[Bipolar , active electrode for 4-channel recording of dynamic surface EMG during electric stimulation]

In this paper we present an electrode for measuring the surface electromyogram (EMG) that combines high quality of signal recording with the ease of use in clinical routine. Additional requirements have been the use of the electrode in combination with electrical stimulation and under dynamic conditions like walking. Special focus was put on the minimization of movement artifacts by integration of a dual impedance transformer (active electrode) and by a self-adjusting fixation of the two contacts of the electrode via proprietary springs. An elaborate preparation of the skin is not necessary due to a very high input impedance of the amplifier. A special circuit for overvoltage protection makes the electrode suitable for use in the presence of high voltage stimulation pulses without the risk of destroying the FET-input stages.