Table 3: Electrocochleography criteria [27]. The diagnostic level was chosen as the nearest whole figure to the level which provides a false-positive diagnosis rate of 5%. The likelihood of hydrops is a Gibson score of >7/10 [6]. Clicks: abnormal if SP/AP ratio ≥0.50.

Tone bursts

Tone burst frequencyHearing level dBHLAbnormal if SP ≤

0.5 kHz (75 dBHL)Under 25−2 μV
20–35−2 μV
40–55−2 μV
60–75−1 μV

1 kHz (90 dBHL)Under 25−6 μV
20–35−6 μV
40–55−6 μV
60–75−3 μV

2 kHz (100 dBHL)Under 25−9 μV
20–35−7 μV
40–55−5 μV
60–75−5 μV

4 kHz (75 dBHL)Under 25−9 μV
20–35−5 μV
40–55−5 μV
60–75−5 μV