AbstractStudy ObjectivesMany adults without a diagnosed sleep disorder report poor sleep. Recently, there has been a dramatic increase in the use of app-based audio tools to aid sleep by the general public, yet there is a paucity of evidence on whether such tools are efficacious. This study evaluated the feasibility and preliminary efficacy of two categories of audio tools, comprising music and narrated stories, featured on the Unmind app.MethodsWe conducted an online, parallel, multi-arm, external pilot randomized controlled trial, with two intervention arms and a waitlist (WL) control group. Participants were working adults who were screened for poor sleep. Feasibility was assessed via objective and self-report measures. Preliminary efficacy was evaluated via self-report measures of sleep disturbance, work productivity, and other mental health outcomes, captured at baseline (t0) and following a 4-week intervention period (t1), and analyzed using mixed effects models with intention-to-treat principles.ResultsThree hundred participants were randomized, and 92% were retained att1. 90.5% of participants completed at least one intervention session. 82.1% reported being “satisfied” or “very satisfied” with their intervention, and 84.3% rated their intervention as “good” or “excellent.” The between-group Hedges’geffect size for sleep disturbance was 0.92 [0.63–1.22] and 1.09 [0.80–1.39] for the two interventions compared to the WL group.ConclusionsBoth interventions are feasible and acceptable. Preliminary efficacy findings suggest that audio tools designed to aid sleep could have widespread financial and public health implications, and should be investigated in a definitive trial.Clinical TrialInternational Standard Randomized Controlled Trial Number (ISRCTN), 12614821,http://www.isrctn.com/ISRCTN12614821.