[High resolution EEG and whole head MEG].
A low-noise multichannel EEG-Amplifier-System has been designed and analyzed, which is electromagnetically compatible with SQUIDs. The EEG- together with the MEG-System is operated inside the quiet environment of a magnetically shielded room, hence no electrical 50 Hz-Artifact is detectable. Measurements pointed out that the influence of amplifier- and electrochemical-noise of electrodes to averaged EEG-spectral densities is less than 1% within the frequency range 0.5 to 70 Hz. Thermal noise of the skin-electrode-interface, equivalent to a resistor of 30 k omega, only begins to take effect above 20 Hz, suggesting that there is no need of skin abrasion.
Scheer
H J
HJ
Physikalisch-Technische Bundesanstalt, Berlin. Hans-Juergen.Scheer@ptb.de
Burghoff
M
M
D000513:Alpha Rhythm; D000669:Amplifiers, Electronic; D016477:Artifacts; D004566:Electrodes; D004569:Electroencephalography / Q000295:instrumentation*; D004867:Equipment Design; D005583:Fourier Analysis; D006801:Humans; D015225:Magnetoencephalography / Q000295:instrumentation*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D014584:User-Computer Interface