Effects of Consonant-Vowel Transitions in Speech Stimuli on Cortical Auditory Evoked Potentials in Adults
Michael Doellinger*, a, Martin Burgera, Ulrich Hoppeb, Enrico Boscob, Ulrich Eysholdta
a Department of Phoniatrics and Pediatric Audiology, University Hospital Erlangen, Bohlenplatz 21, 91054 Erlangen, Germany
b ENT Department, University Hospital Erlangen, Waldstraße 1, 91054 Erlangen, Germany
We examined the neural activation to consonant-vowel transitions by cortical auditory evoked potentials (AEPs). The aim was to show whether cortical response patterns to speech stimuli contain components due to one of the temporal features, the voice-onset time (VOT). In seven normal-hearing adults, the cortical responses to four different monosyllabic words were opposed to the cortical responses to noise stimuli with the same temporal envelope as the speech stimuli. Significant hemispheric asymmetries were found for speech but not in noise evoked potentials. The difference signals between the AEPs to speech and corresponding noise stimuli revealed a significant negative component, which correlated with the VOT. The hemispheric asymmetries can be referred to rapid spectral changes. The correlation with the VOT indicates that the significant component in the difference signal reflects the perception of the acoustic change within the consonant-vowel transition. Thus, at the level of automatic processing, the characteristics of speech evoked potentials appear to be determined primarily by temporal aspects of the eliciting stimuli.
Keywords: Auditory evoked potentials, voice-onset time, speech stimuli, N1/P2 complex.
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* Address correspondence to this author at the Department of Phoniatrics and Pediatric Audiology, University Hospital Erlangen, Bohlenplatz 21, 91054 Erlangen, Germany; Tel: +49 9131 8533814; Fax: +49 9131 8532687; E-mail: firstname.lastname@example.org