Electrically evoked mismatch negativity from speech stimuli as an objective measure of cochlear implant performance

Florian Hermann Schmidt Pattric Stauga David Mißler Karsten Ehrt Wilma Großmann Robert Mlynski Lichun Zhang ^*

• Department of otolaryngology, University hospital Rostock, Rostock, Germany

Postoperative assessment of cochlear implant (CI) success often relies on the subjective tests such as word recognition scores (WRS), which are not useful for children, non-native speakers, and individuals with intellectual impairments. A promising method for objectively assessing speech perception involves deriving cortical potentials in the form of mismatch negativity (MMN). In this study, a MMN paradigm was employed to evaluate speech perception of CI patients. Speech stimuli were presented in a MMN paradigm at 70 dB nHL via audio input on the CI processor to 23 ears with a CI fitting duration of over six months. The standard and deviant stimuli were the syllables 'ba' and 'da'. CI performance was determined based on speech perception in the WRS. We found a significant correlation between WRS and MMN, with poor performers among CI patients exhibiting both significantly smaller MMN amplitudes and delayed latencies compared to good performers. The speech-induced MMN could be applied to evaluate the quality of speech perception in CI patients. This method has the potential to offer valuable insights for necessary adjustments in fitting process, enhancing thenot only speech perception but also the overall quality of life for CI patients who cannot undergo subjective testing.