Sleepless in the sleep laboratory
Text: Yannik Sprecher
My night was not as unpleasant as I had anticipated – wearing electrodes on my head was certainly unusual, but less awkward than expected. Also, my bed was comfortable and the carers were kind. Still, I would not want to spend my nights in the sleep lab for weeks on end. A first-hand account.
“The traces clearly show that you were asleep by this point,” says Franziska Rudzik as we talk in the morning. She points to an array of lines on her computer screen that have little meaning to me, apparently skeptical about my claim that it took me a long time to go to sleep.
One possible explanation for the discrepancy between my subjective sleep experience and objectively measured brain activity is “sleep state misperception”: On waking, some people feel as though they did not get a single wink of sleep when in reality they did actually doze off. As a result, they tend to underestimate their total sleep time, explains Franziska Rudzik, who is a doctoral student at the Centre for Chronobiology at the Psychiatric Hospital of the University of Basel (UPK).
Unfamiliar environment
That ties in perfectly with my own experience of the sleep lab. I had a feeling of constantly being on the verge of sleep without ever really achieving it. Surprisingly, that had nothing to do with all those electrodes that Franziska Rudzik’s colleague Laurie Thiesse had taken 45 minutes to attach to my head and face.
The procedure involves having your head measured and spots marked for the sensors, which are then placed directly on the scalp. The special adhesive used sets quickly and becomes very hard, almost like concrete. Still, it is difficult not to worry about inadvertently pulling off sensors or disconnecting leads. Fortunately, I had to wear only eight electrodes. Depending on the type of test, a significantly larger number can be used, sometimes as many as 128 or even 256, says Laurie Thiesse.
After fast-forwarding the electroencephalogram (EEG) of my night in the sleep lab, Franziska Rudzik agrees with me after all: “The trace of your brain waves shows periods of greater activity – what we call arousals – at regular intervals. Something kept making your sleep shallower or even waking you.” Ironically, I had specially prepared for my stay at the Center for Chronobiology by turning in extra-late the two previous nights so that I would be really tired.
It is not unusual for study participants to initially have difficulty in settling down in their unfamiliar surroundings. Many spend one or two weeks in the UPK’s basement facility and so have ample time to familiarize themselves with the beds (which are comfortable) and their environment (which takes some getting used to). These participants have to be even more careful, as their electrodes are reattached only every three days.
Surprising sleep position
I had not expected to find a comfortable position to sleep in, what with the concrete in my hair, adhesive strips on my face, and electrode leads down to my hips. As it turned out, however, I quickly got used to having to turn over carefully, and the electrodes on my head hardly bothered me. Nonetheless, I did not really get off to sleep until the middle of the night.
“Here you can see a nice REM phase,” says Franziska Rudzik, pointing to a succession of symmetrical peaks and troughs in the eye electrode curve. REM sleep is characterized by rapid eye movements, which is also what the abbreviation stands for. “But you wouldn’t normally expect to see a prolonged deep sleep phase here, at 4.30 am. That is quite late.” I probably needed to compensate for the lack of rest during the preceding hours. The finding came as no surprise to me, since I would often sleep very poorly even as a child and still tend to have trouble dropping off. Something else amazed me, however: The night vision camera footage revealed that I had rolled onto my back during the night, despite the fact that I invariably lie on my side to go to sleep. The main reason I am afraid of breaking a leg is that I would be forced to sleep on my back for weeks.
Similarly, I could not imagine living in the sterile environment of the sleep lab for several weeks at a time, let alone if I were to have my ingrained sleep-wake cycle altered through changes in lighting or my sleep disturbed by artificial traffic noise. Otherwise, however, conditions in the lab are ideal: It is very quiet, the beds are comfortable and the staff is friendly and attentive. To accompany me in my laboratory experience, Franziska Rudzik also spent the night at the facility, even though I was the only participant. I showed my appreciation by letting her take charge of proceedings in the morning – she had a whole day of working on her doctoral project ahead of her. After going over my brain wave tracing, she says, “You could definitely have done with some more sleep,” which coincides with what goes through my mind every morning.
Deeper sleep with bedfellow
Typical laboratory sleepers are served three meals a day. After all, they need to stay within the grounds of the facility at all times so as not to distort the test results. I traded breakfast, which would only have caused the doctoral students more work, for the opportunity to go home immediately after a shower. The adhesive dissolved surprisingly quickly in the warm water, although washing it out was certainly less pleasant than having it gently applied. While highly water-soluble, the concrete kept getting stuck in my hair.
Unlike what many people experience, I sleep very well when my girlfriend is lying in bed beside me. “That’s very interesting,” says Franziska Rudzik. “You should find out why it’s easier for you to relax when she’s next to you. Perhaps you could find another way of bringing to mind the idea that there’s somebody there for you.” It is probably true that her presence calms me, but there might be an alternate or additional explanation: When we spend the evening together, I never stay up late in front of the blue-light-emitting screens of consumer electronic devices. Once Franziska Rudzik finishes her doctoral thesis, she wants to research the causes of insomnia. I would not mind being her first study participant – I could certainly manage one more night in the sleep laboratory.