The contribution of apical stimulation to Mandarin speech perception in users of the MED-EL COMBI 40+ cochlear implant

Abstract

Conclusion: Not stimulating the apical cochlear region in tonal language speaking cochlear implantees significantly reduces discrimination of Mandarin vowels. The data presented here suggest that electrode arrays that allow complete cochlear coverage with stimulation pulses seem to be preferable over shorter arrays for use in cochlear implant (CI) indications. Objective: To assess the contribution of electrical stimulation beyond the first cochlear turn on tonal language speech perception. Methods: Twelve Mandarin-speaking users of the MED-EL COMBI 40+ cochlear implant with complete insertion of the standard COMBI 40+ electrode array participated in the study. Acute speech tests were performed in seven electrode configurations with stimulation either distributed over the whole length of the cochlea or restricted to the apical, middle or basal regions. The test battery comprised tone, consonant, and vowel identification in quiet as well as a sentence recognition task in quiet and noise. Results: While neither tone nor consonant identification depended crucially on the placement of the active electrodes, vowel identification and sentence recognition decreased significantly when the four apical electrodes were not stimulated.

Keywords::

• Electrode
• insertion depth
• tonal language

Acknowledgment

This study was supported, in part, by the Science and Technology Ministry, PR China, grant no. 2009DFA32200 and 2008BAI50B08.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.