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[previous episode : blackly fiendish ]

An appointment for anything at 8.45am on a Monday morning is pretty grim, but if you have to chose something, an EEG scan isn't so bad, consisting as it does of lying flat on your back in a darkened room. Oh, and if you start to find yourself falling asleep, she told me (after we had chatted about gunk, hair, and gunk in hair, the relative likelihood of children, pets and pot-plants figuring in our lives, taken a quick but surprisingly useful and relevant skate through my symptoms, ritually complained about the weather, traffic, and the earliness of the hour, considered the relevance of head injuries, and been reassured more times than I could count. while she attached sensors to my scalp with gritty blue paste) don't worry, it'll just make the readings clearer. So I had to open my eyes, close my eyes, open my eyes, close my eyes, all the while trying to remain as calm and relaxed as possible. Lying there in the dim, I found my mind grabbing and grabbing after whatever stimuli it could find; people talking downstairs, the smell of the conductive paste (lemony and abraisive), the scratch of the Doctor's pencil as she made the occasional note. For while I was able to relax my body just fine, my mind just seemed to keep flickering away, it doesn't like having nothing to feed on, nothing to do. Then I had to lie there and hyperventilate for three solid minutes, while my head got light and my little fingers went numb. Oxygen drunk, mm-mmm. After that little bit of fun I got to lie there in the dim some more, and go to sleep if I wanted. I started to drift, but then started to wonder if she was still there. Pencil noise. Yup, still there. Had to keep reminding myself to keep my eyes shut. Got uncomfortable. Don't really like lying on my back. Eventually, that stopped and I got something to do: look into a strobe light and hallucinate (she warned me that people who get migraines often see colours and shapes during this bit of the test), which for the next few minutes was exactly what I did. Eyes open, it was a bit wincey (my eyes were watering quite badly by the end) but as soon as I was onto eyes closed the flashing of the strobe quickly began to resolve into vivid dotted patterns and colourful kaleidoscopic progressions. Pretty! Unfortunately, every time it was beginning to get interesting she stopped the strobe, and I had to go onto the next pattern. Still, I wasn't there to chase imaginary shapes in a dream machine, and anyway, some of the patterns were not at all fun. And that was that. She pulled the wires off my head and told me I wasn't epileptic (no surprises there) and for the first time I noticed the enormous pile of resuscitation equipment in the corner of the room (and was quite glad I'd noticed it before) and wondered if things went wrong very often.

After it was over, I asked her what the data looked like, and (I'd arrived early, so we finished early) she took a moment to show me my brain-waves, pointing out blinks, small movements, and the cycling where I had briefly begun to drift off to sleep. Then she showed me the spectacular mess a bright flashing light makes -- lines flying off the chart! -- and how the back of my brain had been mimicking the flashing pattern precisely, which showed sensitivity to light (again, common in migraine patients) and how, once the brain got used to the flashing light, it stopped paying attention and calmed right down again.

As I left, she told me that I needed to tell the next consultant I saw about my history of head injury, which (along with all the rest of her behaviour) established her in my mind as a lot more use than the neurologist had been.

And I forgot my hat, but only for the space of a lift-journey to the ground floor, so my hair (though sticky) did not get wet.

[ next episode : the ink trance ]

Comments

( 3 worms — Feed the birds )
andypop
20th Jan, 2003 13:56 (UTC)
I'd love to see my brain waves.
cleanskies
21st Jan, 2003 04:17 (UTC)
it struck me as being more like music than pictures
Almost like an orchestral score, from the top lines (all the exciting stuff at the top of my brain) making complex, variable patterns, all the way down to the steady beat of my pulse underneath it all. If MRI is looking at the brain, this seems to have more in common with listening to it. Wonder if anyone has tried to make music out of brain waves? I think it might be rather clashy and chaotic. I remember music made from the electrical activity of plants (or was it some sort of transalation of cellular data?) making the news a while ago for sounding surprisingly tuneful.
elleblue
21st Jan, 2003 06:05 (UTC)
If you like EEG experiments, one of my colleagues is ready to run some more brain-computer interfacing experiments. You get to sit and play a very simple computer game while recordings are taken from a few (3 or 5) electrodes. We do have blue scratchy paste, but only because we lost the nicer white stuff we used to have when I was running my experiments last year and the technicians helpfully boxed up the kit and hid it in the basement without warning :-( Anyway, I think I'm running in the experiment on Thursday evening.. if you want more EEG fun, I can volunteer you...
( 3 worms — Feed the birds )