Valid for Safety Analysis Set was used.

Air conduction: The atmospheric transmission of sound to the inner ear through the external auditory canal and via structures of the middle ear. The ability of hearing is measured in decibel (dB). The hearing threshold, is the lowest sound pressure where the ear can perceive still a sound.

The endpoint deterioration of hearing threshold ≥15 dB in two contiguous test frequencies means that hearing worsens ≥15 dB in two neighboring sound frequencies.