HD-tES + EEG

Soterix Medical state of the art HD-tES systems can be integrated with the most trusted research grade EEG systems

Two fundamental issues underpin the rational integration of tDCS and EEG: mechanical compatibility and electrical compatibility.

Electrical Compatibility with HD-tDCS:

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 artifacts 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 that it is 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 Comparison between SMI device and Other Commercial Devices

Mechanical compatibility with HD-tDCS:

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/tES or HD-tDCS/HD-tES stimulator. Moreover, Soterix Medical provides HD electrode holders for integration with any research-grade EEG headgear including ANT Neuro, Brain Products, Biosemi, mbt, Neuroscan, Wearable Sensing and several others. HD-tDCS electrode models are designed to fit existing EEG system adaptors and are the only electrodes validated in multiple clinical trials to produce tolerated stimulation.

WARNING: HD electrodes were developed by Soterix Medical to enable safe and well-tolerated HD-tES. Soterix Medical cannot provide technical or equipment support for the use of non-validated "small" electrode designs.

SMI Device Integration Support More on HD - tDCS

Soterix tDCS⁺ Brain Products EEG

Soterix Medical Inc. is proud to announce a partnership with Brain Products 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 a validated HD-tDCS hardware, integrated Neurotargeting support, embedded seamlessly with EEG. Our joint technical support teams can develop an optimal solution around the equipment you have. Whatever the application, Soterix Medical+Brain Products ensures immediate productivity and validated quality and safety.


Compatible EEG System/Caps: actiCAP slim, actiCAP SNAP, actiCAP Xpress, BrainCap, actiCAP Xpress Twist, and BrainCap MR.

Compatible Stimulation Modality: All Soterix Medical Bench-top tDCS and HD-tES devices plus the Hand-held mini-CT stimulators.

Soterix Medical⁺ Wearable Sensing EEG

Soterix Medical and WEARABLE Sensing collaborate to provide a complete solution for HD-tES and Dry EEG. The integration options are available for DSI 7 and DSI 24 systems.



Any of the recording electrodes from the DSI 7 and DSI 24 can be swapped out by the user with our dedicated stimulation holders made for Wearable Sensing EEG systems.

Soterix Medical⁺ mBrainTrain EEG

Soterix Medical stimulation and mBrainTrain wireless EEG systems can be combined for sleep and awake experiments to acquire research-grade EEG data while providing optimized HD-tES.



Soterix Medical HD Holders can be inserted at any location inside the mBrainTrain EEG cap. Custom Hybrid holders are also available that allow stimulation and recording from the same location.

Soterix tDCS⁺ ANT-Neuro EEG

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.


Fully integrated Soterix Medical and ANT-Neuro cap for HD-tDCS plus EEG.

Soterix-ANT cap layout with 32 recording EEG electrodes (white) in combination with 29 HD-tDCS electrodes (gold over turquoise) in an exemplary 4 x 1 montage consisting of one center cathode (blue) and four anodes (red) over an F3 target (black).

Soterix Medical+ Soterix tDCS⁺ Biosemi

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.

If you are familiar with the 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) Soterix Medical HD BioSemi Hybrid Electrode Holder, which allows EEG and tDCS from the same location.
3) The standard Soterix Medical HD1 Electrode Holder for dedicated stimulation.

Integrate HD-tDCS electrodes (HD-BSM Mini-stim model) with any EEG system. HD electrodes indicated with arrow.


Soterix Medical HD BioSemi Hybrid Electrode Holders allow tolerated stimulation and monitoring from the same location.

Caution! Investigational Device. Federal (or United States) law limits device to investigational use.