Coming soon: R-Net MR – a sponge-based electrode system for simultaneous EEG-fMRI
by Dr. Tracy Warbrick
Application Specialist EEG-fMRI (Brain Products)
You may not be surprised to learn that we have been working on a sponge-based electrode system for simultaneous EEG-fMRI and we are delighted to announce that our R-Net MR will be available soon.
The R-Net MR is based on the same principles as the regular R-Net. It consists of saltwater sponges and passive Ag/AgCl electrodes housed in a durable and flexible silicone structure. The MR version of the R-Net also has current limiting resistors for safe recordings in the MRI environment and a gel-based ECG electrode.
R-Net MR 128 channel system (left) and R-Net MR sponge-based electrode (right)
The R-Net MR will be available in configurations of 32, 64, 96, and 128 channels. It will initially be available in four adult sizes with children’s sizes to follow later. The R-Net MR will be available for the BrainAmp MR (plus) and can be used in scanners up to 3T. Its use is subject to our general 3T EEG-fMRI safety guidelines.
This is exciting news, but let’s cover a few key points on ‘R-Net MR vs. BrainCap MR’
Sponge-based electrode systems allow for quick preparation and for some EEG applications a fast gel-free preparation is essential, for example, in some clinical populations. In contrast, gel-based electrodes take longer to prepare but they are the most popular choice for EEG recordings, and for EEG-fMRI most of the published literature uses gel-based electrodes. The gel reduces the contact impedance between the skin and electrode, allowing for a higher quality signal to be recorded. The sponge-based electrode system does not offer the same contact between skin and electrode that a gel-based electrode allows.
This is an important factor when choosing between a sponge-based system or a gel-based system in a challenging recording environment like an MRI scanner. Consequently, you should consider which factors are most important for your research. If a speedy preparation time is critical then the R-Net MR is for you. On the other hand, if you can afford the preparation time associated with gel-based electrodes, you will reach lower impedances and record EEG data with a better signal to noise ratio with the BrainCap MR.
By offering the R-Net MR in addition to the BrainCap MR we are providing the flexibility to choose the right solution for your research needs. Importantly, we are also here to provide advice on which of our EEG-fMRI solutions is the best one for you.
As with all our products, we like to test them thoroughly and be able to make the most appropriate recommendations for our customers. We were in the final stages of data quality testing when the current global health situation arose. Therefore, we ask for your patience while we wait for the situation to improve so that we can continue our measurements without risk to us, our volunteers, or our cooperation partners. In the meantime, we are happy to discuss your research needs and whether the R-Net MR is a good solution for you.