CSD 212 Chapter 5: Vestibular System hearing loss
22 Dec 2017
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Cone of confusion = 45deg from axis line between ears where one cannot differentiate whether a sound came from top, bottom, left or right. Along the same axis, the sounds would have same interaural time difference and same interaural level difference. Cup ear, tilt head, moving torso, using pinnae of ear, use visual cues. Interaural time difference = difference in time it takes a sound to reach the left vs the right ear. Interaural level difference = difference in sound pressure level between the ears. The head dampens the overall sound to the far ear and reduces the intensity of the high frequency tones, but not the low frequency tones. Sound is not conducted through the external auditory canal to the tympanic membrane/ossicles: acute otitis media, perforated eardrum, foreign body in external canal. Damage to inner ear (hair cells of cochlea) or nerve pathways from inner ear brain: exposure to loud noise, head trauma, aging (presbycusis)
