Performance and Reliability of a Smartphone Digits-in-Noise Test in the Sound Field

Purpose This study compared the speech reception thresholds (SRTs) and test-retest reliability of the smartphone digits-in-noise (DIN) test coupled to various sound-field transducers. Method Fifty normal-hearing participants (bilateral pure- tone thresholds 0.5-8kHz ≤ 15dB HL) between the ages of 18 and 25 years (M = 20, SD = ±1.9) were recruited. The study used a repeated measure counterbalanced Latin square design to compare the SRTs of the smartphone DIN test recorded with earphones, 2 smartphone speakers, and 2 external loudspeakers in a sound booth. Test-retest reliability across sound field conditions was also determined. Results Mean SRTs across earphone and different sound field transducers ranged from -11.3 (SD = 0.8) to -11.7 (SD = 1.2). SRTs across the 4 different loudspeaker transducers and earphones were not significantly different (p > .05) between test and retest sessions. Conclusion The smartphone DIN test is reliable and can be conducted using various sound field transducers in a sound booth. To allow home-based testing without earphones, with special application to aided performance for speech-in-noise testing, the smartphone DIN test should be evaluated in home environments.