Frequently Asked Questions

Full FAQ List by Topic

NeurOne EEG system (2)

Maybe.  There is no way the EEG system can harm the TMS system, but there are some TMS systems that are essentially useless with some EEG systems.  You need a a suitable combination of features in each to be successful at all in using TMS with EEG.

Desirable attributes:

  • Coils designed specifically for use with EEG will have a cable that exits the coil tangential to the head surface so that the coil does not pass close by EEG electrodes and cables.
  • A coil to be used with EEG should be passively cooled, since active cooling by means of a fan will induce electromagnetic interference in the EEG.
  • The TMS recharge mechanism should be designed to avoid inducing electromagnetic artifacts in the EEG.
  • The TMS system should be shielded so that no more than 3 milligauss of electromagnetic interference from the TMS system’s power supply reaches the electrodes and cables.
  • The TMS system should be able to produce a TMS pulse in response to an input trigger with a low and predictable latency.  Long, but especially unpredictable latency in responding to an input trigger will result in TMS artifacts that are difficult to impossible to remove from the EEG.

Aside from attributes of the TMS system, there are also important considerations regarding the EEG system in this relationship. See the other FAQ entry on that topic.

No.  There are a few special attributes that are required and others that are desirable.

Required attributes:

  • Inputs should be protected so that they are not damaged by the TMS pulse
  • Frequency response on all channels should be from DC on the low end, since AC coupled inputs will “ring” when presented with a large voltage transient like the TMS artifact

Desirable attributes:

  • Electrodes should have a low-profile so that the TMS coil can be placed as near the head as possible, maximizing penetration depth and current delivery
  • It is important for the EEG system to be able to trigger the TMS system at precisely the same phase with respect to the EEG samples each time a stimulus is delivered.  This will improve the performance of artifact removal algorithms

Aside from these attributes of the EEG system, there are also important considerations regarding the TMS system in this relationship. See the other FAQ entry on that topic.