Induced Event-Related Coherence Measures during Auditory Change Detection

Humans have different react to the different the auditory inputs and have the capability to automatically differentiate them. But, people cannot feel auditory change when auditory brain areas are damaged, in this paper a novel evaluation method is proposed based on induced event-related coherence (ERCoh), which quantified auditory brain areas response during auditory input change. To investigate the functional coupling of brain areas under auditory stimuli, sixtyfour-channel scalp electroencephalogram (EEG) were recorded for 14 subjects who were asked to listen different sounds. ERCoh of the EEG different bands (δ, θ, α1, α2, β and y) was calculated and compared statistically among different stimuli. The results suggest that alpha frequency band may reflect the cerebral processing of auditory changes by showing differential ERCoh phenomena among standard-, deviantand novel-elicited responses. The bilateral hemisphere coherence of the standard stimulus is higher than the deviant and novel stimulus in alpha band. For each stimulus, the coherence difference was clearly larger in the right hemisphere, which is mainly involved in auditory perception. Furthermore, the right frontal and temporal ERCoh is brought about by an increase in auditory changes. Thus, induced ERCoh does not only appear to be generated by distinct neurophysiological mechanisms but also differ with regard to their functional significance to evaluation auditory brain areas impairment. In addition, EEG classification task is accomplished based on ERCoh for potential BCI applications, which provide potentially the only communication channel for severely disabled people who are otherwise unable to articulate their thoughts and needs, Therefore, ERCoh is a very promising approach in the future.