Aud. & Hearing Impairment Flashcards by Sylvia Bettencourt

The external auditory meatus (EAM) is an s-shaped oval canal ___ to ___ mm in length. It opens at the ______ and terminates at the _____________.

25 to 33 mm
pinna
tympanic membrane
(p. 410)

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The tympanic membrane does what?

It transduces sound (p. 410)

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What is the function of the outer ear?

collects sounds and channels it to the middle ear. (p.410)

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Besides auditory function, what other function does the OE serve?

protection

cerumen ‘noxious’ to introders
s-shape prevents foreign objects from reaching ME and TM (p. 411)

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What does the ossicular chain consist of and what does it do?

3 bones (smallest in human body)

transfers the mechanical vibrations from TM to inner ear
p. 411

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______= the most lateral ossicle, consisting of manubrium, head, neck and lateral and anterior processes; attached to the TM and the incus.

Malleus (p. 411)

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______ = the middle and largest bone in the ossicular chain consisting of a body and a short, long, and lenticular process.

Incus (p. 411)

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______= the most medial third and smallest ossicle consisting of a head, footplate, and 2 crura. The footplate is held in the oval window by annular ligament.

Stapes (p. 411)

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What are the 2 muscles in the ME?

The tensor tympani and the stapedius muscle (p. 411)

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impedance mismatch = ?

loss of sound energy (p. 411)

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How does the ME compensate for impedance mismatch? How much is compensated?

two primary mechanisms –> lever effect and ME muscles increase sensitivity

25 to 27 dB of estimated 30dB is compensated
(p. 411)

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What are the 2 functions of the IE?

sense of hearing (cochlea) and sense of balance (semicircular canals and otolithic organs) (p. 411)

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a bony canal that surrounds a membranous tube, about 35 mm in length and coils around central core approx 2 3/4 turns.

cochlea (p. 412)

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________= upper canal running from oval window to helicotrema; contains perilymph

scala vestibuli (p. 412)

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_______= lower canal running from the round window to helicotrema; contains perilymph

scala tympani (p. 412)

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______= middle canal divided from scala vestibuli by Reissner’s membrane and from scala tympani by basilar membrane; contains organ of corti and contains endolymph.

scala media (p. 412)

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The organ of corti consists of ?

sensory hair cells, support cells and support membranes and ligaments (p. 412)

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How many (sensory) Outer Hair Cells (OHC) are there approx?

13,500 per ear; housed in 3 to 4 rows (p. 412)

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The OHC serve as?

biologic modifier increasing or decreasing sensitivity to sounds by changing length of hair cells ( p. 412)

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How many (sensory) Inner Hair Cells (IHC) are there approx?

3500 per ear housed in 1 row (p. 412)

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The IHC serve as?

serve to process frequency, temporal and intensity info to auditory pathway (p. 413)

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The basilar membrane yields what?

Tonotopicity in which high frequencies are processed at the base and low frequencies at the apex (p. 413)

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What is the tectorial membrane responsible for?

For shearing the stereocilia of the hair cells (p. 413)

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What is the main function of the IE?

Changes the mechanical energy into hyrdomechanical energy and then into neural impulses (p. 413)

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Middle Ear contains what?

``` tympanic membrane Malleus Incus-Middle bone Stapes Tensor tympani Stapedius muscle Eustachian tube connects middle ear to nasopharynx ```

What does Inner Ear house?

Oval window Labyrinths Vestibular system Cochlea

Cochlea

- -inner ear - -Contains basilar membrane, organ of Corti, cilia - -Receives wavelike movements that transform them into electrical energy that can stimulate nerve endings and carry sound to the brain

Oval window

- -inner ear - -Beginning of inner ear - -Small opening in temporal bone that houses inner ear.

Labyrinths

- -in inner ear | - -Interconnecting tunnels in inner ear that are filled with perilymph

Vestibular system

- -inner ear | - -3 semicircular canals responsible for equilibrium

What does Cranial nerve VIII do?

- -Vestibular branch-equilibrium and balance | - -Auditory branch-Supplies hair cells of cochlea and conducts electrical sound impulses from cochlea to brain

Speech frequencies

125-8,000Hz

Normal frequency for humans to hear

20-20,000 Hz

display disproportionately low word recognition in comparison to pure tones, worst type of HL for word recognition, acoustic neuroma

Retrocochlear

What allows things to vibrate?

Elasticity and inertia

dip in audiogram at 2000 Hz due to stapes fixation

Carhart’s notch specifically with Bone conduction

faking it

Pseudohypacusis

-10-15 dB HL

normal

16-25 dB HL

slight

26-40 dB HL

mild

56-70 dB HL

moderately severe

71-90 dB HL

severe

91+ dB HL

Profound

Degrees of hearling loss (7)

``` normal slight mild moderate moderately severe severe profound ```

decreases intensity of sound

attenuates

Types of assessment

- -pure tone - -speech auditometry - -acoustic immittance - -tympanometry - -electrocochleography - -ABR

threshold

intensity in which tone is faintly heard 50% of time

Assessment: - -Determines threshold - -Types: Air conduction and Bone conduction

Pure tone Testing

Assessment: - -Measures how well someone understands speech - -Speech reception threshold - -Spondee words

Speech Audiometry

Assessment: - -Transfer of acoustic energy - -Tympanic membrane and middle ear structures off impedance, or resistance to the flow of sound - -Admittance is the counterpart of impedance

Acoustic Immittance

Assessment: - -Procedure in which acoustic immittance is measured with an electroacoustic instrument - -Measures changes in acoustic energy acoustic reflex is measured and is valuable in detecting middle ear diseases.

Tympanometry

Tympanomtery Scores

``` A As Ad C B ```

Tympanomtery Scores | A

normal

Tympanomtery Scores | As

shallow compliance | suggesting otosclerosis or beginign of an ear infection

Tympanomtery Scores | Ad

deep compliance | suggesting ossicular disarticulation

Tympanomtery Scores | C

negative pressure | suggesting eustachian tube dysfunction

Tympanomtery Scores | B

flat | no pressure or compliance

Assessment - -measures electrical activity - -records electrical activity in auditory nerve, brainstem and cortical areas of the brain. - -Used to test newborns

ABR

Assessment of Infants and Children

Newborns: OAE and ABR Infants: Localization techniques Children: operant audiometry

Air bone gap

difference of 10 db or more, indicates conductive loss

Types of Amplificatn

- -hearing aids - -cochlear implants - -tactile aids - -assistive devices

hearing aids

- -Amplifies sound and delivers it to ear canal | - -Includes microphones, receivers and amplifiers

Cochlear Implants

- -Electronic devices surgically placed in cochlear and deliver sound directly to the acoustic nerve endings in cochlea - -Contains a microphone, processor, external transmitter and electrode - -Used for people with minimal or no hearing, utilizes residual hearing.

Tactile Aids

- -Sensory substitution method for those who are deaf | - -Promote comprehension of speech by touch

Assistive Devices

- -Safety alerting devices - -Closed-captioning - -Telecommunication devices

Types of communication training for comprehension

auditory, speech reading, cued

Designed to teach a person with hearing impairments to listen to amplified sounds, recognize their meanings and discriminate sounds from each other

Auditory Training

Involves deciphering speech by looking at the face of the speaker and using visual cues to understand what the speaker is saying.

Speech Reading

Cued Speech

- -Produced with manual cues that represent sounds of speech | - -A form of sign language, but composed of only eight signs for consonants and four signs for vowels

Oral language training

Aural/oral method Manual Approach Total Commun. ASL

Nonverbal communication and a language

ASL

Teaching both verbal and nonverbal approaches

Total Commun.

Means of nonverbal communication, whether it be signing or fingerspelling

manual approach

Use of amplification, auditory training, and speech reading in order to be mainstreamed into society.

Aural/oral method

A person with otosclerosis often has an audiogram reflecting Carhart’s notch. What is Carhart’s notch?

A specific loss at 2,000 Hz, as indicated by bone-conduction testing