Charges associated with threshold excitation of peripheral nerves using various waveforms

The dependence of sensory and motor nerve excitation on phase charge and total pulse charge of five waveforms was investigated. A neuromuscular stimulation system provided a monophasic waveform, a symmetric biphasic and multiphasic waveform of 10 pulses per burst or 25 pulses per burst, and an amplitude-modulated waveform. These waveforms were delivered through surface electrodes to the right forearm or leg of four healthy human subjects. The results indicate that for threshold excitation of the sensory and motor nerves the phase charge for the five waveforms do not differ markedly while the corresponding total pulse charge increases substantially with multiphasic and amplitude-modulated waveforms