me, but I can’t remember whether I’ve eaten breakfast or lunch today.

The scientists find me fascinating. I sit in their testing rooms trying to memorise a phone number or a list of words, but it seems that after a few minutes I’ve forgotten, although sometimes I’m able to guess them correctly. My short-term memory works but I can’t keep hold of memories of new events or facts for very long. That’s why I’m standing at this bus stop wondering why I came here today. Is it someone’s birthday party? Do I have a doctor’s appointment?

At least I can remember how to read. My old semantic memories – knowledge of objects, words and their meanings that I learnt while growing up - will help me study this bus map, read the information and try to make some sense of where I am. Bother! The names of nearby places mean nothing to me, so I head for something called a golf course up the road.

I can see people swinging metal sticks at little white balls. It looks very difficult. Let me try with this branch lying in the gutter. I pick up the branch and flick a discarded coffee cup up in the air. Yes! It lands squarely where I’ve aimed it, in the middle of a car roof up the road. So I can play this game called golf, though I can’t remember having any lessons or learning the rules.

This must be something I learnt to do after my accident, so my procedural memory – my ability to learn actions – is still intact. But my semantic memory has evidently been damaged by the blow to my head, which is why the word golf seems so alien to me.

The scientists tell me that a part of my brain shaped like a sea-horse – the hippocampus – is no longer working properly, which is why I can’t remember important things like whether my mother is still alive.

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