Pocket Audiometry: Validation of Selected Software Applications for the Assessment of Hearing Thresholds

Abstract

Aims. Firstly, to investigate and evaluate the accuracy and test-retest reliability of three smartphone- and tablet-based manual threshold audiometry applications (apps) – AudCal, hearTest and shoeBOX Audiometry Professional. Secondly, the reported experience and opinions of audiology clinicians were used to investigate each app’s suitability for clinical use in both sound-proof and non-sound-proof environments. Methods. The investigation comprised of two studies. Firstly, 60 participants with an average age of 38 years and clinically heterogeneous hearing thresholds (76.1% of thresholds < 15 dB HL) were recruited for the validity and reliability investigation. A repeat-measure, withinsubject design was employed whereby the air-conduction hearing thresholds determined by each app were compared to those determined by conventional PTA. Participants were randomly allocated to be retested with one app. Secondly, 14 second-year audiology interns were recruited to trial the apps with a volunteer patient and comment on their experiences via a questionnaire. Results. Paired samples t-tests showed that the differences were statistically significant for shoeBOX at all frequencies, all except 8 kHz in the left ear for AudCal and all except 0.5 kHz in the right ear and 1 and 6 kHz in the left ear for hearTest. Only the results for hearTest met the clinical criteria for similarity for each ear overall; it also had high sensitivity and the highest specificity. All apps had very high reliability: 98.7% of hearTest thresholds were within 5 dB of the conventional PTA thresholds; this figure was 98.4% for shoeBOX and 97.0% for AudCal. In contrast, clinicians felt that shoeBOX was the most valid, reliable and effective app. Conclusions. hearTest appears to be the most valid app, though shoeBOX Audiometry Professional was preferred by clinicians overall. As the first study comparing manual, appbased alternatives to conventional threshold PTA, these results must be perceived in a preliminary manner, but nevertheless set a positive precedent for ‘pocket audiometry’ solutions to be considered for use in a widespread clinical capacity, be it a sound-proof booth or in a primary healthcare context.