Consists of outer, inner and middle ear

Located in temporal bone section of the skull

Outer ear is made up of pinna and external auditory canal - pinna gathers sound waves and transports into the ear canal/

Middle ear consists of ear drum, malleus, incus, stapes and eustachean tube. The ear drum converts the sound energy to sound waves

Inner ear consists of the cochlear, eighth nerve, semicircular canals, facial nerves. Cochlea converts sound waves/vibrations to electrical signals, sending nerve impulses.

When nerve impulses arrive at the brain stem, it is received by the auditory cortex

Role of the Pinna:

• Cartilage covered with skin

• Unique configuration of ridges and grooves 

• Gathers sound waves from the environment, into the ear canal

• Assists in sound localization – where is the sound coming from?

Role of Ear Canal:

• Opening at the pinna

• 25mm in adults

• Direct the sound energy to the eardrum

• Outer – cartilaginous portion

• Inner – bony portion

• Hair follicles and glands – produces ear wax/sporinum

  • Sticky and smelly, prevents flys, dust, protects ear drum

  • Skin of ear canal grows outward

Ear drum (tympanic membrane), malleus, incus, stapes

• Thin membrane made up off several layers of skin 

Ear drum is fairly taught, concave, turning toward ear drum

Ear drum should be greyish in color, converts acoustic energy to magnetic energy

Malleus – long arm is behind the ear drum

Stapes reflex – activated with loud sounds, tightening the bones which lessens the sounds that travel

Ossicles link the tympanic membrane to the oval window

Middle ear improves the sound energy from the air to the fluid cochlea

Ossicles add as a lever, increasing amplitude at the stapes

• 3 smallest bones in the human body 

 Eustachean tube – links to the nasal pharynx

• Responsible to equalize air pressure from the middle ear and environment

• Yawn/Swallow to open eustachean tube

•  Provides exit for mucus of fluids that may collect in this area

Consists of the cochlea – snail shaped bone, inner part of the ear with 2 and half turns in its axis

• Base and bottom, top and apex of the cochlea

• Footplate is embedded in the oval window near the base of the cochlea 

• Exiting out from the cochlea is the cochlear nerve

• Partitioned into 3 fluid filled chambers 

  • Scala media, scala vestibuli, scala timpani – filled with endolymph, perilymph, and perilymph 

• Sound from the air vibrates the ear drum, sound energy increases the ossicles, then transferred to the fluid filled cochlea 

• Scala media

• Basilar membrane runs along the cochlea and divides the three chambers

  • Organ of corti lies on the basilar membrane – very important as it contains the sensory cells of hearing, inner and outer ear cells

Organ of corti – inner hair cells sit on the basilar membrane and send nerve impulses

• Basilar membrane is arranged according to frequency

  • Each specific frequency stimulates a different place along the basilar membrane 

• Lower frequency – further along the basilar membrane where it is wide and floppy

• Higher frequency – closer to the basal end

Eighth nerve – beginning of this deeper system

Modiolus – essential bone of the cochlear, which it surrounds

Nerve fibers exit the organ of corti where the cell bodies form the spiral ganglion, forming the modiolus

Exits and maintains tonotopic (spiral) organization with nerve fibers from the basal end where the high frequency and low frequency nerve fibers are on the inside

30,000 nerve fibers in the cochlear which carry information to the brain stem

As the eighth nerve exits the cochleas through the internal auditory canal of the temporal bone, it joins to the vestibulocochlear nerve 

• Together they travel to the central auditory system

Infection of the meninges -- can be bacterial or viral

Sensorineural hearing loss occurs in 30% of cases of bacterial meningitis

Leads to inflammation and damage to inner ear/cochlea → sensorineural hearing loss

Ossification of cochlea – hardening into bone, growth with less permeable cochlea, challenging the placements of the ossicles

Bilateral, permanent, severe sensorineural hearing loss

Inadequate opening of the tube – usually when we yawn or swallow it opens/closes, normal reaction

Lets air into the nuclear space, equalizes pressure

Dysfunctions will not let pressure be equalized, negative pressure will build up and cause the ear drum to be retracted inward, toward the middle ear space and will interfere with normal vibration

Prolonged eustachian tube dysfunction can lead to fluid build up

Build up of fluid in the middle ear space

Eustachian tube cannot open and close

So the middle space sucks the fluid from surrounding tissue, builds up in middle ear space and impede movement of ossicles and ear drum

Common in children – shorter and more horizontal tube

More susceptible to otitis media as fluid isn't being drained

More floppy eustachian tube

Worse during winter months

Cleft palate and down syndrome – more risk

Temporary Threshold Shift (TTS) - Reversible

Permanent Threshold Shift (PTS) - Irreversible

Can be unilateral or bilateral depending on noise source

Important Factors

• Length of Exposure

• Intensity and frequency of sound

• Certain audiometric configuration

Can be caused by extremely loud bursts of sound, such as gunshots or explosions, which can rupture the eardrum

Can cause Tinnitus

SPL is greater in smaller spaces

Noise destroys the hair cells of our ears → broken and bent hair cells

The audiogram of familiar sounds is a great visual tool to help explain what regular sounds are being heard. The familiar sounds model is great to plot a person's threshold against the sounds that are audible (or not), indicating the type and degree of hearing loss.

The speech banana is the yellow shaded area that explains the speech sounds in that given range. On the lower frequencies, more of the vowels can be heard, and the higher frequencies are fricatives, and whispers that can be heard.

• This is helpful in plotting a person's results against the sounds to understand what they can hear.

Both ears are symmetrical

The mid-range frequencies are hard to hear

No significant airborne gaps between bone and air conduction - SNHL

Even when speech is loud enough to hear, it may still be unclear or sound muffled

Can have loss of both clarity and loudness

Damaged inner ear result in distortion of the signals

Airborne gaps more than 10dB

Symmetrical

Bone conduction - slightly abnormal

Air conduction - moderately severe

Configuration is sloping

Pretty symmetrical

Airborne gaps suggest it is CHL

Air Conduction channel thresholds are poorer due to a blockage of the sound when listening through the headphone or insert

• Blocked by inner or middle ear

Clarity of speech is maintained

The Ling 6 sounds represent different speech sounds from low to high pitch frequency.

It helps to test hearing and to check that individuals can hear speech sounds necessary for learning language.

Ling 6 text

• /a/

• /u/

• /i/

• /sh/

• /m/

• /s/

• They need to repeat the sounds they hear

• Each ear should be tested individually

Red "o" marks the air conduction results for the right ear

Blue "x" marks the air conduction results for the left ear

If the two lines are essentially overlapping, your hearing loss is considered symmetrical

Bone conduction -- marked with a “[“ or a “<” symbol and vibrations occur on the mastoid bone

Conductive Hearing Loss

• If the difference between Air Conduction and Bone Conduction is greater than 10dB, there is a significant air-bone gap (ABG) at that frequency and the hearing loss is conductive

• Air Conduction channel thresholds are poorer due to a blockage of the sound when listening through the headphone or insert

  • Suggests it is blocked by outer or middle ear

• Presence of air bone gap, greater the gap, greater the hearing loss

• Abnormality in outer or middle ear that prevents sound from being conducted properly

• Usually abnormal tympanogram with absent reflexes

Sensorineural Hearing Loss

• Air Conduction and Bone Conduction thresholds are abnormal with no significant air bone gaps

• Due to damage of the sensorineural mechanism 

  • Missing or damaged hair cells in the cochlea

  • Abnormality of the auditory nerve

• Likely impaired speech recognition discrimination score

• Even when speech is loud enough to hear, it may still be unclear or sound muffled

• Can have loss of both clarity and loudness

• Damaged inner ear result in distortion of the signals

Mixed Hearing Loss

• Sound is being delivered to an impaired cochlea that is attenuated by a disordered middle or outer ear

• Both air conduction and bone conduction thresholds are abnormal

• Air bone gaps present

• Combination both conductive and sensorineural components

• Speech recognition score could be depressed

• Tympanogram usually abnormal – due to outer or middle ear

  • Bone conduction thresholds should NEVER be worse than air conduction thresholds

Determined by air conduction threshold

Considers the entire auditory system

Lower the threshold, the more severe hearing loss is

Adults have higher thresholds

Used for:

• Conductive and mixed hearing loss.

• Single-sided deafness (SSD).

Bypass outer and middle ear by sending vibration directly to cochlea.

1 transmitter can send to unlimited receivers

Dynamic FM receiver

Clipped within 6 inches of teachers mouth

Can no longer shut the FM from receiver end

National Association of the Deaf (NAD) – Civil rights organization advocating for the rights of deaf and hard of hearing individuals in the U.S.

Hearing Loss Association of America (HLAA) – Focuses on education, advocacy, and support for people with hearing loss.

American Society for Deaf Children (ASDC) – Advocates for early language access and family support.

Deaf CAN! – Promotes empowerment and advocacy through education and awareness.

Deaf Youth USA (DYUSA) – Youth-led organization advocating for equity and justice for deaf youth.

Described and Captioned Media Program (DCMP): Free accessible educational media for deaf, hard of hearing, blind, and visually impaired students.

National Deaf Center on Postsecondary Outcomes (NDC): Offers tools and research to improve accessibility in education and employment.

Gallaudet University Accessibility Resources: accessibility for deaf students in higher education.

Apple Accessibility Features: Built-in iPhone and iPad features like Live Captions, Sound Recognition, and Visual Alerts.

Google Accessibility Tools: Live Transcribe, Sound Amplifier, and Android captioning settings.

Hands and Hearts - children's picture book about a mother and daughter who spend a day at the beach communicating through ASL, the story incorporates teaching 15 basic ASL words in the side bars

You're Welcome, Universe - teenage girl gets expelled from her school. Now, in a mainstream school, she’s treated like an outcast as the only deaf student.

https://www.dailymoth.com/blog

• News delivered in ASL

https://www.nyfoundling.org/what-we-do/our-programs/child-welfare/family-services-for-deaf-children-and-adults/

• Many resources and forums individuals can join

https://support.apple.com/en-by/guide/iphone/iphe0990f7bb/ios

• Speech to text app

https://childrenshearing.org/children-and-families/programs-for-parents/

• Children's Hearing Institute (CHI) is a non profit that brings together the pediatric hearing loss community in New York, New Jersey, and Connecticut.

Hearing in a Deaf World

• https://www.thehummingbirdpost.com/life/hearing-in-a-deaf-world-part-four

Deaf YouTuber and activist sharing life experiences and accessibility topics

• https://www.youtube.com/user/rikkipoynter

Marlee Matlin - Academy Award-winning American actress and activist who was the first deaf performer to win an Oscar, for her role in Children of a Lesser God

Dr. Glenn Anderson - famous for achieving his doctoral despite discrimination as a Black deaf man

Claudia Gordon – First Deaf Black female attorney in the U.S., advocate for disability rights