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Otorinolaringologia 2012 December;62(4):173-82


language: English

Direct acoustical cochlear stimulation

Stieger C. 1, 2, Bernhard H. 3, Kompis M. 4, Caversaccio M. 4

1 Department of ENT Head and Neck Surgery I ARTORG Center, Inselspital, University of Bern, Bern, Switzerland; 2 Department of Otology and Laryngology, Harvard Medical School, Eaton Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, MA, USA; 3 Helbling Technik Bern AG, Liebefeld, Switzerland; 4 University Department of ENT, Head and Neck Sugery, Inselspital, Bern, Switzerland


Direct acoustic cochlear stimulation (DACS) is an implantable hearing system for the treatment of patients suffering moderate to severe mixed hearing loss. The working principle consists of a powerful electromechanic actuator that provides an equivalent sound pressure level (ESPL) of at least 115 dB SPL for low frequencies. This actuator is implanted in the mastoid cavity and drives a conventional stapes prosthesis at the oval window, which couples directly to the inner ear fluid. The DACS concept was clinically tested in three clinical studies, in a total of 28 patients with moderate to severe mixed hearing loss. No device related explantations occurred in any of the studies. Today, published results include 12 patients with an BC thresholds of at least 35 dB HL and, additional air bone gap of at least 30 dB HL. All patients suffered from otosclerosis. Bone conduction levels did not deteriorate due to the implantation of the DACS. On average the DACS improved threshold by 50 dB. Speech discrimination scores at conversation level (65 dB SPL) were higher than 80% for patients where the average bone conduction threshold (BC PTA) did not surpass 60 dB HL. For patients with higher BC PTA thresholds, speech discrimination may be considerably lower. This effect is also observed for other hearing devices. In conclusion, the published results of DACS studies show that the DACS is a safe and powerful treatment for patients with severe mixed hearing loss.

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