| We purchased a new BioSemi this year (with a modified design allowing it to be used simultaneously with MEG, i.e., without active electrodes). Our experience has been uniformly positive, with quick & easy gel application, and working right off the bat with our non-BioSemi real-time EEG software (because they use open standards).
I’ll add a shout-out to the BioSemi USA representative, Lloyd Smith of Cortech solutions, who has been a fantastic resource throughout the process.
Jonathan --
Jonathan Z. Simon (he/him) University of Maryland
Dept. of Electrical & Computer Engineering / Dept. of Biology / Institute for Systems Research
8223 Paint Branch Dr.
College Park, MD 20742 USA
Office: 1-301-405-3645, Lab: 1-301-405-9604, Fax: 1-301-314-9281
Dear Carlos, and list members: Carlos, keep in mind that in the Biosemi ActiveTwo system a not-so-widely-known problem exists, of the signal being contaminated by the dithering process in the Sigma-Delta ADC box, at frequency-multiples related to the sampling rate. This problem disturbs mainly if you are interested in spectrum analysis at higher frequencies, as for examples in studies of the Frequency Following Response (FFR), where presentation of the stimulus in alternate polarities leads you to look for a response at double the stimulus frequency. Because of the 1/f decrement, mechanical 'side-effects' infiltrating the signal, unremovable, are more and more disturbing. the higher your frequency region of interest. Biosemi intends to implement a whole different technology in their next model (ActiveThree?), which would eliminate this problem, but I have not seen it on their site yet. This problem may not disturb some kinds of analysis, but you may want to consider it. Good luck with your new lab! Sincerely, Amos Boasson I cannot recommend strongly enough AGAINST the EGI setup. I had inherited one of their systems. It was terribly buggy. Lost parts of the signal. Lost triggers. My PhD student lost many months trying to debug the device or find work-arounds. Their customer service was unresponsive. It was simply terrible. What rescued my student was that we were able to get an ANT EEGo system from a friend, which perhaps hasn't the greatest S/N but it was quite adequate, and at least it was relatively straight-forward to get to work as advertised and we got some nice studies done with it. ANT now also offer a sponge cap for their EEGo system which can reduce prep time. We ordered one but we haven't received it yet so I can't tell you whether the S/N is adequate. Under absolutely no circumstances would I ever again waste a single dollar or minute of my time on anything EGI.
Best wishes,
Jan
--------------------------------------- Prof Jan Schnupp
City University of Hong Kong
Dept. of Neuroscience
Dear Carlos,
I have used neuroscan a little and EGI a lot, but I do prefer Biosemi. The system is more simple and modular than EGI. I have done about 250 recordings with 4-6 year olds in pre-schools using Biosemi. While I do think it is possible to have good
signal in EGI, it is easier to troubleshoot bad signals in Biosemi, usually a single or a few bad electrodes that can be fixed with more gel. In EGI problems are often more vague and indirect. If you use Biosemi 64 channels with children, time of application
can be an issue. Two well trained assistants could do it in 15-20 minutes, but is is still an issue. Depending on your research question 32 channels could be good enough and considerably faster.
Customer support is fast but brief with Biosemi, and a lot of times I have solved things based on forum discussions rather than direct support, I am still more satisfied with support from Biosemi compared to EGI. Biosemi is more to the point and
technical, whereas EGI has a slow and somewhat bureaucratic support.
Signal quality should be better with Biosemi active electrodes compared to EGI, but I have actually not tested this thoroughly. When I have looked at amplitudes of MMN responses the effects have been quite similar between EGI and Biosemi. I was
surprised by this but it could be a larger difference in paradigms with fewer events.
Best wishes!
/Petter Kallioinen, EEG technician at linguistics dept, Stockholm University
Dear Auditory List,
I am planning on purchasing an EEG system for my new lab at UW-Madison, USA. I have been in contact with several EEG providers, and I’m still undecisive on which system would be best for my lab. I’m familiar with Neuroscan
and EGI, but I’m actually leaning towards Biosemi or Brain Products (Brain and Vision in the US). I run simple auditory paradigms with children (ages 3 to 14) and adults. The main characteristics that I’m looking for are (not necessarily in order):
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Ease of use
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Prep cap time (important to minimize with children)
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Customer support
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Signal quality
I’m shooting for a 64-channel system. Also, I’m still hesitating between saline caps or gel caps. I heard that the Biosemi caps despite of being gel based are very fast to get going.
Anyway, I’m just looking for some advice from any of you working with these systems. Any experiences or recommendations will help!
Thank you in advance for your taking your time to reply!
Sincerely,
Carlos
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