SHS: Lab Nine

Explain the use of speech intelligibility tests as means to evaluate communication systems for listeners

They evaluate the effect on intelligibility of the noise in the transmission system to evaluate the effect of restricted frequency bandwidth on speech intelligibility.

Explain the use of speech intelligibility tests as means to evaluate hearing loss

They evaluate the effect of hearing loss on the ability to perceive speech to evaluate the effect of listener experience on speech intelligibility.

Explain the use of speech intelligibility tests as means to evaluate speaker proficiency

They evaluate the intelligibility of individuals with motor speech disorders to provide a longitudinal index of improvement of speech intelligibility to intervention.

List the ways to measure speech intelligibility

• Word identification tests (% intelligibility)

• Scaling tests

• Phonetic Transcription Test

Which anatomical structures are included in the conductive component of the auditory mechanism

Pinna, external auditory/acoustic meatus, tympanic membrane, Malleus, Incus, and Stapes

Which anatomical structures are included in the sensorineural component of the auditory mechanism

Semi-circular canals, cochlea, and vestibulocochlear nerve

Explain impedance mismatching

The measure of how much a medium resists the flow of sound energy through it; Mismatch occurs through different mediums such as the inner and middle using air to move sound energy, but then gets to the inner ear and then impedes or mismatches with fluid in the inner ear.

How is impedance mismatching overcome

It is overcome by area difference; sound pressure at the footplate of the stapes is around 20 -25 dB greater than sound pressure at the tympanic membrane (The Big tympanic membrane area to the stapes window area)

State the functions of the peripheral vestibular system

• Head position and space

• Balance/steadiness

Diagram of pathway through the cochlea

Sensory organ → Hair cells → Nerve fibers → Sensory cells → Vestibular cochlear nerve → Brainstem

The membranes that separate the three cochlear ducts

Reissner’s and Basilar membrane

The organ of Corti

• The end organ of hearing

• Sits on top of the basilar membrane

• Contains hair cells and other supporting structures

• Moves from shortest to longest (Hair cells)

What are stereocilia?

• Hair cells with the role of sensorial function

• Connected their “tips” and move as a unit “Tip-linked”

• Stereocilia bend toward the longest hair cell, which ion channels open, leading to hair cell depolarization and triggering an action potential in the connected nerve

What is the tonotopic organization of the basilar membrane

The highest frequency Sensitivity (20,000 Hz) is at the base (front), and the lowest frequency sensitivity (20 Hz) is at the apex (The end). Piccolo → Tuba (Base → Apex)