Whitepaper_ETD-Diagnostics_E

SPIGGLE & THEIS Academy
Diagnostics for Eustachian Tube Dysfunction
A summary of published clinical research
Dr. Jennifer Knuth, Dr. Kathrin Warnking, Clinical Affairs SPIGGLE & THEIS Medizintechnik GmbH
Purpose
Diagnostic tests for Eustachian tube dysfunction (ETD) are
necessary to
1. identify ETD, and differentiate between multiple subtypes
of ETD and other conditions, to decide which
treatment is indicated,
2. measure and compare outcomes of various interventions
intended to treat ETD.
Our previous white papers 1,2 focused on #2, i.e. measurements
of outcomes of interventions. This white paper aims
to provide information primarily regarding #1, i.e. to assist
the ENT practitioner in their decision-making regarding diagnosis
of ETD, in preparation for subsequent treatment.
This publication summarizes the relevant scientific
literature, it does not attempt to provide a statistical metameta-analysis
of existing systematic reviews and original
papers. It does not provide a general overview of ETD,
treatment options, and outcomes. Also, it does not replace
any official product documentation.
Context
Eustachian Tube
The Eustachian tube (ET) connects the middle ear (ME)
space to the nasopharyngeal (NP) space. It consists of a
bony part facing the ME, and a cartilaginous part facing the
NP. In normal function, this medial part can be opened and
closed through attached muscles, M. tensor veli palatini
(mTVP) and M. levator veli palatini (mLVP).
The purpose of the ET is (a) to ventilate the ME and provide
pressure equalization between ME and ambient air when
necessary, (b) to drain secretions from the ME when open,
and (c) to protect the ME from sounds, pathogens and nasopharyngeal
secretions when closed. 4
ET function is influenced by its physical composition, mechanical
properties and geometry (muscle attachment). 5
The mechanical properties as well as the functional efficiency
can be measured with specialized tests (see section
“Special tests of ET function” below).
Eustachian Tube Dysfunction
Eustachian tube dysfunction (ETD) is the general term for
any condition where the opening and closing of the tube is
impeded. Prevalence of ETD was estimated at 4.6% in the
general US population. 6 ETD includes patulous ETD (PETD,
ICD-11 AB10.1 7 ), where the valve remains permanently open,
and obstructive ETD (OETD, ICD-11 AB10.3 7 ), where the tube
does not open. This latter condition and its diagnosis are
the focus of this paper. It can be caused by muscular failure,
inflammation inside the ET, or anatomical obstruction at
the ET opening. 8
Figure 1:
Eustachian tube patency test by Grüber (1870),
reproduced in Avoort (2005) 3
Balloon Eustachian Tuboplasty (BET)
Transnasal balloon dilatation of the cartilaginous part of
the ET, called “Balloon Eustachian Tuboplasty (BET)” 9 is
being used to treat OETD. 1,2 An inflatable balloon catheter
is inserted in the cartilaginous part of the ET, under endoscopic
control. Once in position, the balloon is inflated. This
appears to reduce “inflammatory epithelial changes and
submucosal inflammatory infiltrate.” 10
Dr. Jennifer Knuth, Dr. Kathrin Warnking – Clinical Affairs SPIGGLE & THEIS Medizintechnik GmbH 1

Current state of ETD diagnostics
Diagnosis of ETD begins with anamnesis, and common tests
performed in any ENT practice or clinic, such as visual inspection,
audiometric tests, and possibly imaging. In addition,
questionnaires are often used. Finally, special tests for
ET function may be performed, as described below.
Several studies report low correlation between subjective
reporting of symptoms (via questionnaires) and objective
measurements of ET function, 11,12 which may be due to the
fact that objective functional test are a snapshot of the
situation at the time of testing, whereas patient reported
symptoms also take into account past experience.
A correct differential diagnosis of OETD is important. For
example, BET is contraindicated for patients with PETD, 13
because BET may cause or worsen a patulous ET. 14
Symptoms
There is a wide range of symptoms, complaints, and clinical
findings that are commonly seen as potential indicators of
ETD. 15 Patients suffering from OETD may often report some
or all of the following symptoms: 15
• recurrent or chronic otalgia 8,13
• ear pressure, a feeling of “aural fullness” 8,13,16
• autophony (often indicates PETD 8,13,16 )
• habit of frequent sniffing, typical for PETD 8,16
• difficulty clearing ears with flights or swimming underwater,
inability to “pop the ear”, typical for OETD 15,17–19
• barotrauma, i.e. diver’s otalgia or otitis, flight-related
otitis (indicates OETD) 15
• tinnitus 8,19 (pulsatile tinnitus indicates PETD 13 )
Improvement of symptoms when the patient is in a supine
position is often observed with PETD. 8,20–22
Some other otologic pathologies are often associated with
or caused by OETD, including
• otitis media (OM), including recurrent acute OM, OM
with effusion, chronic OM with effusion, and the recurrence
of OM and/or symptoms after tympanoplasty 8,15,17
• Tympanic membrane (TM) retraction, 15,17 TM perforation,
the failure of TM perforation repair
• mild to moderate (≥15 dB 19) conductive hearing loss 8,18,19
Note that patients with mild OETD, who have problems aerating
their ears only after rapid changes in ambient pressure,
may not exhibit negative ME pressure under examination,
so their history is critical for the diagnosis. 23
General ENT diagnostic methods
Basic tests
Valsalva’s test attempts to inflate the ET and ME by forced
expiration with the mouth closed and the nose manually
compressed. 22 Inability to do this indicates OETD. Most clinical
studies include an assessment of the ability to perform
the Valsalva maneuver successfully, either via subjective
reporting by the patient, or by observing TM movement
otoscopically. 1
Politzer’s test inflates the NP space through an air bag inserted
in one nostril, and instructs the patient to swallow,
in order to create positive ME pressure. 22
In the Toynbee test, the patient swallows while the nose is
manually compressed. This creates positive pressure in the
NP, followed by a negative pressure phase, and in a healthy
ear the ME pressure will change as well. 22
Figure 2:
Illustration of patient receiving Politzer test.
From Politzer (1874)
Otoscopy/Otomicroscopy
The clinical consensus 8,13,24 is that otoscopy is an essential
part of ETD diagnostics. Possible observations are
• ME Effusion: The presence of effusion may prevent performing
most of the special function tests described
below. Note that effusion does not necessarily imply
ETD, it could be strictly infectious, especially in infants
and toddlers. 15
• Retracted TM: TM retraction implies negative ME pressure,
and is more likely related to OETD; however, it can
also be present in PETD due to repeated sniffing. 16
• Intact TM, neutral position: In the absence of ME ef-
2 Dr. Jennifer Knuth, Dr. Kathrin Warnking – Clinical Affairs SPIGGLE & THEIS Medizintechnik GmbH

fusion, this indicates that air is able to get into the ME
through the ET, 15 which is inconsistent with OETD, but
PETD cannot be excluded. 15
• TM movements: TM movements synchronous with breathing
confirm PETD. 8,13,15,16,25
Pneumatic otoscopy, i.e. the application of EAC pressure
during visual inspection, can help to distinguish adhesive
vs. non-adhesive retractions of the TM. 13
Nasopharyngoscopy
The clinical consensus 8,13,24 is that nasal endoscopy is an essential
part of ETD diagnostics, to rule out extrinsic causes
of ETD.
Visual inspection of the ET from the nasopharynx side, also
called “trans-nasal video-endoscopy,” 15 aims to visualize
the opening of the ET, and identify possible underlying
causes of ETD, such as inflammation near the ET orifice,
neoplasms, or scarring. 18 It is typically performed using a
30-45° viewing angle, or a flexible endoscope turned 90°. 23
There are cases where the visual inspection shows partially
impaired opening of the ET, or structural abnormalities
such as edema, but functional tests as described below still
have normal results. 26
A commonly used 27 grading scheme for mucosal inflammation
and ET opening ability was introduced in 2015. 28 It is
sometimes referred to as the “MEELO” assessment, (mucus,
edema, erythema, lymphoid hyperplasia, and degree
of opening of the valve). 29
• Grade 1: Normal mucosa and opening of the valve
• Grade 2: Mild inflammation, no apparent compromise
regarding ET dilation when swallowing
• Grade 3: Moderate inflammation, with compromised ET
dilation when swallowing
• Grade 4: Severe inflammation of the mucosa, unable to
open the valve on swallowing
Grades 3 and 4 are indicative of OETD. 27
Audiometry
The clinical consensus 8,13,24 is that pure-tone audiometry,
or at least Rinne’s and Weber’s tuning fork tests, 8 are an
essential part of ETD diagnostics, to detect conductive
hearing loss.
Tympanometry
The clinical consensus 8,13,24 is that tympanometry is an essential
part of ETD diagnostics, to measure ME pressure.
In the classic interpretation of a tympanogram, 15
• Type A (impedance-vs-pressure curve with peak within
±50 daPa) is indicative of a normal TM, with no pressure
difference between ME and outside. In patients
with PETD, continuous impedance measurement may
show fluctuations synchronized with nasal breathing. 16
• Type B (flat curve without distinct peak) indicates a
fluid-filled ME.
• Type C (curve with peak at -100 daPa or below) indicates
a retracted TM due to negative ME pressure, which
can be caused by insufficient ventilation, indicative of
OETD, 30 or it can be caused by repeated sniffing, often
found with PETD. 16
One study 31 recommends reporting the value of tympanometric
peak pressure (TPP) rather than just type A-B-C
classification, to diagnose less severe ME problems such
as OETD.
In patients with chronic rhinosinusitis, not all cases with
visually confirmed ET opening difficulties also showed a
non-type-A tympanogram. 27
Imaging
According to a published consensus statements, “radio-logical
evaluation does not routinely play a role in diagnosis of
ETD,” 8 and CT imaging is “not essential in all cases” 24 before
BET.
The use of the Valsalva maneuver during CT has had mixed
results, it is not recommended as a screening tool, 32 but
may be useful as a visualization tool. 33
One recent review 18 recommends to attempt localization of
the ET lesion, and states that “if the obstruction is located
in the bony part or isthmus of the ET, BET is not indicated.” 18
Special tests of ET function
The literature contains several specialized tests for ET
function, whose rationale is to provide objective measurements
indicative of active (muscle-driven) or passive (pressure-driven)
opening of the ET.
Several studies 34,35 have investigated in healthy ears the
ability of each test to detect ET opening, which sheds light
on the basic validity of the tests, but doesn’t allow conclusions
on their ability to help with differentiating between
different conditions (OETD, PETD) and underlying causes
and mechanisms (active vs. passive opening).
One of these studies 35 found no significant difference between
tympanometry, sonotubometry, TTAG, and TMM in
their ability to detect ET opening. Another study 34 investigated
the repeatability of functional tests, expressed as
“intraclass correlation coefficient” (ICC), and cautions that
Dr. Jennifer Knuth, Dr. Kathrin Warnking – Clinical Affairs SPIGGLE & THEIS Medizintechnik GmbH 3

“when tests of ET function are used in clinical practice, they
should be performed more than once to gain a more reliable
result.”
Below, we will describe function tests that have been described,
evaluated, and used in multiple studies, beyond
a pure research environment, and beyond the institution
where the test was invented.
All tests apply pressure differentials between NP and ME,
either through “natural” means (Valsalva maneuver or swallowing)
or through “technical” means (tympanometer or
pump). The tests then measure the “openness” of the ET,
either via observing NP and EAC pressure or airflow, or by
measuring sound conduction through the ET.
For each quantitative test, we will specify
• The objective: what function or condition is tested?
• The general idea: a high-level description of the setup.
• Any prerequisites that must be satisfied, such as an intact
or perforated TM.
• The required equipment: can this test be performed
using commercially available clinical instruments, or is
some custom setup of research equipment necessary?
• The popularity of the test: how many of the publications
considered here describe the test in some detail?
How many evaluate the test or correlate it with other
tests? How many use the test to address some other
clinical research question?
• A detailed step-by-step description of the procedure.
• The metrics, i.e. which physical quantities are measured,
which parameters are calculated from measured values?
• The diagnostic criteria: how are metrics interpreted to
arrive at clinically meaningful diagnoses?
• Information regarding validity of the test: published
data on repeatability, and on correlation with other
tests or clinical observations.
Sonotubometry
• Objective: measure active and passive opening of ET.
• General idea: present sound through a speaker inserted
in nostril, pick up sound with a microphone in the external
auditory canal (EAC). Sound pressure in EAC is
higher when ET is open. 15,36
• Prerequisites: no otorrhea or middle ear effusion. 36
• Equipment: in Japan, a clinical instrument is commercially
available (Rion JK-05A). Otherwise, specialized lab
equipment 3,37 is required.
• Popularity: the test was mentioned and explained in
8 reviews, 3,15,18,22,30,38–40 evaluated or correlated with other
methods in 10 studies, 12,34,36,41–47 and used to answer other
clinical research questions in 3 studies 21,25,48 analyzed
for this paper.
• Procedure:
1. Place and seal acoustic transducer in one nostril,
and place and seal microphone in EAC
2. Apply acoustic stimulus, typically a tone or band
limited noise in the 6-8 kHz range, 3,37 at high loudness
levels of 100-130 dB 3
3. Ask patient to perform swallowing or other maneuvers
typically related to ET opening, 18 or apply
pressure gradient via a tympanometer 15,49
4. Measure changed EAC sound pressure in response
to NP pressure change
• Metric: Amplitude change in EAC sound level.
• Diagnostic criteria:
• An amplitude change of >5 dB is typically considered
an indication of ET opening, 3 smaller changes may
indicate OETD. The threshold can be adapted to make
the test more specific or more sensitive. 43
• fluctuating or continuously high EAC SPL occurs with
PETD. 15
• Validity:
• Changes in EAC sound level during swallowing correlate
with visually observed ET opening. 41
• ICC indicates almost perfect agreement for measured
values, and moderate agreement for ET opening detection.
34
• Caveats:
• While there is typically higher SPL during swallowing,
“absence of an increase in the sound level during
swallow when there is no pressure gradient does not
indicate an abnormal ETF.” 15
• the result can be influenced by the sound of swallowing,
saliva movement, and breathing, 18 which is
why recent studies 44 try to improve reliability with
optimized test signals or signal processing.
Figure 3:
Example sonotubometry trace while swallowing, in a healthy ear. Courtesy
of Dr. Matthew E. Smith MA, PhD, FRCS (ORL-HNS), Consultant ENT Surgeon,
Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
4 Dr. Jennifer Knuth, Dr. Kathrin Warnking – Clinical Affairs SPIGGLE & THEIS Medizintechnik GmbH

Multiple sonotubometry measurements before and after
postural changes have been described as a means to detect
PETD, called the Ohta method. 36
The diagnostic criteria for PETD proposed by the Japan
Otological Society (JOS) 25 refer to sonotubometry as one
of several criteria.
Tubomanometry (TMM)
• Objective: measure active and passive opening of ET. 18
• General idea: generate pressure in NP, detect EAC pressure
change transmitted via ET and ME.
• Equipment: a clinical instrument was commercially
available in the past (Tubomanometer, SPIGGLE & THEIS,
Germany).
• Popularity: the test was mentioned and explained in 6
reviews, 4,15,18,30,38,50 evaluated or correlated with other
methods in 8 studies, 12,34,42,51–55 and used to answer other
clinical research questions in 6 studies 9,56–60 analyzed
for this paper.
• Procedure:
1. Place and seal pressure transducer in nostrils, and
place and seal pressure sensor in EAC
2. Deliver defined overpressure to NP, usually 300,
400, and 500 daPa 54
3. Ask patient to swallow
4. Measure pressure change in sealed EAC
• Metrics: delay between NP pressure change and EAC
pressure change, expressed as “R value.”
• Diagnostic criteria:
• R ≤1 indicates Regular ET function
• R < 0.6 indicates PETD according to 55
• R > 1 indicates delayed ET opening, i.e. OETD
• R not being measurable implies no detectable ET opening
• Validity:
• One study on 432 ears 54 reported that “TMM results
correlate with otomicroscopy findings and Valsalva
maneuver performance.”
• A recent review of ET function tests 18 states that “the
repeatability of TMM is limited, especially when the
repeat testing is delayed.”
• ICC indicates substantial agreement for measured values
and moderate agreement for ET opening detection.
34
Figure 4:
Example tubomanometry response for a healthy ear (top), courtesy of Mr.
Waldmann, and obstructed ET (bottom), courtesy of Dr. med. Sara Euteneuer,
Hals-, Nasen- und Ohrenklinik, Heidelberg University Hospital Head Clinic
Center, Heidelberg, Germany.
Tubomanometry can be combined with subjective reports
to calculate the Eustachian Tube Score (ETS or ETS-5), 52 with
the extended ETS-7 also including tympanometry and objective
Valsalva maneuver.
Tubomanometry is currently not considered an essential
part of best clinical practice, 24 and “should not be used as
the only instrument for diagnosing diseases of the ET.” 61
Tubo-tympano-aerodynamic-graphy (TTAG)
This test, similar to TMM, measures EAC pressure as an indicator
of ME pressure, in response to pressure changes
induced in the NP space by Valsalva maneuver, swallowing,
deep breathing or sniffing. It is mainly mentioned in publications
from Japan. 36 A clinical instrument is commercially
available in Japan (Rion JK-05A). The test was mentioned
and explained in two reviews, 30,36 evaluated or correlated
with other tests in two studies, 12,35 and used to answer other
clinical research questions in two studies 25,48 analyzed here.
Dr. Jennifer Knuth, Dr. Kathrin Warnking – Clinical Affairs SPIGGLE & THEIS Medizintechnik GmbH 5

Nine-step test
• Objective: assess a patient’s ability to equilibrate middle
ear pressure by swallowing. 39
• General idea: increase or decrease pressure in EAC,
measure ME pressure, swallow, measure ME pressure
again.
• Prerequisites: intact TM, no effusion.
• Equipment: Available in commercially available clinical
instruments (e.g. Grason-Stadler TympStar Pro).
Step Activity Model Tympanogram
1. Resting Pressure
2. Inflation and
Swallow (x3)
3. Pressure after
equilibration
4. Swallow (x3)
5. Pressure after
equilibration
6. Deflation and
swallow (x3)
7. Pressure after
equilibration
8. Swallow (x3)
9. Pressure after
equilibration
Figure 5:
Sequence of steps, position of TM, and expected tympanogram
for a healthy ear. Based on Bluestone (2005) 22
• Popularity: the test was mentioned and explained in two
reviews, 3,22 and evaluated or correlated with other methods
in three studies 12,39,62 analyzed for this paper.
• Procedure: 22
1. Tympanogram #1 measures resting ME pressure.
2. Increase EAC pressure to +400 daPa, causing an
increase in ME pressure. Patient swallows 3x to
equilibrate middle ear overpressure.
3. Return EAC pressure to normal, causing the TM to
move outward, and a slight (15-20 daPa) negative
ME pressure, recorded by tympanogram #2.
4. Patient swallows to equilibrate negative middle ear
pressure, causing airflow from NP to ME.
5. Tympanogram #3 records the extent of equilibration.
6. Decrease EAC pressure to -400 daPa, causing lateral
deflection of TM and decrease in ME pressure.
Patient swallows 3x to equilibrate negative middle
ear pressure.
7. Return EAC pressure to normal, causing TM to move
inward and slight (15-20 daPa) positive ME pressure,
measured by tympanogram #4.
8. Patient swallows to equilibrate positive middle ear
pressure causing airflow from ME to NP
9. Tympanogram #5 documents the extent of
equilibration.
• Metric: maximum difference between the pressure at
the peak of the tympanogram curves, over all conditions.
Called “maximal peak pressure difference” (MPD
or ETTmd).
• Diagnostic criteria: Higher MPD is better (indicative of
normal ET). Typical cutoff is 10 or 15 daPa, 39 which can
be adjusted for a tradeoff specificity vs sensitivity. MPD
below the threshold can be caused by OETD or PETD. 39
The highest diagnostic performance for OETD patients
was observed when the cut-off value was 13 daPa (sensitivity
74%, specificity 90%). 39
• Validity:
• ICC indicates almost perfect agreement for measurement
values, and moderate or substantial agreement
for detection of ET opening. 34
• Variants:
• The procedure implemented in a clinical instrument
(GSI) only does tympanogram #1, #2, #4.
• A similar procedure was described as “Eustachian
tube swallow test.” 26
Forced Response Test (FRT)
• Objective: quantify structural properties of ET influencing
passive opening, and functional efficiency of active
opening.
• General idea: run air through EAC > ME > ET > NP, measure
pressure and flow rate. 63,64
• Prerequisites: non-intact TM.
• Equipment: specialized lab equipment 5 is needed.
• Popularity: the test was mentioned and explained in
6 Dr. Jennifer Knuth, Dr. Kathrin Warnking – Clinical Affairs SPIGGLE & THEIS Medizintechnik GmbH

one review, 15 and evaluated or correlated with other
methods in six studies 5,63–67 analyzed here.
• Procedure: 5,15,65
1. Pump air into EAC + ME at constant flow rate (11 or
23 ml/min) 15
2. Pressure increases until it passively forces open
the ET, at the “opening pressure” P O
3. After ET opening, pressure decreases to a steadystate
pressure P S
, when flow rate Q S
through ET is
equal to pump flow rate
4. Instruct patient to swallow. This should activate
mTVP and mLVP muscles, which causes a change in
ET lumen diameter, resulting in changed flow rate
Q A
(“maximum air-flow during a swallow” 5 )
• Metrics for each flow rate:
• Passive tubal resistance R S
= P S
/Q S
→ a measure of the
ease of air flow through ET 5
• Passive tubal conductance C S
= Q S
/P S
63
• Active tubal conductance C A
= Q A
/P S
63
• ET dilatory efficiency DE = Q S
/Q A
: 5,15,63 “a measure of
the functional efficiency of muscle-assisted ET lumen
dilation independent of surface adhesive forces” 5
• Ratio of ET resistance at 11 and 23 ml/min flow rates:
a measure of ET compliance
• Diagnostic criteria:
• The difference between the P S
and the P O
is an indicator
of the force needed to separate the closed surfaces
of the ET lumen.
• Normative data for adults without middle ear disease
are available, 67 the range of opening pressure P O
for
normal ears is 200-500 daPa 15
• Low opening pressure (P O
< 200 daPa) and low closing
pressure (P C
< 30 daPa) are characteristic of PETD. 15
• High opening pressure (P O
> 500 daPa) is consistent
with OETD. 15
Questionnaires
Patient-Reported Outcome Measures (PROMs) 42 in the form
of questionnaires are a popular means for evaluating OETD
interventions. However, for purposes of diagnosing ETD,
the clinical consensus 13 is that “patient-reported symptom
scores alone are insufficient to establish a diagnosis of
obstructive ETD” and a recent review cautions that “even
a panel of world experts on ETD failed to diagnose ETD
and differentiate it from non-ETD etiologies based on patient-reported
symptoms.” 15
Eustachian Tube Dysfunction Questionnaire
(ETDQ-7)
This questionnaire, first described and validated in 2012 68
is now available in many languages. It is very popular in
studies on OETD and BET outcomes, and is mostly used in
adults. It measures seven symptoms commonly reported by
patients (pressure, pain, clogged ears, sinusitis, crackling,
ringing, muffled hearing) on a Likert scale, combined into
a total score (range 7-49, normal <14.5) or an average score
(range 1.0-7.0, normal <2.1).
There is consensus that the instrument is “an important
patient-reported outcome measure” 38 and its use is considered
best clinical practice 24 for reporting the outcome
of interventions such as BET.
The tool is good at distinguishing between healthy ears and
“some otological disorder,” 42 but it is unable to discriminate
between OETD and PETD. 18,30,42 Its correlation with objective
measures of ET function is limited. 18,54
Differential diagnosis
The clinical consensus is that “establishing a diagnosis
of OETD requires ruling out other causes of aural fullness
such as patulous ETD, temporomandibular joint disorders,
extrinsic obstruction of the ET, superior semicircular canal
dehiscence, and endolymphatic hydrops.” 13
Name of ET function test Preconditions Type of
Equipment
Tests active
ET opening
Tests passive
ET opening
Detect PETD
Discriminate
OETD v PETD
Sonotubometry No ME effusion Research* YES YES YES YES
Tubomanometry No ME effusion Research YES YES YES YES
Tubo-tympano-aerography
(TTAG)
Nine-step test
No ME effusion Research* YES YES
No ME effusion,
intact TM
Commercial YES no YES no
Forced-response test Perforated TM Research YES YES YES YES
*An instrument is commercially available in Japan
Dr. Jennifer Knuth, Dr. Kathrin Warnking – Clinical Affairs SPIGGLE & THEIS Medizintechnik GmbH 7

Before recommending the BET procedure, clinicians will
commonly try to identify and treat, if applicable and necessary,
other potential causes of OETD, 1,2 such as adenoids,
nasal polyposis, allergic rhinitis, rhinosinusitis, or laryngopharyngeal
reflux.
Diagnostic pathways
Since “there is no reference (gold standard) method to diagnose
OETD or PETD, and the clinical diagnosis of an experienced
clinician has been the default reference standard for
many years,” 12 assessments and tests as described above
must be combined to achieve differential diagnosis, in the
form of a decision tree or decision table.
One proposed diagnostic pathway 12 is based on extensive
review of assessment of accuracy of many diagnostic tests.
It starts with clinical history, includes tympanometry, sonotubometry,
tubomanometry and continuous impedance or
TTAG, and arrives at a conclusion of OETD, PETD, possible
ETD, and ETD unlikely.
Another published decision tree 23 starts with an observation
of aural fullness, considers TM status, patient reported
symptoms, and arrives at a conclusion of OETD, PETD, or
other pathologies (TMD, otic capsule dehiscence, endolymphatic
hydrops, otologic migraine).
A very detailed matrix of test results vs possible ET dysfunction
types is provided by Alper (2023). 15
at one point in time may be overcome with continuous 24-
hour measurement of middle ear pressure, as proposed by
Tideholm (1996). 69 A combined analysis of multiple different
measurements and data sets may be a task solvable
with machine learning, which has already been successfully
used to support other areas of ENT diagnostics. 70
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List of Abbreviations
Conclusion and Outlook
Many specialized tests for ET function have been described
in the literature, but most of them require special lab
equipment and are currently not used in clinical routine.
One study on patients “with symptoms or examination findings
suggestive of ETD” 12 concluded that “tympanometry,
sonotubometry and tubomanometry have the best diagnostic
performance for obstructive ETD.”
There is no single test or assessment that will result in an
unequivocal diagnosis of OETD. Assessment of symptoms
and clinical history must be combined with clinical tests
to arrive at a likely diagnosis, and to distinguish between
OETD and PETD.
For many clinicians, visual inspection of the nasopharyngeal
opening of the ET and of the TM, in combination with
a tympanogram and an assessment of reported symptoms,
clinical history and Valsalva test, serve as the basis for a
diagnosis of OETD, in accordance with published guidelines.
8,13
In the future, the constraint of a “snapshot” measurement
Abbreviation
CT
BET
EAC
EPPmd
ETD
ICC
ME
MEP
MPD
mLVP
mTVP
NP
OETD
OME
PETD
PP
SPL
TM
TMD
TPP
Explanation
Computer Tomography
Balloon Eustachian Tuboplasty
External Auditory Canal
Maximal Peak Pressure Difference
Eustachian Tube Dysfunction
Intraclass Correlation Coefficient
Middle Ear
Middle Ear Pressure
Maximal Peak Pressure Difference
musculus Levator Veli Palatini
musculus Tensor Veli Palatini
Nasopharynx
Obstructive ETD
Otitis Media with Effusion
Patulous ETD
Peak Pressure
Sound Pressure Level
Tympanic Membrane
Temporomandibular Disorder
Tympanometric Peak Pressure
8 Dr. Jennifer Knuth, Dr. Kathrin Warnking – Clinical Affairs SPIGGLE & THEIS Medizintechnik GmbH

References
1. Knuth, J. & Warnking, K. Balloon Eustachian Tube Dilatation as the Standard
Causal Intervention for Eustachian Tube Dysfunction ?! https://www.spigg
le-theis.com/images/Instrumente/BET_WhitePaper.pdf (2022).
2. Knuth, J. & Warnking, K. Balloon Eustachian Tube Dilation in Children. htt
ps://www.spiggle-theis.com/images/Instrumente/Whitepaper_
BETinPediatrics_E_2023.pdf (2023).
3. Avoort, S. J. C. van der, Heerbeek, N. van, Zielhuis, G. A. & Cremers, C. W. R.
J. Sonotubometry: Eustachian tube ventilatory function test: A state-of-theart
review. Otol. Neurotol. 26, 538–543 (2005).
4. Luukkainen, V., Kivekäs, I., Silvola, J., Jero, J. & Sinkkonen, S. T. Balloon eustachian
tuboplasty: Systematic review of long-term outcomes and proposed
indications. J. Int. Adv. Otol. 14, 112–126 (2018).
5. Doyle, W. J. et al. Sensitivity and Specificity of Eustachian Tube Function
Tests in Adults. JAMA Otolaryngol. Neck Surg. 139, 719 (2013).
6. Shan, A. et al. Prevalence of Eustachian Tube Dysfunction in Adults in the
United States. JAMA Otolaryngol Head Neck Surg 145, 974 (2019).
7. World Health Organization. International statistical classification of diseases
and related health problems. https://icd.who.int/ (2021).
8. Schilder, A. G. M. et al. Eustachian tube dysfunction: Consensus statement
on definition, types, clinical presentation and diagnosis. Clin. Otolaryngol.
40, 407–411 (2015).
9. Oehlandt, H. et al. Efficacy of Balloon Tuboplasty for Baro-Challenge-
Induced Eustachian Tube Dysfunction : A Systematic Review and a Retrospective
Cohort Study of 39 Patients. Otol. Neurotol. 43, 611–618 (2022).
10. Kivekäs, I. et al. Histopathology of balloon-dilation eustachian tuboplasty.
Laryngoscope 125, 436–441 (2015).
11. Teixeira, M. S., Swarts, J. D. & Alper, C. M. Accuracy of the ETDQ-7 Questionnaire
for Identifying Persons with Eustachian Tube Dysfunction. Otolaryngol
Head Neck Surg 158, 83–89 (2018).
12. Smith, M. E. et al. Eustachian tube dysfunction: A diagnostic accuracy study
and proposed diagnostic pathway. PLoS One 13, 1–28 (2018).
13. Tucci, D. L. et al. Clinical Consensus Statement: Balloon Dilation of the
Eustachian Tube. Otolaryngol. - Head Neck Surg. (United States) 161, 6–17
(2019).
14. Hubbell, R. D. et al. Patulous Eustachian Tube Dysfunction Symptoms Following
Balloon Dilation. Laryngoscope 133, 3152–3157 (2023).
15. Alper, C. M., Teixeira, M. S., Mandel, E. M. & Swarts, J. D. Dissecting eustachian
tube dysfunction: From phenotypes to endotypes. PLoS One 18, 1–17 (2023).
16. Ward, B. K., Nieman, C. L. & Poe, D. S. Patulous Eustachian Tube and the Differential
Diagnosis of Autophony. in Textbook of Otitis Media 143–151 (2023).
doi:10.1007/978-3-031-40949-3_15.
17. Plaza, G., Navarro, J. J., Alfaro, J., Sandoval, M. & Marco, J. Consensus on treat
ment of obstructive Eustachian tube dysfunction with balloon Eustachian
tuboplasty. Acta Otorrinolaringol. Esp. 71, 181–189 (2020).
18. Liu, S., Ni, X. & Zhang, J. Assessment of the Eustachian tube: a review. Eur.
Arch. Oto-Rhino-Laryngology 280, 3915–3920 (2023).
19. Llewellyn, A. et al. Interventions for adult Eustachian tube dysfunction: A
systematic review. Health Technol. Assess. (Rockv). 18, 1–180 (2014).
20. Schröder, S. & Ebmeyer, J. Diagnostik und Therapie von Funktionsstörungen
der Tuba auditiva. HNO 66, 155–166 (2018).
21. Virtanen, H. Relation of body posture to eustachian tube function. Acta
Otolaryngol. 95, 63–67 (1983).
22. Bluestone, C. D. Eustachian Tube: Structure, Function, Role in Otitis Media.
(2005).
23. Poe, D. S. & Metson, R. B. Surgical Management of Obstructive ET Dysfunction.
Bull. Off. content hub Am. Acaddemy Otolaryngol. Neck Surg. 1–20
(2023).
24. Plaza, G., Navarro, J. J., Alfaro, J., Sandoval, M. & Marco, J. Consensus on Treatment
of Obstructive Eustachian Tube Dysfunction With Balloon Eustachian
Tuboplasty. Acta Otorrinolaringol. Esp. (English Ed. 71, 181–189 (2020).
25. Kawamura, Y. et al. The characteristic of patulous eustachian tube patients
diagnosed by the JOS diagnostic criteria. PLoS One 14, 1–13 (2019).
26. Augustine, A. M., Varghese, L., Michael, R. C., Albert, R. R. & Job, A. The efficacy
of dynamic slow motion video endoscopy as a test of eustachian tube
function. J. Laryngol. Otol. 127, 650–655 (2013).
27. Wuraola, O. A., Afolabi, A. O. & Ologe, F. E. Tympanometry and Endoscopic
Diagnosis of Eustachian Tube Dysfunction in Patients with Chronic Rhinosinusitis.
Niger. Postgrad. Med. J. 126–131 (2023) doi:10.4103/npmj.npmj.
28. Kivekäs, I., Pöyhönen, L., Aarnisalo, A., Rautiainen, M. & Poe, D. Eustachian
tube mucosal inflammation scale validation based on digital video images.
Otol. Neurotol. 36, 1748–1752 (2015).
29. Chen, J. X., von Sneidern, M. & Poe, D. Office-based Eustachian tube endoscopy.
Oper. Tech. Otolaryngol. - Head Neck Surg. 32, 79–86 (2021).
30. Smith, M. E., Bance, M. L. & Tysome, J. R. Advances in Eustachian tube function
testing. World J. Otorhinolaryngol. - Head Neck Surg. 5, 131–136 (2019).
31. McCoul, E. D. Unlearning the ABCs of Tympanometry. Otolaryngol. - Head
Neck Surg. (United States) 165, 491–492 (2021).
32. Kourtidis, S., Hempel, J. M., Saravakos, P. & Preyer, S. Diagnostic value of
computed tomography in Eustachian tube dysfunction. Auris Nasus Larynx
49, 352–359 (2022).
33. Lee, S. et al. The usefulness of Valsalva computed tomography as an assessment
tool for the Eustachian tube. Am. J. Otolaryngol. - Head Neck Med.
Surg. 41, 102499 (2020).
34. Smith, M. E. et al. The repeatability of tests of eustachian tube function in
healthy ears. Laryngoscope 127, 2619–2626 (2017).
35. Ruan, K., Li, J., Tan, S., Liu, L. & Tang, A. Comparison of sonotubometry,
impedance, tubo-tympano-aerography, and tubomanometry to test eustachian
tube function. Am. J. Otolaryngol. - Head Neck Med. Surg. 41, 102384
(2020).
36. Ikeda, R. et al. A manual of Eustachian tube function tests–illustration of
representative test results obtained from healthy subjects and typical disorders
with suggestion of the appropriate test method of choice. Auris
Nasus Larynx 51, 206–213 (2023).
37. Virtanen, H. Sonotubometry: An acoustical method for objective measurement
of auditory tubal opening. Acta Otolaryngol. 86, 93–103 (1978).
38. Andresen, N. S., Sharon, J. D., Nieman, C. L., Seal, S. M. & Ward, B. K. Predictive
value of the Eustachian Tube Dysfunction Questionnaire-7 for identifying
obstructive Eustachian tube dysfunction: A systematic review. Laryngoscope
Investig. Otolaryngol. 6, 844–851 (2021).
39. Bae, S. H., Moon, S., Jeong, M. & Moon, I. S. Revisiting the Diagnostic Performance
of the Modified Nine-Step Test for Obstructive and Patulous Eustachian
Tube Dysfunction. Diagnostics 12, (2022).
40. Alper, C. M. et al. Panel 2: Anatomy (Eustachian Tube, Middle Ear, and Mastoid—Anatomy,
Physiology, Pathophysiology, and Pathogenesis). Otolaryngol.
- Head Neck Surg. (United States) 156, S22–S40 (2017).
41. Alper, C. M., Teixeira, M. S. & Swarts, J. D. Correlations between videoendoscopy
and sonotubometry of eustachian tube opening during a swallow.
Laryngoscope 126, 2778–2784 (2016).
42. Smith, M. E., Cochrane, I. L., Donnelly, N., Axon, P. R. & Tysome, J. R. The
Performance of Patient-reported Outcome Measures as Diagnostic Tools
for Eustachian Tube Dysfunction. Otol. Neurotol. 39, 1129–1138 (2018).
43. Swarts, J. D., Teixeira, M. S., Banks, J., El-Wagaa, J. & Doyle, W. J. A method
to assess the accuracy of sonotubometry for detecting Eustachian tube
openings. Eur. Arch. Oto-Rhino-Laryngology 272, 2111–2119 (2015).
44. Beleskiene, V. et al. Eustachian tube opening measurement by sonotubometry
using perfect sequences for healthy adults. Clin. Exp. Otorhinolaryngol.
9, 116–122 (2016).
45. Jonathan, D. A., Chalmers, P. & Wong, K. Comparison of sonotubometry with
tympanometry to assess Eustachian tube function in adults. Br. J. Audiol.
20, 231–235 (1986).
46. Mondain, M., Vidai, D., Bouhanna, S. & Uziel, A. Monitoring eustachian tube
opening: Preliminary results in normal subjects. Laryngoscope 107, 1414–1419
(1997).
47. Munro, K. J., Benton, C. L. & Marchbanks, R. J. Sonotubometry findings in
children at high risk from middle ear effusion. Clin. Otolaryngol. Allied Sci.
24, 223–227 (1999).
48. Ikeda, R. et al. Efficacy of a silicone plug for patulous eustachian tube: A
prospective, multicenter case series. Laryngoscope 130, 1304–1309 (2020).
49. Li, J. et al. A Novel Eustachian Tube Test: Preliminary Research of Sonotubometry
With Nasopharynx Under Pressure. Otol. Neurotol. 43, 580–586
(2022).
50. Sudhoff, H. H. & Mueller, S. Treatment of pharyngotympanic tube dysfunction.
Auris Nasus Larynx 45, 207–214 (2018).
51. Lu, H. et al. Clinical value of the Eustachian Tube Function Scoring System
T-ETDQ: a prospective diagnostic study. Eur. Arch. Oto-Rhino-Laryngology
279, 2223–2230 (2022).
52. Schröder, S., Lehmann, M., Sauzet, O., Ebmeyer, J. & Sudhoff, H. A novel
diagnostic tool for chronic obstructive eustachian tube dysfunction-the
eustachian tube score. Laryngoscope 125, 703–708 (2015).
53. Herrera, M., Eisenberg, G. & Plaza, G. Clinical Assessment of Eustachian
Tube Dysfunction Through the Eustachian Tube Dysfunction Questionnaire
(ETDQ-7) and Tubomanometry. Acta Otorrinolaringol. (English Ed. 70, 265–271
(2019).
Dr. Jennifer Knuth, Dr. Kathrin Warnking – Clinical Affairs SPIGGLE & THEIS Medizintechnik GmbH 9

54. Oehlandt, H., Lindfors, O. & Sinkkonen, S. T. Tubomanometry correlations
with patient characteristics and other diagnostic tests of Eustachian tube
dysfunction: a cohort study of 432 ears. Eur. Arch. Oto-Rhino-Laryngology
279, 5153–5160 (2022).
55. Ros, L. et al. Place of Tubomanometry in Patulous Eustachian Tube Diagnosis.
Otolaryngol. - Head Neck Surg. (United States) 168, 707–713 (2023).
56. Ockermann, T., Reineke, U., Upile, T., Ebmeyer, J. & Sudhoff, H. H. Balloon
dilatation Eustachian Tuboplasty: A clinical study. Laryngoscope 120, 1411–
1416 (2010).
57. Bächinger, D. et al. Endolymphatic hydrops mimicking obstructive Eustachian
tube dysfunction: preliminary experience and literature review. Eur.
Arch. Oto-Rhino-Laryngology 278, 561–565 (2021).
58. Gey, A. et al. The Rate of Eustachian Tube Dysfunction in Adult Patients with
Chronic Inflammatory Middle Ear Disease Is Low. Otol. Neurotol. 44, E305–
E310 (2023).
59. Weiss, N. M., Bennöhr, F., Lenz, J. H., Mlynski, R. & Rettschlag, S. Eustachian
tube dysfunction after cleft palate surgery: Use of the latest diagnostics.
HNO 70, 557–563 (2022).
60. Leichtle, A., Hollfelder, D., Wollenberg, B. & Bruchhage, K. L. Balloon Eustachian
Tuboplasty in children. Eur. Arch. Oto-Rhino-Laryngology 274, 2411–
2419 (2017).
61. Schröder, S. et al. Evaluation of tubomanometry as a routine diagnostic
tool for chronic obstructive Eustachian tube dysfunction. Clin. Otolaryngol.
40, 691–697 (2015).
62. Bae, S. H. et al. Results of Eustachian tube balloon dilation measured using
the nine-step test. Nat. Sci. Reports 13, 1–7 (2023).
63. Doyle, W. J., Mandel, E. M., Seroky, J. T., Swarts, J. D. & Casselbrant, M. L.
Reproducibility of the Forced Response Test in Children With Chronic Otitis
Media With Effusion. Otol. Neurotol. 34, 16–21 (2013).
64. Cantekin, E. I., Bluestone, C. D., Saez, C. A. & Bern, S. A. Airflow through the
eustachian tube. Ann. Otol. Rhinol. Laryngol. 88, 603–612 (1979).
65. Casselbrant, M. L., Mandel, E. M., Seroky, J. T., Swarts, J. D. & Doyle, W. J. The
forced‐response test does not discriminate ears with different otitis media
expressions. Laryngoscope 124, 2619–2623 (2014).
66. Alper, C. M., Teixeira, M. S., Richert, B. C. & Douglas Swarts, J. Presentation
and eustachian tube function test results in children evaluated at a specialty
clinic. Laryngoscope 129, 1218–1228 (2019).
67. Swarts, J. D., Cuneyt M. Alper, Mandel, E. M., Villardo, R. & Doyle, W. J. Eustachian
Tube Function in Adults Without Middle Ear Disease. Ann Otol Rhinol
Laryngol. 120, 220–225 (2011).
68. McCoul, E. D., Anand, V. & Christos, P. J. Validating the Clinical Assessment of
Eustachian Tube Dysfunction: The Eustachian Tube Dysfunction Questionnaire
(ETDQ-7). Laryngoscope 122, 1137–1141 (2012).
69. Tideholm, B., Jönsson, S., Carlborg, B., Welinder, R. & Grenner, J. Continuous
24-hour measurement of middle ear pressure. Acta Otolaryngol. 116, 581–
588 (1996).
70. Shaikh, N. et al. Development and Validation of an Automated Classifier
to Diagnose Acute Otitis Media in Children. JAMA Pediatr. (2024) doi:10.1001/
jamapediatrics.2024.0011.
10 Dr. Jennifer Knuth, Dr. Kathrin Warnking – Clinical Affairs SPIGGLE & THEIS Medizintechnik GmbH