Open-Ended Tympanometric Screening: A New Concept Neil Lewis; Allen
Dugdale, MD, FRACP; Anthony Canty, FRCS;
\s=b\ We introduce the concept of openended, successive-day, tympanometric
screening. In impedance screening of children for middle ear disorders, there is a serious risk of over-referral if decisions are made on the basis of a single tympanogram. Serial tympanometric studies of Australian aboriginal children show that, whereas the type B tympanogram is usually stable, type A and type C patterns are prone to vary from day to day, inviting inappropriate referral decisions unless the classifications are confirmed by tests on successive days.
(Arch Otolaryngol 101:722-725, 1975)
James
Jerger,
PhD
electro-acoustic impedance is widely esteemed as a aid for hearing and ear disorders.1 3 Considerable interest is now being· shown in the use of modi¬ fied impedance audiometry as a screening; device for the identi¬ fication of middle ear disorders in young children. In advocating its use for this purpose, Brooks45 has stressed that the impedance method is easy to administer and is not greatly influenced by either environ¬ mental or motivational factors. More¬ over, it is capable of yielding accurate and reproducible results that permit more confident identification of ab¬ norm ality than is possible from either visusJ otoscopy or pure-tone audiome¬ try. Cooper et al6 also attest to the su¬ periority of impedance audiometry in screening children for middle ear dis¬ orders, but express some concern that it atppears to generate a fairly high rate of over-referrals. In auditory screening programs, it ha« been customary to assign individ¬ uals to a "pass" or "fail" category on
The bridge diagnostic
Accepted for publication July 7, 1975. From Mater Misericordiae Hospital, South Brisbane, Australia (Mr Lewis and Drs Dugdale a.nd Canty), and the Department of Otorhinolaryngology and Communicative Sciences, Baylor College of Medicine, Houston (Dr Jerger). Reprint requests to the Department of Speech and Hearing, University of Queensland, Brisbane, Australia 4067 (Mr Lewis).
Downloaded From: http://archotol.jamanetwork.com/ by a University of Victoria User on 06/05/2015
the basis of a single, brief examina¬ tion. Accordingly, an effective screen¬ ing device is regarded as one that nei¬ ther "fails" too many ears that are normal nor "passes" too many ears that are abnormal. Most investiga¬ tors, however, accept a liberal tol¬ erance of false-negative screening errors as preferable to possible misidentification of any case that might stand in genuine need for medical fol¬
low-up. During
the past several years, we have made extensive use of imped¬ ance audiometry in screening pro¬ grams for Australian aboriginal chil¬ dren who suffer an unusually high prevalence of serous otitis media and other middle ear diseases.7·8 Our experience leads us to believe that impedance audiometry senses the presence of middle ear disease long before the appearance of oto¬ scopie or audiometrie manifestations. In the case of serous otitis media, early detection followed by prompt medical treatment would seem to af¬ ford the best prospects of successful intervention into the course of a dis¬ ease that is singularly resistant to treatment once it has progressed to a chronic stage. To take full advantage of the exquisite sensitivity of im¬ pedance audiometry in detecting in¬ cipient disease processes, however, it may be necessary to develop new con-
Table
1.—Day-to-Day Tympanometric Changes in Ten Aboriginal Children
LEFT EAR AHL* CASE
(dB) 40
2
4
metric
Normal
25
TM retracted, scarred
MEP
Normal
Type
MEP
9
10
-120 -120
MEP
-40 -300
21
-220 -160 -160 -140 -160
MEP
Type
TM retracted
MEP
Type MEP
-50 -100
-10
-40
-100
Type -60
MEP
-40
-80 -100
-80
Type
TM retracted
-380
-220 -320
MEP
-380
Otoscopie Findings
Tympano¬
16
Normal
Findings Type
Normal
Type
MEP MEP MEP
Normal
12.5 21
A -60
-30
-60
-340 -300 -380
-300
MEP
-20 -280
-60
-100
-30
-80
-240
-240 -240 -140
-160
-160
-200 -200 -180
Type MEP
Type
Normal
23
-30
Type
Normal
Normal
-30
Type
TM retracted, scarred
31
Test Day
metric
TM retracted, scarred
-40
Type
Normal
22
-40
Type
perforation
16
-140
27
17.5 -340 -240 -300 -300 c c c c c 22 -200 -200 -120 -130 -140
MEP
Healed
13
-20
Type
Normal
32.5
8
C C -200 -360
Type
19
17
AHL
(dB)
Findings Type TM| retracted
Normal
7
Test Day
Tympano-
Otoscopic Findings
MEPJ
17.5
6
RIGHT EAR
MEP
Type -360
Type MEP
-140 -300 -140 -200 -200
Type
Normal
MEP
-60
-60
-40
-250
-60
-60
-80
-200
-60
Type
TM retracted
MEP
AHL, average hearing level.
*
t TM, tympanic MEP, middle
Table
membrane. pressure
ear
(mm H20).
2.—Day-to-Day Tympanometric
Changes
Table 3.—Test-Retest Variability in the Tympanometric Patterns of 76 Ears
Tympanometric
Status on Successive Daily Tests (Type) Ato A Ato B AtoC Bto A BtoB BtoC CtoA CtoB C to C
No. of Occurrences
Î5 0 8 0 13 3 7 3 27
cepts of auditory screening. The
on a
pro¬
government reservation in
Queensland. SUBJECTS AND METHODS An electro-acoustic impedance bridge used to derive individual tympano¬ grams of each ear of each child. These functions, relating middle ear compliance change to induced pressure variation in the internal ear canal, were classified into types A, B, or C in accordance with Jerwas
No. of Ears 1 5 1 5 6 17 3 16
2!
ger's widely accepted nomenclature.9
posals set forth herein have been in¬ spired primarily by the results of two studies of the day-to-day variability in the tympanometric patterns of Australian aboriginal children who live
Type A to A A to A toC to A to BtoC CtoA Cto CtoC
Calibration checks of the instrument be¬ fore and after each test session established that the manometer unit of the impedance bridge consistently gave readings within ± 10 mm HjO of the pressures developed in a simple water manometer over a range of -300 mm H20 to +300 mm H20. The compliance scale of the instrument gave readings within .05 eu cm of the known vol¬ umes of 1 cu cm and 2 eu cm hard-walled cavities. Prior to the tympanometric evaluation, each child was examined otoscopically by a medical otologist, and audiometrically by a
qualified audiologist. The first study examined short-term
variations in the tympanogram. For this purpose, a group of ten Australian aborigi¬ nal children (age 5 to 6 years) was selected
represent a variety of ear conditions. These children were tested tympanometrically on each of five consecutive days. In the second study, 38 children from the same community were examined on two occasions with a two-month separation be¬ tween tests. The age range in this sample was 4 to 14 years. Quite by chance, none of these children received treatment for ear disorders during the test-retest interval. to
RESULTS Short-Term Variations The audiometrie, otoscopie, and daily tympanometric findings of the
ten children
are
shown in Table 1.
Two
findings are strikingly apparent. First, the incidence of an abnormal tympanogram (types and C) was unexpectedly high. Second, the tym¬ panometric status of ears changed frequently from day to day. These changes have been tabulated in Table
2. If an ear showed a type A response on any one day, there was a 35% chance that it would show a different response on the following day. The change was always to type C, never to type B. Ears that gave a type response showed much greater con¬ sistency. Only 19% of these could be
Downloaded From: http://archotol.jamanetwork.com/ by a University of Victoria User on 06/05/2015
Table 4.—Illustrative Decision Matrix Used In
Open-Ended, Successive-Day Screening Concept*
Case
Day 1 (Type) A
A
C C C C
19% •^-
*
8%
expected to change on a succeeding day, the changes always being to type
C. Ears with a type C response had a 27% chance of changing within a day, the change usually going to type A, and only occasionally to type B. The directions and probabilities of change are summarized in the Figure.
Long-Term Variations Table 3 displays the test-retest variations in the tympanograms of 76 ears (38 children) that were tested on two occasions, two months apart. In 32% of the untreated ears, the second tympanogram reversed the indica¬ tions of the first. Type C tympano¬ grams showed the most variability, shifting frequently to type A on retest, and sometimes to type B. Fewer ears attracted abnormal classifica¬ tions on the second test. Only one ear that was initially classified as type showed spontaneous recovery to type A. COMMENT
Previous studies of clinical tym¬ panometry have suggested that the
yields highly repeatable testotologically normal
retest data in
Brooks10 retested one individual nine separate occasions during an 18-month period, and reported re¬ markable consistency in the pressurecompliance functions. Lidén et al11 ob¬ tained similar consistency in repeated tympanograms of three otologically normal subjects who were tested 20 times during a ten-hour period.
ears. on
Decision Pass
A C A
(Type)
A C
A C
Retest Retest Fall Fail Retest Fail
C A
Serial tympanogram results
Day 3 (Type)
are
shown for
Day 4
Decision Pass Fail
Fail seven
hypothetical
cases.
_^
Changes in tympanometric patterns on successive daily testing. Percentages indi¬ cate probabilities of change at next test.
method
Day 2
(Type)
The tympanogram has no such stable expression, however, for the children in our study, who belong to a population that is exceptionally vul¬ nerable to serous otitis media. Al¬ though little knowledge exists about the cause of this disease, faulty middle ear ventilation has been impli¬ cated as a predisposing factor.12 In children, the course of the disease ap¬ pears to be characterized by frequent remission and recidivation. Some ears appear to recover spontaneously, but others develop a "glue ear" stage that often requires surgery. The capricious nature of serous oti¬ tis media that is evident in our stud¬ ies creates serious difficulties for con¬ ventional screening philosophies that stipulate that a pass-fail designation should be made after a single exami¬ nation. As Cooper et al6 have shown, there is a real danger of over-referral in abbreviated impedance audiome¬ try, especially in regard to type C tympanograms, which often reflect a transitional phase of pathologic fea¬ tures. Adding otoscopy and pure-tone audiometry to the screening battery is not likely to solve the problem, since the day-to-day variations in middle ear status that are exposed by serial tympanometry are too subtle to produce visually discernible changes or substantial shifts in hearing sensi¬ tivity.8 Two cases that are described in Table 1 highlight the problem. In one patient (Table 1, case 5), otoscopy revealed that the left ear was normal; the right ear had a re¬ tracted drum with scarring. On the third test day, the left tympanogram changed from type C to type A. On the following day (day 4), it reverted to type C, with a middle ear pressure registration of —300 mm H20. On day
Downloaded From: http://archotol.jamanetwork.com/ by a University of Victoria User on 06/05/2015
5, the tympanogram returned
to
type
(middle ear pressure, 40 mm H20; compliance, 0.65 eu cm). If this ear had been tested only on day 3 or day 5, it would have passed the screen despite an obvious Eustachian tube dysfunc¬ A
tion. In another patient (Table 1, case 2), otoscopie and audiometrie assessment gave "pass" classification on both ears.
Tympanometric findings were (type A) on each day except
normal
when the classification shifted type C (middle ear pressure, 140 mm H20). On this one day, the child would have failed the tympanometric screen, possibly on the basis of a tran¬ sient and clinically insignificant pres¬
day 3, to
sure
variation.
OPEN-ENDED, SUCCESSIVE-DAY SCREENING
findings show a clear need for open-ended tympanometric screening on successive days for children in high-risk populations. In many in¬ stances, responsible referral decisions should be possible after two such tests, although transitional patients, Our
whose results fluctuate between type A and type C tympanograms, can re¬ quire as many as four successive tests. Specific recommendations in il¬ lustrative cases have been tabulated in Table 4 in the form of a decision matrix. The recommendations in each case are based exclusively on serial tympanometric configurations. It should be noted that a type tym¬ panogram always dictates a "fail" designation, whereas initial type A and type C tympanograms always re¬
quire further testing. The proposal calls for a heavier in¬
vestment of time and money than is
customary in conventional screening
procedures. We believe, however, that screening strategies should be conso¬
nant with the character of the dis¬ order under investigation. It is unre¬ alistic to expect more than token validity from single-occasion screen¬ ing of populations that suffer from a disease that is intrinsically labile. Our results show that serous otitis media in young children varies its expres¬ sion from day to day. During a longer time span, the disease appears to fol¬ low a hesitant course, frequently leading to a state of chronic middle ear effusion that might persist for months or even years.7 Its intermittencies are monitored accurately
and reliably by serial tympanometry, which shows systematic changes from types A to C to during progression, and from types to C to A during re¬ mission. Successive-day tympanometry would be wasteful, of course, in screen¬ ing situations in which the target disorders are intrinsically stable; it would be no more wasteful, per¬ haps, than inappropriate use of puretone audiometry or visual otoscopy in populations that are known to have a high prevalence of serous otitis me¬ dia. Over-referral in screening pro¬ grams adds a considerable cost bur¬ den in the form of unnecessary
medical follow-up. Under-referral pe¬ nalizes any child whose auditory inefficiency passes unnoticed during the years in which he is acquiring linguistic and educational compe¬ tence. In this context, the addition¬ al expenditures of successive-day screening might be a small price to pay for a more exact definition of middle ear status at the time that a referral decision must be made.
The
Department of Aboriginal and Island
Af¬
fairs, Queensland, and the Department of Abo¬ riginal Affairs, Canberra, Australia, cooperated in this
study.
References 1. ance
Jerger J: Clinical experience with impedaudiometry. Arch Otolaryngol 92:311-324,
1970. 2. Alberti
P, Kristensen R: The clinical application of impedance audiometry. Laryngoscope 80:735-746, 1970. 3. Jerger J, Jerger S, Mauldin L: Studies in
impedance audiometry: I. Normal and sensorineural ears. Arch Otolaryngol 96:513-523,1972. 4. Brooks D: A new approach to identification audiometry. Audiology 10:334-339, 1971. 5. Brooks D: Hearing screening: A compara-
tive study of an impedance method and pure tone screening. Scand Audiol 2:67-72, 1973. 6. Cooper J, Gates G, Owen J, et al: An abbreviated impedance bridge technique for school screening. J Speech Hear Dis 40:260-269, 1975. 7. Stuart J, Quayle C, Lewis A, et al: Health, hearing and ear disease in aboriginal school children. Med J Aust 1:855-859, 1972. 8. Lewis A, Barry M, Stuart J: Screening procedures for the identification of hearing and ear disorders in Australian aboriginal children. J Laryngol Otol 88:335-347, 1974.
Downloaded From: http://archotol.jamanetwork.com/ by a University of Victoria User on 06/05/2015
9. Jerger J: Suggested nomenclature for impedance audiometry. Arch Otolaryngol 96:1-3, 1972. 10. Brooks
D:
Electro-acoustic
impedance
bridge studies on normal ears of children. J Speech Hear Res 14:247-253, 1971. 11. Lid\l=e'\nG, Petersen J, Bj\l=o"\rkmanG: Tympanometry. Arch Otolaryngol 92:248-257, 1970. 12. Fagan P: Glue ear: An unnecessary problem. Med J Aust 1:501-506, 1973.
Dugdale, MD, FRACP; Anthony Canty, FRCS;
\s=b\ We introduce the concept of openended, successive-day, tympanometric
screening. In impedance screening of children for middle ear disorders, there is a serious risk of over-referral if decisions are made on the basis of a single tympanogram. Serial tympanometric studies of Australian aboriginal children show that, whereas the type B tympanogram is usually stable, type A and type C patterns are prone to vary from day to day, inviting inappropriate referral decisions unless the classifications are confirmed by tests on successive days.
(Arch Otolaryngol 101:722-725, 1975)
James
Jerger,
PhD
electro-acoustic impedance is widely esteemed as a aid for hearing and ear disorders.1 3 Considerable interest is now being· shown in the use of modi¬ fied impedance audiometry as a screening; device for the identi¬ fication of middle ear disorders in young children. In advocating its use for this purpose, Brooks45 has stressed that the impedance method is easy to administer and is not greatly influenced by either environ¬ mental or motivational factors. More¬ over, it is capable of yielding accurate and reproducible results that permit more confident identification of ab¬ norm ality than is possible from either visusJ otoscopy or pure-tone audiome¬ try. Cooper et al6 also attest to the su¬ periority of impedance audiometry in screening children for middle ear dis¬ orders, but express some concern that it atppears to generate a fairly high rate of over-referrals. In auditory screening programs, it ha« been customary to assign individ¬ uals to a "pass" or "fail" category on
The bridge diagnostic
Accepted for publication July 7, 1975. From Mater Misericordiae Hospital, South Brisbane, Australia (Mr Lewis and Drs Dugdale a.nd Canty), and the Department of Otorhinolaryngology and Communicative Sciences, Baylor College of Medicine, Houston (Dr Jerger). Reprint requests to the Department of Speech and Hearing, University of Queensland, Brisbane, Australia 4067 (Mr Lewis).
Downloaded From: http://archotol.jamanetwork.com/ by a University of Victoria User on 06/05/2015
the basis of a single, brief examina¬ tion. Accordingly, an effective screen¬ ing device is regarded as one that nei¬ ther "fails" too many ears that are normal nor "passes" too many ears that are abnormal. Most investiga¬ tors, however, accept a liberal tol¬ erance of false-negative screening errors as preferable to possible misidentification of any case that might stand in genuine need for medical fol¬
low-up. During
the past several years, we have made extensive use of imped¬ ance audiometry in screening pro¬ grams for Australian aboriginal chil¬ dren who suffer an unusually high prevalence of serous otitis media and other middle ear diseases.7·8 Our experience leads us to believe that impedance audiometry senses the presence of middle ear disease long before the appearance of oto¬ scopie or audiometrie manifestations. In the case of serous otitis media, early detection followed by prompt medical treatment would seem to af¬ ford the best prospects of successful intervention into the course of a dis¬ ease that is singularly resistant to treatment once it has progressed to a chronic stage. To take full advantage of the exquisite sensitivity of im¬ pedance audiometry in detecting in¬ cipient disease processes, however, it may be necessary to develop new con-
Table
1.—Day-to-Day Tympanometric Changes in Ten Aboriginal Children
LEFT EAR AHL* CASE
(dB) 40
2
4
metric
Normal
25
TM retracted, scarred
MEP
Normal
Type
MEP
9
10
-120 -120
MEP
-40 -300
21
-220 -160 -160 -140 -160
MEP
Type
TM retracted
MEP
Type MEP
-50 -100
-10
-40
-100
Type -60
MEP
-40
-80 -100
-80
Type
TM retracted
-380
-220 -320
MEP
-380
Otoscopie Findings
Tympano¬
16
Normal
Findings Type
Normal
Type
MEP MEP MEP
Normal
12.5 21
A -60
-30
-60
-340 -300 -380
-300
MEP
-20 -280
-60
-100
-30
-80
-240
-240 -240 -140
-160
-160
-200 -200 -180
Type MEP
Type
Normal
23
-30
Type
Normal
Normal
-30
Type
TM retracted, scarred
31
Test Day
metric
TM retracted, scarred
-40
Type
Normal
22
-40
Type
perforation
16
-140
27
17.5 -340 -240 -300 -300 c c c c c 22 -200 -200 -120 -130 -140
MEP
Healed
13
-20
Type
Normal
32.5
8
C C -200 -360
Type
19
17
AHL
(dB)
Findings Type TM| retracted
Normal
7
Test Day
Tympano-
Otoscopic Findings
MEPJ
17.5
6
RIGHT EAR
MEP
Type -360
Type MEP
-140 -300 -140 -200 -200
Type
Normal
MEP
-60
-60
-40
-250
-60
-60
-80
-200
-60
Type
TM retracted
MEP
AHL, average hearing level.
*
t TM, tympanic MEP, middle
Table
membrane. pressure
ear
(mm H20).
2.—Day-to-Day Tympanometric
Changes
Table 3.—Test-Retest Variability in the Tympanometric Patterns of 76 Ears
Tympanometric
Status on Successive Daily Tests (Type) Ato A Ato B AtoC Bto A BtoB BtoC CtoA CtoB C to C
No. of Occurrences
Î5 0 8 0 13 3 7 3 27
cepts of auditory screening. The
on a
pro¬
government reservation in
Queensland. SUBJECTS AND METHODS An electro-acoustic impedance bridge used to derive individual tympano¬ grams of each ear of each child. These functions, relating middle ear compliance change to induced pressure variation in the internal ear canal, were classified into types A, B, or C in accordance with Jerwas
No. of Ears 1 5 1 5 6 17 3 16
2!
ger's widely accepted nomenclature.9
posals set forth herein have been in¬ spired primarily by the results of two studies of the day-to-day variability in the tympanometric patterns of Australian aboriginal children who live
Type A to A A to A toC to A to BtoC CtoA Cto CtoC
Calibration checks of the instrument be¬ fore and after each test session established that the manometer unit of the impedance bridge consistently gave readings within ± 10 mm HjO of the pressures developed in a simple water manometer over a range of -300 mm H20 to +300 mm H20. The compliance scale of the instrument gave readings within .05 eu cm of the known vol¬ umes of 1 cu cm and 2 eu cm hard-walled cavities. Prior to the tympanometric evaluation, each child was examined otoscopically by a medical otologist, and audiometrically by a
qualified audiologist. The first study examined short-term
variations in the tympanogram. For this purpose, a group of ten Australian aborigi¬ nal children (age 5 to 6 years) was selected
represent a variety of ear conditions. These children were tested tympanometrically on each of five consecutive days. In the second study, 38 children from the same community were examined on two occasions with a two-month separation be¬ tween tests. The age range in this sample was 4 to 14 years. Quite by chance, none of these children received treatment for ear disorders during the test-retest interval. to
RESULTS Short-Term Variations The audiometrie, otoscopie, and daily tympanometric findings of the
ten children
are
shown in Table 1.
Two
findings are strikingly apparent. First, the incidence of an abnormal tympanogram (types and C) was unexpectedly high. Second, the tym¬ panometric status of ears changed frequently from day to day. These changes have been tabulated in Table
2. If an ear showed a type A response on any one day, there was a 35% chance that it would show a different response on the following day. The change was always to type C, never to type B. Ears that gave a type response showed much greater con¬ sistency. Only 19% of these could be
Downloaded From: http://archotol.jamanetwork.com/ by a University of Victoria User on 06/05/2015
Table 4.—Illustrative Decision Matrix Used In
Open-Ended, Successive-Day Screening Concept*
Case
Day 1 (Type) A
A
C C C C
19% •^-
*
8%
expected to change on a succeeding day, the changes always being to type
C. Ears with a type C response had a 27% chance of changing within a day, the change usually going to type A, and only occasionally to type B. The directions and probabilities of change are summarized in the Figure.
Long-Term Variations Table 3 displays the test-retest variations in the tympanograms of 76 ears (38 children) that were tested on two occasions, two months apart. In 32% of the untreated ears, the second tympanogram reversed the indica¬ tions of the first. Type C tympano¬ grams showed the most variability, shifting frequently to type A on retest, and sometimes to type B. Fewer ears attracted abnormal classifica¬ tions on the second test. Only one ear that was initially classified as type showed spontaneous recovery to type A. COMMENT
Previous studies of clinical tym¬ panometry have suggested that the
yields highly repeatable testotologically normal
retest data in
Brooks10 retested one individual nine separate occasions during an 18-month period, and reported re¬ markable consistency in the pressurecompliance functions. Lidén et al11 ob¬ tained similar consistency in repeated tympanograms of three otologically normal subjects who were tested 20 times during a ten-hour period.
ears. on
Decision Pass
A C A
(Type)
A C
A C
Retest Retest Fall Fail Retest Fail
C A
Serial tympanogram results
Day 3 (Type)
are
shown for
Day 4
Decision Pass Fail
Fail seven
hypothetical
cases.
_^
Changes in tympanometric patterns on successive daily testing. Percentages indi¬ cate probabilities of change at next test.
method
Day 2
(Type)
The tympanogram has no such stable expression, however, for the children in our study, who belong to a population that is exceptionally vul¬ nerable to serous otitis media. Al¬ though little knowledge exists about the cause of this disease, faulty middle ear ventilation has been impli¬ cated as a predisposing factor.12 In children, the course of the disease ap¬ pears to be characterized by frequent remission and recidivation. Some ears appear to recover spontaneously, but others develop a "glue ear" stage that often requires surgery. The capricious nature of serous oti¬ tis media that is evident in our stud¬ ies creates serious difficulties for con¬ ventional screening philosophies that stipulate that a pass-fail designation should be made after a single exami¬ nation. As Cooper et al6 have shown, there is a real danger of over-referral in abbreviated impedance audiome¬ try, especially in regard to type C tympanograms, which often reflect a transitional phase of pathologic fea¬ tures. Adding otoscopy and pure-tone audiometry to the screening battery is not likely to solve the problem, since the day-to-day variations in middle ear status that are exposed by serial tympanometry are too subtle to produce visually discernible changes or substantial shifts in hearing sensi¬ tivity.8 Two cases that are described in Table 1 highlight the problem. In one patient (Table 1, case 5), otoscopy revealed that the left ear was normal; the right ear had a re¬ tracted drum with scarring. On the third test day, the left tympanogram changed from type C to type A. On the following day (day 4), it reverted to type C, with a middle ear pressure registration of —300 mm H20. On day
Downloaded From: http://archotol.jamanetwork.com/ by a University of Victoria User on 06/05/2015
5, the tympanogram returned
to
type
(middle ear pressure, 40 mm H20; compliance, 0.65 eu cm). If this ear had been tested only on day 3 or day 5, it would have passed the screen despite an obvious Eustachian tube dysfunc¬ A
tion. In another patient (Table 1, case 2), otoscopie and audiometrie assessment gave "pass" classification on both ears.
Tympanometric findings were (type A) on each day except
normal
when the classification shifted type C (middle ear pressure, 140 mm H20). On this one day, the child would have failed the tympanometric screen, possibly on the basis of a tran¬ sient and clinically insignificant pres¬
day 3, to
sure
variation.
OPEN-ENDED, SUCCESSIVE-DAY SCREENING
findings show a clear need for open-ended tympanometric screening on successive days for children in high-risk populations. In many in¬ stances, responsible referral decisions should be possible after two such tests, although transitional patients, Our
whose results fluctuate between type A and type C tympanograms, can re¬ quire as many as four successive tests. Specific recommendations in il¬ lustrative cases have been tabulated in Table 4 in the form of a decision matrix. The recommendations in each case are based exclusively on serial tympanometric configurations. It should be noted that a type tym¬ panogram always dictates a "fail" designation, whereas initial type A and type C tympanograms always re¬
quire further testing. The proposal calls for a heavier in¬
vestment of time and money than is
customary in conventional screening
procedures. We believe, however, that screening strategies should be conso¬
nant with the character of the dis¬ order under investigation. It is unre¬ alistic to expect more than token validity from single-occasion screen¬ ing of populations that suffer from a disease that is intrinsically labile. Our results show that serous otitis media in young children varies its expres¬ sion from day to day. During a longer time span, the disease appears to fol¬ low a hesitant course, frequently leading to a state of chronic middle ear effusion that might persist for months or even years.7 Its intermittencies are monitored accurately
and reliably by serial tympanometry, which shows systematic changes from types A to C to during progression, and from types to C to A during re¬ mission. Successive-day tympanometry would be wasteful, of course, in screen¬ ing situations in which the target disorders are intrinsically stable; it would be no more wasteful, per¬ haps, than inappropriate use of puretone audiometry or visual otoscopy in populations that are known to have a high prevalence of serous otitis me¬ dia. Over-referral in screening pro¬ grams adds a considerable cost bur¬ den in the form of unnecessary
medical follow-up. Under-referral pe¬ nalizes any child whose auditory inefficiency passes unnoticed during the years in which he is acquiring linguistic and educational compe¬ tence. In this context, the addition¬ al expenditures of successive-day screening might be a small price to pay for a more exact definition of middle ear status at the time that a referral decision must be made.
The
Department of Aboriginal and Island
Af¬
fairs, Queensland, and the Department of Abo¬ riginal Affairs, Canberra, Australia, cooperated in this
study.
References 1. ance
Jerger J: Clinical experience with impedaudiometry. Arch Otolaryngol 92:311-324,
1970. 2. Alberti
P, Kristensen R: The clinical application of impedance audiometry. Laryngoscope 80:735-746, 1970. 3. Jerger J, Jerger S, Mauldin L: Studies in
impedance audiometry: I. Normal and sensorineural ears. Arch Otolaryngol 96:513-523,1972. 4. Brooks D: A new approach to identification audiometry. Audiology 10:334-339, 1971. 5. Brooks D: Hearing screening: A compara-
tive study of an impedance method and pure tone screening. Scand Audiol 2:67-72, 1973. 6. Cooper J, Gates G, Owen J, et al: An abbreviated impedance bridge technique for school screening. J Speech Hear Dis 40:260-269, 1975. 7. Stuart J, Quayle C, Lewis A, et al: Health, hearing and ear disease in aboriginal school children. Med J Aust 1:855-859, 1972. 8. Lewis A, Barry M, Stuart J: Screening procedures for the identification of hearing and ear disorders in Australian aboriginal children. J Laryngol Otol 88:335-347, 1974.
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9. Jerger J: Suggested nomenclature for impedance audiometry. Arch Otolaryngol 96:1-3, 1972. 10. Brooks
D:
Electro-acoustic
impedance
bridge studies on normal ears of children. J Speech Hear Res 14:247-253, 1971. 11. Lid\l=e'\nG, Petersen J, Bj\l=o"\rkmanG: Tympanometry. Arch Otolaryngol 92:248-257, 1970. 12. Fagan P: Glue ear: An unnecessary problem. Med J Aust 1:501-506, 1973.
