Surface electromyographic electrode assembly

An electrode assembly for use on a surface of biological tissue to measure bio-electric signals thereof, said electrode assembly comprising:

• an electrode apparatus having an electrode device adapted to directly contact the surface of the biological tissue to receive and transmit original bio-electric signals sensed from the biological tissue having an original first voltage and an original minute first current;
• a shielded signal transmission line having a signal transmission conductor electrically coupled at one portion to the electrode device for transmission of said bio-electric signals, and a shield conductor electrically coupled to the electrode apparatus and arranged to substantially shield the transmission line from ambient electric fields generated from sources external to said transmission line;
• a high impedance amplifier device having a signal input and a signal output, said signal input being electrically coupled to another portion of the signal transmission conductor for receipt of the transmitted bio-electric signals, said signal output being electrically coupled to the shield conductor, in a feedback loop, for receipt of at least a portion of the transmitted bio-electric signals, such that the voltage of the signals at said signal input of the high impedance amplifier device is maintained substantially equal to the voltage of the signals output from said signal output thereof.

An electromyographic surface electrode assembly for use on a surface of biological tissue to measure bio-electric signals thereof, said electrode assembly comprising:

• a flexible, surface electromyographic electrode apparatus including
• a conductive electrode device adapted to directly contact the surface of the biological tissue to receive and transmit bio-electric signals sensed from the biological tissue having an original first voltage and an original minute first current;
• a conductive guard device positioned substantially adjacent and substantially over said electrode device such that the measured bio-electric signal passing therethrough is substantially shielded from ambient electric fields generated from sources external to said electrode apparatus;
• and
• a substantially non-conductive, flexible, first sheet material positioned between said electrode device and said guard device to substantially prevent conductive contact therebetween;
• a co-axial cable having an inner conductor and an outer conductor shielding the inner conductor, at one portion of said co-axial cable, said inner conductor being electrically coupled to the electrode device for transmission of said bio-electric signals, and said outer conductor being electrically coupled to the guard device to substantially shield the inner conductor from said ambient electric fields generated from sources external thereto;
• and
• a buffer amplifier device having a signal input and a signal output, said signal input being electrically coupled to the inner conductor of the co-axial cable at another portion thereof for receipt of the transmitted bio-electric signals, said signal output being electrically coupled to the outer conductor of the co-axial cable, in a feedback loop, for receipt of at least a portion of the transmitted bio-electric signals, such that the voltage of the signals at said signal input of the high impedance amplifier device is maintained substantially equal to the voltage of the signals output from said signal output thereof.