Mattingly JK, et al. - In the present study, the researchers contrasted contralateral to ipsilateral stimulation with percutaneous and transcutaneous bone conduction implants. Fresh–frozen whole human heads were prepared bilaterally with mastoidectomies. Fresh–frozen whole human heads with mastoidectomies are prepared bilaterally. Intracochlear pressure (P_IC) was measured with fiber optic pressure probes in the scala vestibuli (P_SV) and tympani (P_ST) at the same time as cochlear promontory velocity (V_Prom) through laser Doppler vibrometry during stimulation provided with a closed-field loudspeaker or a bone conduction implant. In all measures, contralateral stimulation yielded lower response magnitudes and longer delays than ipsilateral, especially for high-frequency stimulation. Transcranial attenuation and delay indicate that ipsilateral stimulation should predominate for frequencies over ~1 kHz, and that complex phase interactions will occur during bilateral or bimodal stimulation. These effects indicate a mechanism through which bilateral users may obtain some bilateral benefit.