Improving Sensitivity of the Digits-In-Noise Test Using Antiphasic Stimuli

Pure-tone audiometry without bone-conduction thresholds: using the digits-in-noise test to detect conductive hearing loss

Objective: COVID-19 has been prohibitive to traditional audiological services. No- or low-touch audiological assessment outside a sound-booth precludes test batteries including bone conduction audiometry. This study investigated whether conductive hearing loss (CHL) can be differentiated from sensorineural hearing loss (SNHL) using pure-tone air conduction audiometry and a digits-in-noise (DIN) test.Design: A retrospective sample was analysed using binomial logistic regressions, which determined the effects of pure tone thresholds or averages, speech recognition threshold (SRT), and age on the likelihood that participants had CHL or bilateral SNHL.Study sample: Data of 158 adults with bilateral SNHL (n = 122; PTA_0.5-4 kHz > 25 dB HL bilaterally) or CHL (n = 36; air conduction PTA_0.5-4 kHz > 25 dB HL and ≥20 dB air bone gap in the affected ears) were included.Results: The model which best discriminated between CHL and bilateral SNHL used low-frequency pure-tone average (PTA), diotic DIN SRT, and age with an area under the ROC curve of 0.98 and sensitivity and specificity of 97.2 and 93.4%, respectively.Conclusion: CHL can be accurately distinguished from SNHL using pure-tone air conduction audiometry and a diotic DIN. Restrictions on traditional audiological assessment due to COVID-19 require lower touch audiological care which reduces infection risk.

FreeHear: A New Sound-Field Speech-in-Babble Hearing Assessment Tool

Pure-tone threshold audiometry is currently the standard test of hearing. However, in everyday life, we are more concerned with listening to speech of moderate loudness and, specifically, listening to a particular talker against a background of other talkers. FreeHear delivers strings of three spoken digits (0–9, not 7) against a background babble via three loudspeakers placed in front and to either side of a listener. FreeHear is designed as a rapid, quantitative initial assessment of hearing using an adaptive algorithm. It is designed especially for children and for testing listeners who are using hearing devices. In this first report on FreeHear, we present developmental considerations and protocols and results of testing 100 children (4–13 years old) and 23 adults (18–30 years old). Two of the six 4 year olds and 91% of all older children completed full testing. Speech reception threshold (SRT) for digits and noise colocated at 0° or separated by 90° both improved linearly across 4 to 12 years old by 6 to 7 dB, with a further 2 dB improvement for the adults. These data suggested full maturation at approximately 15 years old SRTs at 90° digits/noise separation were better by approximately 6 dB than SRTs colocated at 0°. This spatial release from masking did not change significantly across age. Test–retest reliability was similar for children and adults (standard deviation of 2.05–2.91 dB SRT), with a mean practice improvement of 0.04–0.98 dB. FreeHear shows promise as a clinical test for both children and adults. Further trials in people with hearing impairment are ongoing.