Low-gain hearing aids for individuals with normal hearing thresholds: a scoping review of listening-related outcomes

Listening difficulties (LiD) can occur despite normal hearing thresholds, affecting speech understanding in complex environments and increasing listening effort. Audiologists have increasingly considered hearing aids for this population despite supporting evidence remaining unclear. This scoping review examined whether amplification should be used in individuals with normal hearing thresholds with or without LiD.

Following PRISMA-ScR guidelines, 67 studies were reviewed: 14 involving adults and/or children with normal hearing thresholds with LiD and 54 involving adults with normal hearing thresholds without LiD. All studies assessed at least one listening-related outcome in aided versus unaided conditions.

For adults and children with LiD, amplification was predominantly associated with improvements in subjective outcomes but variable effects on speech perception. Benefits were greatest when signal-processing features improved signal-to-noise (SNR) ratio. In contrast, adults without LiD showed predominantly mixed or no benefit from amplification, with some evidence of poorer subjective outcomes and speech perception.

Amplification could provide functional benefit for adults and children with normal hearing thresholds with LiD, particularly when targeting SNR rather than audibility. However, it is less likely to benefit - and could impair - performance in adults with normal hearing thresholds without LiD.