Hearing Problems and Testing Final Exam

• Describe what happens during one cycle of an acoustic sine wave. 

• Given a sine wave, identify the phase.

Each cycle consists of one compression, one rarefaction, and it’s frequency determines the pitch, the cycle continues as long as the wave continues through the medium

Calculate frequency, period, and wavelength of a sine wave, given the formulas.

• Period=1/frequency (f=1/t)

• Wavelength=velocity/frequency (wavelength=343m/s in air at room temperature (wavelength=v/f)

• Frequency= the number of cycles in one second  (t=1/f)

• What is the relationship between frequency and period?

• inversely related; they are reciprocals of each other

• What is the relationship between frequency and wavelength?

have an inverse relationship; when one increases, the other decreases, and vice versa.

What is a resonant frequency?

the number of cycles per second (or frequency) at which it moves with the least amount of energy

•  How do mass and stiffness affect resonance?

• Energy must be continually applied which results in increased amplitude

• Physical characteristics, such as size; shape; tension, mass; length, etc., determine the resonant frequency. 

  • Bigger        lower resonant frequencies.

  • Lax             lower resonant frequencies

Using the sound pressure level scale, a 20 dB increase corresponds to a 10-fold increase in intensity

• A sound needs to be about 10 times more intense to be perceived as twice as loud

• Why is a log scale used?

• it matches our experience of how loud things actually seem.

• Does 0 dB SPL mean “no sound?” Why or why not?

• It doesn’t because this is the threshold that the human ear can hear to, it corresponds to .0002dynes/cm^2

• What is the inverse square law? Can you apply it to an example problem (as was completed in class)?

describes how the intensity of a sound decreases as the distance from the source increases.

ΔdB=20⋅log10​(41​)

2. Calculate the ratio:
   
   

log⁡10(0.25)=−0.602\log_{10}(0.25)= -0.602 

Multiply:

ΔdB=20⋅(−0.602)=−12.04

Subtract from the original SPL:

• 90−12.04=77.96 dB SPL at 4 meters90

• Calculate the signal-to-noise ratio given the level of the signal of interest and the level of the background noise. 

SNR (dB)=Signal Level (dB)−Noise Level (dB)

Let’s say:

• Signal level = 75 dB SPL
  
  

• Background noise level = 60 dB SPL
  
  

➗ Calculate SNR:

• SNR=75−60=15

How do we hear? Describe the function of the outer, middle, and inner ears.

• Soundwaves are caught by the outer ear through the ear canal, to the eardrum which vibrates the malleus, incus and stapes, and increase the sound vibrations. They send the signals to the cochlea, which makes the fluid inside create waves, the hair cells in the cochlea move and they are turned into electrical signals. Ions are released to the auditory nerve and the signals are sent to the brain.

What is otoscopy?

• is a clinical procedure used to examine the ear, particularly the outer ear canal and the tympanic membrane

• How did you perform it in the lab?

• I performed in the lab by washing my hands, getting the speculum prepped, bracing my client with my fingers, tugging on her ear a little and using the speculum attached to the otoscope to look inside her ear at all the different structures.

• What instruments did you use in the lab?

• I used a disposable speculum on an otoscope

• A speculum is a funnel shaped tool used to gently expand the ear canal and get a better look at the tympanic membrane and the surrounding structures.

• What is admittance?

• It refers to the ease with which sound energy flows through the middle ear system

What happens during tympanometric testing, e.g., what does the client experience and why?

• a small probe is placed in the ear canal to create a seal. The client may feel a slight pressure change in the ear and hear a humming sound as the device measures the ear's response to air pressure changes.This test is quick, painless, and helps assess the health and function of the middle ear. 

How are distortion product otoacoustic emissions generated?

• are generated when the cochlea is stimulated by two simultaneous pure tone

• What two pieces of information are used to determine whether DPOAEs are present or absent?

• Amplitude and signal to noise ratio

• At what hearing level do we anticipate OAEs will be absent? 

when hearing loss due to outer hair cell dysfunction is greater than 40 dB HL

• Explain the two pathways of hearing.

• Air and bone conduction.

What is an audiometer?

• a device used to measure hearing ability. It’s the tool audiologists use to perform hearing tests, like pure-tone audiometry.

What is a transducer?

• is the part of the system that delivers the sound to the person being tested. It converts electrical signals from the audiometer into audible sound or vibration.

What is an audiogram?

• is a graph that shows a person’s hearing thresholds — in other words, the softest sounds they can hear at different frequencies (pitches).

What do the axes represent?

• X axis Frequency (Hz) — the pitch of the sound

• Y axis Intensity (dB HL) — the loudness of the sound

• Why is dB HL used for intensity instead of dB SPL?

• dB HL is standardized to human hearing sensitivity

• What is a threshold or hearing level?

• The intensity (in dB HL) at which a person detects a tone at least 50% of the time
  
  

• It's measured separately for each ear and for each test frequency (250 Hz – 8000 Hz)

• screening

• a quick “filter” to catch potential hearing loss early, but it does not tell you how severe or what configuration of loss someone has.

Threshold searching

• provides the precise measurement of hearing sensitivity needed for diagnosis, management, and intervention.

• What is the adult screening intensity level for the frequencies of 1000, 2000, and 4000, according to ASHA guidelines?

• 25 dB HL

What is the interaural attenuation for headphones?

Typically 40 dB

• What is the interaural attenuation for insert earphones?

• Attenuation (IA): Typically 60 dB to 70 dB

Why and when is masking for air conduction completed?

• To make sure the nontest ear isn't helping the test ear. Air conduction threshold of the test ear is greater than or equal to the bone conduction threshold of the nontest ear + interaural attenuation (IA).

• Why and when is masking for bone conduction completed?

• BC vibrations stimulate both cochleae equally, so it's hard to tell which ear is actually being tested. Masking is needed when there is an air-bone gap ≥ 15 dB in the test ear.

Conductive hearing loss

air conduction outside of typical range, air-bone gap greater then 10 dB HL

Sensorineural Hearing loss

Air conduction outside of typical range, bone conduction outside the typical range

Mixed hearing loss

Air conduction outside the typical range, bone conduction outside the typical range, air-bone gap greater than 10 dB SPL.

• What is a spondee?

• A foot that consists of two long or stresses syllables.

Explain how and why speech (word) recognition testing is completed.

• to evaluate how well someone can understand spoken words at comfortable listening levels, and it's often used to assess hearing loss and its impact on speech perception. 

• The test involves presenting a list of words and asking the person to repeat them, with the results indicating the percentage of words understood correctly. 

• When and why is ABR testing used?

• The test is mostly done on infants and children who may not be able to respond to behavioral hearing tests because of their age.

• How is this objective test different from OAE testing?

• OAEs assess the function of the outer hair cells in the cochlea, while conventional tests assess the entire auditory pathway.

Cerumen impaction

Flat (Type B) with a small ear canal volume

Conductive

Causes: hearing aid use; frequency use of cotton swabs Treatment: removal by a physician

Tympanic membrane perforation

Type B with large ear canal volume

Conductive hearing loss

Causes:Trauma (rapid increase in pressure), skull fracture, injury, burns, foreign bodies, middle ear infections

Eustachian tube dysfunction

Type C tympanogram

conductive hearing loss

Cause: swelling of the eustachian tube due to infection or allergy, as examples; when the tube does not open and close sufficiently, then negative middle ear pressure can form

Otitis media with effusion

Type B with typical ear canal volume

Conductive hearing loss

Causes:Otitis media with effusion (OME) occurs with fluid in the middle ear space

Otosclerosis

not sensitive* to detecting otosclerosis because Type A can be the result

Conductive hearing loss.

a spongy layer of new bone forms on the footplate of the stapes; the footplate of the stapes wedges into the oval window, resulting “stapes fixation” (immobile stapes footplate)

Presbycusis

Normal (Type A) tympanograms

sensorineural hearing loss

Cause: Aging

Noise-induced hearing loss

Type A

sensorineural hearing loss

Prolonged or sudden noise exposure

Tinnitus

Type A

Noise exposure, age related, meniere’s disease, blockage, etc.

Congenital Cytomegalovirus (CMV)/CMV acquired shortly after birth

(viral infection) either in utero or outside. In utero, it would be developmental CMV. -Transmission of bodily fluids

Sensorineural hearing loss (SNHL): disturbance in the inner ear affecting outer hair cells and inner hair cells, typically permanent; sensory + neutral are possibilities.

-Sensorineural hearing loss

-Different for everybody Healthy: usually goes away on its own Unhealthy: can be very dangerous, get tested as early as possible

-Antivirals -Speech Therapy -Occupational Therapy

Sudden sensorineural hearing loss

Viral infections (e.g., CMV, HSV) Vascular events (e.g., stroke, ischemia) Autoimmune diseases Trauma (e.g., head injury, barotrauma) Ototoxic drugs Tumors (e.g., vestibular schwannoma) Idiopathic (most common)

Rapid onset (within 72 hours) Hearing loss in one ear (usually) Tinnitus (ringing in the ear) Ear fullness or pressure Possible vertigo No obvious external cause

-sensorineural hearing loss --Moderate to severe loss in the left ear and Mild loss in the right ear with an asymmetric hearing loss. -After treatment:  Mild to moderate sloping loss bilateral sloping sensorineural loss

Time of onset, the age of the patient, a presence of vertigo, and severity of hearing loss

Treatment depends on the severity. Acute cases, mainly Sudden Sensorineural Hearing Loss and Idiopathic Sudden Sensorineural Hearing Loss.  Management-  *Corticosteroids How to manage Sensorineural Hearing Loss:  -Hearing aids  Cochlear implants  Personal frequency modulation (FM) systems  Roger Pens Emerging Interventions:  *Defibrinogen

Meniere’s disease

An excess amount of build-up of endolymphatic pressure in the inner ear

-Vertigo -Tinnitus -dizziness -sensorineural hearing loss -progression worsens overtime

-sensorineural hearing loss

-Meniere’s is a lifelong disease, and treatment will only minimize the effects of symptoms on patients, not cure them

-Low-salt diet  -surgery to try to reduce symptoms -diuretics -medications to deal with nausea/other less severe symptoms

Treacher Collins syndrome

Genetic mutations in TCOF1 (most common), POLR1C, or POLR1D Autosomal dominant inheritance (mostly) De novo mutations (in ~60% of cases, no family history)

Facial bone underdevelopment (cheekbones, jaw) Down-slanting eyes Eyelid colobomas Malformed or absent ears Hearing loss (conductive) Cleft palate (sometimes) Normal intelligence

Conductive HL, due to microtia (w/ atresia). Tested audiologically through soundfield speakers due to absence of ear canal.

Typical lifespan and average intelligence. Some severe cases do require lifelong medical care though.

Varies on severity: possible hearing aid or cochlear implant, surgical reconstruction. Support from, medical care teams like SLP, Audiologist, Surgeon, etc.

• What does 1-3-6 mean as it relates to newborn hearing screening?

• 1 month check, 3 months check, 6 months check

• Explain two behavioral methods to assess hearing in children from about 7 months to 26 months of age and from 27 months to 59 months of age.

• Video Reinforcement Audiometry (VRA)

• Conditioned Play Audiometry (CPA)

• When do infants start to look toward the source of sound?

6 months

• When do infants respond to their name?

six months