Interaural attenuation using insert earphones: electrocochleographic approach.

We measured the interaural attenuation for click stimuli using insert earphones. Electrocochleographic thresholds were determined when clicks were presented both ipsilaterally and contralaterally to the recording ear. The interaural attenuation was calculated as the difference between ipsilateral and contralateral thresholds. Results from normal listeners showed that crossover occurred. Results agree with previous investigators who used a different approach. Results confirm that one may need to mask the nontest ear in clinical evoked potential testing even though insert earphones are used. Several approaches to the question of when to mask are proposed.