[Eeglablist] EEG Amplifier responses

Mon Dec 18 11:53:05 PST 2006

I placed a request for information regarding EEG amplifiers a couple
weeks ago...I want to thank everyone for their responses.  I have
compiled the responses and am sending it to the list in case there are
others out there with the same questions.  Again thanks for the
responses,

Jamie

Hi all -

I am looking into buying an EEG system for research looking at cortical
activity associated with motor behavior.  I'd love to find a system that
would allow me to collect EEG, and both surface and intramuscular EMG.
It should also allow for synchronization to other behavioral system
(force and position trackers).  I have had some experience with
Neuroscan (about 4 years ago) and had some issues with it.  I was
wondering what systems are being used out there and whether I could get
some pros and cons about them.

Thanks

Jamie

Dear Jamie,

I was informed that you are looking for a biosignal amplifier to measure
EMG and EEG activity together with position and behavioral data. My
company g.tec medical engineering, located in Austria, has equipment
which runs under MATLAB and Simulink. Therefore it is quite easy to
integrate other devices. I will be happy to send you further information
and to discuss with you the application of the devices.

Best regards

Christoph

Dear Jamie,

I monitor EEGlablist server and I saw your query on EEG amplifiers. I
work with Electrical Geodesics, Inc. (EGI), and we are a world leader in
manufacturing Dense Array EEG Systems. You can visit us at www.egi.com
<http://www.egi.com/> 

For your immediate review, I attach our product flyer for the new
Geodesic EEG System 300, which can be configured for 32, 64, 128 and 256
channels of EEG. EGI's patented HydroCel Geodesic Sensor Nets allow you
to record 128 channels in less than 5 minutes. There is no scalp
abrasion or gel application! 

In your email, you also mention that you would like to record other
physiological measures apart from EEGs. May I ask if you would be using
EEGlab to analyze your non-EEG data? Also, how many channels of EEG v/s
non-EEG you wish to record?

Currently our Net Station software (acquisition and analysis software)
can not handle non-EEG channels; however, if you are using some other
software then you can export raw data from our software to say, Matlab
and other softwares.

By the way, do you know people from Kinesiology Department at University
of Georgia? I ask this because they are using EGI's 256 channel system
and have come up with some interesting data.

Best regards,

Viral

Jamie,

 We have a system from Sensorium http://www.sensoriuminc.com/ and works
perfect, we use it to run EEG and EMG (surface) simultaneously with out
any issue.

 Let me know if you need anything else.

 Rafael Escobedo

Hi, Jamie.  BioSemi's ActiveTwo system can be equipped with EEG, sEMG
and buffered inputs with spring contacts for intramuscular fine wire
electrodes.  The acquisition software is open-source LabVIEW and the
data file format (BDF, a 24-bit version of EDF) is supported by EEGLAB /
BIOSIG.  My company sells and supports ActiveTwo in the US and Canada.
I can provide a list of the pros for ActiveTwo and cons for other
brands, but I should probably do that off-line.  Let me know if you are
interested to know more.

Best regards,

Lloyd Smith

Neuroscan SynAmps 1 works fine for me, since it can easily do 20kHz
sampling rate and the data format is easily accessible. The SynAmps2
might even have some advantages (channel number, s/n ratio, active noise
cancellation). The SynAmps2 does not supply analog output though.

If you need something cheaper, you could also go for BrainVision, a
German product.

Best,

Johannes

Dear Jamie, receiving the EEGlab digest I have found your
question...Well: no, at the moment I have no answer and I am very busy
with other problems, but as I asked myself the same question you wrote
about, few years ago, I am sending you this e-mail. For many years I
have been a professional dancer and at the end of the last...millennium
I began again to look at the connections between dance & newtech (I
wrote an eight-pages article for the First Monaco Forum, in 2000...for
the Forum: see an example here:
http://portal.unesco.org/culture/fr/ev.php-URL_ID=32305&URL_DO=DO_TOPIC&
URL_SECTION=201.html )...and I asked mysel some questions you probably
are asking yourself! Next year, if possible, I will go on with a little
project concerning "trance" and movement, may be using EEGlab...If I
will have any news concerning your needings I will send some news!
Best wishes for your researches!
Giorgio

Hi,

What are the "hard" criteria for you ,like number of channels, sampling
rate?

Be sure to have a look at Brainproducts. Amplifiers are modular
(Brainamp) 32 ch. Referential or 8 bipolar or 8bipolar + 8 Aux/sensor,
16 bit ttl trigger input etc. Specially for research. Website
http://www.brainproducts.com <http://www.brainproducts.com/>  

Regards,

Harm-jan

Hello Jamie, 

look at Biosemi site. They have "active" electrodes which preamplify the
EEG signal on scalp and reduce noise. They have 8 EMG channels and 3
additional inputs for measuring other variables, like position trackers
(inputs have power supply). There is also the Advanced Neural Technology
system which comes with a software for various signal processing. It is
convenient for combination with TCM. It has a shielding of each
electrode so 50 Hz is suppressed. Biosemi can have up to 256 electrodes
and the other system can have at least 128 electrodes.

However none of the systems has a hardware manual....but  I think that
both have representatives in the USA. ANT promises to come and teach you
how to use the system. Biosemi have a good customer support on the phone
and email.

We have Biosemi and use EEG and EMG. It works fine but I had to program
myself a protocol (in C) for sending markers that were event driven (I
work on BCI). You need the LabView to make your additional software for
it, especially if you want to run it in on-line experiments. My
colleagues are working on the on-line data collection and further
processing in Matlab using C instead.

Hope this help,

Greetings,

Dr Aleksandra Vuckovic

In our lab we use both neuroscan and biosemi.  Biosemi is newer to us,
and in terms of time to set up the cap, it is much faster and we get
lots of decent quality data.  However, our lack of experience with it
makes troubleshooting sometimes difficult, and the electrodes themselves
are a bit fragile.  However, if you are using it exclusively or training
everyone who uses it, you shouldn't have too much to worry about.  And,
having my  head scraped with all different sorts of caps, I can say that
the biosemi cap is the most comfortable and requires the least abrasion.

enjoy the hunt!
Brian

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