Download The Advanced User's Guide
Transcript
3 3.2 3.2.5 Pulse width or duration Pulse width or pulse duration describes the time in microseconds (µsec) taken to complete one section of the waveform usually the positive phase. Typically, this is 200µsec. Variations of pulse width have no discernible effect on the efficacy of treatment but if they become too long, >500µsec, problems related to polarisation, electrolysis, destruction and burning of the tissue under the electrodes can result. It is a standard practice to increase the pulse width as the frequency of the current is reduced, eg. the standard setting for 2pps is 200µsec and for 80pps and above 80µsec. This titration of pulse width to frequency leads to a greater degree of patient comfort during treatment. Pulses wider than 1.0msec do not further enhance nerve activation but increase problems due to polarisation, electrophoresis and tissue heating and limit the pulse rates which can be used 8.