Measuring amplitude and latency in evoked responses

The peak of interest is chosen in the evoked response to represent the anatomic structure at risk (eg, sensory cortex) or from a structure that is located such that the anatomic structure at risk is between the peak and the stimulation site (eg, using the cortical response during spine surgery). Measuring evoked responses for monitoring is measuring the time from stimulation to the peak of interest (latency) and the peak to adjacent peak amplitude (amplitude). The term "onset" represents the time from stimulation to the beginning of a multi-peaked muscle response (compound muscle action potential).