Oscillations corticales et intelligibilité de la parole dégradée (Oscillatory cortical activity and intelligibility of degraded speech) [in French]

________________________________________________________________________________________________________ Oscillatory cortical activity and intelligibility of degraded speech Many neurocognitive aspects associated with the processing of speech were up to now studied by the analysis of event-related potentials. However, none of these cortical responses can be considered as a direct indicator of successful lexical access during speech comprehension. The aim of the present study is to develop an experimental paradigm and a statistical analysis on electrophysiological data, in order to identify timefrequency patterns in the oscillatory cortical activity that correlate with the intelligibility of degraded speech. For this purpose we used noise-vocoded speech that is very difficult to understand without prior exposure. Noise-vocoded words were presented before and after a short period of perceptual learning, and we compared the oscillatory activity following stimuli rated as “intelligible” or “unintelligible” by participants (N=12). Results show that we were able to identify three oscillatory activities with specific topology and latency resulting from a successful lexical access. MOTS-CLES : Intelligibilité, Noise-vocoded speech, EEG, Oscillations corticales