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I'm in a psychology lab and we're having trouble getting participants for an fMRI study. We pay $150 per subject and we need to have several hundred healthy controls for one study. For the 20-minute study, the participant has to look at certain words and think about them, like imagining a scenario where "family" or "pride" was important.

We keep finding participants from recruiting around campus who will seem enthusiastic, then fall asleep immediately in the scanner. Our IRB states that we have to let them sleep for the full scan and pay them the full amount. I don't know how to prevent this. We've wasted thousands of dollars and weeks to months of time running studies with garbage data. Has anyone figured out how to recruit better participants?

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    $\begingroup$ Change the contract based on paid for viable results. One pays for "work" completed... Otherwise I am worth a fortune.... $\endgroup$ – Solar Mike Jul 2 at 20:21
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    $\begingroup$ @SolarMike, for that you need to go back to the IRB, I think. $\endgroup$ – Buffy Jul 2 at 20:23
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    $\begingroup$ @Buffy probably, but it was badly written to leave a loophole like that... To make it the equivalent of "sleep in our MRI scanner for an hour and get $150 for the privilege" and that does not even take into account the hourly cost of the scanner... $\endgroup$ – Solar Mike Jul 2 at 20:27
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    $\begingroup$ You could keep your study the same but instead frame it as a study of boredom-induced somnolence. It would be in keeping with a time-honored scientific tradition of trying to make the most of uncooperative subjects, errr, participants :) $\endgroup$ – BrianH Jul 2 at 20:28
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    $\begingroup$ I think you need to redesign your task rather than your subject recruitment. It sounds really boring to me. People learning meditation fall asleep all the time, for example. Blaming the participants is probably not the right approach. $\endgroup$ – Bryan Krause Jul 2 at 22:31
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Based on my own experience as a student, the problem is probably not that your participants are lazy... the problem is that, like many university students, they're severely sleep-deprived.

While a student, I once agreed to participate in a friend's (non-MRI) study, which involved listening to sounds and clicking buttons in response. To my embarrassment, despite being enthusiastic about participating, I kept drifting off briefly during the study. I managed to complete it, but I'm sure my results were affected. I'm pretty sure that if I had ever tried to participate in an MRI study, I would have fallen completely asleep.

I don't have experience running MRI studies so I'm not really sure what to suggest to solve this problem, other than to try recruiting from less sleep-deprived populations, or redesigning the study tasks to be more engaging.

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  • $\begingroup$ Or redesigning the study to account for the phenomenon. $\endgroup$ – Buffy Jul 2 at 20:27
  • $\begingroup$ Oh, it also occurs to me that time of day is important -- my guess is that participants are much more likely to fall asleep during an early morning session than a midmorning/afternoon one. $\endgroup$ – ekl Jul 2 at 20:32
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    $\begingroup$ We've analyzed time-of-day results and found no correlation between morning and evening, though subjectively it "feels" like morning subjects have done much better. $\endgroup$ – rooty Jul 2 at 20:33
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    $\begingroup$ Maybe, but my naps come just after lunch. But then, I'm older than the rivers and mountains. $\endgroup$ – Buffy Jul 2 at 20:33
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    $\begingroup$ Does your IRB approval allow you to require your subjects to drink coffee? Only half joking. $\endgroup$ – ekl Jul 2 at 20:41
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The problem is not your participants. It is your stimuli. They are too boring. Change them, or add a task participants must perform. It could be as simple as "Press a button to continue."

You will need to go through the ethics board again.

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  • $\begingroup$ I think the lack of any action the participant has to take other than thinking might be part of the problem. Could you add an action at the end of each word display, such as pick the picture that most closely relates to the scenario they imagined? (with IRB approval) $\endgroup$ – Patricia Shanahan Jul 4 at 0:11
  • $\begingroup$ @PatriciaShanahan, If I read it correctly, the problem is with the control group who are not given the words so that the scans of the test group can be compared to a base. Making the control group active might invalidate their use as a control. I think the design issue is fairly deep. $\endgroup$ – Buffy Jul 4 at 0:20
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    $\begingroup$ @Buffy The only time I lie down flat with no entertainment, nothing to read, no TV is when I intend to go to sleep. I think even with the sleep opportunities of a retiree, not a student, that design would put me to sleep. $\endgroup$ – Patricia Shanahan Jul 4 at 0:24
  • $\begingroup$ @PatriciaShanahan, yes, and thus it is hard to design the experiment so that you get a valid base line. "Stimulating" the controls just voids the experiment. I don't know the expected MRI difference between sleep and lying down quietly. But it isn't my field. $\endgroup$ – Buffy Jul 4 at 0:29
  • $\begingroup$ I thought the experiment was much more practical, such as comparing reactions to different sets of words. $\endgroup$ – Patricia Shanahan Jul 4 at 3:53

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