PR-3. CENTRAL AUDITORY SYSTEM ACTIVATION DURING SPEECH LISTENING IN QUIET AND IN NOISE: AN FMRI STUDY

Juen-Haur Hwang (Buddhist Dalin Tzu Chi General Hospital ), Tien-Chen Liu (National Taiwan University Hospital ), Chang-Wei Wu, Jyh-Horng Chen (National Taiwan University, Taiwan)

Objectives: The purpose of this study was to investigate the exact sites of central auditoy system that were responsible for speech perception in background noise in the young healthy subjects

Methods: Twelve healthy subjects with normal hearing participated. fMRI was performed while subjects attentively listened to speech sounds in quiet and in white noise binaurally

Results: In general, speech signals in quiet or in white noise mostly elicited activation of superior temporal gyrus and sulcus, middle temporal gyrus, as well as inferior frontal gyrus. Compared to speech stimulation alone, group data represented that putamen of left hemisphere, anterior pole of right superior temporal lobe and anterior part of inferior frontal gyrus of right hemisphere showed greater activation significantly during speech plus white noise stimulation. Besides, fusiform gyrus and inferior occipital gyrus of right hemisphere were also activated additionally. However, except putamen, we failed to demonstrate additional activation in the subcortical area or brainstem. But, we still cannot exclude the involvement of inferior colliculus and MOC system, on the task of speech perception in noise.

Conclusion: This study revealed that, in human, the putamen of the left hemisphere, anterior pole of right superior temporal lobe and anterior part of inferior frontal gyrus of right hemisphere might play a role in extracting relevant acoustic features of speech from background noise. But, we cannot exclude the involvement of inferior colliculus and MOC system, on the task of speech perception in noise.