Essay On Audio Visual Impairing

Introduction:

Speech is traditionally thought of an exclusively auditory percept. However, when the face of the speaker is visible, information contained primarily in the movement of the lips contributes powerfully to our perception of speech. This combined interaction between auditory and visual modalities improves our ability to interpret speech accurately; particularly in low signal to noise ratio (Bertelson, 2003).This multisensory integration provides a natural and important means for communication. The benefit of integrating audio visual cues has been well documented in normally hearing individuals especially in difficult listening conditions and for listeners with hearing impairment (Sumby& Pollack, 1954). The benefit derived from speech reading can be substantial allowing unintelligible speech to become comprehensive, or even exceeding the benefit derived from the use of assistive listening devices, counseling or training especially those with hearing impairment (Walden et al, 1981). Two fundamental questions concerning audio visual integration is that, what acoustic and optical cues are integrated? and how and where exactly in brain this

This illusion is evoked when a listener is presented with an audio recording of one syllable, eg: /pa/ while watching a synchronized video recording of speaker’s face articulating different syllable, /ka/. Under these conditions, the majority of adults typically report hearing the syllable /ta/. The illusion is robust and obligatory, and has been demonstrated in adults and children and in numerous languages. The McGurk effect is based on the motor theory of speech perception which tells that production and perception are related. The McGurk effect demonstrates that in most people, the central nervous system combines visual information from the face with acoustic information in creating the speech