gms | German Medical Science

The cognitive components of auiditory event-related potentials (mismatch negativity, N2b and P300) signify the brain’s detection of acoustic change. Theese potentials may be evoked by a number of physical differences in acoustic tone stimuli including pitch, intensity and duration, using passive condition to verify the mismatch negativity (MMN) component and using active condition to verify the other (N2b, P300) components.

We recorded cognitive responses to study the central auditory processes in cochlear implant users (with Nucleus and Med-El implants) and normal hearing subjects (as control group). Our investigations was performed with PEGAZUS EEGMP equipment. We used acoustic oddball paradigm under passive and active condition. The stimuli consisted of 1000 Hz frequent, 2000 Hz and 500 Hz deviant. The different stimuli were presented in pseudorandom order with a fixed interstimulus interval. The ERPs were recorded on 22 chanels. In parallel speech recognition tests were performed in quiet and under different background noise conditions. The tests covered number, word, and sentence recognition tests. The results of these tests were compared with the parameters of auditory event-related potentials

The cognitive evoked potentials registrated in cochlear implant recipients are similar to the waveform measured in normal hearing individuals to the same stimuli. The parameters of cognitive ERP components (MMN, N2b and P300) reflect to the tone and speech perception and the patient’s performance with cochlear implant. So this is a useful method for assessing the discriminability of stimulation patterns produced by cochlear implant, that may yield important information for developing rehabilitation programs for individual cochlear implant users.