Guinea Pig

 I decided to dedicate my brain to science. Why wait until I’m dead?

Actually, I have applied several times to be included in various medical studies and trials. As the National Institutes of Health are nearby, there are bunches of trials around. I was turned down for an early Covid vaccine trial, due to my migraines. The migraines have knocked me out of several trials.

A year or more ago I applied for a study on the effect of exercise on memory being done at the University of Maryland. I was disqualified because I was already an active exerciser - they were looking for sedentary old people who would start an exercise program. They would be studied longitudinally, for at least six months. 

I was contacted again by the same folks this February, where they were conducting a related study, looking at short-term effects of exercise on memory. For this, they needed old people who had a basic fitness level, so we wouldn’t drop dead exercising for the experiment. I was excited to be included this time! There was no compensation for participating, but also no expense. Three visits to the nearby University of Maryland campus, at least two hours each. 

It was an interesting experience. I had to be cleared by my primary care physician for exercise, and by my dentist for the MRI machine - to verify I didn’t have any big metal things in my mouth. The first visit was to get a baseline of both my fitness and cognitive level. I was met at the door by a personable young man, Dan, who was in charge of this experiment for his doctoral research. I was led into the basement of the School of Public Health, into a bleak cinder block and linoleum room with just a Formica table and a couple of plastic chairs, where I signed a whole bunch of releases. I was run through a number of standard memory and cognitive tests: “remember these five words” and “draw a clock face and put the hands at ten minutes past eleven” and “name as many words starting with “F” as you can in two minutes”. I don’t have a great memory, but I’ve done these tests before. I knew it was just to establish a general baseline to qualify for the real test - make sure I wasn’t impaired - but of course I really put a lot into it, wanting to do well. Then, we went down the hall to an exercise lab. They strapped a mask on my face, a heart rate strap around my chest, and put me on an exercise bike. I had to pedal until my heart rate reached 85% of my predicted maximum, to get a “VO2 Max”, used as a proxy for overall fitness. Again, they were only interested in establishing a general category of “fit enough”, but of course I asked to see my numbers and figure out what they meant. (Dan told me I was “toward the top” of his test subjects, but I was then disappointed when I got home and did more research to realize the number put me in the “average” category for my age and sex. I want to be above average, of course!)

The next two visits were to involve a lot of time having my brain scanned in an MRI, while performing a cognitive task and also scanning before and after and the task, while simply lying there in the tube. The difference between the two visits was that one time I would first pedal on an exercise bike for 30 minutes, and the other time while sitting still for 30 minutes, before going into the tube. The MRI was in a different building on the edge of campus, adjacent to  a veterinary facility, betraying U of Md’s land grant college roots. The MRI is a scarce resource - Dan told me several times that it was costing nearly a thousand dollars an hour, so he was excited to have a grant big enough to handle 40 people with two scans each. But also, the scheduling had to be exact, with no wasted time. They have sorted through a lot of test subjects that can’t do the long MRIs, either because of metal in their body or inability to tolerate the confined and noisy space. So Dan was very pleased that I was able to do this. There were a long list of requirements for clothing - besides the obvious of no underwire bra, but apparently a lot of exercise leggings that are shiny have metal in them. So cotton sweats and tees are the preferred attire, unless you are willing to be put in scrubs or a hospital gown. Even some tattoos are problematic for MRIs. Who knew?

The first day, I found the test site, arriving early, just as Dan was also pulling up in his car so he could lead me in. MRI machines are often below ground, always shielded from outside interference, so of course there was no cell or internet reception there. The building seemed empty except for us - me, Dan, another grad student assistant, and the MRI operator. I was the second subject of the day, starting at 10 am. That first day, I sat and pedaled on an exercise bike, in an empty cinder block room with no music or entertainment and my seat got sore - I haven’t been biking in a couple of years. Every five minutes they took my heart rate and asked me for my relative exertion level. After my exercise, I went into the control room for the MRI, where I was stripped of my watch and glasses and shoes, and then the MRI operator wanded me down with a metal detector, like a TSA agent. I was insulated with ear plugs and pads, effectively rendering me deaf. We went into the room with the MRI itself, where I lay down on the pad and had my head caged in and a display fastened on top. I was handed a small keypad with three buttons to use with my right hand for the task, and a bulb to squeeze in case of emergency, and a finger tip heart rate monitor anchored my left hand. I was slid into the tube, and they communicated with me by typing messages that appeared on a display above me. After a moment, they started with the scans. Each was announced with a typed message, like "this first scan will be 20 seconds. Are you ready?"  It took me a beat to realize there was a microphone in there, so while I couldn't hear them, they could hear me if I talked, and they needed to hear me agree each time.

I recall some previous MRI scans as being mechanically noisy, with whirring and banging. These scans were all noisy, but in a more electronic way, beeping and booping and squealing. I couldn't really assess how time was passing, except by what they typed about how long each scan would be. There were some shortish scans, and then I did my "task". They showed me a series of pictures, and I had to push a button indicating whether the picture was new, a repeat of one previous, or similar to one previous. The "new" versus "similar" was nuanced and a bit difficult. I'm not sure how long each trial was - five or ten minutes? - and there were two different trials.Of course I worked really hard to get them right. And then after the trials more scans, some really lengthy, with at least four that were eight minutes a pop. During each scan I made an effort to be truly motionless, and in between I could flex my fingers and squeeze my muscles a bit, but all told it was 75 minutes in the tube. After my task was complete, I relaxed and just drifted while they continued to scan. And each scan had its own song, either high pitched or low, steady or syncopated rhythms, monotone or two or three notes. Finally, they told me we were done and slid me out, uncaged my head, and I got to sit up. I was stiff from staying still all that time.

The second day was just like the first, except instead of peddling on the bike, I sat on it for 30 minutes. My seat got sore again! And they took my heart rate and my perceived exertion every five minutes. They strove to make the session as similar to the first as possible, except for the actual exercise part.

The scan was long and tedious again, except for the tasks. I had been feeling sluggish all morning, and I know I didn't do as well on the tasks - I was conscious of mistakes right after I made them. I don't know if the difference was at all due to the exercise, but I'm sure they'll be able to see a difference. After my tasks, I was nearly able to fall asleep inside the machine, despite the beeps and boops, but I thought actually going to sleep would be a bad thing for what my brain looked like, so instead I mentally sorted through my mess of tools in the basement, trying to come up with a better way of storing things so I can find them again.

So I did my bit for science. I am on a list of potential test subjects for future tests as well - they are always looking for guinea pigs, and apparently I was a good one for them.