The effects of frequency lowering on speech perception in noise with adult hearing-aid users

Abstract

Objective Frequency lowering (FL) strategies move high frequency sound into a lower frequency range. This study determined if speech perception differences are observed between some of the different frequency lowering strategies that are available. Design A cross-sectional, repeated-measures design was used to compare three hearing aids that used wide-dynamic range compression (WDRC) and either non-linear frequency compression (NFC), linear frequency transposition (LFT), or frequency translation (FT). The hearing aids were matched to prescriptive real ear targets for WDRC. The settings for each FL strategy were adjusted to provide audibility for a 6300 Hz filtered speech signal. Sentence recognition in noise, subjective measures of sound quality, and a modified version of the speech intelligibility index (SII) were measured. Study Sample Ten adults between the ages of 63 to 82 years with bilateral, high frequency hearing loss. Results LFT and FT led to poorer sentence recognition compared to WDRC for most individuals. No difference in sentence recognition occurred with and without NFC. The quality questionnaire and SII showed few differences between conditions. Conclusion Under similar fitting and testing conditions of this study, FL techniques may not provide speech understanding benefit in certain background noise situations.

Effectiveness of Frequency-Lowering Hearing Aids and Electric Acoustic Stimulation Cochlear Implant for Treating People with a Severe-To-Profound High-Frequency Hearing Loss

“…This suggests that there is a potential risk to degrade the patient's hearing abilities with the use of FL, even if the person reports a better benefit in real-life with this technology, as it was the case for three participants during this study (S3, S9 and S12). This risk may be greater with LFT HAs, as reported in previously published studies [41,42]. Then, FL HAs may not be suitable for all patients with a HFHL, particularly those with a more severe hearing loss in mid frequencies.…”

The Effects of Nonlinear Frequency Compression and Digital Noise Reduction on Word Recognition and Satisfaction Ratings in Noise in Adult Hearing Aid Users

“…In addition, Hopkins et al (2014) and Ellis and Munro (2015) indicated consonant recognition performance in noise was significantly improved when using NLFC. Conversely, other studies did not find a significant sentence recognition performance differences (Hopkins et al, 2014;Picou et al, 2015;Miller et al, 2016) or speech recognition performance differences when using NLFC (McDermott and Henshall, 2010;Perreau et al, 2013). Furthermore, performance on the QuickSIN, Modified Rhyme Test, or dual-task cognitively loaded tests of speech intelligibility was not improved when using NLFC (Kokx-Ryan et al, 2015).…”

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

“…The fourth category, termed frequency translation, uses adaptive signal processing to lower high-frequency signals, while maintaining the conventional hearing aid signal (or bandpass) in addition to the transposed one. 12 This type of FL is also referred to as spectral envelope warping, and is similar to transposition in that a portion of the high-frequency spectrum is translated down without compression; however, it is different from the other types in that high-frequency peaks are synthesized at lower frequencies by increasing the energy present in the destination channel. 49 Transposition and translation both allow adjustments to the gain applied only to the lowered or translated signal, independently of the gain applied in the destination channel itself.…”

“…Methods of FL that overlap the transposed frequencies with lower frequencies have been reported to degrade speech recognition in one study. 12 Another study compared speech recognition and subjective ratings of performance for a group of adults who wore both transposition and compression devices, one of who later received a cochlear implant. 55 Many of these participants had cochlear DRs.…”

“…[1][2][3][4][5][6][7][8][9][10] This literature also suggests that some listeners may not benefit from FL and may even experience adverse speech perception effects. [11][12][13] In addition to speech perception, some of the more recent studies have focused on how FL may affect outcomes of sound quality and objective measures of listening effort for listeners with high-frequency hearing loss. For example, perceived sound quality of speech may improve with FL, compared with conventional fittings.…”