Biosignal

The usual understanding is to refer only to time-varying signals, although spatial parameter variations (e.g. the nucleotide sequence determining the genetic code) are sometimes subsumed as well.

Thus, among the best-known bioelectrical signals are: EEG, ECG, EOG and EMG are measured with a differential amplifier which registers the difference between two electrodes attached to the skin.

However, the galvanic skin response measures electrical resistance and the Magnetoencephalography (MEG) measures the magnetic field induced by electrical currents (electroencephalogram) of the brain.

Research and practice in the field go back decades in various forms[8][9] and have lately been enjoying a resurgence, thanks to the increasing availability of more affordable and less cumbersome technologies.

[10] An entire issue of eContact!, published by the Canadian Electroacoustic Community in July 2012, was dedicated to this subject, with contributions from the key figures in the domain.