Electrocochleography is a complex hearing test designed to record the electrical activity of the cochlea, a part of the inner ear. This test is commonly done to diagnose a condition called Meniere's Disease. The ECOG is performed by placing an electrode that consists of a wire, wick or spring, or a sponge into the ear canal as close as possible to the cochlea. The ear is then stimulated with alternating clicks of different polarities, or tone bursts. These tone bursts are transformed into vibrations in the middle ear, your ear does this naturally and automatically all the time. The vibrations are turned into electrical impulses in the inner ear and are recorded and measured using computer software.

The main objective of this test is to magnify and record wave-1 of the 5-waves present in a evoked potential study to detect the summating potential which is located on the shoulder of wave-1. The results of an ECOG test are reported in an SP/AP ratio. Calculating the SP/AP ratio in electrocochleography requires the interpreting audiologist to identify the peak of the SP wave. If different points are selected, different SP/AP ratios will result. Hence, this is not a test that is usually performed by inexperienced audiologists or technicians.

The results are then compared to established patterns typical of normal hearing and to data from Meniere's patients. Hydrops (Ménières) is suggested when the ratio is greater than 35%, although most audiologists and technicians today say 50% is a more reliable number due to noise common during the test.  To achieve a ratio above 50% can be difficult when trying to diagnose Meniere's Disease unless the patient is symptomatic at that time. Accordingly, the SP/AP ratio is higher if it is performed during a symptomatic period, but it is difficult to get patients scheduled for the test when they are symptomatic. This problem has led to the popularity of a test called Vestibular Evoked Myogenic Potential (VEMP) which can test the integrity of the saccule portion of the inner ear, and can detect Meniere's Disease even when a patient is currently non-symptomatic.