Identifying CHL in young infants can be difficult to do with tympanometry, and there is no standard interpretation. Prieve et al. (2013) evaluated tympanometry variations along with wideband reflectance, and showed the latter was just as effective as tympanometry in identifying CHL in infants.
Prieve et al. evaluated infants less than 6 months old (3-26 weeks) who had been referred in an infant hearing screening program. The babies received both air and bone ABR tests along with tympanometry and wideband reflectance. 43 ears had normal hearing, 17 ears had CHL. Because the number of ears with CHL is small, the diagnostic indicators from this study should be interpreted and used cautiously.
Prieve et al. found that wideband reflectance between 800 and 3000 Hz was higher in CHL ears compared with normal ears. This is consistent with increased stiffness in the middle ear. Prieve et al. found that a criterion for reflectance greater than 69% in the one-third octave band around 1600 Hz produced the highest likelihood ratio for CHL.
Prieve et al. used the wideband chirp in their study, because they wanted to evaluate multiple frequency ranges. The OtoStat uses a chirp stimulus. HearID can use either a tone or a chirp stimulus: either use the default chirp, or change the stimulus protocol to use a 1.6 kHz tone. The benefit to doing this, especially if you test primarily infants, is that the tone test is faster and achieves a higher signal-to-noise ratio. However, you lose potentially interesting information at other frequencies. Although Prieve et al. didn't evaluate tone stimuli, elsewhere they have been shown to produce identical results (e.g., Hunter et al., 2010).
Use the Reflectance Area Index (RAI) for the 1/3rd octave around 1.6 kHz for the chirp stimulus, or the reflectance at 1.6 kHz for the tonal stimulus. The RAI is the average reflectance across a frequency region.
This research was published after HearID's release, so the calculation isn't included in these versions. To make this calculation manually:
Prieve, B. A., Werff, K. R., Preston, J. L., and Georgantas, L. (2013). "Identification of conductive hearing loss in young infants using tympanometry and wideband reflectance," Ear & Hearing 34, 168-178.
Hunter, L. L., Feeney, M. P., Lapsley Miller, J. A., Jeng, P. S., and Bohning, S. (2010). "Wideband Reflectance in Newborns: Normative Regions and Relationship to Hearing-Screening Results," Ear & Hearing 31, 599-610.
Hunter, L., and Shahnaz, N. (2013). Acoustic Immittance Measures: basic and advanced practice. (Plural, San Diego, CA).
infant hearing screening, newborn hearing screening, INHS, Universal Newborn Hearing Screening Programme, sensorineural hearing loss, middle-ear wideband reflectance, tympanometry.
This guide was compiled by Mimosa Acoustics from peer-reviewed scientific research to assist clinicians in interpreting results from HearID and OtoStat. It will be updated as new research becomes available. HearID and OtoStat do not provide diagnoses. All diagnostic decisions are the responsibility of the clinician.
Version 1.1, 5 April 2015.
Original Version 1.0, 13 July 2013.
Prepared by Judi Lapsley Miller, PhD.