The NEURO PRAX® TMS/tES* is a full-band DC-EEG system, which is primarily intended for use in neuroscientific applications. The system measures physiological signals such as EEG, EMG and EP in the frequency range of 0 to 1,200 Hz simultaneously and synchronously for all channels. The unique amplifier technology captures EEG activities from infraslow (0 – 0.3 Hz) to ultrafast (80 – 1,200 Hz) frequencies.

The high amplifier dynamics and the high sampling rate make the NEURO PRAX® TMS/tES* system particularly suitable for EEG measurement during transcranial magnetic stimulation and transcranial electrical stimulation with direct current (tDCS), alternating current (tACS) and random noise current (tRNS).

We can supply our high-performance full-band DC amplifiers with 32, 46 or 128 channels. The neuroConn software, specially tailored to the hardware, is intuitive, flexible and easy to use. There are a large number of software-based functions available, such as online the online correction on artifacts caused by eye and muscle movements, topographical analyses, spectral and amplitude mapping and online averaging.

Combining non-invasive brain stimulation with neuroimaging

Simultaneous recording of DC- EEG during non-invasive brain stimulation (NIBS), such as transcranial direct current stimulation (tDCS), transcranial alternating current stimulation (tACS, tRNS) or transcranial magnetic stimulation (TMS) is a painless method to evaluate the modulation of cortical oscillatory brain activity and cerebral plasticity. These methodologies allow neuroscientists to investigate a broad range of research topics, such as:

  • establishing a causal link between brain functions and behavior
  • understanding the online mechanisms of brain stimulation
  • assessing how non-invasive brain stimulation locally affects neural processing by means of objective measures of cortical activity, reactivity, and connectivity
  • determining in vivo the brain areas directly or indirectly affected by non-invasive brain stimulation
  • improving stimulation protocols based on direct effects to brain activity

The neuroConn DC-STIMULATOR PLUS* and NEURO PRAX® TMS/tES* work hand in hand to provide noisefree EEG while stimulating the brain with tDCS and even with tACS. The DC-STIMULATOR PLUS delivers a galvanically isolated reference signal of the applied stimulation, whilst NEURO PRAX® eliminates the stimulation-induced artefacts from all EEG channels in real time using an innovative correction software. The high dynamic range of 219 mV allows to record brain signals during tES without the EEG-amplifier going into saturation.

A worldwide unique solution for neuroscientists: The DC-STIMULATOR PLUS combined with the NEURO PRAX® TMS/tES* provide artifact-free EEG-tACS.

Noise-free EEG during tES: The worldwide unique neuroCare solution

Why combine EEG with tES (tDCS, tACS, tRNS)?

  • tES-EEG for functional neuroimaging in science and clinic
  • detailed understanding of tES-induced effects in motor and non-motor regions
  • detailed understanding of local and network effects of tES
  • discover brain-behavior relationships
  • guiding tES input parameters by monitoring brain states

NEURO PRAX® TMS/tES*: short recovery times of 3 - 5 ms after the TMS pulse allow correction of TMS-induced artefacts in realtime for all channels

Simultaneous EEG with TMS, even in combination with neuronavigation

Why combine EEG with TMS?

  • TMS-EEG for functional neuroimaging
  • better insights into cortico-cortical and interhemispheric interactions
  • detailed understanding of local and network effects of tES
  • more direct assessment of cortical inhibitory processes
  • deeper understanding of cortical plasticity
  • prospects of clinical applications


The combination of NEURO PRAX® TMS/tES* and the DC-STIMULATOR PLUS* with the option Signal Out now allows to measure a noise-free EEG during the stimulation with alternating or random noise current.

NEURO PRAX® TMS/tES* uses an integrated innovative correction software to eliminate the stimulation-induced noise from the EEG signals. Click on the picture for more detailed information.

Areas of Application

  • Recording and analysis of cortical and sub-cortical TMS-EEG activity
  • Investigation of functional connectivity between areas of the brain
  • Investigation of TMS-induced modulation of brain rhythms
  • EEG-triggered TMS/tES stimulation
  • Quantitative EEG analysis and cognitive evoked potentials before, during and after treatment with transcranial stimulation (tDCS-EEG, tACS-EEG, tRNS-EEG)
  • Investigations into the safety of transcranial stimulation
  • MEP-threshold detection and MEP-brain mapping
  • NEURO PRAX® TMS has exclusively a direct data transfer option to BRAINSIGHT® for displaying artifact corrected TMS-EEG data during TMS navigation
  • Neuro- and biofeedback


  • Brochure
  • neuroConn product portfolio for NIBS-EEG

  • Poster
  • Closed-loop application and artefact correction for tACS-EEG

  • Poster
  • Closed-loop apparatus for brain state-dependent tES: a proof of principle based on SMR

  • Poster
  • Overview of hardware artefacts during simultaneous tES and EEG

  • Poster
  • A Method for Online Correction of Artifacts in EEG signals during Transcranial Electrical Stimulation

Interpreting the Results

The first screen of the report shows the visit notes that were entered prior to the test. The second screen shows the patient identifier, the date of the test and a summary of the test results, which are described further below.

The third screen of the report shows a plot of the patient’s Eyes-Open and Eyes-Closed phybrata power aligned to their age, against the backdrop of a graph of the average power of healthy individuals across a range of ages. This chart allows the patient and their caregiver to see how the results from the current test relate to the average of healthy people the same age.

Three phybrata measures are derived from the raw sensor data:

  • Phybrata Power
  • Eyes-Closed/Eyes-Open Phybrata Power Ratio (EC/EO Ratio)
  • Left/Right Phybrata Power Ratio (L/R Asymmetry)

The Phybrata Power and L/R Asymmetry are present for both the Eyes-Open and Eyes-Closed tests. Each measure is compared to a normative threshold (0.5 for Eyes-Open, 0.6 for Eyes-Closed), above which the patient’s result is flagged for further assessment. For quick identification, results below the threshold appear in green and results above the threshold appear in red.

The Phybrata Power represents the aggregate power (in Watts) of the movement of the body measured at the head. A higher than threshold Phybrata Power indicates a potential neurological impairment that should be investigated further.

The Left/Right Ratio measures any asymmetry present in the patient’s phybrata measurement. An asymmetry of zero indicates that the patient is centered. An asymmetry less than or above zero indicates that the patient leans preferentially to either the left or right side, respectively. Favoring one side beyond the normative threshold (+/- 0.5) indicates a potential orthopedic impairment that should be investigated further.

  • PValues < -0.5 indicate a lean to the left beyond the normative threshold, indicative of a potential right leg injury.
  • Values > 0.5 indicate a lean to the right beyond the normative threshold, indicative of a potential left side injury.

The Eyes-Closed/Eyes-Open Ratio quantifies vestibular performance. An EC/EO Ratio above the normative threshold (2.0) means the Phybrata Power is much higher with the eyes closed, indicating a potential vestibular impairment that should be investigated further.

Sample of good phybrata data

Sample of bad phybrata data


Items marked with* are investigational devices and for research use only. CAUTION - Investigational Device. Limited by Federal (or United States) law to investigational use.