use EEG electrode cap for sleep study ? [resolved]

mhoskensmhoskens New Zealand
edited August 2021 in Cyton

Hi,
We're planning to buy the All-in-one EEG electrode cap starter kit including 16 channels. We don't have the facilities and expertise to build our own EEG set up, so therefore we thought the starter kit would be the best option. We have some experience using EEG, however, we are now planning to perform a sleep study which we haven't done before. Based on the spisop website I understand that we need EOG and EMG as well. Would it be possible to inform me what we need from OpenBCI additionally to the starter kit to be able to measure EOG and EMG as well?

Thank you.

Comments

  • wjcroftwjcroft Mount Shasta, CA

    Hi MHoskens,

    I'm going to mention Frederick, @Frederik_D_Weber, who is the author / creator of the Spisop tools and site. Hope he sees this post on the forum. Otherwise I think you can email through his site,

    https://www.spisop.org/openbci/

    In particular I'm wondering what his impression is of using an electrode cap overnight for sleep studies. We've had some past comments from cap users, that may imply the gel dries out overnight, reducing EEG quality after some period of time. So the recording may not be sufficient for an entire 8 hours.

    https://openbci.com/forum/index.php?p=/discussion/2848/electrode-cap-signal-quality-drops-out

    I have not done overnight use myself, but have used various spandex + gel based electrode caps in the past (Electro-cap). And they tend to become uncomfortable after some period. Due to compression of the natural movement of the skull plates.

    Actual sleep labs may use different tech these days, such as caps or gels specific to long period use. There are also some other threads on the forum here discussing more conventional manual EEG electrode placement, using cups and special Grass EC2 or EC3 paste, then wrapping / covering such as to avoid dry out. Actually Fredrick recommended a particular combination of EC2 paste and wraps. See the pdf on this page.

    https://openbci.com/forum/index.php?p=/discussion/2313/headband-kit-for-sleep-eeg-longterm-eeg-techniques

    William

  • retiututretiutut Louisiana, USA
    edited August 2021

    I have not tried tried the Electrode Cap overnight, but I can help answer another part of your post.

    Based on the spisop website I understand that we need EOG and EMG as well. Would it be possible to inform me what we need from OpenBCI additionally to the starter kit to be able to measure EOG and EMG as well?

    You could always use Gold Cup Electrodes with the Cyton or Cyton+Daisy in addition to the Electrode Cap. If you need EMG from somewhere else besides the face you could even use Sticky Electrodes. This versatility for custom setups is a strength of the OpenBCI Cyton and Cyton+Daisy.

    https://shop.openbci.com/collections/frontpage/products/openbci-gold-cup-electrodes
    https://shop.openbci.com/collections/frontpage/products/emg-ecg-snap-electrode-cables
    https://shop.openbci.com/collections/frontpage/products/skintact-f301-pediatric-foam-solid-gel-electrodes-30-pack

    To help with placing the Gold Cup Electrodes on the scalp, you could briefly train your staff on this process (best option using free YouTube videos) or maybe 3D print your own UltraCortex Mark IV headset. You would only use the headset to help align the electrodes in the correct spot (like a guide), then remove it once all of the electrodes are placed.

    Both Gold Cup Electrodes and the Electrode Cap provide higher quality data for long-term recordings in comparison to dry electrodes.

    Hope this helps,
    RW

  • wjcroftwjcroft Mount Shasta, CA

    I see a number of EOG illustrations online using the 'small' / pediatric size foam stick ons. The ground lead should not be needed because your EEG already has a ground / Bias connection.

    As for cup placement on scalp, there is a good video from Brainmaster here:

    https://openbci.com/forum/index.php?p=/discussion/176/placing-electrode-sensors-on-the-scalp

    re: 10-20 placement templates, the video above is excellent, but there are also these template 'caps' that just have holes to aid in using some type of marker to place a dot.

    https://bio-medical.com/disposable-rhythmlink-template-cap.html

    Regards, William

  • wjcroftwjcroft Mount Shasta, CA

    This quote below from @Frederik_D_Weber's page does say he uses cups with the EC2. (EC3 is the newer replacement for EC2.) So I'm inclined to think he does not believe an electrode cap and gel would last all night.

    https://www.spisop.org/openbci/#Hardware_Setup

    Any standard EEG electrodes will do, however best are Silver/SilcerChloride electrodes for such sleep recordings, but any other will do fine. For electrode paste, I have good experience with “Grass EC2 Electrode Cream” which is a commercially available paste that keeps the electrodes fixed to the head, and the impendances low over the whole night, also it washes off quite well with just warm water. In brief, to place an electrode, use a Q-tip and some abbrasive (peeling) cream (< $2 in store) to scratch of your skin a little in an 1cm² region, wipe of with skin desinfectant (to get rid of any residues on skin) and aply the heavily creamed electrode to the site, fix with two finger-long medical bandage stripes of tape in a criss-crossed way (do not use medical tape that is hard to remove from hair or skin, and that does soften on warm water).

    The pdf at this comment (previously mentioned), shows a way to wrap after placing the cups, that minimizes evaporation.

    https://openbci.com/forum/index.php?p=/discussion/comment/11834/#Comment_11834

  • wjcroftwjcroft Mount Shasta, CA

    Inexpensive (10 packs) of disposable silver chloride cups are available online. Frederick recommends the silver chloride over plain silver or gold cups. One advantage is that no cleanup of the cups is needed. Another is that silver chloride gives better stability than solid metals.

    https://www.google.com/search?q=eeg+silver+chloride+cups

  • mhoskensmhoskens New Zealand

    Thank you for your replies, this was really helpful!
    Just one other question, can we live stream the sleep stages? To be more specific, we want to do targeted memory reactivation in sleep so we need to know in what sleep stage the participants are. Is this possible with openBCI software or any other software that works with openBCI?

  • wjcroftwjcroft Mount Shasta, CA

    ...can we live stream the sleep stages?

    You should ask Frederick, he is the SPISOP expert / creator. If his staging only operates from recordings, you may still be able to modify it to score in real-time. Instead of using OpenBCI_GUI to create a recording file, you could write your own code (Python or other languages supported), using BrainFlow, to read in real-time and call the classifiers.

    https://brainflow.org/
    https://brainflow.readthedocs.io/en/stable/Examples.html

    To contact him directly, click on his username @Frederik_D_Weber, then press the Message button. That will send him an email. He may have other web sites as well.

    https://www.google.com/search?q=Frederik+D+Weber+sleep

    I'm not sure if he is seeing these at-sign notifications from our Forum. Try reaching him via the Message button or other website contacts. Frederick, if you are seeing these Forum post, please post a short reply here.

  • wjcroftwjcroft Mount Shasta, CA

    Ah, it seems that the underlying app for both SPISOP and COSLEEP, is already real-time, and in Python. So Frederick is reading the Cyton serial port in real-time, and then displays a GUI and various control buttons.

    https://github.com/Frederik-D-Weber/cosleep

    However the other Github, for SPISOP, shows a Matlab based app that only runs on certain older versions of Matlab. So my guess, COSLEEP is the newer and more maintained real-time app. SPISOP may run from recordings only; possibly produced by COSLEEP app.

    https://github.com/Frederik-D-Weber/spisop

    Dates on that SPISOP folder are from 2 to 5 years old. Whereas the COSLEEP dates look much more recent. Some even from 2021. You could probably mod the COSLEEP code to do what you want.

  • retiututretiutut Louisiana, USA

    @mhoskens

    To be more specific, we want to do targeted memory reactivation in sleep so we need to know in what sleep stage the participants are. Is this possible with openBCI software or any other software that works with openBCI?

    Since sound or smell stimuli timing isn't as time-critical as visual stimuli, you could setup a button to press when stimulus is deployed using a separate Raspberry PI or Arduino to send an "External Trigger" directly to the Cyton via a wire (connected through an OptoIsolator to remove noise). The data received by the computer will have this trigger perfectly in-line with the data.

  • mhoskensmhoskens New Zealand

    Thank you for your replies, I'm slowly getting to understand everything. The "external trigger" sounds useful. Does this mean that, for example, an external optical tracker could be connected to the Cyton + Daisy board as well? Thanks

  • wjcroftwjcroft Mount Shasta, CA

    External trigger documentation is here:

    https://docs.openbci.com/Cyton/CytonExternal/

    https://www.google.com/search?q=photoresistor+trigger+site:openbci.com
    https://www.google.com/search?q=photodiode+trigger+site:openbci.com

  • mhoskensmhoskens New Zealand

    Great, thanks a lot for your help!

Sign In or Register to comment.

© Vanilla Keystone Theme 2026