Validity and reliability of an automatic audiometry application for iOS iPads with consumer-grade headphones.

Objective: To investigate the validity and reliability of the Sound Scouts Automatic Audiometer application and derive Equivalent Sound Pressure Level (ETSPL) values for Sennheiser HD 300 headphones.

Design: Cross-sectional, where subjects self-administered automated pure tone audiometry (A-PTA), with HD 300 headphones, and clinicians administered conventional pure-tone audiometry (C-PTA; with GSI Pello audiometer and Radio Ear DD45 headphones), both inside a sound booth. Both tests were repeated, in counterbalanced order, on a different day by a different examiner.

Study sample: 30 adults aged 23-78 years, with hearing threshold levels from normal to severe.

Results: Mean differences between the two methods were less than 2 dB from 250 to 4000 Hz, but increased substantially at 6000 and 8000 Hz. The two methods were strongly correlated (r ≥ 0.78, p < 0.00001) from 500 to 8000 Hz. Test-retest differences and standard deviations were indistinguishable between the two methods. ETSPL values for the HD 300 headphones were derived from the mean threshold differences between A-PTA and C-PTA at each frequency.

Conclusions: Automatic audiometer hearing thresholds were easy to obtain and agreed closely with conventional audiometry, except at 6000 and 8000 Hz where the calibration values should be changed to those found in this study.