Development and verification of non-supervised smartphone-based methods for assessing pure-tone thresholds and loudness perception

Objective The benefit of using smartphones for hearing tests in a non-supervised, rapid, and contactless way has drawn a lot of interest, especially if supra-threshold measures are assessed that go beyond audiogram-based measures alone. It is unclear, nevertheless, how well these measures compare to more supervised and regulated manual audiometric assessments. The aim of this study is to validate such smartphone-based methods against standardized laboratory assessments. Design Pure-tone audiometry and categorical loudness scaling (CLS) were used. Three conditions with varying degrees of supervision were created and compared. In order to assess binaural and spectral loudness summation, both narrowband monaural and broadband binaural noise have been examined as CLS test stimuli. Study sample N = 21 individuals with normal hearing and N = 16 participants with mild-to-moderate hearing loss. Results The tests conducted here did not show any distinctions between smartphone-based and laboratory-based methods. Conclusions Non-supervised listening tests via smartphone may serve as a valid, reliable, and cost-effective approach, e.g., for pure-tone audiometry, CLS, and the evaluation of binaural and spectral loudness summation. In addition, the supra-threshold tests can be constructed to be invariant against missing calibration and external noise which makes them more robust for smartphone usage than audiogram measures.