Researching of the efficiency of wideband absorbance measurement in determining middle ear pathology in children

Introduction and Objective: Otitis media with effusion (OME) is the most common reason of childhood hearing impairment. While a comparison of pure-tone air-and bone-conduction thresholds provides the definition of conductive hearing loss (CHL), an objective method to detect CHL may be helpful when evaluating difficult-to-test populations such as infants and children. Most of ENT doctors usually make benefit from conventional tympanometric measures. However, the relationship between conventional tympanometric measures and degree of CHL is not clear cut. Nowadays, a new technology called "Wideband Tympanometry (WBT)" in the assessment of the middle ear has been developed. WBT uses a wideband click stimulus and provides a more detailed information than 226-Hz tympanometry in the assessment of the middle ear. The aim of the present study was to evaluate the efficiency of wideband absorbance (WBA) measurement in identifying OME and in predicting CHL in children. Material and Methods: WBA and pure tone audiometry thresholds were measured from 34 children (56 ears) with normal middle ear status (age range 3.58 to 10.83 years, mean 7.01 years) and 40 children (73 ears) with CHL (age range 3.42 to 9.67 years, mean 6.04 years). Participants were included the CHL group based on the following criteria: (1) air-bone gap (ABG) 20 dB for at least one frequency or 15 dB for at least two frequencies, and (2) otitis media or tuba Eustachii dysfunction considered to be the possible cause of CHL. Titan model equipment provided by Interacoustics was used for WBA measurement. WBA was measured in the ear canal over frequencies from 226 to 4 8000 Hz and as a joint function of air pressure (-400 to +200 daPa). Pure tone audiometry testing was performed using Interacoustics AC40 model audiometer. Two measurements data were analyzed to explain the relationship between WBA and the degree of CHL. Pearson correlation and the regression analysis were used to evaluate the predicting ability of WBA. ROC analysis was performed to determine the sensitivity and the specificity rates. Results: Absorbance at all frequencies in the CHL group was smaller than the control group. In the Pearson correlation analysis, strong, significant and negative correlation (R>0,69, p<0,000) between ABG and WBA at ambient pressure were found. In the regression analysis, at linear model R-squared=0,779, at cubic model R-squared=0,810, at logarithmic model R-squared=0,783 between ABG and WBA at ambient pressure were found. Based on the area under the ROC (AUC), WBA in ambient pressure was a better predictor of CHL than 226 Hz compliance and tympanometric width. Conclusions: WBA accurately predicted CHL in children. WBA testing may be used as a clinical diagnostic tool to measure the mechanic properties of the middle ear and also may give more detailed information about OME. Key words: Wideband Tympanometry, Wideband Absorbance, Otitis Media, Conductive Hearing Loss.