Postersession 2
Poster #: 104
Topic: Speech and language (incl. deficits)
Thursday, Sep 10, 2015
1st floor

Differences in sensory processing of German vowels and physically matched non-speech sounds as revealed by the mismatch negativity (MMN) of the human event-related brain potential (ERP)

Corinna Christmann1, Stefan Berti2, Claudia Steinbrink3, & Thomas Lachmann4

1Department of Computer Science, AG wearHEALTH, Center for Cognitive Science, University of Kaiserslautern, Kaiserslautern, Germany
2Klinische und Neuropsychologie, University of Mainz, Mainz, Germany
3University of Erfurt, Erfurt, Germany
4University of Kaiserslautern, Kaiserslautern, Germany

In most studies comparing the processing of speech versus non-speech sounds the complexity of both stimulus types has not been matched. As stimulus complexity has already been shown to have an influence on the auditory mismatch negativity (MMN), care should be taken to avoid this potentially confounding factor. In our study we compared processing of speech and non-speech by means of the MMN. For this purpose, the MMN elicited by German vowels was compared to those elicited by two non-speech stimulus types: spectrally rotated versions of the vowels, having the same stimulus complexity as the speech stimuli, and sounds based on the bands of formants of the vowels, representing non-speech stimuli of lower complexity compared to the other stimulus types, while preserving the most important frequencies of the speech sounds. This design allows controlling for effects of stimulus complexity when comparing neural correlates of processing speech to non-speech. Deviants within a modified multi-feature design differed either in duration or spectral property (timbre) according to the German vowel system. Moreover, the difficulty to discriminate between the standard and the two deviants was controlled for each stimulus type by means of an additional active same-different discrimination task. Even though active discrimination scores were lowest in the vowel condition, vowels elicited a larger MMN compared to both non-speech stimulus types, supporting the concept of language-specific phoneme representations and the role of the participants’ prior experience in auditory processing.