PMS III Week 9 (Hearing Loss)

How do we hear?

Complex pathway that changes sound waves traveling through the air into electrical signals to the auditory nerve which carries these signals to the brain.

Hearing Pathway

1.Sound waves enter outer ear & travel through EAC leading to the TM

2. TM vibrates from sound waves and sends vibrations to ossicles (malleus, incus, stapes) w/in middle ear space

3. Vibrations from ossicles pass thru the oval window into inner ear. The inner ear, the cochlea, houses fluid which ripples secondary to the vibrations causing a traveling sound wave along the basilar membrane consisting of hair cells that generate the signal for the auditory nerve

4. The sound wave ends at the round window where the energy is released

common cc of hearing loss

"I can't hear." "My hearing is muffled." My family and friends say I can't hear." "I have ringing in my ear." "My ear is clogged."

H&P: Important Questions

• One ear? Both ears? One ear worse than the other?

• Duration? Sudden vs Gradual

• What makes it better/worse?

• Provocative vs Palliative factors

• Injury/Trauma/Recent travel?

• Recent infection/illness?

• History of surgery, trauma, recurrent ear infections, pregnancy

• Family history of hearing loss? What age?

• New medications?

• Noise exposure? Occupational, military, hobbies

H&P associated symptoms

pain, pressure, popping, drainage, ringing, headache, vertigo

Physical Exam: External Ear and EAC

External ear: lesions, injury/trauma, proptosis, redness, drainage

External Auditory Canal: cerumen, FB (bugs, Q-tips, cotton, ear buds, ear plugs, beads, earrings), drainage, blood, lesions, mass

Physical Exam: TM and Middle ear

TM: intact? Perforation - how big? Thick? Scarring (tympanosclerosis), retraction, cholesteatoma

Middle ear: effusion - serous vs mucoid?, masses (glomus tumor)

Tuning Fork - Rinne Test

Conduction

1. Normal hearing will show an air conduction that is longer and louder than bone conduction

2. If you have conductive hearing loss, the bone conduction is heard louder than the air conduction sound.

3. If you have sensorineural hearing loss, air conduction is heard louder than bone conduction, similar to normal hearing

Tuning Fork - Weber Test

Localization

1. Normal hearing will produce equal sound in both ears.

2. Conductive loss will cause the sound to be heard best in the abnormal ear.

3. Sensorineural loss will cause the sound to be heard best in the normal ear.

Pneumatic Otoscopy

• Helpful to detect middle ear effusion and key in dx of otitis media w/ effusion (OME)

• Allows determination of the mobility of TM in response to pressure changes

• Normal TM moves in response to pressure

• Immobility due to fluid in the middle ear, perforation, tympanosclerosis

Toynebee Maneuver

Used in office to equalize pressure within the middle ear. Combination of the valsalva maneuver and swallowing

Instruct pt to plug both nostrils and position their tongue on the roof of their mouth and swallow --> causes tongue to move upward, which facilitates the muscle movement of the palate required to equalize the pressure

If the TM is retracted, you will see the tympanic membrane "pop" laterally toward you.

Normal vs Abnormal TM

•First, know what is normal.

•Look at every ear that walks through the door! You may need to look at 100 ears to realize what is normal and abnormal.

•Don't get discouraged!

•No ear looks the same

identify A, B, C, D

A - Normal

B - Otitis Media (abt to rupture)

C - Eustachian tube dysfunction

D - Ear tube

perforation

tympanosclerosis (scarring from recurrent ear infections)

Clytostoma → BAD

may lead to mastoidectomy

retracted TM

Ear lesions

•Lesions on external ear/pinna, lesions in the canal

•Think about BCC, exposure to sun. We see a lot of lesions on the pinna that turn out to be cancer - refer to dermatology for MOHS.

Pure Tone Audiometry

•Determines the type, degree, and configuration of hearing loss

•PTA (pure tone average) = 500, 1000, 2000 Hz average

Speech Reception Threshold (SRT)

•Confirms the pure tone results (should be same as PTA)

•Records the faintest speech that can be heard half the time

Speech/Word Discrimination

Ability to correctly repeat back words at a comfortable decibel level

Air Conduction

Assesses sensitivity when the signal is transmitted through the outer, middle, and inner ear and then to the brain (entire hearing pathway)

Bone Conduction

Assesses sensitivity when signal is transmitted through the bones of the skull to the cochlea and then to the brain (stimulates nerve directly)

Tympanometry

An examination used to test the condition of the middle ear and mobility of the TM and the ossicles by creating variations of air pressure in the ear canal.

Tympanometry is an objective test of middle ear function.

identify each

A - Normal

B - No eardrum movement. Perforation or fluid.

C - Eustachian tube dysfunction (negative pressure)

As - Shallow or stiff movement. Tympanosclerosis.

AD - Hypermobile (flaccid/floppy eardrums).

degree of hearing loss (dB and Hz)

degree of hearing loss (dB and Hz)

Types of Hearing Loss

1. Sensorineural Hearing Loss (SNHL) --> age related, degeneration to auditory nerve

2. Conductive Hearing Loss (CHL) --> mechanical, something that can be fixed

3. Mixed Hearing Loss --> very common

anything about ____ dB is normal

anything about 20 dB is normal

this is an example of a normal hearing test

Sensorineural Hearing Loss (SNHL) is referred to as?

Presbycusis

- "hearing loss of old age"

- most common type of hearing loss!

Sensorineural Hearing Loss (SNHL) occurs when?

occurs when there is damage to the inner ear (hair cells) or to the nerve pathways (CN VIII) from the inner ear to the brain

SNHL reduces ability to hear ?

SNHL reduces ability to hear faint sounds

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

•Symmetric vs. Asymmetric

speech recognition (word score), once declined is ?

speech recognition (word score), once declined is not reversible

word score vs dB

dB: frequency (like on hand raise test)

word recognition - list of words, they repeat to the pt at different dB levels. what is the faintest speech level they can hear the word at. testing for CLARITY of the word.

lose high or low frequency first?

high frequency first (laterally located)

low frequency (medially located)

as graph progresses to the right, hearing loss worsens

Asymmetric SNHL

≥10 dB difference at 2-3 contiguous frequencies --> do further work up

concerned about acoustic neuroma

acoustic neuromas

benign tumors

slow growing. balance, ringing, one sided hearing loss.

Causes of SNHL: aging

presbycusis

Causes of SNHL: Exposure

Exposure to loud noise (NIHL)

Acoustic trauma

Causes of SNHL: Head Trauma

- damage to cochlea

- temporal bone fx with otic capsule fx

Causes of SNHL: Disease/Illness

• Sudden Sensorineural Hearing Loss (SSNHL) → likely viral, tx with steroids within 72 hours!! get them in to r/o.

• Congenital - prenatal exposure to Rubella, CMV, HSV, maternal DM

Causes of SNHL: Autoimmune inner ear disease

Think about when you see asymmetric SNHL

i.e.: Multiple Sclerosis, RA, Lupus

Causes of SNHL: Meniere's Disease

Usually one ear → Asymmetric SNHL, low frequency

QUADRAD:

- unilateral aural pressure

- unilateral hearing loss

- tinnitus

- vertigo

Causes of SNHL: Tumors

Acoustic neuroma → asymmetric SNHL

Causes of SNHL: Medications/Ototoxicity

aminoglycosides

chemotherapeutic agents

Presbycusis & the Geriatric Patient

Effects on Quality of Life?

At present time, 50-60% of today's population over 70 years of age experiences hearing impairment

•Negative impact on social interactions leading to social isolation

•Decreased employment opportunities leading to lost income

•Patient safety relating to automobile, occupational, environmental and other hazards is a concern for the hearing impaired since they cannot appropriately receive the auditory stimuli that alert them to presence of danger

Noise Induced Hearing Loss

Can be caused by a one-time exposure to an intense "impulse" sound (ie: explosion) or by continuous exposure to loud sounds over time (i.e.: woodworking, machinery, recreational activities such as target shooting, hunting, playing in a band)

Caused by damage and eventual death of hair cells

Sounds less than ____ dB are unlikely to cause hearing loss.

Sounds at or above ____ dB can cause hearing loss.

- Sounds less than 75 dB are unlikely to cause hearing loss.

- Sounds at or above 85 dB can cause hearing loss.

The louder the sound (dB), the shorter the amount of time it takes for NIHL to occur!

OSHA standards for noise exposure

"Noise notch" at 4,000 Hz

common

Treatment Options (SNHL)

• Conventional Hearing Aids

• BiCross Hearing Aids (Unilateral SNHL, SSNHL)

• Cochlear Implants (surgically implanted - Profound SNHL)

• EarLens - new technology, non-invasive procedure done in office. A tiny lens is placed directly on the ear drum. The ear tip transmits high fidelity audio signals directly to the lens which vibrates the ear drum directly across the full frequency range. Not compatible with MRI - needs to be removed by ENT and then replaced.

Meniere's Disease

Disorder of the inner ear that causes episodes of vertigo, tinnitus, fullness/pressure, and fluctuating hearing loss

Usually affects one ear and is preceded by fullness in that ear

Average attack lasts 2-4 hours

Meniere's Disease - occurence and

• Usually in those over 40 with equal distribution btwn M and F

• Episodes may occur in clusters (several attacks in a short period of time) or there may be many years that pass btwn (in which most people are symptom free)

• Low frequency SNHL pattern is commonly found initially, but as time goes on, usually changes into flat loss or a "peaked" pattern

Meniere's Disease Audiogram

What causes Meniere's Disease?

Underlying cause is really unknown

Most often attributed to viral infections of the inner ear, head injury, hereditary predisposition and allergy

Acute attack → "hydrops"

Meniere's Disease: Acute attack → "hydrops"

Fluctuating pressure of the fluid within the inner ear (endolymph).

The membranes become dilated like a balloon when pressure rises (endolymphatic duct/sac becomes blocked or if too much fluid is secreted (stria vascularis)

Diagnosing Meniere's Disease

• Refer to ENT

• Workup includes Audiogram (should see low frequency SNHL but overtime will typically flatten out)

• ENG - Electronystagmogram (Vestibular weakness, not always)

• ECOG - Electrocochleography

• MRI - r/o acoustic neuroma, hydrops

Treatment of Meniere's: Medications

Usually self-limiting, may take years

Medication

•Meclizine (antivert)

•Betahistine TID as prophylaxis

•Valium

•Diuretics (Dyazide)

•Zofran

Treatment of Meniere's: Diet

•Low sodium

•Avoid caffeine, alcohol, tobacco

Treatment of Meniere's: Vestibular Therapy

Exercises aimed at strengthening the vestibular system and central compensation

Treatment of Meniere's: Surgery

• Middle ear injections of steroid

• Ablative therapy - middle ear injection of gentamycin- vestibulotoxic/ototoxic and can ablate vestibular system to "turn off" in order to compensate for loss

• Endolymphatic sac decompression

Ototoxicity and SNHL - Common Medications affecting hearing and/or balance

•Gentamycin - primarily vestibulotoxic, but can be both

•Streptomycin - primarily vestibulotoxic, rarely used

•Neomycin - primarily cochleotoxic (topical drops) — not for use with TM perforation or open tubes***

•Polymixin B - primarily cochleotoxic (topical drops)***

•Tobramycin - primarily vestibulotoxic (topical drops)

•Erythromycin/azithromycin -cochleotoxic in high IV doses

•Cisplatin - primarily cochleotoxic, synergistic with gentamicin, high doses can cause profound deafness

•Furosemide - cochleotoxic, rarely seen

•Bumetanide - same as furosemide but less often seen

Conductive Hearing Loss

Occurs when sound is not conducted efficiently though the outer ear to the TM and ossicles of the middle ear

Usually involves a reduction in sound level or the ability to hear faint/quiet sounds

Often can be corrected medically or surgically

"Mechanical hearing loss"

Causes of Conductive Hearing Loss

• Otitis media with effusion

• Allergies (SOM)

• ETD

• Perforation TM (Large volumes)

• Benign tumors (glomus tympanicum, osteoma)

• Impacted wax, foreign body

• Otitis externa ("swimmer's ear")

• Absence or malformation of outer ear, canal or middle ear

• Cholesteatoma

• Otosclerosis

Cerumen Impaction

Acute Otitis media with Effusion

Serous Otitis Media

Acute Otitis Media: Causes

ET becomes blocked due to allergies, cold, flu, sinus infection, enlarged adenoids

bacteria: strep pneumo, H flu, M Catarrhalis

Acute Otitis Media: Risk Factors

6-36 months old, pacifier, daycare, bottle fed, exposure to cigarette smoke, drinking while laying down, changes in altitude/climate

Acute Otitis Media: Symptoms and PE

SYMPTOMS

-Fussiness/Intense crying (in infants), irritability, sleeplessness

-Clutching the ear while wincing in pain (toddlers)

-Complaining of pain in ear (older children/adults)

-Fever, hearing loss, off balance, fullness in ear, drainage if perforation

PE: redness, bulging TM, pus, air bubbles, perforation

Acute Otitis Media: Audio

Conducive Loss/B tymp (low volume)

Acute Otitis Media: Treatment

Majority resolve on own

Home pain medications, warm washcloth, amoxicillin, medrol pack, adenoidectomy, myringotomy tubes

Chronic Otitis Media

Occurs when fluid remains in the ear for a long time or returns over and over again, even without acute infection

Most common cause of pediatric CHL

Also due to ETD, adenoid hypertrophy, URI, allergic rhinitis

Chronic Otitis Media: Treatment

myringotomy tubes

TM Perforation - tx options

paper patch (small only)

tympanoplasty

Otitis Externa

Otitis Externa "Swimmer's Ear"

Inflammation or infection of the EAC, auricle or both

classifications of otitis externa

•Acute diffuse OE

•Acute localized OE (furunculosis)

•Chronic OE

•Eczematous (eczematoid) OE

•Necrotizing (malignant) OE

•Otomycosis

Acute diffuse OE

Most common form of OE, typically seen in swimmers

Acute localized OE (furunculosis) - associated with?

Associated with infection of a hair follicle

Chronic OE

Same as acute diffuse OE but is of longer duration (>6 weeks)

Eczematous (eczematoid) OE

Encompasses various dermatologic conditions (eg, atopic dermatitis, psoriasis, systemic lupus erythematosus, and eczema) that may infect the EAC and cause OE

Necrotizing (malignant) OE

Infection that extends into the deeper tissues adjacent to the EAC

occurs primarily in immunocompromised adults (eg, diabetics, patients with AIDS)

Otomycosis

Infection of the ear canal from a fungal species (eg, Candida Aspergillus)

Otitis Externa causes

water sports/activities, preceding ear trauma (ear cleaning, cotton swabs, water in ear canal)

Bacteria - most commonly pseudomonas, also staph aureus

Fungal - candida, aspergillus

Otitis Externa Symptoms

pain with palpation of tragus or traction to the pinna, otalgia, hearing loss, ear fullness, redness, edema, narrowing of EAC, tinnitus, fever, itching (fungal/chronic), deep pain (immunocompromised/necrotizing), discharge, cellulitis/LAD ipsalateral neck

Otitis Externa Diagnosis

Clinical.

*If patient is immunocompromised with severe pain, the ear should be examined by ENT to r/o necrotizing OE

Otitis Externa Treatment

pain management, removal of debris from EAC, topical medications (Otic Ciprofloxacin, Otic ofloxacin, dexamethasone)

Fungal- Vosol (hydrocortisone/acetic acid otic), otic clomitrazole, nystatin powder)

**AVOID TRIGGERS**

may need surgical debridement (usually for NOE or complicated OE)

Tympanic Membrane Retraction

Cholesteatoma

Glomus Tympanicum

Osteoma

Otosclerosis

Caused by abnormal bone remodeling in the middle ear which is a usually a lifelong process which bone tissue renews itself by replacing old tissue with new.

Abnormal remodeling disrupts the ability of sound to travel from the middle ear to the inner ear.

Many thought to be inherited

RF for Otosclerosis

White, middle-aged women are most at risk.

women who carried male babies

Otosclerosis - hearing loss

•Hearing loss is described as gradual with associated tinnitus, sometimes balance issues

•Audiogram - will show a mixed hearing loss with a "carhart notch" at 2000 khz

Otosclerosis - Diagnosis

CT scan - abnormal growth, soft tissue, etc

Otosclerosis - Treatment

Mild otosclerosis can be treated with a hearing aid but surgery is often required

Surgery --> Middle Ear Exploration with ossicular chain reconstruction or Stapedectomy

Otosclerosis - Other Options for Treatment (Surgical)

• OCR - Ossicular Chain Reconstruction (any repair to the ossicles)

• Stapedectomy - Similar to OCR, but replacing stapes with a prosthesis

• Typanomastoidectomy - COM, cholesteatoma, tumors

Otosclerosis - Other Options for Treatment (Hearing Aids)

•Traditional hearing aids

•Bone anchored hearing aid (BAHA) - implantable hearing aids into temporal bone that provides vibration to bone directly

Mixed Hearing Loss

•Occurs when there is a combination of a conductive hearing loss with a sensorineural hearing loss

•In other words, there is damage to the outer ear and middle ears' ability to conduct sound into inner ear (usually corrected medically / surgically) and damage to the inner ear (cochlea) or auditory nerve (corrected with hearing aids)

•Treatment therefore may be a combination approach