Effect of ear canal pressure and age on wideband absorbance in young infants

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.

Characteristics of the wideband absorbance of acoustic energy in children (3-7 years old) with otitis media with effusion

OBJECTIVE

This study aimed to investigate the characteristics of the wideband absorbance (WBA) of acoustic energy in children (3-7 years old) with otitis media with effusion (OME) under environmental ear-canal air pressure and tympanometric peak pressure and to determine the diagnostic value of the acoustic energy absorption rate (AR) in OME at different frequencies.

METHODS

A total of 178 children aged 3-7 years were enrolled in the study between April and October 2018. They were separated into two groups: those with middle ear effusion were placed in the OME group (n = 80; 136 ears), while those without OME (n = 98; 182 ears) were placed in the control group. A WBA test was performed on the children in both groups under environmental ear-canal pressure and tympanometric peak pressure to analyze the changing characteristics of the AR value within the 0.226-8 kHz range.

RESULTS

Under ambient ear-canal air pressure, the AR of the OME group in each frequency band was significantly lower than that of the control group (P < 0.01). Under tympanometric peak pressure, the AR of the OME group in most frequencies was also significantly lower than those of the control group (P < 0.01) except in the 2-2.5 kHz range. The area under the receiver operating characteristic curve (AUROC) was highest at 0.47-1.03 kHz: 0.96 and 0.94 at ambient ear-canal pressure and tympanometric peak pressure, respectively. Of the single frequency points, those at 0.65, 0.67, 0.69, 0.71, and 0.73 kHz had a higher AUROC value (0.96-0.97) under both ambient ear-canal air pressure and tympanometric peak pressure. The difference in the AUROC values of the two pressure conditions was not statistically significant (P < 0.01).

CONCLUSION

Overall, WBA is an effective method of diagnosing OME in children. The frequency band with the most predictive value of AR for OME is 0.47-1.03 kHz. Middle ear effusion can be quickly identified by observing AR values in this frequency range, which provides a diagnostic basis for OME.

Differentiating among conductive hearing loss conditions with wideband tympanometry

OBJECTIVE

This study was aimed to investigate whether wideband tympanometry (WBT) can distinguish among various kinds of conductive hearing loss and provide additional information.

METHODS

We recruited normal subjects and patients with conductive hearing loss due to the following reasons: tympanic membrane perforation only, ossicular chain problem only, and one or other of those conditions combined with mastoid problems. Wideband absorbance at ambient pressure, peak pressure, resonance frequency, and averaged tympanogram data were measured by WBT and compared between the normal, tympanic membrane perforation only, ossicular chain problem only, and combined with mastoid problems groups.

RESULTS

The normal subjects showed an average peak pressure of -19.51daPa and an average resonance frequency of 965.94Hz. Tympanic membrane perforation only patients showed a very low peak pressure (-124.93daPa) and resonance frequency (73.12Hz). When patients have ossicular chain problems, they showed slightly low peak pressures (43.08daPa) without changes in the resonance frequency (1024.8Hz). Mastoid problem subjects showed slightly decreased resonance frequencies (787.71Hz). Tympanic membrane perforation subjects showed decreased absorbance at low frequencies and ossicular chain problem subjects showed decreases at high frequencies. When comparing the perforation only and ossicular chain subjects by absorbance at 707Hz, the area under the ROC curve was 0.719 (P<0.022). Mastoid problems subjects showed decreased absorbance at all frequencies.

CONCLUSION

WBT can help to distinguish tympanic membrane perforation only and ossicular chain problem patients. WBT may provide additional information on "combined with mastoid problems" patients.

Pressurized Wideband Absorbance Findings in Healthy Neonates: A Preliminary Study

PURPOSE

The present study aimed to establish normative data for wideband absorbance (WBA) measured at tympanometric peak pressure (TPP) and 0 daPa and to assess the test-retest reliability of both measurements in healthy neonates.

METHOD

Participants of this cross-sectional study included 99 full-term neonates (165 ears) with mean chronological age of 46.7 hrs (SD = 26.3 hrs). Of the 99 neonates, 58 were Malay, 28 were Indian, and 13 were Chinese. The neonates who passed high-frequency (1 kHz) tympanometry, acoustic stapedial reflex, and distortion product otoacoustic emission screening tests were assessed using a pressurized WBA test (wideband tympanometry). To reduce the number of measurement points, the WBA responses were averaged to 16 one-third octave frequency bands from 0.25 to 8 kHz. A mixed-model analysis of variance was applied to the data to investigate the effects of frequency, ear, gender, and ethnicity on WBA. The analysis of variance was also used to compare between WBA measured at TPP and 0 daPa. An interclass correlation coefficient test was applied at each of the 16 frequency bands to measure the test-retest reliability of WBA at TPP and 0 daPa.

RESULTS

Both WBA measurements at TPP and 0 daPa exhibited a multipeaked pattern with 2 maxima at 1.25-1.6 kHz and 6.3 kHz and 2 minima at 0.5 and 4 kHz. The mean WBA measured at TPP was significantly higher than that measured at 0 daPa at 0.25, 0.4, 0.5, 1.25, and 1.6 kHz only. A normative data set was developed for absorbance at TPP and at 0 daPa. There was no significant effect of ethnicity, gender, and ear on both measurements of WBA. The test-retest reliability of WBA at TPP and 0 daPa was high with the interclass correlation coefficient ranging from 0.77 to 0.97 across the frequencies.

CONCLUSIONS

Normative data of WBA measured at TPP and 0 daPa for neonates were provided in the present study. Although WBA at TPP was slightly higher than the WBA measured at 0 daPa at some frequencies below 2 kHz, the WBA patterns of the 2 measurements were nearly identical. Moreover, the test-retest reliability of both WBA measurements was high.