Two important components are used to measure the fluid pressure in the ear; one is summating potential (SP) and the action plan (AP). The audiologist collects several responses from the ear in the waveform with the help of electrochelograph, which contains these two components ( SP & AP). Both of these waveform components are direct results of providing sound stimulation to the cochlea. The calculation is made on the SP/AP ratio, and any increase in the value of this SP/AP ratio indicates an increase in fluid pressure in the ear.