An improved method for rapid measurement of accommodation and firing frequency of single motor units in man

A stimulator is described producing trapezoid wave forms with accurately defined linear rise and fall at pre-determined slopes independent of the maximum current which is limited at the threshold for a motor unit recorded by discriminative electrodes. The stimulation threshold, measured in rheobase units, is directly proportional to the latency of response and is more accurately measured by sweep expansion (by computer). Thresholds to linearly rising currents of pre-selected slopes are rapidly measured and plotted on a grid calibrated to allow immediate measurement of the time-constant of accommodation.