Electrocochleography: a comparison of action potential and behavioral thresholds

Using the technique of electrocochleography with transtympanic electrode placement, it is possible to estimate behavioral thresholds from AP data for a acoustic stimulus. The correlation between behavioril and AP "thresholds" for the same stimulus was statistically significant and there was a better correlation for subjects with a mild hearing loss than for those with normal hearing or larger degrees of hearing loss (as determined by the pure tone average). Larger amplitudes of the AP at the maximum stimulus level tended to be associated with a more accurate threshold estimation. The AP "thresholds" showed best correlation with the pure tone audiometric thresholds at 1 000 Hz, at other tone frequencies the correlation was poorer. This agrees with the spectral contents of the click.