recording of Speech Evoked Auditory Brainstem Response with Ganglion
Hello
I am Perminder Singh currently a student at University of Ottawa, Canada. I am working on the OpenBCI(Ganglion Board with Wifi shield) system. Can you tell me how I can record Speech Evoked Auditory Brainstem Response through OpenBCI(Especially with the Ganglion board+ Wifi shield) system?
Thanks.
Comments
Psingh, hi.
This page shows the montage in section 3.2,
https://www.intechopen.com/books/advances-in-clinical-audiology/speech-evoked-brainstem-response
Since it is only one channel, you could use another channel, to record some type of 'external trigger' level that corresponds to when your auditory stimulus is presented. For example if you were using the laptop audio output for the stimulus, that same audio output could be run through a voltage divider to get the amplitude down into the microvolt range (say ~ 50 microvolts). This then would be input to your trigger channel.
Your signal processing would then synchronize the analysis of the EEG, to begin when the stimulus starts.
There could be other ways you do this without the 2nd channel trigger, but in that case you would need to do calibration runs to determine all the delay factors involved. The trigger approach would give you precise alignment of stimulus and EEG response.
Regards, WIlliam
https://www.google.com/search?q=voltage+divider
Perminder asked via Forum Message: "How can I record the click evoked response??"
Did you read the earlier link to the book chapter, section 3.2? It lists the montage (single electrode at Cz).
Regards, William
Wjcroft I read that chapter but I need information how it’s works
Perminder, hi.
Have you done ERP / P300 in the past? You need to provide the stimulus and then precisely time the EEG recording 'epoch' to begin at the exact start of the stimulus. This then allows you to use signal averaging to increase the signal to noise level.
https://www.google.com/search?q=p300+tutorial
https://backyardbrains.com/experiments/p300
I have not personally done speech evoked brainstem recording, but understand that it has similarities to other ERP / P300 techniques. Suggest you do some more reading on how this is done in online papers and clinical studies.
Regards, William
See chapter 3.4 in the book to read how they did signal averaging.
However I don't quite understand their use of the term 'sweeps' and thousands of them. Usually for P300 oddball, only several trials are needed to produce better signal to noise levels by signal averaging. Suggest more reading on this technology and usage of terms.
If this is click induced BAER and neither speech induced BAER nor P300, the click rate is in Hz, and thousands of trials or "sweeps" would be possible in under fifteen minutes:
https://www.tandfonline.com/doi/abs/10.3109/00206099109072882?journalCode=iija19
Bill, thanks. My understanding is that click evoked brainstem tests differ from speech evoked. But you're right, maybe it is possible to loop the speech segments almost as rapidly as clicks. "...da da da da da da da da..."
Interesting here they show only prefrontal electrodes. Maybe click based differs from the previous speech based paper link which used Cz montage.
William thanks for the information but my question is that how can I record this signals with Ganglion Board with wifi shield?? And I am trying to connect with EEGlab but it’s not working. Can you help me in that
I assume you can connect ok with OpenBCI_GUI? GUI can make recordings, either in CSV format or EDF/BDF format. You can then import recordings into EEGLAB.
https://irenevigueguix.wordpress.com/category/research-tool/eeglab/
Here is more info on the protocol used in the video. They do use a frontal electrode with ear reference, it seems, and it is not speech but clicks or chirps, for testing hearing of sounds not words, I suppose:
https://www.audiologyonline.com/articles/update-on-auditory-evoked-responses-19040