Listener Performance with a Novel Hearing Aid Frequency Lowering Technique

Abstract

Background Sloping hearing loss imposes limits on audibility for high-frequency sounds in many hearing aid users. Signal processing algorithms that shift high-frequency sounds to lower frequencies have been introduced in hearing aids to address this challenge by improving audibility of high-frequency sounds. Purpose This study examined speech perception performance, listening effort, and subjective sound quality ratings with conventional hearing aid processing and a new frequency-lowering signal processing strategy called frequency composition (FC) in adults and children. Research Design Participants wore the study hearing aids in two signal processing conditions (conventional processing versus FC) at an initial laboratory visit and subsequently at home during two approximately six-week long trials, with the order of conditions counterbalanced across individuals in a double-blind paradigm. Study Sample Children (N = 12, 7 females, mean age in years = 12.0, SD = 3.0) and adults (N = 12, 6 females, mean age in years = 56.2, SD = 17.6) with bilateral sensorineural hearing loss who were full-time hearing aid users. Data Collection and Analyses Individual performance with each type of processing was assessed using speech perception tasks, a measure of listening effort, and subjective sound quality surveys at an initial visit. At the conclusion of each subsequent at-home trial, participants were retested in the laboratory. Linear mixed effects analyses were completed for each outcome measure with signal processing condition, age group, visit (prehome versus posthome trial), and measures of aided audibility as predictors. Results Overall, there were few significant differences in speech perception, listening effort, or subjective sound quality between FC and conventional processing, effects of listener age, or longitudinal changes in performance. Listeners preferred FC to conventional processing on one of six subjective sound quality metrics. Better speech perception performance was consistently related to higher aided audibility. Conclusions These results indicate that when high-frequency speech sounds are made audible with conventional processing, speech recognition ability and listening effort are similar between conventional processing and FC. Despite the lack of benefit to speech perception, some listeners still preferred FC, suggesting that qualitative measures should be considered when evaluating candidacy for this signal processing strategy.

Evaluation of a Frequency-Lowering Algorithm for Adults With High-Frequency Hearing Loss

“…This last factor is probably the most important. Our participants had more severe hearing loss, and their values of Thr f (mean of 2.65 kHz for the ears with better audibility) were much lower than the values of the “maximum audible frequency” reported by Kirby et al. (2017) .…”

“…At the time of performing this study, there were no published studies evaluating Fcomp. Recently, a version of Fcomp implemented in Oticon hearing aids ( Angelo, Alexander, Christiansen, Simonsen, & Jespergaard, 2015 ) was evaluated for a group of adults and children ( Kirby et al., 2017 ). No benefit of Fcomp-on was found for speech intelligibility (monosyllabic words and sentences, VCV test in background noise), plural detection, or listening effort, although the participants preferred the sound quality with Fcomp-on, at least in some situations.…”

The Use of Frequency Lowering Technology in the Treatment of Severe-to-Profound Hearing Loss: A Review of the Literature and Candidacy Considerations for Clinical Application

“…In a recent study, composition was described as a variation of compression and transposition, in which signal processing is used to locate and copy multiple adjacent segments of high-frequency bands from the upper channel to compress and overlap these multiple bands with the lower channel. 15 This type of lowering has been evaluated in research including listeners with cochlear DRs. 10 Like frequency transposition, some recent signal processors allow the conventional hearing aid bandwidth to be preserved (as a fitting option) and mixed with the frequency lowered signal.…”

“…More recently, Kirby and colleagues published a sound quality questionnaire tailored to the evaluation of FL benefit that has potential in a clinical context. 15 A real-world performance measure was used by Glista and colleagues to compare multimemory performance for FL and conventional hearing aid fittings. Individual preference for FL (compression) was found to relate to age group and to benefit; children were more likely to have preference for FL than were adults, and listeners were more likely to prefer FL if they benefited from it.…”

“…In addition, listening effort was not negatively affected for the one type of FL tested. 15 In other studies, HI listeners have reported a broad range of settings in which the quality of speech is similar to that of conventional technologies and that FL can adversely affect sound quality, with poorer ratings reported for stronger FL settings. 16,17 Findings for music perception suggest ratings are unaffected, on average, 14,17 or are negatively affected by stronger settings.…”