Acoustic overexposure can induced temporary or hearing loss. Usually hearing loss is associated with cochlear cell damages. Recently, a new pathological entity was described and called hidden hearing loss. In animal model, the histopathology revealed a selective reduction in the number of auditory fibers, resulting in a decrease in the amplitude of wave I of the auditory brainstem response. Electrocochleography (Ecog) is a method for recording the electrical potentials of the cochlea (e.g. wave I). In clinical routine, Ecog is performed invasively with sedation or local anesthesia. Actually, a non invasive approach could be perform but it seems necessary to optimize this method and to define reference values in healthy volunteers.