Wideband Absorbance Outcomes in Newborns: A Comparison With High-Frequency Tympanometry, Automated Brainstem Response, and Transient Evoked and Distortion Product Otoacoustic Emissions.

OBJECTIVES: The purpose of this study was to evaluate the test performance of wideband absorbance (WBA) in terms of its ability to predict the outer and middle ear status as determined by nine reference standards. DESIGN: Automated auditory brainstem response (AABR), high-frequency (1000 Hz) tympanometry (HFT), transient evoked otoacoustic emission (TEOAE), and distortion product otoacoustic emission (DPOAE) tests were performed on 298 ears (144 right, 154 left) of 192 (108 males, 84 females) neonates with a mean age of 43.7 hours (SD = 21.3, range = 8.3 to 152.2 hr). WBA was measured from 0.25 to 8 kHz using clicks under ambient pressure conditions. Test performance of WBA was assessed in terms of its ability to identify conductive conditions in neonates when compared with nine reference standards (including four single tests and five test batteries) using the receiver operating characteristic analysis. RESULTS: The test performance of WBA against the test battery reference standards was better than that against single test reference standards. The area under the receiver operating characteristic curve reached a high value of 0.78 for HFT + TEOAE + DPOAE and AABR + TEOAE + DPOAE reference standards. Within the ears that passed each of the reference standards, there were no significant differences in WBA. However, for the ears that failed each of the test standards, there were significant differences in WBA. The region between 1 and 4 kHz provided the best discriminability to evaluate the conductive status compared with other frequencies. CONCLUSIONS: WBA is a desirable measure of conductive conditions in newborns due to its high performance in classifying ears with conductive loss as determined by the best performing surrogate gold standards (HFT + TEOAE + DPOAE and AABR + TEOAE + DPOAE).

Sweep frequency impedance measures in Australian Aboriginal and Caucasian neonates.

OBJECTIVE: Despite high prevalence of otitis media in Aboriginal children, the acoustic-mechanical properties of their outer and middle ear during the neonatal period remain obscured. The objective of this study was to compare the acoustic-mechanical properties of outer and middle ear using Sweep Frequency Impedance (SFI) measures between Australian Aboriginal and Caucasian neonates. METHODS: SFI data from 40 ears of 24 Aboriginal neonates (16 males, 8 females) with mean gestational age of 39.57 weeks (SD = 1.25) and 160 ears of 119 Caucasian neonates (57 males, 62 females) with mean gestational age of 39.28 weeks (SD = 1.25) serving as controls were analysed. SFI data in terms of resonance frequency (RF) and mobility of the outer and middle ear (ΔSPL) were collected from neonates who passed a test battery that included automated auditory brainstem response, distortion product otoacoustic emissions test and 1000-Hz tympanometry. SFI data were analysed using descriptive statistics and analysis of variance. RESULTS: There was no significant difference in mean gestational age, age of testing and birth weight between the Aboriginal and Caucasian neonates. The mean resonance frequencies for the outer ear (mean RF1 = 264.9 Hz, SD = 58.6 Hz) and middle ear (mean RF2 = 1144 Hz, SD = 228.8 Hz) for Aboriginal neonates were significantly lower than that of Caucasian neonates (mean RF1 = 295.3 Hz, SD = 78.4 Hz and mean RF2 = 1241.8 Hz, SD = 216.6 Hz). However, no significant difference in the mobility of outer ear (ΔSPL1) and middle ear (ΔSPL2) between the two groups was found. Middle ear resonance was absent in 22.5% (9 ears) of Aboriginal ears but present in all Caucasian ears. CONCLUSIONS: This study provided evidence that despite passing the test battery, Aboriginal neonates had significantly lower resonance frequencies of the outer and middle ear than Caucasian neonates. Furthermore, 22.5% of Aboriginal neonates showed no middle ear resonance, indicating the possibility of subtle middle ear issues not detected by the test battery. Reasons for the different acoustic-mechanical properties between the two ethnic groups remain unclear and require further investigation.

Normative sweep frequency impedance measures in healthy neonates.

BACKGROUND: Diagnosing middle ear disorders in neonates is a challenging task for both audiologists and otolaryngologists. Although high-frequency (1000 Hz) tympanometry and acoustic stapedial reflex tests are useful in diagnosing middle ear problems in this age group, they do not provide information about the dynamics of the middle ear in terms of its resonance frequency (RF) and mobility. The sweep frequency impedance (SFI) test can provide this information, which may assist in the diagnosis of middle ear dysfunction in neonates. PURPOSE: This study aimed to investigate the feasibility of testing neonates using the SFI technique, establish normative SFI data for RF and mobility of the middle ear in terms of changes in sound pressure level (∆SPL in dB), and describe the dynamics of the middle ear in healthy Australian neonates. STUDY SAMPLE: A prospective sample of 100 neonates (58 males, 42 females) with a mean gestational age of 39.3 wk (SD = 1.3 wk; range = 38-42 wk), who passed all three tests, namely, automated auditory brainstem response, transient evoked otoacoustic emissions, and 1000 Hz tympanometry, were included in this study. DATA COLLECTION AND ANALYSIS: A SFI research prototype was used to collect the data. First, the SPL in the ear canal was measured as a probe-tone frequency was swept from 100-2000 Hz with the ear canal static pressure held constant at 200 daPa. Then, this measurement was repeated with the static pressure reduced in 50 daPa steps to -200 daPa. Additional measurement was also performed at the static pressure, where the peak of the 1000 Hz tympanogram occurred. A graph showing the variation of SPL against frequency at all static pressures was plotted. From this graph, the RF and ∆SPL at tympanometric peak pressure (TPP) were determined. Descriptive statistics and an analysis of variance (ANOVA) were applied to the RF and ∆SPL data with gender and ear as independent variables. RESULTS: The results showed two resonance regions of the outer/middle ear with the high RF (mean = 1236 Hz; 90% range: 830-1518 Hz) being approximately equal to four times that of the low RF (mean = 287 Hz; 90% range = 209-420 Hz). The low RF was more easily identifiable than the high RF. The ∆SPL at the low RF (mean = 8.2 dB; 90% range = 3.4-13 dB) was greater than that at the high RF (mean = 5.0 dB; 90% range = 1.5-8.1 dB). There were no significant differences or interactions between genders and ears. CONCLUSION: The study showed that the SFI is a feasible test of middle ear function in neonates. The SFI results revealed two regions of resonance with the lower resonance (287 Hz) possibly related to the movements of the outer ear canal wall and higher resonance (1236 Hz) related to the resonance of the middle ear. The normative data developed in this study will be useful in evaluating outer and middle ear function in neonates.