Exam 2 -- Intro to Audiology

Ch. 3

True Positive (TP)

Test correctly identifies a disorder

True Negative (TN)

Test correctly eliminates an incorrect diagnosis

False Positive (FP)

Test says a disorder is present when that diagnosis is incorrect

False Negative (FN)

Test incorrectly eliminates a correct diagnosis

Sensitivity

How well the test correctly diagnoses a disorder → True Positive

Specificity

How well the test correctly rejects an incorrect diagnosis → True Negative

Efficiency

Percentage involving false positives + false negatives

Predictive Value

Percentage involving true positives + true negatives

Air Conduction — AC

Outer ear → Middle ear → inner ear/cochlea → Auditory nerve → Brain

AC travels through the outer and middle ear before reaching the cochlea

Bone Conduction —BC

Bone → Cochlea → Auditory nerve → Brain

BC SKIPS the outer and middle ear.

Outer Ear

• Pinna

• Ear canal

• Tympanic membrane/eardrum

Middle Ear

• Air-filled space

• Ossicular chain:

  • Malleus

  • Incus

  • Stapes

Inner ear

• Cochlea

• then sounds to:

  • Auditory nerve → Brainstem → Auditory cortex

Sensorineural Hearing Loss - SNHL

Where is the problem?

• cochlea and/or auditory nerve

Audiogram Rule

• AC = Abnormal

• BC = Abnormal

But: NO significant 15+ dB Air-Bone Gap

Mixed Hearing Loss

• Conductive + SNHL = Mixed

• The problems lie in the Outer/Middle ear + Inner ear/Nerve

• Audiogram rules

  • AC = Abnormal

  • BC = Abnormal

  • Air-Bone Gap = 15+ dB

How do you identify each type on an audiogram?

• Type → AC → BC → ABG

  • Conductive → Abnormal → Normal → >/ = 15dB

  • SNHL → Abnormal → Abnormal → No >/= 15 dB gap

  • Mixed → Abnormal → Abnormal → >/= 15 dB

How do you calculate Pure-Tone Average — PTA?

• PTA uses:

• 500 + 1000 + 2000 Hz

• you will add them up and divide by 3

What frequencies are typically tested for AC?

250, 500, 1k, 2k, 3k, 4k, 6k, & 8k Hz

What frequencies are typically tested for BC?

500, 1000, 2000, & 4000Hz

What is Threshold?

The lowest/softest level at which the patient correctly identifies the tone at least 50% of the time.

What tells you the TYPE of loss?

Bone Conduction

What tells you SEVERITY of loss?

Air conduction

Why are patient instructions important?

Because incorrect understanding can produce false responses.

A patient may:

• Misunderstand instructions

• Forget instructions

• Fake a respones

• Guess

False Negative responses can make hearing appear worse

False Positive responses can make hearing appear better.

Why does the correct headphone/insert need to be on the correct ear?

• Because you need to make sure you’re actually testing the intended ear.

  • the recorded right/left ear results would not represent the ear you intended to test.

Why is the audiologist always looking for faking?

Because false responses affect the accuracy of the hearing test. W

What is auditory processing?

• Central hearing loss/auditory processing disorder:

  • a decrease in auditory comprehension, regardless of language or cognitive ability, without a measurable deficit in AC or BC hearing levels

What is Masking and why is it needed?

Masking is used in the:

• Non-Test Ear

* Test ear → we’re measuring it.

Non-test ear → masking noise prevents it from helping.

What noise is used for pure-tone masking?

Narrow Band Noise - NB

What noise is used for speech masking?

Speech Noise — SN

Speech = Speech Noise

Why are insert earphones best?

• Reduce background noise

• Better infection control

• Deep insertion is best

• Help avoid collapsed ear canals

What’s the negative of using inserts'?

Cost

Is live voice or recorded material best for speech testing?

Recorded Material.