gms | German Medical Science

Fourth International Symposium and Workshops: Objective Measures in Cochlear Implants

Medical University of Hannover

01.06. bis 04.06.2005, Hannover

Clinical application of the P300 event-related potential as a predictor for speech performance?

Meeting Abstract

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  • corresponding author A. Beynon - Radboud University Nijmegen, ENT Dept.
  • A.F.M. Snik - Radboud University Nijmegen, ENT Dept.

Medical University of Hannover, Department of Otolaryngology. Fourth International Symposium and Workshops: Objective Measures in Cochlear Implants. Hannover, 01.-04.06.2005. Düsseldorf, Köln: German Medical Science; 2005. Doc05omci050

The electronic version of this article is the complete one and can be found online at:

Published: May 31, 2005

© 2005 Beynon et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.




The speech processor of a cochlear implant, can process speech with different encoding paradigms - implemented in speech-coding strategies. These different coding strategies might induce differences in cognitive processing. If it is possible to evoke consistent strategy-dependent ERPs, one might for example question if it is possible to predict the ‘best’ speech-coding strategy on the basis of these measurements. To answer this question, it is of primary importance to initially gain knowledge in the acquisition of auditory cortical potentials. Therefore, electrophysiological responses were studied in normal hearing as well as in CI subjects.

Materials and Methods

Speech-processing and perception via a CI can be simplified as a four-stage process: signal processing by the CI speech processor (first stage), the transfer of electrical coded signals to neural tissue (spiral ganglion cells) referred to as the ‘electro-neural interface’ (second stage), neural subcortical processing through the pathway between the early brainstem until the auditory cortex (third stage) and the processing related to cognition, like stimulus discrimination (fourth stage). The present research on the event-related potentials in CI subjects is performed in the light of this four-stage model of speech perception. Since the P300 component is assumed to represent cortical activity associated with discriminative tasks, it is used as a measure for discrimination of speech contrasts. The general purpose of this research is to improve the knowledge of processing of speech sounds in cochlear implant recipients and to study the clinical value of cognitive P300 measurements with speech stimuli for the treatment of cochlear implant users.


Neural activity of afferent (sub)cortical processing is studied by obligatory exogenous slow vertex potentials N1 and P2, while the event-related P300 potential is used to assess cortical processing of speech. Several retrospective and prospective ERP studies are performed with respect to cortical processing using different speech coding strategies. Cortical stimulus evaluation times (P300 latency) for speech stimuli are investigated in relation to speech recognition and predictability for speech performance on the long term.


Results of our ERP studies show that 1) P300 potentials are rather similar to ERPs in normal hearing, but they are speech coding strategy-dependent 2) it is possible to study auditory neural development due to electrical stimulation with ERPs (cortical adaptation and learning effects) 3) other factors than pure ‘technical’ processing by the CI processor primarily determine speech processing. Latest data on N2 and N3 will be addressed as well as the predictive value of P300 measures on choosing the best speech coding strategy on the long term.