Physiology of hearing practical Flashcards
What should you see in a normal ear when looking at it through a auriscope/otoscope?
Tympanic membrane = bluey/grey and translucence
Short process of the mallus = in the middle and ends as the UMBO near the center
Triangular light portion - reflection of light
What is the difference between conduction deafness and sensorineural deafness?
Conduction deafness - due to disease of the middle ear interfering with transmission of sound to the cochlea
Sensorineural deafness - Injury or degeneration of the cochlea or auditory nerve
What is the Webers test and what would a normal hearing person, a person with conductive deafness and a person with neural deafness experience?
Striking a tuning form and then placing it on the patients forehead
Normal = hear it equally in both ears
Conductive deafness = louder in damaged ear due to auditory masking
Neural = louder in normal ear
What is the Rinne’s test and what would a normal hearing person, a person with conductive deafness and a person with neural deafness experience?
Striking a tuning form, wait for it to become silent and then placing it on the patients mastoid
Normal = can’t hear anything
Conductive = can hear it
Neural = can’t hear it
What are monoaural cues?
Used in median plane sound localisation
Pinna, head, shoulders, torso
One earphone needed
Called head-related transfer function (HRTF)
What are binaural cues? How do they localise sound?
Two earphones needed
Come under two catagories:
Interaural time differences (ITDs) - caused by the different propagation times the sound wave is from the source to both ears e.g. sound on the left will reach the left ear slightly before the right
Interaural level differences (ILDs) - caused by the acoustic “shadow” of the head. For e.g. sound from the left, the sound wave will arrive at the left ear slightly louder than at the right ear
Exaplain the tonotopic oraganisation of the cochlea
High frequencies = base of cochlea
Low frequencies = apex of cochlea
