Hi sorry I saw your other comment and thought it was very interesting. I took a while to reply because I think an experiment was attempted once (I remember learning about the attempt in a university class) and I wanted to find more info about that to send here. But I couldn’t find anything with a superficial search so I was hoping to eventually find the time to do a bit a deep dive and dig it up.

From what I remember the experiment ran into serious issues with the sample size. It started out with a very large number of participants, but they got filtered out precipitously at several points along the way. To begin with, the researchers couldn’t predict who among the participants was going to eventually flatline. Of the handful of participants who did, the research team couldn’t always control or predict where and when they died, so they couldn’t always set the room up accordingly. And of the participants who did flatline in a somewhat predictable manner, the majority of them just died for good and did not come back to tell the tale. Of the remaining participants, some were further prevented from continuing with the study on the order of their physician, because they were in such bad shape (they did literally just die, after all) that even just being interviewed by the researchers would have been too much. This left the researchers with very few participants to work with.

I remember there also being criticisms about the experimental set-up, specifically regarding information the participants were quizzed on afterwards. I think the way the experimenters set it up there was a colourful sheet or something on a shelf above their body. This sheet was only visible from the ceiling looking down, so the idea was that if the participants reported its colour correctly then we could verify their claims of leaving their body and looking down at the room. The critique of this though was that, if you literally just died, you’re going to be paying attention to details that are relevant to you, such as what the doctors are doing to your body or how your family is taking the situation. You probably don’t even think that you’re going to come back (and in most cases, you’d be right) and you definitely wouldn’t have the mental wherewithal to scan the room for mundane details so they could accurately report it back to the researchers after you're resuscitated.

I think the way you described things is actually a better setup though, for this reason. We should just give a multiple choice quiz about events that happened in the room when the patient flatline, specifically details that would be relevant / emotionally salient to the patient. This setup would also have the added benefit of meaning that the researchers would not need to setup the room ahead of time, which could play a modest role in mitigating some of the same size issues. Unfortunately this would mean that this information would change from patient to patient, so it can’t be as standardized as we might want it to be. But that’s just the price we’d have to pay to get a study like this off the ground to begin with.

Despite all these issues though I think studies like this should definitely be conducted, especially with the multiple choice structure you suggested because that seems more practical. The sample size issues are a real obstacle though, and to overcome it we would need to start with a truly large cohort of participants so that we could still have a workable sample by the end of it all. And studies of that scale require funding! Unfortunately, due to the social stigma around this topic (as evidenced by the vitriol being flung my way on this thread) this is a chronically underfunded area of research. But let’s hope that changes! Because studies like the one you described are too interesting for us not to conduct.