Best Caps to use with Cyton in 2018

retiututretiutut Louisiana, USA
edited March 2018 in Headware
What are some well reviewed, cost effective caps to use with the Cyton for sleep studies? 

@wjcroft recommended this option in another thread to keep from damaging the Mark IV headset. I'm also wondering if any new products have come into the market. I'm open to try both dry and wet electrode options. Cheers!


Comments

  • wjcroftwjcroft Mount Shasta, CA
    R, hi.

    If we look back at the thread you mentioned,


    Many sleep studies use just 2 or 4 channels on the scalp. With others around the eyes, etc. Also you might have seen this,


    So my impression, is that a full head cap may be uncomfortable. You may just need some head bands, maybe elastic velcro, etc. Possibly a chin strap to help hold the C3 C4 band down. Even a sports type swim cap, I think would be uncomfortable when worn for hours at a time.

    The sleep labs use paste or gel, plus Collodion to glue the electrodes to the head. So no pressure on the cranial bones. The bony plates of the head move and breathe naturally. There is a whole field called cranio-sacral therapy, included in some forms of osteopathy, that points out the natural movement of these plates is a sign of health. When they are frozen or locked in place for long periods, all kinds of wider systems are impacted.


    Regards,

    William



  • wjcroftwjcroft Mount Shasta, CA
    FRI recently added a cap to their headband list,


    The Austrian g.tec g.GAMMAcap2 is still a good option if you can find it. There used to be a US distributor on the east coast, Cortech. Don't see it there anymore. Another link that came up on web search,


    Many different elastic eeg caps available. The one I've used the most (Electro-cap), is just intended for brief sessions of QEEG acquisition or training. Wearing it any more than 30 minutes to an hour, results in substantial head pain.

  • retiututretiutut Louisiana, USA
    edited March 2018
    I hadn't seen the https://www.spisop.org/openbci/ project! The electrode mappings are very clear. I guess I will go with gel/electrode/medical_tape option as it's the clear winner on affordability and reliability for adults.

    • Would you use a cap for 4-16 channel EEG on infants and toddlers? 
    • When are caps most appropriate in EEG/EMG research?
  • wjcroftwjcroft Mount Shasta, CA
    re: infants / toddlers. This requires extreme caution because of,


    Unless you are working with an MD / neurologist, I would avoid any EEG in young children.

    re: EEG caps in research. The g.tec has excellent equipment, but it's astronomically priced. Electro-cap is the standard in neurofeedback research and clinical use. And is just in the couple hundred dollars range. Just do a search on eeg caps and you'll find lots of others.
  • retiututretiutut Louisiana, USA
    edited March 2018
    re: infants / toddlers

    That makes sense. Thanks for sharing the medical term.
  • retiututretiutut Louisiana, USA
    edited April 2018
    Here's a journal article from the NIH database, Are Electrode Caps Worth the Investment? An Evaluation of EEG Methods in Undergraduate Neuroscience Laboratory Courses and Research, which states the following in the abstract:

    ""
    Therefore, we conclude that programs can comfortably decide which to use based on their own needs and resources as well as the relative advantages and disadvantages of each setup. For example, individual electrodes may be better for programs with low budgets looking to introduce students to EEG data recording, whereas electrode caps may be better for programs looking to better prepare students for future EEG research or to perform multichannel recordings.
    ""
  • wjcroftwjcroft Mount Shasta, CA
    This statement in the paper: "... and a set of two EEG caps costs $750–1000." is considerably inflated, versus pricing for normal Electro-caps.


    $260 each.

    When I last checked, the g.tec g.GAMMAcap2 was in that range as well.

    The paper also stated: "According to average reaction scores calculated from the surveys, laboratory students tended to prefer individual electrodes over electrode caps, and when explicitly asked about their overall preference, a majority of laboratory students chose individual electrodes over electrode caps."

    The systems that use bands to hold electrodes in place, seem to offer a middle ground. Less stress on the cranial bones and usually easier to put on and take off. 

    After doing a full cap QEEG with 19 channels (using gel injection), your head looks and feels a bit like a 'zombie'.  :-)

    Some saline systems exist that do not use gel, instead using a saline solution. See the commercial systems tab on this page,


    However neither gel nor saline alone can work for sleep studies, since the water dries out over a couple hours. That is why the sleep labs coat the individual electrodes in collodion to stop evaporation. 
  • benevans101benevans101 France
    edited June 2018
    Hey Retiutut & William -

    Thanks for posting the links and info. I'm interested in doing similar things. Retiutut - How have things worked out since your last post? Let me know what works if you've found some success.

    For me, given that professional caps are currently too expensive for me, swimcaps are too tight/sweaty, etc etc, I thought I might experiment with a rugby "helmet" (just padding) -


    I'm hoping this will help keep the back, top and earlobe/mastoid electrodes in place, but I'm a bit worried that it might transmit any any movement to everywhere else.  The face and chin sensors for EOG and EMG can just stay with the tape. I've also just realized (I'm not a real sleep scientist) that it is totally acceptable to do all three EEG readings from the same side, and that any more than that is just backup. This means that people can sleep on one side without much disturbance. So far I've just experimented with naps, where the subject (my poor wife) is on a couch with her head elevated on the armrest, which seems to work OK. But I've only had my board for a week, so I'm curious to know what is working for others!
  • retiututretiutut Louisiana, USA
    edited June 2018
    @benevans101 Things are going well. I'm getting everything in order to do recordings just before falling asleep while using the Mark IV. I think the cheapest option for me to do sleep studies would be to use electrodes w/ collodion (which I guess I would need help placing) and also 3D printed enclosure for the Cyton+Daisy. The most important factors in my decision being quality of signal, no damage to components, and price! It may be more work to use individual electrodes, but I think the extra effort makes it worth it.
  • retiututretiutut Louisiana, USA
    edited June 2018
    I forgot I mentioned I would try the medical tape first. I'll have to try medical tape and collodion adhesive method when I try sleep recordings. I don't see a need to use a cap for now for awake recordings since I have a Mark IV helmet.

    I think William said it best already:
    ""
    However neither gel nor saline alone can work for sleep studies, since the water dries out over a couple hours. That is why the sleep labs coat the individual electrodes in collodion to stop evaporation.
    ""
  • Great. Thanks for the quick feedback. I'm still toying with getting a Mark IV for a range of easy uses (if I get an upcoming grant I think I will!). But tell me - are your subjects lying in regular beds with regular pillows wearing the Mark IV? Cool as it is, it doesn't look super comfortable to wear to bed. I could see it if they're in a more upright posture, like a semi-reclined lazy-boy type thing. But then, depending on why you're doing the sleep study, making them sleep in a chair kind of screws with the results!

    I'll let you know how my own paste/tape experiments go...

    Cheers,
    Ben
  • retiututretiutut Louisiana, USA
    edited June 2018
    I'm the only subject for now, and I'm not an EEG tech, lol. The only other advice I can offer for using the Mark IV for awake study is probably prop up the head with pillows at the base of the neck. Maybe a neck pillow? That's why I mentioned the 3D printed enclosure: to move the Cyton away from the head during sleep. Here is another thread with videos to describe how to attach electrodes.
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