Purpose: This study aimed to compare performance between unilateral and bilateral bone conduction hearing device (BCHD) use for speech understanding and subjective listening difficulty. Method: This study involved prospective investigation of bilateral BCHD with human subjects at an academic medical center. Twelve individuals (five children, seven adults) with BCHD were recruited (eight unilateral BCHDs, four bilateral BCHDs). Speech recognition was assessed in colocated noise (Bamford–Kowal–Bench Speech in Noise), diffuse noise (AzBio/BabyBio), and roving speech in diffuse noise (Basic English Lexicon sentences) as well as patient-reported outcomes of listening difficulty and Speech, Spatial and Qualities of Hearing Scale. Results: Statistically significant bilateral BCHD benefit was noted for roving speech. Bilateral BCHDs resulted in speech understanding scores that were not significantly different across speech location, whereas unilateral BCHD revealed significantly poorer performance with speech directed to the unaided ear. However, bilateral BCHD benefit may not be easily quantified in clinical settings, as we observed no significant bilateral benefit for the clinical assessments of speech in colocated noise. Conclusions: Significant bilateral BCHD benefit was noted for roving speech in diffuse noise, similar to group conversations in noisy restaurants. Significant benefits were not observed for a fixed sound source in colocated noise making clinical assessment of the potential benefit of a second BCHD challenging; however, performance in the bilateral BCHD condition was either similar to or better than the best single ear alone thereby consistent with clinical benefits observed in complex noise. Overall, the study provides evidence in support of bilateral BCHD, but further investigation with larger samples is warranted.
Gifford et al. (Mon,) studied this question.