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Audiology Review: Preparing for the Praxis and Comprehensive Examinations
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to the patient and have the patient verbally repeat the words (or point to pictures in the case
that verbal repetition is not an option). Note that some tests, like the NU-6, have options to
present the 10 most difficult words instead of a full list of 25 or 50.
The test is scored as a percentage of words correct. There are many variables that must be
determined with completing word recognition testing:
●
Stimulus delivery: recorded stimuli are preferred for reasons previously discussed.
●
Type of stimuli: monosyllabic words; sentences; nonsense syllables/phonemes
●
Response method: verbal (most circumstances); alternate forms (written or picture
pointing)
●
Presentation levels and number of presentation levels: consider the purpose of the
test
— if PB
is being sought or if the patient’s performance at typical conversational
max
levels is being examined.
●
Presence of competing noise: again, consider the purpose of the test.
●
Masking: generally accepted speech testing IA is 45 dB HL for supra-aural headphones
and approximately 60 dB HL for insert earphones.
Speech Testing Considerations
The advantages and disadvantages of using MLV versus recorded speech material were previously
discussed, so this section will discuss the stimuli used in WRS.
Speech Stimuli
The most common stimulus used as part of the comprehensive audiologic evaluation is the monosyllabic word. Common word lists utilized are the:
n
Phonetically Balanced 50 (PB-50) (Egan, 1948)
Created in the Psychoacoustic Laboratory at Harvard
A 1,000-word bank was divided into 20 different lists of 50 words each that were built
so that the phonetics aspects of the English language were proportionally represented in
each list.
n
CID Auditory Test W-22 (W-22) (Hirsh et al., 1952)
Evolved from initial PB-50 word lists
Based on familiarity ratings of the 1,000 words that initially were used by in Harvard
Psychoacoustic Laboratory
Took 120 original words plus 80 new words to develop four 50-word lists known as the
CID W-22 lists
n
Northwestern University Auditory Test Number 6 (NU-6) (Lehiste & Peterson, 1959)
Developed with focus on a phonemically balanced word list as opposed to phonetically
balanced lists used with the PB-50 and W-22
Phonemic balancing could be accomplished using the consonant-vowel-consonant structure
by using the frequency of each initial consonant, the vowel, and final consonant across
word lists. The NU-6 comprises four 50-word lists.
CHAPTER 5 Adult Assessment and Differential Diagnosis
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While monosyllabic words are likely the most commonly utilized stimulus for word recognition
testing, sentences and nonsense syllables can also be used.
n
Sentence testing was initiated during World War II as a method to evaluate military
communication equipment.
n
Introduced into clinical practice with the CID Everyday Sentences with 10 lists of 10
sentences (Silverman & Hirsh, 1955)
n
Each list of the CID Everyday Sentences Test has 50 key words with the responses being
scored as a percentage of key words correctly identified. The thought process was that
monosyllabic words provided useful information in regard to the patient’s hearing status, but
not representative of daily speech.
n
The Nonsense Syllable Test (NST) was introduced with the goal to examine the usefulness of
nonsense stimuli as a component of speech audiometry (Lawson & Peterson, 2011).
There are two forms of NST with six randomizations of 25 high-frequency consonant-
vowel-consonant-vowel stimuli in each form. The patient is instructed to repeat the
nonsense syllable heard. The test is scored based on each phoneme identified as a function
of intensity.
The NST test could provide some differentiation of listeners with normal hearing and those
that were hearing impaired. This test was thought to be beneficial in examining auditory,
speech reading, and audiovisual abilities (Lawson & Peterson, 2011).
183
Presentation Level
In choosing a presentation level, most audiologists choose a sensation level in reference to the SRT as
their presentation level to achieve maximum word recognition. However, other approaches include
using a fixed sound pressure level (SPL) or on the basis of loudness measures such as most comfortable
loudness level (MCL).
n
Most researchers recommend utilizing different word lists at multiple presentation levels to
determine PB
n
Approximately 74% of practicing audiologists only present at one presentation level (40 dB SL
(Beattie & Raffin, 1985).
max
re: SRT) (Guthrie & Mackersie, 2009).
This presentation level is thought to correspond to a level that normal-hearing individuals
could achieve maximum speech understanding, but research has shown that the
presentation level necessary for PB
is variable across individuals (Beattie & Raffin, 1985).
max
A 40 dB SL presentation level can also encroach on a patient’s uncomfortable loudness
level/loudness discomfort level (UCL/LDL).
n
In a study of individuals with different degrees of hearing loss, PB
was achieved at 5 dB
max
below UCL and an SL re: 2000 Hz threshold. The SL re: 2000 Hz thresholds varied 10 to
25dB SL depending on the 2000 Hz pure-tone threshold (Guthrie & Mackersie, 2009).
When necessary, during SRT or WRS, the masking rules still apply and therefore must be implemented
when necessary to prevent cross-hearing. Remember that the commonly accepted IA for speech testing
is 45 dB for supra-aural headphones or 60 dB for insert earphones.
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184
AUDIOLOGY NUGGET
One additional phenomenon that can be captured with multiple presentation
levels during WRS is rollover. The rollover effect can be seen in individuals with
retrocochlear pathology in which the WRS will decrease with increased intensity
on speech presentation levels. With retrocochlear pathology, patients can show
improved WRS with increasing intensity of the presentation level. However, at
a certain point, the patient may begin to show decreasing WRS with subsequent
increases in presentation level. This is the rollover effect.
For example: If the clinician is completing multiple word lists, creating
PI-PB function in which word recognition score is measured as a function of
presentation level, to determine PB
obtain a WRS of 76% at 65 dB HL, but then scores 40% at 85 dB HL, this
would indicate rollover and may be suggestive of retrocochlear pathology. Significant rollover for identifying retrocochlear pathology has been suggested to
be greater than 0.35 to 0.45 when using the formula: (PB
(Meyer & Mishler, 1985). In this example, (76 − 40) / 76 equals 0.47, which
would be significant for suspected retrocochlear involvement.
let us look at an example. If a patient
max
− PB
max
min
) / PB
max
Speech Testing in Noise
The main concern for most patients with hearing impairment is not being able to understand speech in
the presence of background noise. Available information through speech-in-noise testing can provide
valuable insight in managing a patient from a rehabilitation standpoint, which can include selection
of appropriate technology with HAs, cochlear implants, and assistive listening devices. Additionally,
this can also help guide appropriate counseling techniques to help the patient understand realistic
expectations and appropriate use of communication strategies.
n
The most common speech-in-noise tests that are clinically available are the Quick Speech-
in-Noise Test (QuickSIN), the Words-in-Noise Test (WIN), the Bamford-Kowal-Bench
Speech-in-Noise Test (BKB-SIN), and the Hearing-in-Noise Test (HINT); the QuickSIN
and the WIN have been shown to be the most sensitive of the four tests to speech recognition
performance in background noise (Wilson et al., 2007).
n
QuickSIN (Killion et al., 2004):
Twelve six-sentence lists that can be utilized with individuals with normal hearing or
hearing impairment and is time efficient for clinical use as each list takes approximately 1 to
2 minutes to complete.
Each word list presents sentences at varying SNRs ranging from 25 dB to 0 dB that
decrease in 5 dB steps with five target words in each sentence.
At the end of the list, the audiologist scores the number of target words that were correctly
repeated, and a SNR loss can be calculated with scores ranging from normal to severe SNR loss.
The SNR loss is defined as the increase (improvement) in the SNR that is required for a
listener to obtain 50% correct words or sentences versus a normal performance.
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The lower the score, the better the patient performs in noise.
One of the goals of the QuickSIN was to provide a more valid representation of daily
speech discourse than what could be accomplished with isolated monosyllabic words in
quiet. This evaluation can be used as part of the diagnostic audiometry evaluation or in
conjunction with the rehabilitative process in an aided or unaided configuration (Killion
etal., 2004).
n
WIN (Wilson & Burks, 2005)
Words-in-noise test with 35 NU-6 words in a background of multitalker babble at varying
SNRs ranging from 24 dB to 0 dB; the SNR changes in 4 dB increments.
The test is scored in terms of the SNR that the patient is able to achieve 50% correct. As
with the QuickSIN, this test can also be used with individuals with normal hearing and
hearing loss (Wilson & Burks, 2005).
Ultra/Extended High-Frequency Audiometry
The frequencies that correspond to a conventional audiologic evaluation are 250 to 8000 Hz, but
humans are capable of hearing ultra- or extended high frequencies (UHF or EHF; UHF will be used)
up to 20,000 Hz.
n
It is well documented that hearing loss in adults that occurs with age, known as presbycusis,
begins in the highest frequencies and, over time, progress downward (rather, upward along the
basilar membrane) to lower frequencies.
n
While UHF may not add much diagnostic value with some patients, in cases of monitoring
hearing due to continued noise exposure or ongoing treatment with ototoxic medications
(cisplatin/chemotherapy or aminoglycosides), UHF may provide crucial information regarding
early detection of changes in the auditory system.
n
This would allow for early preventative measures to be instituted, especially in the case of
noise exposure, which is a preventable contributor to hearing loss.
n
In conjunction with physicians, early detection of hearing loss secondary to ototoxic
medication exposure can lead to changes in treatment plans to prevent further deterioration of
hearing and detrimental effects on daily listening abilities.
n
Research has demonstrated that individuals who reported difficulty with speech understanding
in background noise, as well as performed poorly on sentence-in-noise testing, demonstrated
significantly poorer UHF thresholds compared to controls (Badri et al., 2011).
The two groups demonstrated clinically normal hearing thresholds with no significant
differences between them on standard audiometric frequencies.
Additionally, Braza et al. (2022) found benefits associated with audibility of UHF for
speech-in-speech recognition and noted the potential benefits of clinical evaluation of
thresholds above 8 kHz.
n
One difficulty with UHF is the lack of normative data with which to compare thresholds
obtained clinically. Traditionally, because of the variability of the UHF thresholds with the
age of the listeners, UHF thresholds are often plotted in dB SPL versus dB HL. Plotting
thresholds in dB SPL also does not allow for labeling of the thresholds (normal, mild,
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moderate, severe, etc.) in the same way as thresholds plotted in dB HL. However, some
clinically used audiometers will plot UHF thresholds in dB HL.
n
One additional area of use for UHF audiometry is in patients presenting for management of
tinnitus, which is discussed later in this chapter.
CASE EXAMPLE: OTOTOXICITY
Patient is a 65-year-old male who presented with bilateral hearing loss, tinnitus, and occasional
dizziness. The patient reported that he is currently undergoing chemotherapy with cisplatin for the
past 8 months. He noted that these issues started approximately 4 months ago. He denied noise
exposure, aural fullness, and otalgia.
n
Otoscopy revealed clear canals and normal tympanic membranes bilaterally.
n
Audiometric testing revealed a normal sloping to severe SNHL bilaterally. SRT and PTA
were not in agreement bilaterally due to the sloping nature of hearing loss. WRS was fair
(72%) bilaterally. The audiometric findings can be seen in Figure 5–1.
n
DPOAEs were not completed due to patient’s age.
Note: This is an area of debate — whether to perform OAEs on older adults for
monitoring purposes. In this case, given that the patient has documented highfrequency SNHL and OAEs are not as reliable in frequencies <2 kHz, it is unlikely that
DPOAEs would add value to the differential diagnosis.
n
The overall clinical impression is bilateral SNHL related to ototoxicity.
n
The patient’s oncologist should receive a copy of the results.
n
With medical clearance, amplification should be pursued.
FIGURE 5–1. Ototoxicity case audiogram.
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n
There should be a plan for routine follow-up audiograms while the patient is taking
187
cisplatin and every 3 months for a year after he ceases treatment, then once or twice per
year to monitor.
Specialty Tests
In addition to a standard comprehensive audiologic evaluation that includes pure-tone air and bone
conduction, as well as speech recognition threshold and word recognition testing, there are a number
of specialty tests that may be of use to the audiologist.
Stenger
The first of the specialty tests is the Stenger test. The Stenger test can only be used in cases of unilateral
hearing loss or significant asymmetry. To complete the Stenger test, the asymmetry between ears needs
to be at least 20 dB between AC thresholds. This test is based in the Stenger effect and binaural fusion.
The Stenger effect states that if the same tone is presented simultaneously to the two ears, one tone is
perceived at the midline (binaural fusion); a fused tone is only localized to the ear that would be better
able to perceive it. This is the premise for the Stenger test. Based on the Stenger effect, the ear that is
better able to detect the tone is where the pure tone should be heard (Durmaz et al., 2009.
n
Stenger test administration
The tone in the “good” ear is presented approximately 10 dB above the pure-tone threshold and
the tone in the “poorer” ear is presented approximately 10 dB below the pure-tone threshold.
The patient is instructed to respond if they hear the tone.
The clinician presents two tones simultaneously to the ears.
Negative Stenger: if the hearing loss in the poorer ear is real, then the patient will only hear
the tone in their good ear and should respond appropriately.
Positive Stenger: if the hearing loss in the poorer ear is not real, then the patient will
perceive the presented tone in their poorer ear only, as it is the louder of the two tones and
would be completely unaware of the tone in their good ear. In this case, the patient would
not respond as the tone would be perceived in the poorer ear (the ear in which the patient is
falsifying threshold(s)).
See example of Stenger administration in Figure 5–2 and Table 5–3.
Threshold Equalizing Noise (TEN) Test
n
Utilized to detect cochlear dead regions (areas of the cochlea with loss of inner hair cell
connection)
n
Patients are instructed to detect a pure tone with the presence of a masking background noise.
n
The noise is a spectrally shaped, broadband noise designed so that pure-tone thresholds 250 to
10,000 Hz are essentially equal.
n
When cochlear function is normal, the pure-tone threshold should be within a few dB of the
noise intensity.
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FIGURE 5–2. Stenger audiogram.
TABLE 5–3. Stenger Case Presentation Levels
FREQUENCY (Hz)
500 1000 2000 4000
PRESENTATION
LEVEL (dB HL)
Better Ear
(Right Ear)
Poorer Ear
20 20 25 25
95 95 95 95
(Left Ear)
n
However, if the pure-tone threshold is >10 dB above the noise intensity, this is diagnosed as a
cochlear dead region and the signal is only being detected by nearby areas of the cochlea due
to increased vibrations of the basilar membrane with surviving inner hair cells and neurons
(Moore et al., 2000).
Binaural Loudness Balance Test
n
Created to measure the presence of loudness recruitment or the abnormally rapid growth of
loudness as intensity is increased above the threshold.
n
It is used in cases of unilateral SNHL and can help to differentiate between cochlear and
retrocochlear pathology.
n
The test entails balancing the loudness of a tone in one ear against the fixed loudness of a
reference tone in the opposite ear to obtain a sensation of equal loudness.
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n
The good ear uses a reference tone that is fixed while the listener is asked to indicate when the
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tone being adjusted in the poorer ear is perceived to be of equal loudness to the reference tone.
n
After completing this at multiple intensities, if the dynamic range in the poorer ear is the
same as the good ear (reference tones), then no recruitment is present. However, if the
dynamic range is reduced in the poorer ear, this would indicate a degree of recruitment (Sung
& Sung, 1976).
Tuning Forks
Tuning fork testing is a fundamental clinical screening tool that is still regularly used since its inception
during the 19th century. Prior to the introduction of audiology as a field after World War II, tuning
forks were the primary form of hearing testing. These measures are often used bedside by otolaryngologists to screen for the presence of hearing loss, confirmation of already completed diagnostic
audiometric testing, estimation of hearing loss severity, and as part of the surgical candidacy workup.
n
Tuning fork testing is completed by striking the fork approximately two thirds of the way
along the fork tines against a hard but elastic object (e.g., rubber pad), which in turn produces
a pure-tone stimulus that will decay over time.
n
Each tuning fork corresponds to a specific pure-tone frequency with the most commonly used
forks representing 256 and 512 Hz.
Low-frequency forks may produce vibrotactile sensations and can provide misleading
information.
n
Inferences regarding hearing status are made by comparing hearing with the tuning fork via
AC (holding the fork near the external auditory canal [EAC]) versus BC (placing the fork on
the mastoid or forehead) or with the emphasis on lateralization of the sound via BC.
Two of the most commonly used tuning fork tests currently are the Rinne and the Weber.
Rinne Test. The Rinne tuning fork test, first described by Heinrich Adolf Rinne in 1855, focuses on
the loudness of the stimulus comparing AC to BC. The tuning fork is first held near the opening of
the EAC and then immediately placed on the mastoid process. The patient is asked to indicate if the
pure-tone stimulus is louder by AC or BC. Results would indicate a positive Rinne (normal or SNHL)
if the patient reports that the tone is louder by AC than by BC. In a positive Rinne, AC is perceived
as being louder because of a normal ear canal and middle ear functioning (thus no impedance of the
AC sound) with air being a less dense medium (and thus easier transmission) compared to the higher
density of bone. The test is considered negative (conductive component) if the pure-tone stimulus is
softer via AC when compared to BC. There are two reasons why BC is heard louder than AC:
n
Outer and/or middle ear involvement will likely attenuate a stimulus traveling by AC.
n
Outer and/or middle ear disorder can essentially trap pure tones presented via BC, which
would serve to intensify a bone-conducted signal. This is also known as the occlusion effect.
Weber Test. The Weber tuning fork test was first introduced by C. T. Tourtual and Charles Wheat-
stone in 1827; it is most clinically relevant in cases of unilateral hearing loss with the goal of identifying
the better-hearing cochlea. The test begins by striking and placing the tuning fork on a midline bony
structure, such as the forehead or incisors. The patient is asked to indicate if the pure tone is heard
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TABLE 5–4. Tuning Fork Test Table
TUNING
FORK TEST FINDINGS
Rinne Positive test: AC is louder than BC.
Most commonly associated with
normal peripheral hearing or
sensorineural hearing loss.
Weber Sensorineural hearing loss:
lateralize to the better-hearing ear.
In cases of normal-hearing sensitivity:
tone will remain centralized and be
heard at the midline.
tone will
Negative test: BC is louder than AC
Most commonly associated with
a conductive component to the
hearing (loss).
Conductive hearing loss: tone will
lateralize to the poorer hearing ear.
equally in both ears or if it is louder in one ear versus the other. If the peripheral hearing sensitivity is
normal, the pure tone is heard centrally in the head. In the presence of a CHL, the pure tone should
lateralize to the poorer hearing ear due to the occlusion effect. However, in cases of SNHL, the tone
should lateralize to the better-hearing ear. A summary of the Rinne and Weber tests along with corresponding results can be found in Table 5–4.
Obvious limitations of tuning fork testing would be the limited number of frequencies examined
and difficulty determining the audiometric threshold. Additionally, about 5% of patients with normal
hearing or SNHL are misdiagnosed as having a CHL using the Rinne test, and this test has been
shown to miss patients with significant CHL by as much as 50% of cases (Schlauch & Nelson, 2015).
Therefore, it is important to remember that tuning fork tests are one clinical tool, primarily used by
otolaryngologists, but are not a replacement for conventional pure-tone audiometry.
Potential Age Effects
In any population, challenges may arise that an audiologist or clinician must recognize and adapt in
order to ensure accurate test results. The adult population is no exception. Testing procedures can be
altered based on anatomical changes and cognitive changes/abilities. Later in this chapter, the latter
will be discussed more in detail.
n
Remember that the outer one third of the external auditory canal is made of cartilage and the
inner two thirds is made of temporal bone.
n
With time, that cartilaginous tissue can change: There are degenerative changes in the elastic
tissues associated with the pinna and cartilaginous portion of the external ear canal. With
these changes, the pressure of the earphone against the pinna can cause a closing or collapsing
of the ear canal, thus creating a false air-bone gap, typically in the high-frequency region, and
a patient incorrectly diagnosed with C/MHL.
n
Comparing pure-tone testing using a supra-aural headphone, causing ear canal collapse,
and an insert earphone showed an improvement of 15 to 30 dB in thresholds from 250 Hz
through 2000 Hz when using insert earphones (Mahoney & Luxon, 1996). Collapsing ear
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canals should always be considered with findings that include unexpected air-bone gaps,
especially in the presence of normal acoustic immittance.
Other considerations that should be made during audiometric testing can include response mode.
n
Many clinicians will have adults push a response button during pure-tone audiometry.
n
There should also be consideration for patient dexterity and other response modes may be
necessary such as hand raising or verbal confirmation.
n
Verbal responses to speech stimuli may not always be possible, and therefore, written responses
or a picture-pointing task, such as the Word Intelligibility by Picture Identification (WIPI)
Test, may be necessary.
Physiological Techniques
Physiological or objective measures are a useful tool to utilize on patients of all ages. Physiological
techniques such as immittance, otoacoustic emissions (OAEs), and evoked potentials are a vital crosscheck principle to use on patients throughout the lifespan. A cross-check principle means that findings
from a single test are checked and confirmed against another test to ensure that results are accurate.
This principle is particularly important when working with children or individuals with developmental
delays and is also discussed in Chapter 6.
Immittance
The transmission of sound requires movement through the outer and middle ear space before ending in
the inner ear and auditory cortex. To perceive sound, sound energy is required to be transmitted from
an air medium (with low impedance) to a fluid medium (high impedance).
n
The middle ear acts as an impedance matching transformer to account for this difference in
impedance.
n
To assess the outer and middle ear space, the objective measurement of tympanometry was
created. Tympanometry refers to the measurement of how the middle ear system responses to
both sound energy and atmospheric pressure.
n
Tympanometry is obtained by utilizing a probe tip that contains both a stimulus (226 Hz
pure-tone or wideband clicks for adults) and a microphone.
n
In addition to sound being presented, air pressure is varied from ambient pressure to positive
pressure to negative pressure. The fluctuation in pressure causes the ossicular chain and
tympanic membrane (TM) to stiffen, which impacts the admittance, or flow of energy
through the system. This pressure change causes the TM to move, increasing and decreasing
the volume of the external auditory meatus. The resultant intensity changes in the pure tone
are then transformed into plotted data.
n
The changes are typically plotted on a graph called a tympanogram, where admittance is
plotted on the y-axis and middle ear pressure is on the x-axis.
n
There are five tympanometry classifications based on the Linden-Jerger classification scheme,
which can be found in Figure 5–3 (Jerger, 1970; Liden et al., 1969).
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