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Point and period prevalence of otitis media with effusion evaluated by daily tympanometry
Insights
Automatic impedance tympanoscopes may misdiagnose middle ear conditions. Conventional tympanometry accurately identified persistent middle ear effusion (Type B tympanograms) in children, unlike the unreliable automatic device.
Area of Science:
- Otolaryngology
- Pediatric Audiology
- Epidemiology
Background:
- Previous research suggested high incidences of transient Type B tympanograms from daily screening with automatic impedance tympanoscopes.
- These findings conflicted with established understanding of otitis media with effusion (OME) pathogenesis and pathology.
- A discrepancy exists between automatic tympanoscope readings and the clinical presentation of OME.
Purpose of the Study:
- To re-evaluate the reliability of automatic impedance tympanoscopes in detecting middle ear effusion.
- To compare daily tympanometry results using conventional and automatic devices in healthy children.
- To accurately assess the prevalence of middle ear effusion in a pediatric population.
Main Methods:
- Daily tympanometry was conducted for one month in 51 healthy children (100 ears) using both conventional (AZ7) and automatic (ZS 331) impedance tympanoscopes.
- Data analysis focused on the duration and prevalence of Type B tympanograms.
- Prevalence rates (point and period) were calculated and compared between the two devices.
Main Results:
- The conventional impedance apparatus showed no one-day Type B tympanograms, with only a few short-lasting episodes.
- Several ears consistently exhibited Type B tympanograms throughout the study period, indicating persistent effusion.
- The automatic impedance tympanoscope inaccurately indicated numerous one-day Type B curves, leading to inflated prevalence estimates.
Conclusions:
- Automatic impedance tympanoscopes are unreliable for scientific and clinical assessment of middle ear effusion due to frequent false positives.
- Conventional tympanometry provides more accurate and reliable data for diagnosing persistent middle ear effusion.
- The study supports epidemiological findings for secretory otitis, with point prevalence at 15% and period prevalence at 17%.
Abstract:
Previous studies on daily tympanometric screening using an automatic impedance tympanoscope indicated relatively high incidences of type B tympanograms of one day's duration, which is contrary to our conceptions of the pathogenesis and pathology of otitis media with effusion. We therefore repeated the study in 51 otherwise healthy children (100 ears) attending kindergarten. Tympanometry was performed daily for one month using both the conventional impedance apparatus AZ7 and the automatic impedance tympanoscope ZS 331. The impedance apparatus did not indicate any one-day type B tympanograms and only a few short-lasting episodes occurring either in the beginning or end of the study period. Several ears had type B tympanograms on all days examined. The point prevalence was 15 per cent and the period prevalence 17 per cent, which accord well with findings of previous epidemiological studies of secretory otitis. The impedance tympanoscope indicated 16 cases of B-curves lasting only one day and considerably higher point and period prevalences, which make the impedance tympanoscope unsuited for both scientific and clinical purposes.