DACS A new implantable Hearing system for Moderate to Severe Mixed Hearing Loss.

The adequate treatment of the patients with moderate to severe mixed hearing loss (MHL) is not sufficiently possible with conventional hearing aids. These patients have enough cochlear reserve, but the additional middle ear disorder limits the usage of conventional hearing aids (gain limitation and distortion). The second possibility for such patients would be the bone conduction hearing aids, which indicate an insufficient gain for moderate to severe MHL. On the other hand because of good cochlear reserve there isn't an indication for cochlear implantation. Therefore there is no optimal way to give an adequate gain to patients with moderate to severe MHL. The new improved DACS-system (Direct Acoustic Cochlear Stimulation) realizes a direct transfer to the inner ear. In this way the conductive disorders of middle ear does not have any influence on the sound transfer. After an introduction of the functional principle of the system the pre- and postoperative audiological results of 4 implanted patients will be presented in this paper. The one year post operative results indicate a functional gain of about 50 dB HL and an SRT (Speech Reception Threshold) improvement of about 40 dB SPL. [ABSTRACT FROM AUTHOR]