Re: number of electrodes

Thanks John.


From: John Barker [mailto:[email protected]]
Sent: Thursday, February 26, 2015 2:52 AM
To: Discussion of EEG hardware, software, training protocols, NFB theory - for developers and users.
Subject: Re: [Openeeg-list] number of electrodes

What applications did you have in mind?

Medically, 256+ channel EEG systems may aid in detection of seizure focal points, though this could also be argued as being overkill. The spatial accuracy of an EEG recording is limited by many factors, not in the least smearing of the signal by the skull, CSF, and other obstacles between the electrode and actual neurons in the brain. You should also look into the inverse problem.

QEEG (and very occasionally BCI) can use up to 256 channels. I have never seen nor heard of a 512 channel EEG system or greater - I would imagine these would be rare, if they do exist.

Cheers,
John

From: Raj Mellacheruvu <[email protected]<mailto:[email protected]>>
Reply-To: "Discussion of EEG hardware, software, training protocols, NFB theory - for developers and users." <[email protected]<mailto:[email protected]>>
Date: Wed, 25 Feb 2015 22:38:52 +0000
To: John Ruelas <[email protected]<mailto:[email protected]>>, "[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>>
Subject: Re: [Openeeg-list] number of electrodes


Thanks John.

Appreciate the response.

If price were a non-issue, do you think there is value in having more electrodes? Arbitrarily picking a number here, say a thousand? (assuming we are able to physically place that many electrodes on the cranium). I'm wondering if the real limitation is our brain mapping knowledge. i.e., brain mapping granularity is very coarse at this point and we haven't mapped it to that many regions yet?

Thanks,
Raj


From: John Ruelas [mailto:[email protected]]
Sent: Wednesday, February 25, 2015 4:25 PM
To: Raj Mellacheruvu
Subject: RE: [Openeeg-list] number of electrodes

Price. Price will increase in an almost linear correlation with channel count.

Also, certain projects may only require, say, 24 channels, making the need for a 48 or 64 channel system overkill. For this reason, also, some EEG systems are stackable - i.e. one 24 channel system stacks on top of another and both systems integrate to form a 48 channel system. This way a researcher with the need for only 24 channels may purchase one board, those with a need for 48 channels can purchase two, etc...

Cheers,
John

P.S. There are many EEG systems that support more than 24 channels, they may be more difficult to find, and the price may be significantly higher than smaller systems.

-------- Original message --------
From: Raj Mellacheruvu
Date:02/25/2015 3:22 PM (GMT-06:00)
To: [email protected]<mailto:[email protected]>
Subject: [Openeeg-list] number of electrodes

Hello There,

I am new to this mailing list and not sure if my question is appropriate here.

Does anyone know why EEG systems have up to 24 electrodes and not more? what is the real limitation? Is it electronics?

Thanks,
Raj

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Dive into the World of Parallel Programming The Go Parallel Website, sponsored
by Intel and developed in partnership with Slashdot Media, is your hub for all
things parallel software development, from weekly thought leadership blogs to
news, videos, case studies, tutorials and more. Take a look and join the 
conversation now. http://goparallel.sourceforge.net/