Paired Comparisons of Nonlinear Frequency Compression, Extended Bandwidth, and Restricted Bandwidth Hearing Aid Processing for Children and Adults with Hearing Loss

Abstract

Background Preference for speech and music processed with nonlinear frequency compression and two controls (restricted and extended bandwidth hearing-aid processing) was examined in adults and children with hearing loss. Purpose Determine if stimulus type (music, sentences), age (children, adults) and degree of hearing loss influence listener preference for nonlinear frequency compression, restricted bandwidth and extended bandwidth. Research Design Within-subject, quasi-experimental study. Using a round-robin procedure, participants listened to amplified stimuli that were 1) frequency-lowered using nonlinear frequency compression, 2) low-pass filtered at 5 kHz to simulate the restricted bandwidth of conventional hearing aid processing, or 3) low-pass filtered at 11 kHz to simulate extended bandwidth amplification. The examiner and participants were blinded to the type of processing. Using a two-alternative forced-choice task, participants selected the preferred music or sentence passage. Study Sample Sixteen children (8–16 years) and 16 adults (19–65 years) with mild-to-severe sensorineural hearing loss. Intervention All subjects listened to speech and music processed using a hearing-aid simulator fit to the Desired Sensation Level algorithm v.5.0a (Scollie et al, 2005). Results Children and adults did not differ in their preferences. For speech, participants preferred extended bandwidth to both nonlinear frequency compression and restricted bandwidth. Participants also preferred nonlinear frequency compression to restricted bandwidth. Preference was not related to degree of hearing loss. For music, listeners did not show a preference. However, participants with greater hearing loss preferred nonlinear frequency compression to restricted bandwidth more than participants with less hearing loss. Conversely, participants with greater hearing loss were less likely to prefer extended bandwidth to restricted bandwidth. Conclusion Both age groups preferred access to high frequency sounds, as demonstrated by their preference for either the extended bandwidth or nonlinear frequency compression conditions over the restricted bandwidth condition. Preference for extended bandwidth can be limited for those with greater degrees of hearing loss, but participants with greater hearing loss may be more likely to prefer nonlinear frequency compression. Further investigation using participants with more severe hearing loss may be warranted.

Listening Effort and Speech Recognition with Frequency Compression Amplification for Children and Adults with Hearing Loss

“…The filter bank consisted of eight one-third octave-band filters with center frequencies spaced between .25 and 6.3 kHz. The NFC circuit used an algorithm described by Simpson et al (2005) and others (Alexander, 2016; Brennan et al, 2014; McCreery et al, 2013, 2014). …”

“…The maximum audible input frequency with NFC was 8240 Hz for all participants (maximum audible output frequency = 5 kHz, start frequency = 3.8 kHz, compression ratio = 2.6), except two participants who had a maximum audible input frequency of 6960 Hz with NFC (maximum audible output frequency = 4 kHz, start frequency = 2.7 kHz, compression ratio 2.3). More details about the NFC processing in the hearing aid simulator and the fitting method are described by Alexander (2016), Brennan et al (2014) and McCreery et al (2013, 2014). …”

“…In general, benefit from NFC is better when access to high frequency sounds is increased with NFC (McCreery et al, 2013, 2014) but spectral distortion is minimized (Souza et al, 2013) as well as in listeners with greater high-frequency hearing loss (Brennan et al, 2014; Glista et al, 2009; Souza et al, 2013; but see Kokx-Ryan et al, 2015). Benefit is more likely to occur for stimuli where high-frequency audibility contributes to recognition (Hopkins et al, 2014; Kokx-Ryan et al, 2015; Wolfe et al, 2010, 2011), with decreases in recognition sometimes occurring for specific consonants or vowels (Alexander 2016; Kokx-Ryan et al, 2015).…”

Masking Release in Children and Adults With Hearing Loss When Using Amplification

“…Sentence and noise stimuli were processed with a hearing-aid simulator (Alexander & Masterson, 2015;Brennan et al, 2014;McCreery, Brennan, Hoover, Kopun, & Stelmachowicz, 2013), implemented using MATLAB (R2009b), in order to have more control over the compression parameters than is possible with a typical hearing aid. The stages in the program included an input limiter, filterbank, WDRC, and output limiter.…”

Neural-scaled entropy predicts the effects of nonlinear frequency compression on speech perception

“…Amplification was customized for each listener so that stimuli were presented at output levels prescribed by the Desired Sensation Level algorithm v5.0a (Scollie et al, 2005) using fast-acting, 8-channel wide dynamic range compression in MATLAB (see also Alexander and Masterson, 2015;McCreery et al, 2013McCreery et al, , 2014Brennan et al, 2014Brennan et al, , 2015. All stimuli were low-pass filtered at about 3.3 kHz using a 1024-tap finite impulse response filter to simulate a severe high-frequency hearing loss.…”