Poster #: 88
Wednesday, Sep 9, 2015
Mismatch negativity (MMN) objectively reflects timbre discrimination thresholds in normal-hearing listeners and cochlear implant users
1HNO, Universitätsklinikum Halle (Saale), Halle (Saale), Germany
For cochlear implant (CI) users timbre discrimination is still challenging. This study focuses on psychoacoustical and electrophysiological measures of individual discrimination of single timbre dimensions in 15 normal hearing listeners and 15 CI users. Just noticeable differences (JNDs) in temporal envelope modulation and spectral distribution of complex tones were measured in an adaptive three-alternative forced-choice procedure. For both timbre dimensions two tone pairs were computed, one above and one below the individual JND. With these tone pairs, four randomly arranged oddball paradigms were presented and the EEG was recorded. MMN was present in all normal hearing listeners and CI users when the timbre difference was above the individual JND, but not when below JND.
We conclude that the timbre perception skills of NH listeners and CI users in particular can be assessed timbre dimension specifically with psychoacoustic measurements and MMN recordings. MMN occurrence reflects the individual JND for temporal envelope modulation and spectral distribution differences and can be used as a clinical tool to monitor auditory-verbal therapy after CI surgery.