[Eeglablist] responses to "Time to apply 128 electrodes"
Joseph Dien
jdien at tulane.edu
Wed Jun 11 15:16:26 PDT 2003
I've used both EGI nets and a 94-channel standard electrocap. The
128-channel EGI nets takes me no more than 20 minutes to apply and
adjust. The 94-channel system took me about 90 minutes, which was in
line with experienced hands in the lab. In my opinion, the long
application time had bad effects on subject alertness and subsequent
alpha levels. I think it's better to go for a quick application than
an ultra-high quality application that takes so long you lose the
subject. I haven't had any experience with quick application
electrocaps or pastes.
Cheers!
Joe
On Wednesday, June 11, 2003, at 04:43 PM, Jim Kroger wrote:
> When I posted this request I must have used "reply to all" as the
> responses came to me instead of the list. I've compiled them here for
> interested readers and archival purposes. Thanks for the responses,
> and apologies if I omitted any response.
> ----------------------------------------------------------------------
> --------------------
> From: "Li Yong" <liyong98 at mails.tsinghua.edu.cn>
>
> It is very easy to place electrodes in the EEG system of biosemi
> company.
> It takes me only about no more than half an hour to fix all 128
> electrodes.
> The neuroscan systme may be difficult to fix electrodes.
> ----------------------------------------------------------------------
> --------------------
> From: "Li Yong" <liyong98 at mails.tsinghua.edu.cn>
>
> I always do the experiment alone.
> In the neuroscan system, the electrodes and wires are both in the cap,
> you had to arrange the cap while applying electrode gel .Because no
> electrodes or wires are attached to the cap of the biosemi system, the
> only thing need to do is separating the hair when electrode gel is
> applied. And the active electrodes make it no use to detect the
> residence below 50 K ohm. So the preparation time for experiment is
> reduced. You can get more details in the www.biosemi.com.
>
> The more electrodes the better. In the 128 system, there is also much
> difference between the EEG recorded from neighbor electrodes on the
> scalp.
> The average inter-electrode distance of 128 system is about 2.25 cm,
> and that of 64 system is about 3.3 cm. EEG system with the distance
> between electrodes averaging less than 2.5 cm can provide sufficient
> topography [1].
>
>
> [1] A. Gevins, et al. High resolution EEG: 124-channel recording
> spatial deblurring and MRI integration methods. Electroenceph. Clin.
> Neurophysiol., 1994, 90: 337~358.
> ----------------------------------------------------------------------
> --------------------
> From: "Joe McArdle \(NIDCD\)" <mcardle at nidcd.nih.gov>
>
> Hi Jim, it takes a long time. I beta tested the 128 system and with 2
> other
> people helping me it took well over an hour to get decent impedance
> values.
> I use a 64 channel quick cap now and it takes about 40 minutes if I
> work
> alone. I've used EGI caps and Neuroscan quickcaps. I like the quickcap
> better. Also the newly reformulated quickgel works great, and does not
> require prepping the electrodes.
>
> You know, there is a Neuroscan list similar to this one. You should
> join it
> and ask your question there. You will probably get lots of helpful
> advice. I
> always have when I've asked.
>
> Best of luck,, Joe
> ----------------------------------------------------------------------
> --------------------
> From: "Maurits, NM" <n.m.maurits at neuro.azg.nl>
>
> Dear Jim,
>
> We have a 128-channel system where we use ElectroCap head caps. It
> takes an experienced technician 20-30 minutes to apply all electrodes
> using a syringe and a blunt needle. We use a mixture of 50% normal
> paste and 50% scrub paste. We aim at getting all impedances below 20
> kOhm, but in practice most are between 3-10 kOhm. We have a TMS
> headbox (Dutch company) and measure using Onyx software (also Dutch).
> Hope this helps.
>
> Best regards,
> Natasha Maurits.
> ----------------------------------------------------------------------
> --------------------
> From: M D <astramia at yahoo.com>
>
> Hi Jim
>
> We just ran an experiment with 24 participants. The 128 electrode cap
> took approx 40 minutes to one hour to apply to a participants head
> depending on our ability to get impedances down. We also ran approx 8
> other physiological measures, but I am trying to give you an estimate
> of about how much time the 128 lead cap took.
> I had help from Jeremy who is experienced in these matters and he made
> all the difference in the world as he was able to get impedances down
> pretty fast so it may take longer for someone who is not experienced
> at getting impedances down.
>
> Margery Doyle at <mailto:mdoyl at ai.uwf.edu>mdoyl at ai.uwf.edu
> Jeremy Higgins <mailto:jhiggins at ai.uwf.edu>jhiggins at ai.uwf.edu
> ----------------------------------------------------------------------
> --------------------
> From: M D <astramia at yahoo.com>
>
> Hi
> We were using a NeuroScan with an Electro Cap International 128 lead
> cap system and we did have two people working on one participant at a
> time. However, Jeremy did do most of the impeadance work. I helped put
> electrode gel in the holes and put all the other psychophysiological
> electrodes on the participant.
> Hope that additional information helps
> Margery Doyle UWF IHMC
> ----------------------------------------------------------------------
> --------------------
> From: "Dykman, Roscoe A" <DykmanRoscoeA at uams.edu>
>
> It takes no longer than-10-15 minutes in babies. Ross Dykman
> ----------------------------------------------------------------------
> --------------------
> From: Darren Weber <Darren.Weber at flinders.edu.au>
>
> Hi Jim,
>
> I allow 2 hours. It can be quicker, but I've found it better to allow
> the extra time, in case some electrodes are difficult. Also, dont
> forget about quick insert electrodes. Impedance testing is important,
> but sometimes I have to settle for < 10 kOhms rather than 5 kOhms on
> all electrodes.
> There are some differences between caps and gels etc., but it's too
> hard to discuss this here. I've mainly used ECI electro-caps (tin).
>
> Best regards, Darren
> ----------------------------------------------------------------------
> --------------------
> From: Theresa Vaughan <vaughan at wadsworth.org>
>
> Hi Jim,
>
> Seems like a long time. We use a 64-channel Electrocap. It takes
> about 15 minutes. I have never done one with 128 channels but I think
> that the additional channels would add too much time.
>
> Theresa
>
>
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------------------------------------------------------------------------
--------
Joseph Dien
Assistant Professor of Psychology
Department of Psychology
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Tulane University
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Office: Room 3061
Phone: (504) 862-3300
Fax: (504) 862-8744
E-mail:jdien at tulane.edu
www: http://www.tulane.edu/~jdien/Dien.html
Starting Fall 2003:
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