Hearing preservation in cochlear implantation for electric acoustic stimulation

Abstract

Objective To evaluate the possibility of preservation of low-frequency hearing in atraumatic cochlear implant electrode insertion procedures for combined, ipsilateral electric and acoustic stimulation.

Material and Methods A total of 21 patients were implanted with a MED EL C40+ cochlear implant using an atraumatic electrode insertion technique to preserve residual low-frequency hearing. Pure-tone audiometric thresholds were measured pre- and postoperatively to evaluate the degree of preserved hearing. Speech discrimination tests in quiet and with background noise were performed in a patient with successful hearing preservation.

Results Using the atraumatic electrode insertion procedure with an insertion depth of 360° (18–24 mm), hearing preservation could be achieved in 18/21 patients (85.7%). Three patients (14.3%) lost their residual low-frequency hearing after the implantation. Residual hearing was preserved completely in 13 patients (61.9%) and partial hearing preservation was possible in 5 (23.8%). Preliminary speech discrimination tests showed a dramatic benefit for the combined electric and acoustic stimulation mode compared to cochlear implantation alone.

Conclusion Preservation of low-frequency hearing in cochlear implantation is possible in patients implanted because of profound high-frequency deafness. With the development of new, more atraumatic electrode designs, preservation of residual hearing should be further improved.

Keywords:

• atraumatic electrode insertion
• auditory stimulation
• hearing conservation
• hybrid implant
• neurostimulation

Gstoettner W, Kiefer J, Baumgartner W-D, Pok S, Peters S, Adunka O. Hearing preservation in cochlear implantation for electric acoustic stimulation. Acta Otolaryngol 2004; 124: 348–352.

Gstoettner W, Kiefer J, Baumgartner W-D, Pok S, Peters S, Adunka O. Hearing preservation in cochlear implantation for electric acoustic stimulation. Acta Otolaryngol 2004; 124: 348–352.