An initial validation study of DigiBel, a web-application enabling self-assessment of air and bone-conduction audiometry in the community

80% of primary school children suffer from glue ear which may impair hearing at a critical time for speech acquisition and social development. An online application, DigiBel, has been developed primarily to identify individuals with conductive hearing impairment who may benefit from temporary use of bone-conduction (BC) assistive technology in the community. This preliminary study aims to determine the screening accuracy and usability of DigiBel self-assessed air-conduction (AC) pure tone audiometry (PTA) in adult volunteers with simulated hearing impairment prior to formal clinical validation. Healthy adults, each with one ear plugged, underwent standard automated AC PTA (reference test) and DigiBel audiometry in quiet community settings. Threshold measurements were compared across six tone frequencies and DigiBel test-retest reliability was calculated. The accuracy of DigiBel for detecting more than 20 decibels of hearing impairment was assessed. 30 adults (30 unplugged ears and 30 plugged ears) completed both audiometry tests. DigiBel had 100% sensitivity (95%CI 87.23-100) and 72.73% (95%CI 54.48-86.70) specificity in detecting hearing impairment. Threshold mean bias was insignificant except at 4000 and 8000Hz where a small but significant over-estimation of threshold measurement was identified. All 24 subjects completing feedback rated the DigiBel test good or excellent and 21(87.5%) agreed or strongly agreed that they would be able to do the test at home without help. This study supports the potential use of DigiBel as a screening tool for hearing impairment. The findings will be used to improve the software further and undertake a formal clinical trial of AC and BC audiometry in individuals with suspected conductive hearing impairment. Author SummaryHearing loss is a major global health issue. It can affect many aspects of life such as education, employment, communication, and result in social isolation. Two thirds of people with severe hearing loss live in low and middle countries with poor access both to hearing testing (audiometry) or conventional hearing aids. Several software applications (apps) like DigiBel, studied here, have been developed to enable individuals to test their own hearing in the community. Uniquely, DigiBel has the additional potential to identify individuals with hearing loss who could derive immediate hearing support from an affordable and rechargeable bone-conduction headphone / microphone kit while waiting specialist care. This initial study of DigiBel provides confirmation that the app is easy to use and accurate at detecting simulated hearing impairment. It lays the groundwork for future clinical studies to assess DigiBels performance in children and adults with hearing impairment.