Audiology Midterm S.G.

What two professions joined together to create the profession of audiology?

1. Otology (the medical specialty concerned with diseases of the ear)

2. Speech-Language Pathology

What is certification?

• Certification is NOT a legal requirement for the practice of audiology.

• Audiologists with membership in ASHA (American Speech-Language-Hearing Association) must hold the Certificate of Clinical Competence (CCC) in Audiology.

• CCC-A designation shows that the level of preparation as an audiologist has been met, and documented levels of continuing education are maintained throughout one’s career.

What is liscensure?

• Licensure (and/or registration) is an important form of consumer protection

• W/o documentation of licensure, an individual cannot legally perform clinical audiology services.

How are certification & licensure different?

• Licensure is required

• Certification is not required to practice, it only shows that you did extra (??)

Name several specialty areas of audiology

• Medical audiology

• Educational audiology

• Pediatric audiology

• Industrial audiology

• Dispensing/rehabilitative audiology

List the 5 important aspects of the Decibel (dB)

1. It involves a ratio

2. It uses a logarithm

3. It is nonlinear (it cannot be simply added or subtracted & be meaningful)

4. It must be expressed in term of various reference points

5. It is a relative unit of measure. If your reference point changes, your dB level will also change.

What are the different ways dB can be expressed? What are their reference points? (3)

1. dB IL: 10⁻¹² watts/m²

2. dB SPL: 0.0002 dynes/cm²

3. dB HL: 0 dB HL (the audiometric zero) lowest sound energy to stimulate the human ear at a given frequency

What is the lowest frequency within a complex wave?

Fundamental frequency

What is the relationship between frequency & pitch?

• Frequency is the physical value of pitch

• Pitch is the perceptual value of frequency

• Directly related (frequency ↑, pitch ↑)

What is the relationship between intensity & loudness?

• Intensity is the physical value of loudness

• Loudness is the perceptual value of intensity

• Directly related (intensity ↑, loudness ↑)

What is the function of the auricle?

Gathers sound waves from the environment, funnels sound into the external ear canal, enhances delivery of high frequency sounds relative to low frequency sounds, & aids localization.

How many layers does the human tympanic membrane have?

Three

What is the point of maximum retraction of the tympanic membrane?

The umbo

The outer ear, or auricle, is also known as the _______.

Pinna

What is the auricle made of?

Cartilage

Where is cerumen produced?

The sebaceous glands

What part of the ear canal are the sebaceous glands located in?

The outer portion of the External Auditory Canal (EAM)

What is the light reflex which may be seen when inspecting the tympanic membrane with a bright light directed down the external auditory canal?

The cone of light

The tympanic membrane is held in position at the end of the external auditory canal by a ring of tissue called the _______ _______.

Tympanic annulus

The _____ _____ comprises the greatest surface area of the tympanic membrane.

Pars tensa

What is the purpose of the Eustachian tube?

To match the pressure of the middle ear to the pressure of the outside world.

The three middle-ears bones, aka ossicles, are the… (3)

1. Malleus

2. Incus

3. Stapes

Where is the facial nerve is contained?

The internal auditory canal

What are the muscles that operate in the middle ear?

1. Stapedius muscle

2. Tensor tympani muscle

Which middle ear ossicle is embedded in the fibrous portion of the tympanic membrane?

The Malleus

Which ossicle is the smallest of the middle ear bones?

The Stapes

Which of the middle-ear ossicles rocks in the oval window to transmit the mechanical vibrations of the ossicles to the fluids of the cochlea?

The Stapes

The size difference between the tympanic membrane & the oval window, along with the leverage action creation by the ossicles comprise what is known as _______ _______.

Impedance matching

What is the muscle in the middle ear that stiffens the membrane in the oval window when it contracts in response to loud sounds?

The stapedius muscle

What are the 2 fluids found within the inner ear?

1. Perilymph

2. Endolymph

Balance is maintained through input from the vestibular, visual, and proprioceptive system to the _______.

Cerebellum

What is the portion of the inner ear responsible for equilibrium?

The Vestibular (balance) portion

What is the portion of the inner ear responsible for hearing?

The Cochlear (auditory) portion

• aka Organ of Corti

What are the 3 fluid-containing channels of the inner ear?

1. Scala vestibuli

2. Scale media (aka Cochlear duct)

3. Scala tympani

The scala vestibuli & scala tympani contain _______, while the scala media contains _______.

Perilymph; Endolymph

The basilar membrane supports the _______, while Reisner’s membrane separates the scala vestibuli from the _______.

Organ of Corti; Scala media

The stereocilia on the tips of the outer hair cells are embedded in the _______ _______ & are sheared when the basilar membrane moves up & down in response to fluid wave created by the Stapes’ movement in the oval window.

Tectorial membrane

The Organ of Corti is considered to be the…

Sensory receptor organ of hearing

Once a neuron’s threshold has been reached, it fires with its maximum charge, a phenomenon known as _______ _______.

Action potential

Afferent neurons transmit impulses _______ the cochlea, while efferent neurons transmit impulses _______ the cochlea.

Away from; towards

The clearest explanation of how the ear works is embodied in the…

Beksy’s Traveling Wave Theory

What does the internal auditory canal contain? (4)

• Vestibulocochlear Nerve

  • Auditory & Vestibular nerves count as 2

• Facial nerve fibers

• Internal auditory artery

Efferent neurons carry impulses ____ the brain, while afferent neurons carry impulses _______ the brain.

Away from; towards

Fibers cross from the left cochlear nucleus to the right superior olivary complex through the _______.

Trapezoid body

The cochlear nucleus is divided into the _______ & _______ portions.

Dorsal & ventral

The arrangement of auditory nerve fibers from the cochlea through the central auditory structures reflects a _______ _______.

Tonotopic organization

The reflex activity of the middle ear muscles is mediated at the level of the…

Superior olivary complex

Within the central auditory pathways, the 1st point of bilateral representation of a signal presented to just one ear occurs after the _______ _______.

Cochlear nucleus

Decussation

Crossover points within the brain that unite symmetrical portions

Commissure

Nerve-fiber bundles that unite similar structures on both sides of the brain

Ipsilateral

On the same side

Contralateral

On the opposite side

List the Central Auditory Pathway past the Vestibulocochlear Nerve (6)

1. Cochlear Nucleus

2. Superior Olivary Complex

3. Lateral Lemniscus

4. Inferior Colliculus

5. Medial Geniculate Body

6. Auditory Cortex

What are some differences b/w screening & assessment?

Screening

• No intent to diagnose (pass/fail)

• Measure needs to be sensitive (cast a wide net)

• Not necessarily done by a specialist

Assessment

• Diagnostic in nature (more complete)

• Measure needs to be specific

• Performed by a certified professional in that area

What are the 2 conduction mechanisms of hearing? Describe them.

1. Air Conduction (AC): Sound waves entering the ear canal

2. Bone Conduction (BC): Vibrations picked up by the cochlea

What are the 3 types of hearing loss?

1. Conductive HL

2. Sensorineural HL

3. Mixed HL

Where is the problem in each type of HL?

• Conductive: AC & ABG

• Sensorineural: AC & BC, no ABG

• Mixed: AC, BC, & ABG

What is the normal result from a Weber test?

If the sound radiates to both ears equally

What is an abnormal result from a Weber test?

If the sound lateralizes to oner ear more than the other

What is the normal result from a Rinne test?

Patient can hear in both locations

What is an abnormal result from a Rinne test?

Patient can hear sound through BC, but not at their ear

What frequencies are routinely tested by AC in a routine hearing test?

250-8,000 Hz

What frequencies are routinely tested by BC in a routine hearing test?

500-4,000 Hz

Why is it important that audiological equipment be calibrated annually? (2)

1. To make sure that test results are accurate

2. To comply with industry standards

What is cross-hearing?

When the intensity is such that it crosses over to the other side

What is interaural attenuation?

• As sound travels from one side of the head to the other, a certain amount of energy is lost in transmission.

• This loss of intensity of a sound introduced in one ear & heard by the other is called interaural attenuation.

What is masking? Why is it important?

• Introducing noise to raise the threshold of the non-test ear

• It is important so that that non-test-ear cannot participate & “help out” the test ear

What is an Air-Bone Gap?

The difference between AC thresholds & BC thresholds

What does an ABG mean?

It means that there is middle or outer ear dysfunction

What 3 things are you looking for when interpreting an audiogram?

1. Degree (how much hearing loss)

2. Type (what kind)

3. Configuration (what shape)

Speech Recognition Threshold (SRT)

• SRT is the lowest hearing level at which speech can barely be understood at least 50% of the time.

• Purpose: to determine the softest level at which a subject can hear & repeat some words.

• used as a check of the reliability of pure tone thresholds

Speech Detection Threshold (SDT)

A.k.a. Speech Awareness Threshold (SAT)

• The lowest level, in dB, at which a subject can barely detect the presence of speech & identify it as speech.

• Subject DOES NOT need to understand what is being said, only that it is speech.

Word Recognition Score (WRS)

• A percentage measure that quantifies how clearly a subject can hear speech

• Reported as a percentage

Monitored Live Voice

???

Recorded Materials

Preferred over monitored live voice in almost all instances, as it is regulated and not at risk of skewing test results (???)

Why do we perform Speech Audiometry?

• To measure the degree of HL for speech

• To assess the ability to recognize & discriminate the sounds of speech (SDT, SRT, & WRS)

• To determine the dynamic range for speech sounds (DR)

• To find the patient’s most comfortable listening level (MCL)

• To find the patient’s threshold of discomfort or uncomfortable listening level (UCL)

What should the SRT “match” & why?

• The SRT should match the patient’s PTA (for a given ear)

• It should match because it indicates a good correlation between how well a person can hear pure tones & how well they can understand speech at a similar intensity level.

What is a Dynamic Range (DR)?

The difference between a threshold measure & the UCL (Uncomfortable level) for the same signal

What type of HL is associated with a reduced DR?

Sensorineural HL