Electrical noise - TMSMultiLab/TMSMultiLab GitHub Wiki

Do not use ~50Hz 'notch' filters! (Or use with caution.) The EMG signal and MEPs have a lot of information and energy in the ~25:250Hz range - you probably want to keep these frequencies. TMS will create large transients / artefacts / large MEPs - which can result in long 'ripple' effects in your data, produced by the MEP and filter interacting, which can affect measurement of the MEP.

If you have a lot of ~50-60Hz electrical noise in your data you can/should:

  1. Check your electrodes have not dried out or detached; secure electrodes & cables
  2. Check for loose cable connections
  3. Avoid coils & loops in the cables (or on your participant's body)
  4. Move your participant away from sources of electrical noise (power points, power packs, appliances...)
  5. Improve the skin preparation (cleaning, abrading)
  6. Improve the insulation or use twisted-pair cables
  7. Check whether shoes/clothing is producing static..?
  8. Avoid touching your participant and/or conducting electrical noise to their body