Effects of in-ear-sensor type on bone-conduction-based crosstalk cancellation: an assessment by tone reception thresholds

In bone-conducted sound reproduction, crosstalk is a phenomenon in which sound presented on either side of the head reaches the cochlea in the two ears. However, since the brain compares signals coming from each cochlea, crosstalk at high levels may limit the ability to hear with two ears, especially in patients with two bone-conduction hearing aids (BCHAs). In this study, we intended to suppress crosstalk sounds at the cochlea by canceling them at a sensor in the ear canal. Two sensors were evaluated here: (i) a probe microphone that can record the ear-canal sound pressure and (ii) an accelerometer that can capture the vibration of the inner wall of the ear canal. Since crosstalk cancellation was designed to occur at the sensor location, we used the tone reception threshold (TRT) as a subjective indicator to investigate which sensors contributed the most to the cancellation at the cochlea.