Audiology Midterm

Specialties within audiology

1. Medical audiology

2. Educational audiology

3. Pediatric audiology

4. Dispensing/rehabilitative audiology

5. Industrial audiology

6. Recreational and animal audiology

7. Tele-audiology

8. Forensic technology

Medical audiology key features

• Diagnose, manage, and treat hearing and balance disorders

• Work in hospitals, clinics, and ENT practices

• Diagnostic testing — audiometric evaluations, auditory brainstem response (ABR), and vestibular assessments

• Medical collaboration

• Rehabilitation

• Tinnitus management

• Balance disorder treatment

• Play a role in the interdisciplinary approach to diagnosing and managing auditory and balance disorders, ensuring patients receive comprehensive care and support

Educational audiology key features

• Provide audiological services in educational settings (schools) to ensure students with hearing impairments can access appropriate accommodations and support

• Hearing assessments

• Classroom acoustics

• Hearing aid and assistive technology management

• Collaboration with educators

• IEPs

• Training and education

• Advocacy

• Help students achieve academic success and fully participate in the school environment

Pediatric audiology key features

• Diagnose and manage hearing disorders in infants, children, and adolescents

• Work in various settings like hospitals, clinics, schools, and private practices

• Early Hearing Detection and Intervention (EHDI)

• Diagnostic testing — behavioral audiometry, otoacoustic emissions (OAEs), auditory brainstem response (ABR)

• Management

• Family counseling and support

• IEPs and 504 plans

• Collaboration with other professionals

• Ensure early and effective intervention for children

Dispensing/rehabilitative audiology key features

• Diagnosing and managing hearing loss through the selection, fitting, and adjustment of hearing aids and other assistive devices

• Assessment

• Device selection

• Fitting and customization

• Counseling and education

• Follow-up and support

• Aural rehabilitation — improve listening skills

• Combines clinical expertise with patient-centered care to improve QOL

Industrial audiology key features

• Focuses on preventing and managing hearing loss in workplace environments, particularly in industries with high noise levels

• Noise assessment

• Hearing conservation programs

• Hearing protection devices

• Regulatory compliance

• Employee training and education

• Data management

• Research and development

• Protect workers’ hearing, prevent NIHL, and promote safe auditory environments

Tele-audiology key features

• Using telecommunication technology to deliver audiological services remotely, enhancing accessibility and convenience

• Remote hearing assessments

• Hearing aid fitting and adjustment (virtual)

• Consultations and counseling

• Hearing rehabilitation

• Accessibility

• Integration with traditional care (in-person visits)

• Expands access to audiological care for those with mobility challenges, residing in remote areas, or having busy schedules

Animal audiology key features

• Focuses on the hearing health and management of auditory issues in animals (pets and working animals)

• Hearing assessments (brainstem auditory evoked response)

• Diagnosis and treatment

• Hearing protection

• Rehabilitation

• Education and counseling

• Research

• Enhance QOL for animals

Forensic audiology key features

• Involves the application of audiological principles and practices in legal contexts

• Expert witness testimony

• Evaluation and documentation

• Noise exposure analysis

• Hearing loss verification

• Causation analysis

• Consultation with legal teams

• Rehabilitation and compensation recommendations

• Ensure accurate assessment and interpretation of hearing-related issues in legal disputes

dB HL

How loud we wear the tone… the hearing ability of a person that gives a statement about the severity of hearing loss

“Audiometric normal zero”

HL = hearing level

dB SPL

Sound pressure level — the log scale when referencing the reference level of sound pressure, the local pressure deviation caused by a sound wave

• dB SPL = 20 x log (P0/Pr)

Sound pressure: the amplitude level of sound at a specific location in space

dB SL

Sensation level — dB HL amount relative to the individual’s threshold, the difference between person’s threshold and the level observed

If a person’s threshold is 23 dB HL, then a 33 dB HL sound is __ dB SL this person

10

A patient’s threshold is 20 dB HL, then a 50 dB HL sound is __ dB SL to this person?

30

dB IL

Intensity level — refers to the log scale when referencing the reference level of intensity

Sound intensity is the amount of energy transmitted per second over an area of one square meter

dB IL = 10 x log (I0/Ir)

Relationship between frequency and wavelength

The higher the frequency, the shorter the wavelength

The lower the frequency, the shorter the wavelength

λ = c / f

Overview of otoscopy

Hand-held otoscopes are used for inspection of the outer ear, ear canal, and tympanic membrane

Some disorders may be suggested by the appearance of the tympanic membrane

Shining a light allows some of the structures of the middle ear to become visible (because the tympanic membrane is semitransparent) — cone of light

Malleus, Incus, ear drum… want to see these and the light reflex

How to perform otoscopy in infants/children

• The pinna is pulled downward and back to better straighten the canal for a more direct view of the tympanic membrane.

• The examiner’s fingers brace the head to prevent injury to the ear canal if
  the patient should suddenly move

How to perform otoscopy in adults

• The pinna is pulled upward and back to better straighten the canal for a more direct view of the tympanic membrane.

• The examiner’s fingers brace the head to prevent injury to the ear canal if
  the patient should suddenly move

Eustachian tube

• The eustachian tube enters the middle ear anteriorly at a 30-degree

  angle in adults and passes down into the nasopharynx for 36 mm.

• In adults, the tube is normally kept closed by the spring mechanism of

  cartilage and is opened by the action of four sets of muscle.

  • Levator veli palatini

  • Salpingopharyngeus

  • Tensor tympani

  • Tensor veli palatini

When does the eustachian tube open?

Opening of the tube occurs during yawning, sneezing, or swallowing, or when excessive air pressure is applied from the nose

Eustachian tube in infants

• In infants, the eustachian tube is shorter and wider in relation to its length and in a more horizontal plane than it is in adults.

  • The orifice of the eustachian tube in the nasopharynx tends to

    remain open in infants until the age of about 6 months.

Functions of the eustachian tube

1. Balance pressure in the middle ear (commonly felt as your ears popping)

2. Drain fluid from the middle ear

3. Protect the ear from both hearing sounds your body causes and nasal drainage

Overview/steps of hearing

1. Sound waves enter the outer ear and travel through the ear canal, which leads to the eardrum.

2. The eardrum vibrates from the incoming sound waves and sends these vibrations to three bones in the middle ear.

3. The bones in the middle ear amplify the sound vibrations and send them to the cochlea.

4. When the sound goes into the cochlea, hair cells send a wave of energy to the auditory nerve and then to the brain

Disorders of the outer ear

• Microtia

• Atresia

• Growths in the external auditory canal

• Cerumen impaction

• External otitis

• Perforation of the tympanic membrane

Microtia

Birth defect of the ear in which the external ear is small and not properly formed

Atresia

Absence or underdevelopment of the ear canal and middle ear structures

Osteomas

Bony tumors in the external auditory canal

Exostoses

Outward projections for the surfaces of bone, known as swimmer’s/surfer’s ear, as a result of exposure to cold, wet, windy conditions

Cerumen impaction

Excessive wax in the ear

External otitis

Inflammation of the external ear canal, itching, may cause pain

Tympanic membrane perforation

The tympanic membrane may become perforated in several ways:
• Excessive pressure buildup during a middle ear disorder
• Direct trauma from a pointed object
• Sudden pressure in the ear canal
• Rapid changes in ear canal pressure such as in scuba diving

Myringoplasty — surgical repair

Nystagmus

The reflexive eye responses during head rotation

Dizziness vs. vertigo

Dizziness — a general term to describe unsteadiness, lightheadedness, or feeling foggy

Vertigo — a spinning sensation; you’re spinning or the room is spinning

Degrees of hearing loss

Hughson-Westlake Method

• If the patient responds, decrease stimulus intensity by 10 dB.

• If the patient does not respond, increase stimulus intensity by 5 dB.

• Threshold is determined to be the level where 2 out of 3 correct responses are obtained at the lowest ascending test level.

• The starting intensity for the subsequent frequency will be your previous frequency’s threshold + 10 dB.

Ascending

• Starting inaudibly and ascend in intensity.

• Difficulty conditioning patient to task, responses may be more of
  a minimal response level than threshold.

Descending

• Starting above threshold and turn the volume softer until barely

  audible.

• Patient becomes familiar with stimulus and what to listen for, but

  can also give more false positives, especially if patterning.

Disorders of the middle ear

• Otitis media

• Tympanostomy tubes (PE tubes)

• Middle ear effusion

• Cholesteatoma

• Patulous eustachian tube (PET)

• Otosclerosis

Otitis media

• Most common disorder of the middle ear

• Infection that causes inflammation and behind the eardrum

• Eustachian tube becomes swollen, mucus can build up

• Ear pain, trouble hearing, pressure in the ear, drainage from the ear

• Usually clear up within 3-5 days

Tympanostomy tubes (PE tubes)

• PE tubes might help individuals who have repeated, long-lasting
  ear infections.

• During a tympanostomy, a physician inserts a small tube into a tiny incision in the ear drum.

• The tubes help let air into the middle ear and allow fluid to drain.

Middle ear effusion

• There is thick or sticky fluid in the middle ear but no signs of acute infection

• Places pressure on the tympanic membrane

• May result from a cold, sore throat, or upper respiratory infection

• More common in children due to immature eustachian tube

• Difficulty hearing, tugging at ears, loss of balance, delayed speech development

• Resolves on its own within 4-6 weeks

• If it persists more than 2-3 months, ear tubes may be placed

Cholesteatoma

• Benign growth (skin-lined cyst) that begins at the eardrum and invades the middle ear and mastoid

• Can retain bacteria and cause infection

• Can eat away at the bones and erode the ossicles

• First sign is discharge

• Almost always needs surgery to treat

• As the cyst grows it can become infected

Primary acquired cholesteatoma

Occurs when the ear doesn’t drain or doesn’t even equal out pressure properly (eustachian tube)

Secondary acquired cholesteatoma

Develops when skin cells collect behind the eardrum after a rupture

Congenital cholesteatoma

Forms when skin cells become trapped in the middle ear before birth

Patulous Eustachian Tube (PET)

• Disorder of the valve of the eustachian tube that causes it to remain open

• Pressure in the ears, ability to hear your own voice/bodily functions loudly

• Can be caused by great weight loss, immune disorders, acid reflux, stress/anxiety, chronic nasal allergy

• There are medical treatments to avoid dehydration and surgical treatments to fill surrounding areas

Otosclerosis

• Abnormal hardening of body tissue — abnormal extension of sponge-like bone growing in the middle ear cavity

• Prevents ossicles from vibrating normally in response to sound

• Progressive disorder

• Runs in families, more common in women

• Surgery is often required — stapedectomy (prosthetic device used to allow sound waves to travel to inner ear)

Inner ear disorders

• Inner ear hearing loss (general)

• Presbycusis (age-related hearing loss)

• Noise-induced hearing loss (NIHL)

Perinatal causes of inner ear hearing loss

• Anoxia (deprivation of oxygen to the body), prolapse of umbilical cord, premature separation from placenta, toxic substances in bloodstream

• Head trauma through violent contractions or forceps during delivery

Treatment for inner ear hearing loss

• Watchful waiting

• Amplification

• Implantable devices — cochlear implants

• Aural rehabilitation

Postnatal causes of inner ear hearing loss

• Infections — mumps, measles, chicken pox, meningitis

• Most caused by virus are bilateral but some can be unilateral (mumps)

Presbycusis (age-related hearing loss)

• A gradual decrease in hearing sensitivity in both ears due to increase in age

• 1/3 of people between 65-74 have hearing loss

• Causes: age-related changes in middle ear, complex changes along nerve pathways from ear to brain, long-term exposure to noise, medical conditions like diabetes, genes, medications that are toxic to hair cells in cochlea

• Symptoms: muffled speech sounds, trouble understanding speech, often asking others to speak louder

Causes of noise-induced hearing loss

• Being around loud noises over a long period of time

• Exposure to loud noise in a short period of time, such as gunshot or explosion

• Shooting and hunting

• Listening to music at high volume through earbuds

• Lawn mowing

Symptoms of NIHL

• Decreased hearing

• Inability to hear high-pitched sounds

• Muffled or distorted speech

• Tinnitus

• Aural fullness

• Otalgia: pain in the ear

Prevention of NIHL

• Earplugs

• Earmuffs

Degree of hearing loss

Severity

Configuration of hearing loss

Shape of hearing loss on an audiogram

Type of hearing loss

Location of hearing dysfunction (outer, middle, inner ear)

3 types of hearing loss

• Conductive

• Sensorineural

• Mixed

Conductive hearing loss

Due to disorders in the outer and/or middle ear

• Outer ear:

  • Cerumen obstruction

  • Microtia

  • Atresia

• Middle ear:

  • Otitis media

  • Eardrum perforation

  • Exostoses

Sensorineural hearing loss

Due to disorders in the inner ear (sensory cells or neural region)

• Inner ear (sensory)

  • Age-related hearing loss

  • NIHL

  • Drug-induced hearing loss

  • Genetic-mutation induced hearing loss

• Inner ear (neural)

  • Acoustic neuroma

  • Auditory neuropathy

Mixed hearing loss

• Has both conductive and sensorineural components — due to disorder in outer and/or middle ear AND inner ear

• Ex. an older person with age-related hearing loss and an ear infection.

Air conduction testing

• Identifies patient’s hearing sensitivity at different frequencies — if there is a loss of hearing, the test can specify the degree/severity but not the type (conductive, mixed, or sensorineural) of hearing loss

• Evaluates the outer, middle, and inner ear

Bone conduction testing

• Determines the patient’s sensory/neural sensitivity

• Only evaluates the inner ear

• By using results of both tests you can determine the type of hearing loss (conductive, sensorineural, or mixed)

Order of frequencies for air conduction testing

1000 Hz - 2000 Hz -3000 Hz -4000 Hz -6000 Hz -8000 Hz -500 Hz -250 Hz

Order of frequencies for bone conducting testing

1000 Hz - 2000 Hz - 4000 Hz - 500 Hz - 250 Hz

Which ear do we start with when testing?

Always start with the better ear — if there is not a better ear, or if the thresholds are same for both ears, start with the right ear

Testing frequency for normal hearing

Start at 1000 Hz around 30-40 dB HL

If they do not respond, increase intensity by 10 dB

Testing frequency for hearing loss

1000 Hz around 50-60 dB HL

If they do not respond, increase intensity by 10 dB

Audiogram axes

X-axis: frequency (Hz)

Y-axis: hearing level (dB HL)

Audiogram key

How to record air conduction results on an audiogram

Left ear: blue X

Right ear: red O

Symbol placed at the intersection of frequency and intensity that represents the threshold

How to record bone conduction results for audiogram

Pure tone average

Average of hearing threshold levels at a set of specified frequencies: 500, 1000, and 2000 Hz

Shows hearing level in each ear

How to calculate pure tone average

dB level at 500 Hz + dB level at 1000 Hz + dB level at 2000 Hz = X/3 = PTA

Example: 45 + 35 + 30 = 36

How to report pure tone/audiogram results

Use a sentence or describe the right and left ear separately if there is an asymmetry

Need to include all 4 aspects of the hearing loss

1. Degree

2. Configuration

3. Type (conductive, mixed, sensorineural)

4. Lateralization (bilateral or unilateral, symmetrical or asymmetrical)

Audiogram characteristics for normal hearing

“Normal hearing sensitivity bilaterally”

Audiogram characteristics for conductive hearing loss

“Mild sloping to severe conductive hearing loss in the right ear”

“Moderate rising to mild conductive hearing loss in the left ear”

Audiogram air-bone gap

• The difference between the air and the bone conduction thresholds.

• The gap should be 10 dB or less in subjects without a conductive component (sensorineural hearing loss or normal hearing).

“Right mild flat conductive hearing loss”

Audiogram characteristics for sensorineural hearing loss

“Mild sloping to moderately severe sensorineural hearing loss bilaterally”

Audiogram characteristics for mixed hearing loss

“Mild precipitous sloping to profound mixed hearing loss bilaterally”

Types of lateralization

• Bilateral (both ears)

  • Symmetrical

    • Both ears have the same level and configuration of hearing loss

• Asymmetrical

  • ≥ 15 dB difference at 1 frequency

  • ≥ 10 dB difference at 3 consecutive frequencies

• Unilateral (one ear)

  • Left or right

Configurations of audiograms

• Flat

• Sloping

• Precipitous

• Rising or reverse slope

• Cookie-bite or trough

• Notch

• Corner audiogram

Flat configuration

“Mild flat hearing loss”

Sloping configuration

“Normal sloping to moderately severe hearing loss bilaterally

Normal hearing sensitivity through 500 Hz sloping to severe in the right ear

Normal hearing sensitivity through 1000 Hz sloping to severe in the left ear”

Precipitous configuration

“Normal through 1500 Hz precipitously sloping to profound hearing loss bilaterally”

Rising/reverse slope configuration

“Severe through 500 Hz rising to normal at 1500 Hz hearing loss”

Cookie-bite/trough configuration

“Moderate cookie-bite hearing loss between 1000 Hz - 5000 Hz”

Notch configuration

“Normal-mild hearing with a notch”

Corner audiogram configuration

Formula to describe an audiogram in a sentence

Degree + configuration + type + lateralization

Use air conduction results to determine configuration, lateralization, and degree

Use both air and bone conduction to determine the type

How would you describe this audiogram?

Mild sloping to moderately severe sensorineural hearing loss in the left ear

How would you describe this audiogram?

Mild to moderately severe sensorineural hearing loss bilaterally

How would you describe this audiogram?

Normal hearing sensitivity bilaterally

How would you describe this audiogram?

Mild to moderately severe mixed hearing loss bilaterally

How would you describe this audiogram?

Moderate precipitously sloping to profound mixed hearing loss in right ear

Normal hearing sensitivity through 1000 Hz precipitously sloping to profound hearing loss in the left ear

Outer ear primary function

Collects sound waves and channels them into the ear canal (external auditory meatus) where the sound is amplified

Outer ear structures

• Pinna/auricle

• External auditory canal (EAC)

• Tympanic membrane

Pinna/auricle

• Helps localize the sources of sounds that come from in front of, behind, below, and above the head

• Helps funnel sounds directed to it from the surrounding air into the opening of the ear canal

• Delivers high-frequency sounds better

• Made entirely of cartilage

• Ear lob = lobule

• Helix

• Antitragus

• Antihelix

• Tragus

• Concha