Recording EEG During Repetitive Trans-cranial Magnetic Stimulation

This paper discusses several issues related to recording EEG during repetitive trans-cranial magnetic stimulation (rTMS). The objective of recording EEG is to obtain magnetically evoked and event related potentials. The issue of electrode heating is discussed and experimental results presented that show graphite as well as fully notched or “C” silver, gold or silver-silver chloride are suitable for current rTMS protocols. Standard silver or gold cup electrodes may cause excessive scalp heating. Removal or reduction of the magnetically induced stimulus artefact is also discussed. A new system is presented that uses sample and hold circuitry to block most of the artefact allowing the researcher to record ipsiand contra-lateral evoked potentials occurring within the first few milliseconds of the magnetic stimulus.

[1]  John H. Krystal,et al.  Temporoparietal Transcranial Magnetic Stimulation for Auditory Hallucinations: Safety, Efficacy and Moderators in a Fifty Patient Sample , 2005, Biological Psychiatry.

[2]  M Hallett,et al.  The heating of metal electrodes during rapid-rate magnetic stimulation: a possible safety hazard. , 1992, Electroencephalography and clinical neurophysiology.

[3]  Giorgio Fuggetta,et al.  Modulation of cortical oscillatory activities induced by varying single-pulse transcranial magnetic stimulation intensity over the left primary motor area: A combined EEG and TMS study , 2005, NeuroImage.

[4]  Gregor Thut,et al.  A new device and protocol for combining TMS and online recordings of EEG and evoked potentials , 2005, Journal of Neuroscience Methods.

[5]  M. Archambeault,et al.  Development of an Electroencephalography Data Acquisition System for Clinical Research Into Transcranial Magnetic Stimulation Evoked Potentials , 2007, 2007 Canadian Conference on Electrical and Computer Engineering.

[6]  Sauli Savolainen,et al.  Ipsi- and contralateral EEG reactions to transcranial magnetic stimulation , 2002, Clinical Neurophysiology.

[7]  P. Fitzgerald,et al.  Transcranial magnetic stimulation in the treatment of depression: a double-blind, placebo-controlled trial. , 2003, Archives of general psychiatry.

[8]  E. Wassermann.  Variation in the response to transcranial magnetic brain stimulation in the general population , 2002, Clinical Neurophysiology.

[9]  Risto J. Ilmoniemi,et al.  Prefrontal TMS produces smaller EEG responses than motor-cortex TMS: implications for rTMS treatment in depression , 2005, Psychopharmacology.

[10]  R. J. Ilmoniemi,et al.  Instrumentation for the measurement of electric brain responses to transcranial magnetic stimulation , 1999, Medical & Biological Engineering & Computing.

[11]  Gregor Thut,et al.  Electroencephalographic recording during transcranial magnetic stimulation in humans and animals , 2006, Clinical Neurophysiology.

[12]  W. W. Hartsfield.  Instrumentation for the C-130 Static Test , 1958 .