Automated Adaptive Wideband Acoustic Reflex Threshold Estimation in Normal-hearing Adults

Abstract

Objectives: Acoustic stapedius reflex threshold (ART) tests are included in a standard clinical acoustic immittance test battery as an objective cross-check with behavioral results and to help identify site of lesion. In traditional clinical test batteries, middle-ear admittance of a 226 Hz probe is estimated using ear-canal measurements in the presence of a reflex-activating stimulus. In the wideband (WB) acoustic immittance ART test used in this study, the pure-tone probe is replaced by a WB probe stimulus and changes in absorbed power are estimated using ear-canal measurements in the presence of the activator. The ART is defined as the lowest level at which a criterion change in admittance (clinical) or absorbed power (WB) is observed in the presence of the activator. In the present study, ARTs were obtained in adults with normal hearing using the clinical, manual method and with a new WB automated adaptive threshold detection method. It was hypothesized that the WB test would result in lower ARTs than the clinical test because reflex-related changes in power absorbance could be observed across multiple frequency bands in the WB test compared with a single frequency in the traditional test. Design: Data were collected in a prospective research design. ARTs were obtained in ipsilateral and contralateral conditions using 500, 1000, 2000 Hz, and broadband noise (BBN) activators on a clinical system and on an experimental WB system. The bandwidth of the BBN activator was 125 to 4000 Hz on the clinical system and 200 to 8000 Hz on the wideband system. ARTs were estimated at both tympanometric peak pressure (TPP) and ambient pressure on the WB system. Data were collected in both ears of 39 adults (21 males) of mean age 47.7 years (range 23–72 years). Differences in ARTs among the three threshold estimation methods (clinical, WB at TPP, WB at ambient) were examined using the general linear model repeated measures test in SPSS. Post-hoc pairwise comparisons were completed with Bonferroni correction for multiple comparisons. Statistical significance was defined as p < 0.05 for all analyses. Results: ARTs obtained on the WB system at TPP and ambient pressure were significantly lower than obtained on the clinical system. ARTs obtained on the WB system at TPP were significantly higher than at ambient pressure in the 500 and 2000 Hz ipsilateral conditions. Conclusions: WB automated adaptive ARTs in normal-hearing adults were lower than for clinical methods when measured at TPP and ambient pressure. Lower presentation levels required to estimate ART in the WB test may be more tolerable to patients. Patients with ARTs that are not present at the maximum level of a traditional reflex test may have present ARTs with a WB ART test, which may reduce the need to refer for additional testing for possible retrocochlear involvement. Automation of the test may allow clinicians more time to attend to the other requisite tasks of a hearing evaluation and make the system useful for telehealth applications.

The Rise and Fall of Aural Acoustic Immittance Assessment Tools

“…[59][60][61] Ongoing developments in wideband MEMR testing include refinements of methods and testing paradigms, response quantification, and analysis, including automated/adaptive testing paradigms. 62 For a detailed account of recent wideband MEMR developments and clinical applications, the reader is referred to Feeney et al in this edition. As clinical databases are expanded, and norms are established for different applications, wideband MEMR testing capabilities are likely to be included in commercially available WAI products.…”

Wideband Acoustic Reflex Measurement

“…It would also potentially allow ARTs to be measured in individuals for whom the traditional method results in absent ARTs, thus providing more information about the patient's peripheral and brainstem auditory system. The adaptive WB ART method of Schairer et al 11 holds promise for eventual clinical use of the method to quickly obtain automated ARTs. The ART method of Keefe et al 9 may be used to measure ARGFs for the exploration of noise-induced synaptopathy and auditory deficits caused by ototoxic drugs.…”

“…Schairer et al 11 presented an adaptive method for calculating the ART using the basic WB ART method of Keefe et al 9 with the same equipment used in that study. Schairer et al obtained WB ARTs at ambient pressure and at TPP using an automated adaptive procedure based on the reflex response for each activator presentation.…”

“…Schairer et al 11 obtained ipsilateral and contralateral ARTs from 78 ears of 39 adults with normal hearing using the adaptive WB method in comparison with the manual adaptive clinical method with a 226-Hz probe tone. The AR activator stimuli were pure tones at 500, 1,000, and 2,000 Hz and BBN.…”

Automated Adaptive Wideband Acoustic Stapedius Reflex Thresholds in Adults With Normal Hearing and Sensorineural Hearing Loss

“…Lower reflex thresholds obtained with a WAI system may be due in part to the ability to detect the shift in middle ear function across a broad probe-frequency bandwidth rather than at a single probe frequency as with clinical systems. In addition, BBN reflex activators for the WAI systems in studies cited earlier have had an extended bandwidth to 8 kHz compared with clinical systems that typically roll-off BBN at frequencies above 4 kHz (Schairer et al 2022). The additional one-octave bandwidth should account for at least a 4 dB lower ART compared with the clinical BBN ARTs in participants with NH based on an extrapolation to higher frequencies for the findings of Margolis et al (1980) described earlier.…”