Two fundamental issues underpin the rational integration of tDCS and EEG: mechanical compatibility and electrical compatibility.
Electrical compatibility with optimized stimulator and rational experimental design. It is not prudent to assume that simple high-pass filtering of the EEG signal will remove confounds from EEG recording. Especially given that DC artifact may be non-stationary due to unknown electrode impedance changes during stimulation and that EEG amplifier active electronics can induce non-linear distortion, Soterix Medical biomedical engineers have developed protocols to implement and validate EEG+tDCS compatibility. It is not prudent to ignore noise that is not measured under the assumption is it not an experimental confound. Note that conventional experimental control arms, such as using sham stimulation or a control-montage, will not in themselves control for EEG+tDCS distortion precisely because the stimulation has been changed (e.g. only the active arm will experience artifact). Soterix Medical’s unmatched technical support is ready to guide you through a straightforward validation process that allows you to use your EEG system of choice.
Noise Comparision between SMI device and Other Commercial Devices
Insertion of large sponge electrodes under an EEG cap will not only block the access of EEG electrodes precisely in the area of interest, but also ejection of fluid from the sponges will shunt neighboring EEG electrodes. Soterix Medical offers a simple and unique solution to tDCS+EEG through the use of High-Definition (HD) tDCS electrodes. Compact in size and gel-based, with validated tolerability, HD electrodes can be inserted between EEG electrodes without compromising mechanical compatibility.
HD electrodes are compatible with any Soterix Medical tDCS or HD-tDCS stimulator. Moreover, Soterix Medical provides HD electrode holders for integration with any commercial EEG headgear including Brain Products (HD1-BP) and Biosemi (HD1-BS). HD-tDCS electrode models are designed to fit existing EEG system adaptor and are the only electrodes validated in multiple clinical trials to produce tolerated stimulation.
WARNING: HD electrodes were developed at The City College of New York and Soterix Medical to allow safe and tolerated DC stimulation. Soterix Medical can no longer provide technical or equipment support for the use of non-validated “small” electrode designs.
Soterix Medical Inc. is proud to announce a partnership with Brain Vision LLC to provide a completely integrated HD-tDCS+EEG. This provides you with unparalleled technical support and integration with a partnership that remains the industry standard for concurrent stimulation and recording.
Soterix Medical HD-tDCS and Brain Products EEG systems are used when the highest standard in precision and signal fidelity are required. Don't compromise with a hybrid system with neither quality stimulation nor sufficient electrode density. With Soterix+Brain Products you get the only validated HD-tDCS hardware, integrated Neurotargeting support, embedded seamlessly with EEG. Our joint technical support team can develop an optimal solution around the equipment you have, or quote a single integrated system. Whatever the application, Soterix+Brain Products ensures immediate productivity and validated quality and safety.
Soterix Medical engineers worked with ANT-Neuro to develop a fully integrated HD-tDCS and EEG system. Featuring fully inter-digitted, all embedded electrode holders, the easy-to-use head-gear allows research grade stimulation and recording. Each cap come pre-loaded with embedded HD-Cups allowing tremendous flexibility in the number and position of HD-Stimulation electrodes desired.
The fully-integrated cap is unique in having all positions pre-loaded as opposed to custom loading of HD insets only in locations of interest. For combining tDCS with any EEG system, contact Soterix Medical professional support for application details.
Configuration lay-out showing fully interlaced HD-tDCS with 10-20 EEG.
Full integrated Soterix Medical and ANT-Neuro cap for HD-tDCS plus EEG
Soterix Medical Inc. and Biosemi Instrumentation are both companies founded by engineers and physicists to advance medical science. With Soterix Medical and Biosemi there is no need to compromise on stimulation or recording as a full electrode compliment is needed for state-of-the-art research. Use the data analysis software you know and trust while leveraging the Soterix Medical + Biosemi integrated platform. For the most advanced and automatic clinical imaging of brain disorders Soterix Medical Inc. and Elminda have formed a partnership providing on-site installation, hands-on training (with the HD-tDCS/Biosemi system), and ongoing data analysis support.
If you are familiar with Biosemi Active2 EEG system then Soterix Medical HD-tDCS can be directly integrated with your existing system. Three models of HD-BSM electrodes are available 1) HD-BSM Mini-stim, the smallest form factor HD electrodes ever designed; 2) The standard HD-BSM Macro-1 which allows EEG and tDCS from the same location; 3) HD-BSM Macro-2 which balances increased size with enhanced tolerability for prolonged clinical trials.