Audiometric and radiologic measured frequency mismatch in SSD patients

While most CI users benefit from speech understanding, this is not the case regarding music as the pitch is not correctly transmitted by the implant. The object of this study was to measure the frequency mismatch and to compare the audiometric and the radiologically expected frequency mismatch.

14 SSD patients aged 32 to 73 (mean 55) years and implanted in the ENT department of the Ruhr University Bochum between 2012-2018 were included. All had a CI experience of 11 to 76 (mean 37) months and used FSP or FS4 programs. Subjective frequency mismatch was assessed in comparison to the normal hearing ear. Besides, the size of the cochlea was retrospectively assessed by the Otoplan ^® planning software (MED-EL) and the proposed location of the frequency in the cochlea was compared to the used centre frequencies of the stimulation channels.

All patients had a larger frequency mismatch via Otoplan ^® than the subjective one. In general, the centre frequencies of the stimulation channels were lower than the frequencies expected by CT. Three subjects showed a very large subjective frequency mismatch. This was correlated to a big discrepancy between the length of the cochlea (34-39 mm) and the array (28 mm).

Neuroplasticity and rate pitch might explain the smaller frequency mismatch in the subjective frequency mismatch. As it is strongly influenced by the discrepancy between the best frequencies of the electrode location and the triggering frequencies, preoperative measurement of the cochlea might help to improve music perception in CI users.

Poster-PDF A-1034.pdf

Publication History

Article published online:
13 May 2021