Multimodal contribution to speech perception revealed by independent component analysis: a single-sweep EEG case study.

In this single-sweep electroencephalographic case study, independent component analysis (ICA) was used to investigate multimodal processes underlying the enhancement of speech intelligibility in noise (for monosyllabic English words) by visualizing facial motion concordant with the audio speech signal. Wavelet analysis of the single-sweep IC activation waveforms revealed increased high-frequency energy for two ICs underlying the visual enhancement effect. For one IC, current source density analysis localized activity mainly to the superior temporal gyrus, consistent with principles of multimodal integration. For the other IC, activity was distributed across multiple cortical areas perhaps reflecting global mappings underlying the visual enhancement effect.

Single-sweep EEG analysis of neural processes underlying perception and production of vowels.

This single-sweep electroencephalographic study using independent component analysis was conducted to determine the neural processes underlying both speech perception and production of vowels. The same neural processes located in auditory and motor areas of the brain that significantly distinguish between a speech production and a control mental rehearsal task were found for both auditory evoked responses and speech planning responses. Thus identifying common task dependent neural processes underlying speech production and perception.