Schematic illustrating the subtraction method used to resolve the ECAP. Left panel: traditional forward-masking technique, used to resolve the response to the first pulse in the train. Right panel: modified forward-masking technique, used to resolve the responses to pulses 2–21 (number of pulses indicated by subscript n). MPI = masker-probe interval. In both panels, A = probe alone, B = masker plus probe, C = masker alone, D = zero-amplitude pulse for system artifact. Probe pulses are indicated in bold and labeled “P”; masker pulses are thinner lines labeled “M.”