Wideband reflectance tympanometry in chinchillas and human.

Wideband reflectance tympanometry was performed on twelve chinchillas ears. The complex input impedance of the middle ear, multifrequency admittance tympanograms, reflectance patterns (reflectance versus frequency), and reflectance tympanograms (reflectance versus ear-canal air pressure) were analyzed and compared to human data. The complex impedance of the chinchilla ear has a lower stiffness reactance at low frequencies, a higher mass reactance at high frequencies, and a lower resistance compared to the human. Multifrequency admittance tympanograms from chinchillas follow the same sequence of patterns as humans for low frequencies (<2 kHz). At higher frequencies tympanograms from both species are poorly organized and do not follow a consistent sequence of patterns. Reflectance patterns of chinchillas and humans are different. However, both species show high reflectance at low frequencies, regions of lower reflectance in mid-frequencies (2-6 kHz), and high reflectance at high frequencies (>8 kHz). Reflectance tympanograms for the two species show a single, centrally located minimum at low frequencies (<2 kHz) and are substantially different at higher frequencies. Results are shown for two animals that underwent eustachian tube obstruction. Reflectance patterns obtained with different ear-canal air pressures are substantially different. Reflectance results at any single ear-canal pressure (including ambient pressure) do not completely characterize the effects of middle-ear pathology.

Prospective study of tympanic membrane retraction, hearing loss, and multifrequency tympanometry.

Tympanic membrane retraction is a significant sequela of OME and has been linked clinically to atelectasis, ossicular erosion, and cholesteatoma. We investigated important factors for prediction of tympanic membrane retraction in a prospective study of 112 children. After 4 to 6 years of follow-up, 12% of ears had pars tensa retraction without atrophy, and 28% had various degrees of retraction with atrophy. Mild pars flaccida retraction was present in 23%, and severe pars flaccida retraction was present in 12%. Retraction severity was related to hearing level and multifrequency tympanometry. Three factors were significantly related to retraction severity: type of tube, male sex, and percent of visits in the second year with abnormal tympanograms. This study shows that type of tube was the most important factor in long-term outcome after tympanostomy tube treatment of OME.

Hearing screening in the newborn intensive care nursery: comparison of methods.

Patients in the neonatal intensive care unit were tested by hearing screening tests including auditory brain stem response (ABR), transient and distortion-product otoacoustic emissions (TEOAEs and DPOAEs), and acoustic stapedius reflex (ASR), and by middle ear function tests including multifrequency tympanometry and pneumatic otoscopy. Pass rates on hearing tests were 75% to 89%. TEOAEs produced the lowest pass rate, and DPOAEs the highest. TEOAE, DPOAE, or ASR testing followed by ABR testing of initial failures produced pass rates of about 90%. The most efficient combination was DPOAEs followed by ABR. Pass rates tended to decrease with age. Of patients who failed 226-Hz and 678-Hz tympanometry, 30% to 67% passed hearing tests, suggesting a high false-positive rate for these immittance tests. The 3 ears that failed the 1000-Hz tympanogram failed all hearing tests. Many ears were abnormal by pneumatic otoscopy but passed hearing tests, suggesting that the usual ear examination criteria may not apply to infants.

Effects of tympanic membrane abnormalities on auditory function.

This article discusses how several diagnostic tools used by audiologists inter-relate to anatomical abnormalities viewed by video otoscopy. Background of common middle ear pathology is reviewed, with emphasis on new research findings regarding pathophysiology. A review of video otoscopy, multifrequency tympanometry, and otoreflectance is provided. Case studies illustrate the integrated use of these diagnostic tools. Audiologic results are integrated with video otoscopy through case study analysis and interpretation. Understanding of the complexity of the physiologic and behavioral measurements is enhanced with the ability to closely inspect tympanic membrane pathology through video otoscopy. Multifrequency tympanometry, otoreflectance, and otoacoustic emissions (OAEs) allow us to more easily detect pathologic conditions such as cholesteatoma and chronic (silent) otitis media with effusion (OME).

The family study of otitis media: design and disease and risk factor profiles.

Recurrent acute otitis media (RAOM) and chronic otitis media with effusion (COME) exhibit familial aggregation, but environmental risk factors (day care attendance, cigarette smoke exposure, and bottle feeding) are also important in their development. The Family Study of OM was designed to ascertain the RAOM/ COME status of families whose children participated in Otitis Media Research Center studies between 1978 and 1984. Probands were treated with tympanostomy tubes, and had their RAOM/COME status ascertained as criteria for entry into these studies. For the Family Study of OM parents were interviewed about their otitis media and risk factor history; mothers were interviewed about their children's history, and pertinent medical records were obtained. Members of 173 families were examined with otomicroscopy and multifrequency tympanometry; 19% of parents and 32% of siblings were classified as affected, which is substantially higher than RAOM/COME rates from previous reports. Risk factor profiles differed significantly (P < .001) between parents and their children. Younger generation (adjusted odds ratio [OR] = 4.18, 95% confidence interval [CI], 2.74, 6.36) day care attendance (OR = 1.96, 95% CI, 1.32, 2.91) and male gender (OR = 1.42, 95% CI, 1.03, 1.97) were significantly related to RAOM/ COME using logistic regression. Analyses confirm 1) higher disease rates in families with an affected member compared to existing studies of the general population, 2) increased risk of RAOM/COME associated with known risk factors, and 3) increased risk for parents irrespective of risk factors. Additional analyses will explore competing models of disease susceptibility using genetic models and known risk factors.

Randomized trial of the efficacy of trimethoprim-sulfamethoxazole and prednisone in preventing post-tympanostomy tube morbidity.

This study was designed to determine whether treatment with prednisone and trimethoprim-sulfamethoxazole would reduce first year post-operative morbidity in children with chronic otitis media with effusion undergoing tympanostomy tube insertion (intubation). Eighty children ages 6 months to 8 years were enrolled at intubation and randomized from age strata to receive active drugs or placebos for 14 days after surgery. They were examined with pneumatic otoscopy and tympanometry preoperatively and at 3 weeks and 3, 6, 9 and 12 months after surgery. Active drug treatment significantly reduced tube obstruction or extrusion in the first 3 postoperative months compared with placebos (4% vs. 17%, P = .01). However, rates of repeat intubation, otorrhea and recurrence of otitis media did not differ significantly in the two groups. Children with chronic otitis media with effusion treated with intubation may benefit from a 2-week course of prednisone and trimethoprim-sulfamethoxazole at the time of surgery. However, there is no apparent long term benefit of this treatment.

Tympanic electrocochleography for diagnosis of Menière's disease.

OBJECTIVE: Tympanic electrocochleography (ECOG) is a noninvasive technique for recording cochlear potentials with an electrode placed on the tympanic membrane. Electrocochleography is used clinically in the evaluation of patients for endolymphatic hydrops. This study was undertaken to obtain normative data for ECOG responses to clicks and tone bursts and to determine clinical indicators that result in high test specificities. DESIGN: Three cochlear potentials were measured; the eighth nerve compound action potential, the cochlear microphonic, and the summating potential. The subjects were 53 normal hearing adults with negative histories for symptoms of Menière's disease. The ECOG responses were measured with a silver wire-rayon wick electrode that was placed on the tympanic membrane under direct microscopic visualization. Stimuli were condensation, rarefaction, and alternating polarity clicks and 1- and 2-kHz tone bursts. RESULTS: Measures that appear to be useful in the evaluation of endolymphatic hydrops include the summating potential to action potential ratio, action potential latency difference to condensation and rarefaction clicks, and the tone-burst-evoked summating potential. Relationships among these measures were investigated, and abnormal criteria were determined that result in test specificities of 95%. CONCLUSIONS: Menière's disease is viewed as a progressive disease in which ECOG characteristics vary with the disease state. Cases are presented to illustrate ECOG responses in various stages of the disease. The normative data presented in this article are useful for the detection of Menière's disease in its early stages.

A clinical profile of otitis media without an intact tympanic membrane.

An otitis media with effusion algorithm developed by Paradise et al has become the basis for many studies of otitis media. However, it has been shown to be too ambitious (low specificity) and too optimistic (absence of fluid does not necessarily mean normal ears). We developed a four-point profile to characterize the condition of the middle ear, but it cannot be used when the eardrum is perforated (with a functioning tube or chronic perforation). We propose a three-point profile for use without an intact tympanic membrane, and we report the validation of the profile by findings at myringotomy and by the preoperative profile. This postoperative profile and the previously described profile for ears with an intact tympanic membrane should increase the accuracy of middle ear assessment in following the course of otitis media over time.

Acute otitis media with transient sensorineural hearing loss. A case study.

A patient had acute otitis media with transient sensorineural hearing loss. Early symptoms included otalgia, progressive sensorineural hearing loss, and tinnitus with inflammation of the tympanic membrane. During the second week a conductive component emerged resulting in a 60-dB mixed loss in the 2- to 4-kHz region. The conductive component lasted 15 days while the sensorineural hearing loss recovered more slowly, with complete recovery at 6 months. Audiologic measures included conventional and extended high-frequency audiometry, 226-Hz and multifrequency tympanometry, binaural speech recognition, auditory brain-stem response, and psychoacoustic tuning curves.

Tympanic and transtympanic electrocochleography in acoustic neuroma and vestibular nerve section surgery.

Eighth nerve action potential (AP) amplitudes and latencies and cochlear microphonic (CM) amplitudes were compared using tympanic and transtympanic electrocochleography (ECOG) in two patient groups. Tympanic ECOG was performed with a wick electrode placed on the tympanic membrane (TM). Transtympanic ECOG was performed with a needle electrode placed on the promontory of the anesthetized patient. Eighteen subjects were tested by tympanic ECOG as part of a preoperative assessment for either acoustic neuroma removal or transection of the vestibular portion of the eighth cranial nerve. Surgery occurred within 1 week of the preoperative evaluation. Intraoperative auditory monitoring was performed using transtympanic ECOG. Baseline recordings were compared to the preoperative tympanic ECOG data. Stimuli were condensation and rarefaction clicks and tone bursts, presented by an insert earphone. As expected, the two methods resulted in essentially identical response latencies and large amplitude differences, although the response amplitudes were extremely variable. The AP amplitude and the CM amplitude did not increase by the same factor with the transtympanic (TT) electrode compared to the tympanic electrode. On comparison of preoperative and intraoperative response amplitudes with regard to stimulus polarity, tympanic electrocochleography appears to be a useful method of gathering preliminary information on the status of the patient's auditory system. In this study, tympanic ECOG was found to have some predictive value when trying to ascertain the best intraoperative monitoring situation.

A clinical profile of otitis media.

An otitis media with effusion algorithm developed by Paradise et al and tested by Cantekin et al has become the basis for many studies of otitis media. However, a two-point scale algorithm (otitis media with effusion-no otitis media with effusion) may be too ambitious (ie, low specificity) and too optimistic (ie, absence of fluid does not necessarily mean normal ear). We propose a four-point profile that characterizes the condition of the middle ear, and we report the validation of the profile against findings at myringotomy. Statistically, a four-point scale profile would substantially increase powers of statistical tests, compared with a two-point scale algorithm (in studies of the same size), when used to study changes of the middle-ear condition over time or to compare treatment effects.

Screening tympanometry: criteria for medical referral.

Tympanograms were obtained from normal preschool and adult subjects with a prototype hand-held tympanometer to obtain normative values for four tympanometric variables: static admittance, equivalent ear canal volume, tympanometric peak pressure, and gradient. Effects of age group, sex, and pump speed (200 or 400 daPa/s) were determined. The results were incorporated into a four-part screening protocol (history, visual inspection, audiometry, and tympanometry) designed to reduce the excessive error rates associated with screening strategies that rely exclusively on tympanometry.

The effects of experimentally-produced middle ear lesions on tympanometry in cats.

Tympanometry was performed before and after producing specific lesions in the middle ears of cats. The lesions selected for study included stapes fixation, ossicular discontinuity, and scarred tympanic membranes. Stapes fixation resulted in marked increases in middle ear impedance, easily detected with tympanometry. Ossicular discontinuity resulted in complex tympanometric shapes which were easily accounted for by simple interactions between acoustic resistance and reactance. The complex shapes that occurred in normal and abnormal ears with pressure changing from negative to positive resulted from more complicated interactions. Large surgical incisions in the posterior-superior quadrant of the eardrum were quite visible at otoscopy but could not be detected tympanometrically one month after surgery.