Tympanometry

The basic principles essential for interpreting two-component, multiple frequency tympanograms first are reviewed. These principles then are applied to an analysis of tympanometric shape (conductance, susceptance, and admittance tympanograms) as a function of probe frequency in subjects with normal middle ear transmission systems. The final section presents tympanometric data from patients with confirmed middle ear pathologies that produce an increase in resonant frequency (e.g., middle ear effusion, otosclerosis, ossicular adhesions, and tympanic membrane retraction) or a decrease in resonant frequency (e.g., otitis externa, serous otitis media, tympanic membrane pathology, and ossicular discontinuity). The advantages and disadvantages of a particular probe frequency and/or admittance component are illustrated with individual cases. The cases further demonstrate that the same tympanometric pattern can be recorded from ears with different pathologies (e.g., tympanic membrane perforation with cholesteatoma, tympanic membrane retraction, ossicular adhesions, and middle ear effusion), and conversely, that the same pathology can result in different tympanometric shapes (e.g., tympanic membrane perforation, middle ear effusion, and otosclerosis). Caution, therefore, must be exercised in ascribing a tympanometric abnormality to a specific middle ear lesion.     

The anti-oxidant effect of alpha-tocopherol in the prevention of experimentally induced myringosclerosis.

HYPOTHESIS: The objective of this study was to investigate the possible effect of alpha-tocopherol on the prevention of experimentally induced myringosclerosis. BACKGROUND: Myringosclerosis is a common sequela of ventilation tube treatment of otitis media with effusion. The relationship between oxygen-derived free radicals and occurrence of myringosclerosis has been proven in experimental models, and it was also shown that the formation of myringosclerosis after experimental myringotomy could be reduced by application of various free radical scavengers. METHODS: Eighteen Wistar albino rats were myringotomized on the left side and randomly separated into two groups: group A consisted of rats which received intramuscular alpha-tocopherol injections 100 mg/kg daily and group B which were injected with physiological serum only. The occurrence of myringosclerotic plaques in the tympanic membranes of the two groups was compared by otomicroscopy, histopathology, and tympanometry, which is a novel method of quantification. Blood samples were collected for biochemical evaluation, and the tympanic membranes were harvested on the 15th day of the experiment. RESULTS: In otomicroscopic evaluation, tympanic membranes in group B revealed varying degrees of myringosclerotic plaques; on the other hand, tympanic membranes in group A showed faint or no existence of myringosclerosis. The mean malondialdehyde levels were 1.33 +/- 0.11 micromol/L in group A and 7.49 +/- 1.37 micromol/L in group B (Z = -1.906, p = 0.057). In all ears from group B, the magnitude of the maximum admittance measured by tympanometry reduced to approximately 40% of the values obtained from group A (Z = -2,160, p = 0.031). The mean magnitude of the maximum admittance from group A was very close to the standardization values of Wistar albino rats, which predicts a functional outcome. CONCLUSION: The formation of myringosclerosis after experimental myringotomy can be diminished by intramuscular alpha-tocopherol injections.     

The effect of topical doxycycline in the prevention of experimental tympanosclerosis

Objectives: The aim of this study is to determine the effectiveness of topical doxycycline used in the process of experimental myringosclerosis and tympanosclerosis. Study Design: A prospective experimental animal study. Methods: Experimental tympanosclerosis was accomplished in 25 healthy adult guinea pigs by inoculation with 2.5 × 10⁷ colony‐forming units of type‐3 Streptococcus pneumoniae microorganisms followed by bilateral myringotomy. While the animals' right ears received a topical doxycycline treatment daily, their left ears were left untreated and used as controls. Otomicroscopic examination was carried out weekly and healing tympanic membranes were remyringotomized. After a 6‐week follow‐up, the temporal bones of 24 of 25 animals were removed and light‐microscopy examination was done regarding tympanic membrane myringosclerosis and middle ear mucosal sclerosis. Results: Myringosclerosis was noticed to a lesser extent in the doxycycline‐treated group when compared to the untreated control group. Light microscopy evaluation revealed a difference in the area and thickness of the sclerotic plaques of myringosclerosis of the tympanic membranes in the doxycycline‐treated group and the control group, being significantly smaller and thinner in the treated group (P < .001, P < .04, respectively). Similarly, the area and thickness of the sclerotic plaques in the middle ear mucosa were significantly smaller and thinner in the doxycycline treated group (P < .001, P < .03). Conclusion: This study demonstrated that the potent matrix metallo‐proteinase inhibitor doxycycline plays a preventive role in the development of experimentally induced tympanosclerosis.     

Effect of anesthetic gas on middle ear fluid

Tympanometry was performed before (preoperative) and after (intraoperative) the administration of inhalation anesthesia including nitrous oxide and halothane on 109 children undergoing myringotomy with pressure equalization tube insertion. A total of 213 preoperative tympanograms were compared with their intraoperative counterparts and the presence or absence of middle ear effusion at myringotomy. When preoperative tympanograms were consistent with pneumatized middle ears, intraoperative findings demonstrated a mean middle ear pressure increase of +147 daPa. When preoperative tympanometry suggested middle ear effusion, less than 1% demonstrated intraoperative tympanometric changes and/or findings at surgery that would support anesthesia clearing middle ear effusion. Preoperative tympanometric data were poor predictors of the presence or absence of effusion at myringotomy. The relationship between inhalation anesthetics (i.e., nitrous oxide and halothane) and middle ear fluids, and the reliability of tympanometry to predict middle ear effusion are discussed.     

Determination of reactive oxygen species in myringotomized tympanic membranes: effect of vitamin e treatment

OBJECTIVES/HYPOTHESIS: Recent studies have established a strong relationship between the development of myringosclerosis and reactive oxygen species (ROS). The aims of the present study were to directly detect ROS in the tympanic membrane and middle ear mucosa of rats by measuring luminol amplified chemiluminescence, to evaluate the changes in the levels of ROS after treatment with vitamin E, and to examine the possible changes in the tympanic membranes otomicroscopically and histologically. STUDY DESIGN: Prospective controlled animal study. METHODS: Forty healthy Sprague-Dawley rats were divided into five groups of eight animals each. Animals in all groups except group 1 were bilaterally myringotomized. Group 2 received no treatment, group 3 was treated with topical olive oil, group 4 received topical vitamin E, and group 5 received intramuscular vitamin E. After 24 hours of myringotomy, tympanic membranes were examined otomicroscopically; thereafter, tympanic membranes and middle ear mucosa were peeled off. The right ears of the animals were used for biochemical assay, and the left ears were used for histological study. RESULTS: Reactive oxygen species levels were significantly decreased in group 4 with topical application of vitamin E compared with untreated and myringotomized animals in group 2. Reactive oxygen species levels were also decreased in group 5, although the decrease was not statistically significant when compared with groups 2 and 3. Histological studies confirmed sclerotic changes in the untreated myringotomized animals. The tympanic membranes of animals in groups 2 and 3 showed a white, chalk-like pattern of sclerotic changes, whereas animals in groups 4 and 5, with the exception of two animals in group 5, lacked these changes. CONCLUSION: Although the relationship between the development of myringosclerosis and ROS had been well documented previously, the present study is the first that has directly measured the levels of ROS in the tympanic membrane and middle ear mucosa. These results are relevant because they correlate with histological findings. It has also been demonstrated that topically applied vitamin E is effective in decreasing the ROS levels.     

Does the use of radiofrequency myringotomy for insertion of a ventilation tube reduce the incidence of myringosclerosis?

The aim of the present study was to determine the rate of myringosclerosis after radiofrequency (RF) myringotomy and ventilation tube (VT) insertion and compare it with that after the incisional myringotomy and VT insertion. Thirty children (60 ears), 2–16 years old (mean age 7.06 ± 2.77 years) who were planned to undergo surgical intervention for bilateral otitis media with effusion (OME), were included in this study. The children were treated by RF myringotomy of the right ear, incisional myringotomy of the left ear, and insertion of VTs into both ears. Both ears were examined intraoperatively for bleeding, and patients were evaluated for myringosclerosis formation with otomicroscopy at the end of the ninth month. Myringosclerosis was observed in 22 of the 60 ears. The overall incidence was 36.6 %. Fifteen (50 %) left ears showed myringosclerosis by otomicroscopy, and seven (23.3 %) right ears showed myringosclerosis. The rate of myringosclerosis of the right ear was significantly lower than that of the left ear (p < 0.05). In addition, intraoperative tympanic membrane bleeding was observed in 24 (40 %) of the 60 ears: 21 (70 %) left ears and three (10 %) right ears were perforated by RF. The tympanic membrane bleeding rate of the right ear was significantly lower than that of the left ear (p < 0.01). The present study is the first to determine the myringosclerosis rate after RF myringotomy and VT insertion. Our results indicate that VT insertion with RF myringotomy decreased the incidence of myringosclerosis.     

Topical ascorbic acid reduces myringosclerosis in perforated tympanic membranes. A study in the rat.

Myringosclerosis, a common finding after myringotomy, has been recently associated with an increased production of oxygen free radicals. Ascorbic acid's proposed actions include collagen synthesis, antioxidation, and free radical scavenging. The effects of topical ascorbic acid on healing tympanic membranes were studied. Particular attention was given to detecting the presence of myringosclerosis. Twelve Sprague-Dawley rats were bilaterally myringotomized. Their ears were randomized into group A, which received topical ascorbic acid in Gelfoam, group B, which received topical saline solution in Gelfoam, and group C, which received no treatment. The tympanic membranes were harvested on day 13, after routine otomicroscopy. Under light microscopy, the connective tissue layer of the untouched side of the pars tensa was distinctly thicker in group A than in group B or group C. At this level, the extent of sclerotic lesions was significantly less in the ascorbic acid-treated group. It is inferred that topical ascorbic acid reduces the occurrence of myringosclerosis following tympanic membrane perforations in the rat.     

Comparison of tympanometry and otomicroscopy during healing of otitis media

One hundred ears in 50 children with acute otitis media during healing were examined with tympanometry and the objective measures were compared with the subjective evaluation of otomicroscopy by four otolaryngologists independently. Tympanometric findings could more often correctly suggest reduced tympanic membrane mobility than did otomicroscopy, but both methods gave an equally good indication of middle ear effusion. However, otomicroscopy was necessary when evaluating the colour and the appearance of the tympanic membrane and revealed middle ear effusion in a few cases with 'normal' tympanometry. As a rule: normal tympanometry (Jerger type A) was closely correlated with a normal tympanic membrane and a normal middle ear without effusion; pathological tympanometry (Jerger type B) was accompanied by middle ear effusion and needed follow-up; ears with tympanometric pressure more negative than -150 mmH2O but more positive than a flat curve needed otomicroscopy to identify middle ear effusion.     

Developmental changes in multifrequency tympanograms

The normal maturational course of tympanometric shape, static aural acoustic admittance and ear canal wall characteristics were investigated in healthy infants, who were followed at various time intervals in the first 4 months of life. Susceptance and conductance tympanograms were recorded from both ears of each subject at four probe frequencies or more. In addition, quantitative pneumatic otoscopy was performed utilizing air pressure changes of the same magnitude as those typically used in tympanometry. Results for the group were an increase in admittance magnitude with increasing age at frequencies above 226 Hz. Admittance phase angle increased with age at all frequencies, indicating a growing contribution of compliant elements in the first 4 months of life. The course of development of input admittance at the tympanic membrane differed among individual infants. Otoscopic findings indicated that external ear canal differences cannot completely account for tympanometric differences between young infants and adults.     

Diagnosis and therapy of seromucous otitis. Experience with 2766 operations on children

We compared tympanometric patterns with the type of ear effusion on 1693 ears of children with chronic seromucous otitis. There was no exact agreement between the tympanograms and the viscosity of the middle ear effusion. We inserted ventilating tubes in 943 of 2766 ears with SOM. A tube was only used if there was mucus in the middle ear. In cases of thin fluid we used myringotomy alone. A test to find the best tube is discussed. For a child with SOM the insertion of a ventilation tube is so helpful and complications so rare that in our opinion there is no better way of treatment. The complications are probably related more to the underlying disease than to the ventilation tube.     

Mechanoacoustic properties of the tympanic membrane: a study on isolated Mongolian gerbil temporal bones.

In order to study the mechanical properties of the tympanic membrane in diseased ears, we have designed and evaluated an experimental tympanometric model. Isolated temporal bones of healthy Mongolian gerbils were studied with a Grason-Stadler 1723 typanometer in two-component admittance measurements with probe tones of 220 and 660 Hz. The normal tympanometric curve is described, and the validity and reproducibility of the model are assessed. The morphology of the gerbil tympanic membrane is described and compared with those of other species. Various alterations were produced in the middle ear, and it was found that tympanometry showed high sensitivity for tympanic membrane stiffness but not for mass changes. The condition of the pars flaccida did not significantly influence admittance, which was also resistant to osmotic challenge to the membrane. Ossicular chain disruption caused an increased admittance, whereas malleus fixation, without affecting the tympanic membrane itself, caused a pronounced reduction. The tympanometric patterns during tympanic membrane mass increase, and with hypertrophic myringeal scars and perforations were also determined. We conclude that tympanometry in the in vitro middle ear of gerbils offers possibilities for studying changes of the tympanic membrane physiology in disease.     

分泌性中耳炎临床疗效观察

目的随访分泌性中耳炎患者经单纯鼓膜切开、鼓膜切开冲洗灌药后的恢复情况，探讨有效的治疗方法。方法对2006年1月-2008年12月因分泌性中耳炎住院手术治疗的病人共168例进行随访，实际回应预约随访者40例（67耳）。术后随访时间为6个月-3年，通过手术前后I临床表现、纯音测听、声导抗及鼓膜改善情况评估各组疗效。结果单纯鼓膜切开组与鼓膜切开冲洗灌药组的有效率分别是55.56％和74.19％，两组之间无统计学差异。结论单纯鼓膜切开和鼓膜切开冲洗灌药是治疗分泌性中耳炎的有效方法。     

The effect of anaesthesia on tympanograms of children undergoing grommet insertion.

A prospective study was designed to assess the effect of anaesthesia, including nitrous oxide, on tympanometric results of children undergoing myringotomy and possible grommet insertion. 155 patients (310 ears) were examined with a pneumatic otoscope and had tympanograms performed within 1 hour of operation. The patients were then anaesthetized by a combination of intravenous and gaseous anaesthetic. Immediately before myringotomy, a tympanogram was repeated. In 13% of patients predicted to have fluid at admission, there was a change in their tympanogram after induction of anaesthesia, suggesting clearance of fluid. At myringotomy, these ears were dry. We surmise that there was displacement of fluid from the middle ear by nitrous oxide during the early stages of anaesthesia. Thus we feel that, if an otologist confidently expects to find an effusion at myringotomy, the presence of a dry tap should not change his management plan.     

The effect of anaesthesia on tympanograms of children undergoing grommet insertion

A prospective study was designed to assess the effect of anaesthesia, including nitrous oxide, on tympanometric results of children undergoing myringotomy and possible grommet insertion. 155 patients (310 ears) were examined with a pneumatic otoscope and had tympanograms performed within 1 hour of operation. The patients were then anaesthetized by a combination of intravenous and gaseous anaesthetic. Immediately before myringotomy, a tympanogram was repeated. In 13% of patients predicted to have fluid at admission, there was a change in their tympanogram after induction of anaesthesia, suggesting clearance of fluid. At myringotomy, these ears were dry. We surmise that there was displacement of fluid from the middle ear by nitrous oxide during the early stages of anaesthesia. Thus we feel that, if an otologist confidently expects to find an effusion at myringotomy, the presence of a dry tap should not change his management plan.     

Middle Ear Effusions and the Nitrous Oxide Myth

Myringotomies were performed on 75 ears suspected of having chronic or recurrent otitis media with effusion. Preanesthesia and intraoperative tympanograms with halothane, nitrous oxide, and oxygen anesthesia were compared for possible changes in middle ear pressure due to anesthesia. In addition, preanesthesia tympanograms were compared with tympanograms taken 2 weeks before hospital outpatient surgery. Tympanograms of 11 ears were found to shift from a flat type recorded at the office visit to normal range at pre and postinduction anesthesia. Middle ear fluid was not present in any of these 11 ears. The remaining 64 ears were broken down into three abnormal tympanogram configurations; flat, roll-over, and peaked negative pressure types. Comparing the tympanograms done in the office, preanesthesia and intraoperatively, only one of the 64 ears showed a change after induction of anesthesia. Three of the 64 ears revealed an unpredictable result with negative myringotomies. These results tend to support tympanometry as a means in predicting myringotomy findings, and also refute the contention that short-term nitrous oxide anesthesia changes the middle ear effusion during myringotomy.     

Calcium deposition and expression of bone modelling markers in the tympanic membrane following acute otitis media

BACKGROUND AND OBJECTIVES: In accordance with clinical findings, myringosclerosis develops after otitis media (OM) and paracentesis in an experimental setting. The pathogenesis of this phenomenon of calcification is poorly understood. As the calcification process and the sclerotic plaques of the drum mimics features of bone tissue, this study explores tympanic membrane calcium deposition in association with the expression of three bone modelling markers: osteopontin (OPN), osteoprotegerin (OPG) and osteonectin (ON). OPN is secreted by osteoblasts and is found at calcification sites, e.g. during pathological calcification in chronic OM. The cytokine OPG is an inhibitor of bone resorption and consequently bone remodelling. ON is a calcium binding glycoprotein necessary for the maintenance of bone mass and remodelling. It is found in bone matrix and synthesized by osteoblasts. METHOD: A rat model of acute otitis media (AOM) caused by non-typeable Haemophilus influenzae was used. Four days following middle ear inoculation, a myringotomy was performed in six animals. Another group of ten animals was inoculated only. The drum was dissected in two animals from each group on day 4, 7, 14 and 28 post-inoculation, and the expression of OPN, OPG and ON was determined by immunohistochemistry. von Kossa staining determined the deposition of calcium and immune staining for CD68 identified macrophages. RESULTS: Calcium depositions were initially accumulated in the cytoplasm of macrophages and dispersed in the connective tissue layers of the pars flaccida and tensa. Late accumulation occurred in the lamina propria of pars tensa, more extensively in myringotomized ears. OPN expression was found early in inflammatory cells including especially macrophages and late in pars tensa fibrocytes. OPG expression was initially located to inflammatory cells and late to pars tensa fibrocytes and the inner basal membrane of pars flaccida. Some ears displayed a marked pars flaccida expression of ON in the connective tissue matrix on early days and at the inner basal membrane on later days. The latter cases were from myringotomized ears. Otherwise, no apparent differences of marker expression occurred between myringotomized and non-myringotomized animals. CONCLUSION: We conclude that osteopontin, osteoprotegerin and osteonectin are expressed by different cell types in the tympanic membrane during calcification in association with AOM, with or without myringotomy. These molecules may accordingly play a role in the pathogenesis of myringosclerosis, in which macrophages and fibrocytes appear as potential major players.     

Wideband reflectance in Down syndrome

ObjectiveChildren with Down syndrome (DS) have a high incidence of middle ear disorders and congenital abnormalities of the external, middle and inner ear. Energy reflectance (ER), a wideband acoustic immittance (WAI) measurement parameter, can measure the sound energy reflected or absorbed in the ear canal over a wider range of frequencies more efficiently and faster than conventional single-tone 226 Hz tympanometry. The aim of the present study was to compare the WAI measurements of children with DS with those of typically developing, normal-hearing children according to their tympanometric findings.MethodsFour groups of children with Down syndrome (age range: 2 years and 4 months to 16 years and 3 months; mean age: 8.5 yr) with normal tympanograms (19 ears), flat tympanograms (13 ears), mild negative pressure tympanograms (6 ears between −100 and −199 daPa at the admittance peak) and severe negative pressure tympanograms (4 ears at −200 daPa or lower at the admittance peak) were assessed. All findings were compared with data obtained from 21 ears of a healthy control group (age range: 3 years and 1 month to 13 years and 11 months; mean age: 7.9 yr). The subjects underwent tympanometry with a 226-Hz probe tone frequency and ER measurements along the 200–6,000 Hz range with a chirp stimulus using the Middle-Ear Power Analyzer (MEPA3 – HearID) by Mimosa Acoustics (Champaign, IL), software, version 3.3 [38].ResultsStatistically significant differences were observed in the ER curves for some comparisons between the studied groups. There was also a negative correlation between the static acoustic admittance at the tympanic membrane level and ER measured with a chirp stimulus at 500 and 1,000 Hz. The discriminant analysis technique, which used a chirp stimulus at 1,000 and 1,600 Hz to classify the participants' data based on ER values, achieved a correct classification rate of 59.52% for participants with DS.ConclusionWhile groups with abnormal middle ear status, as indicated by tympanometry, showed higher ER values compared to the DS tymp A group and the control group, similar reflectance curves were observed between control group and the DS tymp A group. WAI shows promise as a clinical diagnostic tool in investigating the impact of middle ear disorders in DS group. However, further research is required to investigate this issue in narrower age range group and a larger sample size.     

Ultrasonic detection of middle ear effusion: a preliminary study

OBJECTIVE: To assess the ability to detect and characterize middle ear effusion in children using A-mode ultrasonography. DESIGN: Prospective nonblinded comparison study. SETTING: Tertiary children's hospital. PATIENTS: Forty children (74 ears) scheduled to undergo bilateral myringotomy with pressure equalization tube placement. INTERVENTIONS: Before myringotomy, ultrasound examination of the tympanic membrane and middle ear space was performed on each ear. Afterward, myringotomy was performed and the type of effusion (serous, mucoid, or purulent) was recorded. Pressure equalization tubes were then placed. MAIN OUTCOME MEASURE: Comparison of ultrasound findings with the visual assessment of the type of middle ear effusion present. RESULTS: Of the 74 ears tested, 45 (61%) had effusion on direct inspection. The effusion was purulent in 8 ears (18%), serous in 9 ears (20%), and mucoid in 28 ears (62%). Ultrasound identified the presence or absence of effusion in 71 cases (96%) (P = .04). Ultrasound distinguished between serous and mucoid effusion with 100% accuracy (P = .04). The probe did not distinguish between mucoid and purulent effusion. CONCLUSIONS: Ultrasonography is an accurate method of diagnosing middle ear effusion in children. Moreover, it can distinguish thin from mucoid fluid. Further refinements in probe design may further improve the sensitivity of fluid detection and allow differentiation of sterile vs infectious effusion.     

Otoacoustic emissions and tympanometry in children with otitis media

OBJECTIVE: To examine otoacoustic emission and tympanometric findings in children with surgically confirmed middle ear effusion (MEE). DESIGN: A total of 102 children aged 0.7 to 11.4 yr undergoing surgery because of otitis media were included in the study. A tympanometric examination and transient evoked otoacoustic emission (TEOAE) measurement were performed on each ear before myringotomy. MEE was aspirated, weighed and classified as mucoid or nonmucoid. TEOAE measurements were compared with the quantity and quality of MEE and to the tympanometric findings. RESULTS: Fifty (72%) ears out of the 65 ears containing effusion showed reduced TEOAE. The quantity of effusion was associated significantly (p < 0.001) with the TEOAE responses, and mucoid effusion reduced the emissions more than nonmucoid. The sensitivity of tympanometry in identifying the ears without recordable TEOAE was 73% and the specificity 81%. CONCLUSION: MEE results in a significant reduction in TEOAEs even when the effusion is nonmucoid. This suggests that transmission of acoustic energy to and from the middle ear is altered in children experiencing any form of otitis media with effusion.