Efficacy of hearing-aid based telephone strategies for listeners with moderate-to-severe hearing loss.

BACKGROUND: Understanding speech over the telephone when listening in noisy environments may present a significant challenge for listeners with moderate-to-severe hearing loss.

PURPOSE: The purpose of this study was to compare speech recognition and subjective ratings across several hearing aid-based telephone listening strategies for individuals with moderate-to-severe sensorineural hearing loss.

RESEARCH DESIGN: Speech recognition and subjective ratings were evaluated for a simulated telephone signal. The strategies evaluated included acoustic telephone, unilateral telecoil, unilateral wireless streaming, and bilateral wireless streaming. Participants were seated in a noisy room for all evaluations.

STUDY SAMPLE: Eighteen adults, aged 49-88 yr, with moderate-to-severe sensorineural hearing loss participated.

DATA COLLECTION AND ANALYSIS: Speech recognition scores on the Connected Speech Test were converted to rationalized arcsine units and analyzed using analysis of variance testing and Tukey post hoc analyses. Subjective ratings of ease and comfort were also analyzed in this manner.

RESULTS: Speech recognition performance was poorest with acoustic coupling to the telephone and best with bilateral wireless routing. Telecoil coupling resulted in better speech recognition performance than acoustic coupling, but was significantly poorer than bilateral wireless routing. Furthermore, unilateral wireless routing and telecoil coupling generally led to similar speech recognition performance, except in lower-level background noise conditions, for which unilateral routing resulted in better performance than the telecoil.

CONCLUSIONS: For people with moderate-to-severe sensorineural hearing loss, acoustic telephone listening with a hearing aid may not lead to acceptable performance in noise. Although unilateral routing options (telecoil and wireless streaming) improved performance, speech recognition performance and subjective ratings of ease and comfort were best when bilateral wireless routing was used. These results suggest that wireless routing is a potentially beneficial telephone listening strategy for listeners with moderate-to-severe hearing loss who are fitted with limited venting if the telephone signal is routed to both ears. Unilateral wireless routing may provide similar benefits to traditional unilateral telecoil. However, the newer wireless systems may have the advantage for some listeners in that they do not include some of the positioning constraints associated with telecoil use.