Pediatrician's view of middle ear effusions: more questions than answers

Use of Wideband Acoustic Immittance in Neonates and Infants

With widespread agreement on the importance of early identification of hearing loss, universal newborn hearing screening (UNHS) has become the standard of care in several countries. Despite advancements in screening technology, UNHS and early hearing detection and intervention programs continue to be burdened by high referral rates of false-positive cases due to temporary obstruction of sound in the outer/middle ear at birth. A sensitive adjunct test of middle ear at the time of screening would aid in the interpretation of screening outcomes, minimize unnecessary rescreens, and prioritize referral to diagnostic assessment for infants with permanent congenital hearing loss. Determination of middle ear status is also an important aspect of diagnostic assessment in infants. Standard single-frequency tympanometry used to determine middle ear status in infants is neither efficient nor accurate in newborns and young infants. A growing body of research has demonstrated the utility of wideband acoustic immittance (WAI) testing in both screening and diagnostic settings. Wideband power absorbance (WBA), a WAI measure, has been shown to be more sensitive than tympanometry in the assessment of outer/middle ear function in newborns. Furthermore, age-graded norms also support successful application of WBA in young infants. Despite its merits, uptake of this technology is low among pediatric audiologists and hearing screening health workers. This report describes normative data, methods for assessment and interpretation of WBA, test-retest variations, and other factors pertinent to clinical use of WAI in newborns and infants. Clinical cases illustrate the use of WAI testing in newborn and infant hearing assessment.

High frequency (1000 Hz) tympanometry in six-month-old infants

OBJECTIVES

High frequency tympanometry (HFT) using a 1000 Hz probe tone is recommended for infants from birth to six months of age. However, there is limited normative HFT data outside the newborn period. The objective of this study was to describe HFT data in healthy six-month-old infants.

METHODS

HFT and distortion product otoacoustic emission (DPOAE) tests were performed on 168 six-month-old full-term healthy infants. Ears that passed DPOAEs and had a single-peaked tympanogram were included for analysis. The tympanometric measures included in the normative HFT data were tympanometric peak pressure (TPP), peak compensated static admittance (Y_tm) and tympanometric width (TW).

RESULTS

A total of 118 ears from 118 infants who passed DPOAE and had single-peaked tympanograms were included in the analysis. Normative data were presented for TPP, Y_tm and TW. A comparison of the present study with studies on neonates and younger infants revealed significantly higher mean Y_tm and lower mean TPP for six-month-old-infants.

CONCLUSION

Significant differences in HFT findings between neonates and six-month-old infants suggest a developmental trend and confirm the need for separate age-appropriate norms for the tympanometric measures. Normative HFT data described in the present study may provide useful information for optimizing the diagnosis of conductive conditions in six-month-old infants.

Normative wideband reflectance measures in healthy neonates

OBJECTIVE

Presently, normative wideband reflectance data are available for neonates who have passed a distortion product otoacoustic emission test. However, passing the distortion product otoacoustic emission test alone does not ensure normal middle ear function. The objective of this study was to establish normative wideband reflectance data in healthy neonates with normal middle ear function, as justified by passing a battery of tests.

METHOD

Wideband reflectance was measured in 66 infants (mean age=46.0 h, SD=21.0, range=13.3-116.5h) who passed a test battery that included high frequency (1000 Hz) tympanometry, acoustic stapedial reflex, transient evoked otoacoustic emissions and distortion product otoacoustic emissions.

RESULTS

The analysis of variance (ANOVA) results showed significant variations of reflectance across the frequencies. There was no significant difference between ears and genders. The median reflectance reached a minimum of 0.21-0.24 at 1-2 kHz, but increased to 0.45-0.59 below 1 kHz and 0.24-0.52 above 2 kHz.

CONCLUSIONS

The normative reflectance data established in the present study were in agreement with, but marginally smaller than, those of previous normative studies, except for the Keefe et al. (2000) study. While the use of a test battery approach to ensure normal middle ear function in neonates has resulted in slightly reduced reflectance across most frequencies when compared to studies that have used only otoacoustic emissions, further research is needed to accurately determine the middle ear status of neonates using test performance measures.

Choice of probe tone and classification of trace patterns in tympanometry undertaken in early infancy

Tympanometry using 226 Hz, 678 Hz, and 1000 Hz probe tones was undertaken on two groups of babies, age 2 to 21 weeks. A group of 104 babies with normal ABR thresholds or TEOAEs were compared with a second group of 107 babies who had evidence of temporary conductive hearing loss based on the findings of a test battery, which included air and bone conduction ABR. The tympanograms were classified by Method 1, a simple visual classification system, and Method 2, adapted from a system described by Marchant et al (1986). The majority of tympanograms recorded in both groups using the 226 Hz probe tone were 'normal' Type A, with no significant difference in middle ear pressure or static admittance. However, both classification methods demonstrated significant differences between the two groups using the higher frequency probe tones, with Method 2 being the preferred system of classification. Tympanometry using 226 Hz is invalid below 21 weeks and 1000 Hz is the frequency of choice.

Developmental outcomes after early or delayed insertion of tympanostomy tubes

BACKGROUND

To prevent later developmental impairments, myringotomy with the insertion of tympanostomy tubes has often been undertaken in young children who have persistent otitis media with effusion. We previously reported that prompt as compared with delayed insertion of tympanostomy tubes in children with persistent effusion who were younger than three years of age did not result in improved developmental outcomes at three or four years of age. However, the effect on the outcomes of school-age children is unknown.

METHODS

We enrolled 6350 healthy infants younger than 62 days of age and evaluated them regularly for middle-ear effusion. Before three years of age, 429 children with persistent middle-ear effusion were randomly assigned to have tympanostomy tubes inserted either promptly or up to nine months later if effusion persisted. We assessed developmental outcomes in 395 of these children at six years of age.

RESULTS

At six years of age, 85 percent of children in the early-treatment group and 41 percent in the delayed-treatment group had received tympanostomy tubes. There were no significant differences in mean (+/-SD) scores favoring early versus delayed treatment on any of 30 measures, including the Wechsler Full-Scale Intelligence Quotient (98+/-13 vs. 98+/-14); Number of Different Words test, a measure of word diversity (183+/-36 vs. 175+/-36); Percentage of Consonants Correct-Revised test, a measure of speech-sound production (96+/-2 vs. 96+/-3); the SCAN test, a measure of central auditory processing (95+/-15 vs. 96+/-14); and several measures of behavior and emotion.

CONCLUSIONS

In otherwise healthy children younger than three years of age who have persistent middle-ear effusion within the duration of effusion that we studied, prompt insertion of tympanostomy tubes does not improve developmental outcomes at six years of age.

Otitis media and reading achievement: a review

Nineteen studies on the relationship between otitis media (OM) or otitis media with effusion (OME) (secretory otitis media (SOM)) and reading achievement were reviewed. The result is that the children catch up in cognitive development when their ears and hearing become normal at about school age. The correlations that have been found between SOM and reading achievement are so small that they have no practical importance for the average child. At the present time we have no knowledge that justifies intervention against SOM as a general preventive task to ensure the cognitive development, or reading achievement. The absent or very small correlation between SOM and reading in the reviewed studies, 'explaining' only 2-4% of the variance, has no implications in comparison with other important factors. Reading achievement was more closely correlated with cognitive, language, and linguistic factors, and to a series of socioenvironmental and classroom related factors. The high frequency of SOM, with resulting hearing loss, and the long duration and high rate of occurrence of OM in 'otitis-prone' children, and clinical observations underlines the need for further research.

The effect of treatment with ventilating tubes on language development in preschool children with otitis media with effusion

The effect of bilateral tube insertion on language development was studied in a randomized controlled trial of 43 preschool children with persistent bilateral otitis media with effusion (OME). Improvement in language scores was observed in both the treatment and non-treatment groups. There was a minor difference in favour of the treatment group which did not reach statistical significance. Although there is a growing consensus that otitis media with effusion can have negative effects on language development in young children, it has not yet been proved that this effect can be reversed by treatment with ventilating tubes.

Environmental risk factors for otitis media with effusion in preschool children

To ascertain risk factors for otitis media with effusion (OME), a cohort of 1439 preschool children, 2 years of age, was investigated by means of tympanometry at 3-monthly intervals until their fourth birthday. Parents were asked about potential risk factors for OME. Data were analysed in a case-control design with incident cases. Age, season, family size, siblings's history of OME, frequent swimming, duration of breast feeding and public day care appear to have a significant effect on OME, even after adjustment for nasal infection. Gender, race, birth weight and passive smoking were not related to OME incidence. With the exception of age and season, the relative risks of environmental factors for OME are always very low. It is concluded that the study of environmental risk factors for OME is necessary to increase the knowledge of the nature of this disease, but that it does not contribute much to medical care at the moment.

The influence of chronic persistent otitis media with effusion on language development of 2- to 4-year-olds

Literature is not conclusive about the effect of otitis media with effusion (OME) on language development in children. As part of a large epidemiological study on OME in preschool children, language development was measured in 52 children with known history of bilateral OME and in 13 children without OME. The test Reynell Developmental language scales-revised (RDLS-r) was performed by one speech therapist under standard conditions. Verbal comprehension scores were not or only slightly reduced in OME children. Expressive language, however, was significantly lower than the standard with the effect being larger when the OME had lasted for a longer period. This is one of the first prospective studies that confirms the hypothesis of an effect of persistent bilateral middle ear effusion on language development.

The structure of the middle ear epithelium of the rat and the effect of Eustachian tube obstruction

The middle ear cavity of the rat is lined with ciliated and squamous epithelium. The arrangement of the ciliated cells, interspersed with secretory cells, in distinct tracts and their continuity with the ciliated epithelium of the Eustachian tube, suggests the existence of a mucociliary transport system for cleaning the middle ear cleft. The secretory cells produce either neutral or sulphated glycoproteins, dependent on their location. In addition to these secretions, the epithelium of the lower part of the Eustachian tube is bathed with secretory products of seromucous glands. Also in the areas with squamous epithelium, numerous small secretory cells, the character of which is only identifiable with the electronmicroscope, are present. It is concluded that the middle ear lining can be considered as a locally modified respiratory epithelium. Blockade of the mucociliary transport system, supposedly a crucial aetiological factor in secretory otitis media, by obstruction of the Eustachian tube, induces pathogenic behaviour of microorganisms normally present in the middle ear. This results in either a transient or a longstanding infective middle ear disease, associated with a large variety of changes of the mucosa, especially with respect to the secretory activity. The data obtained indicate that the increased secretory activity encountered in secretory otitis media cannot be attributed to the isolated effect of tubal occlusion, but rather to an infective process.

Middle ear disease assessed by impedance in primary school children in south London

413 children aged 5 to 6 years from twelve randomly selected primary schools in SE London were screened for middle ear disease by the use of tympanography . Those with abnormal tympanograms were retested 10 weeks later. 41% had an abnormality at first test, but half had recovered by second test. Children of African origin were significantly less likely to show abnormalities and in almost none did the abnormality persist; children from poorer families were significantly more likely to have a persistent abnormality. Tympanography is a feasible screening test in children of this age-group and complements audiometry and otoscopy.

Cells involved in the middle ear defense system

Despite the high incidence and prevalence of otitis media, its pathogenesis is not thoroughly understood. In the last decade, many efforts have been made to provide a better understanding, and abundant information has become available. At the same time the field of immunology has advanced at an extremely rapid pace. We have followed the gradual cellular events in the defense reaction of the middle ear, utilizing eustachian tube obstruction to induce otitis. Seventy-five cats were divided in groups and sacrificed at intervals between one day and six months, and their temporal bones were studied. During an initial phase of inflammation, polymorphonuclears appear at three days in connective tissue; at the same time active fibroblasts synthesize tropocollagen and ground substance while epithelial cells secrete mucus and lysozymes. These cells, together with those involved in the mucociliary transport system and a patent functional eustachian tube, constitute the nonspecific system of defense. The transition cells are the macrophages which appear at one week to interact with T and B cells to produce the specific immune response. Plasma cells appear at two weeks to peak at one month with synthesis of immunoglobulins A, G and M. A secretory immune system is observed. At three and six months, lymphocytes are the predominant cells and occasional accumulations of mononuclears are observed. The reaction involves the entire middle ear, including mucoperiosteum, middle ear muscles and round window membrane. We believe that a better understanding of the middle ear defense system will lead in time to a practical clinical assessment of the immunological status during the evolution of each particular process or disease involving the middle ear, and a more rational approach to the treatment and, hopefully, prevention of chronic ear disease.

Diagnostic and therapeutic studies in childhood serous otitis media. Results of treatment with an antihistamine-adrenergic combination

Fifty-five children with their first recognized episodes of serous otitis media were followed over a three-month period. The efficacy of an antihistamine-adrenergic combination (diphenhydramine and pseudoephedrine), the comparative value of various diagnostic studies of middle ear function, and the prognostic importance of information obtained at the first visit were assessed. Compared double-blindly to a placebo, the pharmaceutical preparations did not appear to influence the clinical course, although more drug patients experienced lethargy or relief of symptoms not directly concerned with middle ear function (mainly upper respiratory congestion). The color and extent of motility of the tympanic membrane, but no other pneumatic otoscopic findings, were related to audiometry, whereas tympanometry correlated with the amount of motility and the presence or absence of visible fluid behind the membrane. The patients with the most severe hearing losses or with visible middle ear fluid at their initial visits improved the most, and those who began to be followed in the summer the least. The last finding may be due to a general but unexplained deterioration of childhood serous otitis media during the fall.

Impedance screening for preschool children. State of the art

As a test for detecting middle ear disease among preschool children, tympanometry -- as opposed to audiometry -- has three advantageous attributes: a high degree of sensitivity, minimal need for subject cooperation, and total objectivity. For these reasons interest has arisen in tympanometry as a method for screening, i.e., identifying children with previously undetected middle ear disease. However, uncertainty persists concerning the importance of detecting apparently asymptomatic middle ear effusions, and concerning optimal methods, or even the advisability, of treating them. Further, the sensitivity and specificity of tympanometry depend on how the pass-fail cutoff point is defined. Defining this cutoff point so as to achieve high sensitivity may result in excessively low specificity, with the production of large numbers of false-positives who then become overreferrals. Data are presented to show how the validity of the test may be increased to some extent by attention to the gradient of "negative-pressure" tympanograms. At the present time, given the various aforementioned uncertainties, and with adequate validation as to the presence or absence of disease often lacking in reported studies of impedance screening in preschool populations, the cumulative results of these studies do not warrant embarking on large-scale screening programs. What is needed instead is additional research to explore the issue further.

Brain stem electric response audiometry and middle ear effusion

Brain stem electric response audiometry has been performed in a group of 41 difficult-to-test children under the age of 8 years. All ears were examined with the pneumatic otomicroscope prior to determination of response thresholds, and middle ear effusion found in 24 (29.3%). Seven of the 14 children requiring hearing aid amplification had fluid in 12 ears (42.9%). The importance of early recognition and treatment of middle ear pathology in children with sensori-neural hearing loss is stressed, and routine otomicroscopy by the attending otologist is recommended.

Microbiology of recurrent and chronic otitis media with effusion

A study was conducted of 274 children who had recurrent acute or chronic otitis media with effusion. Forty-five percent of the ears with effusion were found to contain bacteria, and 11% contained bacteria that were "probable pathogens" (S. pneumoniae, H. influenzae, and S. pyogenes). Bacteria were also found in 40% of the ears without effusions. The type of organism found did not vary with the age of the patient studied or the season of the year. The significance of these bacteria in the etiology of recurrent acute or chronic otitis media with effusion remains to be demonstrated.

Middle-ear impedance measurements in screening

Middle-ear disorders are the major cause of hearing loss in the young school child, the majority of sensorineural disorders already having been detected. Mild conductive deafness may lead to educational retardation, psychological and social problems as well as to more severe middle-ear problems. It is consequently important to detect persistent middle-ear conditions as early as possible. Pure-tone audiometry has been shown to be a poor method of identifying middle-ear effusions. Impedance measurement is considerably more efficient, and different approaches are reviewed in the light of long-term studies of middle-ear effusion.

Common ear diseases: recognition and management

External otitis is directly related to patient habit patterns. It is easily treated, but the habits must be changed to effect permanent cure. Serous otitis media is the most common cause of conductive hearing loss, and its presence my predispose to development of purulent otitis media. Removal of middle ear fluid may be advisable in persistent serous otitis and is recommended in acute purulent otitis.