Tympanometry in neonates with normal otoacoustic emissions: measurements and interpretation

Tympanometry is used in evaluating middle ear functional conditions. Before six months of age its results may be misleading. High frequency studies aim to provide more valid procedures. Aim: To describe and discuss tympanometric measurements and the interpretation in normal hearing neonates at 226, 678 and 1000Hz. Method: 110 neonates that were analyzed had normal otoacoustic emissions and no risk for hearing impairment. The age range was 6 to 30 days. Curves were obtained using the GSI-33-II, at the “Divisão de Educação e Reabilitação dos Distúrbios da Comunicação”, São Paulo, in 2004. Study design: Clinical prospective. Results: There was a balance between single and double peak curves at 226Hz. Most of the curves were asymmetric at 678Hz, and single-peaked at 1000Hz. quantitative measurements showed a significant gender difference in the Equivalent Ear Canal Volume at 226Hz and on the Peak Compensated Static Acoustic Admittance at 1000Hz. The English protocol showed that almost 100% of ears were normal at 678 and 1000Hz. Conclusion: 1000Hz yielded superior results for characterizing normality. The English protocol was efficient to reduce the variability of tympanometric measurements. Data from this study may be used as a guide for diagnosis using tympanometry in neonates.