What's in a name? A systematic review and meta-analysis to assess the effectiveness of non-medical amplification devices in adults with mild and moderate hearing losses

Objective: To assess non-medical amplification devices in adults with mild-to-moderate hearing loss, and the impact of device features on outcomes. Design: A prospectively registered systematic review. Study sample: Ten studies evaluating personal sound amplification products (PSAPs), and four evaluating smartphone amplification applications (or apps). Devices were classified as "premium" or "basic" based on the number of compression channels (>= 16 or <16, respectively). Results: Meta-analyses showed that premium PSAPs improved speech intelligibility in noise performance compared to unaided, whereas basic PSAPs and smartphone apps did not. Premium PSAPs performed better than basic hearing aids. Premium hearing aids performed better than premium and basic PSAPs, smartphone apps, and basic hearing aids. Although data could not be pooled, similar findings were also found for quality of life, listening ability, cognition, feasibility, and adverse effects. Conclusions: Premium PSAPs appear to be an effective non-medical amplification device for adults with mild-to-moderate hearing loss. Given the overlap in features available, it may be that this is a key consideration when drawing comparisons between devices, rather than the device being named a PSAP or hearing aid. Nevertheless, the extent to which PSAPs are effective without audiological input remains to be determined.