The big payoff
Yesterday I finally had the chance to get not one, but two new datasets! Those datasets were for a project I’m calling “big idea.” In my mind, it will change the way a lot of things are done, advance science, and I even joked with hospital-PI that I would need to retire after we publish because I’ll never do anything better. I have a lot of hope for big idea, but the first dataset we got was a fail, so the question was, what happened and did we fix it?
The problem with collecting neurological data is that you can very rarely tell if you’re getting something good. When recording EMG, no problem! When you’re doing a lot of averaging with nicely time locked data, forget about it! But when you’re doing very complex things that have no clear start or stop point, well then you have yourself a gift. It’s a gift because until you figure out what you have, you have no idea what you got.
As an aside before we start, time locked data means we have a clear start, usually this is an electrical stimulus or some sort of visual/auditory cue. Basically we know exactly when we sent the command to the person. Normally in our lab we use electrical stimuli and the equipment will put a little flag in our data to let me know exactly when it was delivered. It’s really cool because you can do 1000’s of repetitions and have the exact start point for each of them.
Now yesterday we collected two different datasets, in two different settings, with two very different sets of tasks. There’s still a lot to be done for both of them, but I have some good news, at least for now. It looks (fingers crossed) like we have good data… at least for one of the datasets. Obviously I can’t say too much about the stuff I’m doing, but I can talk about the good and not so good.
The good is that the data look like we expected. These datasets were to verify everything was working (in a roundabout kind of way), the datasets aren’t my first choice for using big idea. These were more “cherry on top” datasets for hospital-PI. As he puts it, we want to verify the stuff is doing like we expect. We have other data to compare our work to before we get started with how I want to use it. The real (actual) good news is that the data match.
Now the bad news. There was more noise than I would’ve liked in the data. There’s a lot of reasons this could be, electrical equipment is everywhere in the hospital. We use the incandescent lights that you find in a lot of buildings and those pump out electrical interference like it’s was designed to screw with electronics. Oh and there’s the not so ideal way we did the work, we had to run the wires on the ground, which was not good.. Running wires on the ground is by far the worse thing you can do when you’re working with sensitive equipment.
All in all, I can do better, I know I can. I just need more time with people and that hasn’t been possible in any of these cases. I am hopeful that now that we have some good data we can arrange for something more long term or at least a longer experiment. Lately we’ve gotten just a few hours if that to do the work and it’s not ideal. So overall I’m very happy with the outcome so far and I’ve only got to scratch the surface of the data.
Small victories. I mean I knew it would work, but getting the equipment working was the tricky part. In fact, we had to set everything up in a way that didn’t exactly make sense to me and I’m not sure what’s going on. Yet another reason why I really need to get someone to work work with for a longer period of time. I need to try a few different setups to nail down which works and to figure out why the setup I want to use doesn’t appear to work.
Forgive me, I know you’re more trained and this is your project, but I’ve found sometimes people come up too close and miss something, so I’m going to ask a silly question.
I did some off the cuff research, I really enjoy thinking about your technical issues because they’re real and important. I miss stuff like this. I mean, mass shielding, switching to 400 Hz aviation systems, so much that ends up falling apart for any number of reasons, mainly the most sensitive parts cannot be shielded unless you entomb the patient’s head in a hundred pounds of copper. People don’t like that, I’d wager.
So what about room tone? Set up a sensor in parallel with your current sensors to determine the local effect and phase of the 60Hz noise. By definition, anything on a leg will have the same phase, and the same goes for any other leg in two, three, or four phase systems. By knowing the phase and relative amplitude, it’d be easier to pull out the 60 cycle hum without the losses of a generic filter.
Obviously it wouldn’t do anything about phase-shifted noise like capacitive loads or RF bleed from bad solder joints, etc. but hopefully it’s something that either inspires a “Yeah, we’re already doing that, because it’s a good idea,” a “That doesn’t work, but good looking out,” or “Actually, that’s a great idea!”
In any case, I got to troubleshoot for ten minutes today. It was a good day.
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May 24, 2022 at 9:58 pm
No, that’s a really good idea. Normally we filter it out, but having some reference for what the noise looks like could be useful for other ways to filter out the noise. I’ve been trying to come up with better ways to do this, so it wouldn’t hurt to add it to the list of things to try!
Thanks for the help!
May 25, 2022 at 2:01 pm
I was thinking about the experiment with the less than ideal table and it brought to mind the camping mats that we used when my son was in scouts. They have a foam core but also inflate.Being A zero, I am very careful with my skin and I could lay on those for long periods without worry, the roughly 2 inch mattress kept me off the ground better than a 6 inch all air one. They roll up pretty small it might be a good edition to your kit. I wonder if they could also get the cables off the floor.we had 2 types one was flocked and one just vinal. I think the vinal kind might allow static but the flocked kind might do the trick. Or pool noodles, we use those for everything. My maker kit has duct tape, chop sticks, modeling clay, baling wire, pool noodles, hot glue, proto putty, egg cartons, steel wool and thermo morph. The answer always involves at least one of those:) I love how my solution contrasts with the other comment…Sorry I have not been on Twitter to say hi. I deactivated my account because driving down the subscriber count was my way to protest, I could go back but feeling pretty good about not being on right now. Hope you are feeling well. Still reading, but miss saying hi.
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May 25, 2022 at 2:57 am
Haha I love your suggestions, the pool noodle idea or any type of foam would probably help to be honest, I’m sure I could ground it so it wouldn’t hold a charge.
Glad to see you’re still around! I totally understand needing to step away. I completely shut down my facebook page for similar reasons. Thanks for taking the time to say hi!
May 25, 2022 at 2:04 pm