Hearing Listeners Research Articles

Usability and perceived benefit of hearing assistive features in Apple AirPods Pro

Individuals with hearing loss face high personal costs for hearing aids, making over-the-counter hearing aids, or headphones featuring custom audio control, alternative options. Apple Inc.’s AirPods Pro contain a variety of headphone accommodations designed to help people hear better. Recent research has evaluated electroacoustic properties of AirPods Pro demonstrating good ability to fit prescriptive targets for different hearing losses. Here, we examine the usability and perceived benefit from engaging custom audiogram-driven features in AirPods Pro. Listeners with self-assigned hearing profiles ranging from normal hearing to a moderate degree of hearing loss take a hearing screener (Mimi Hearing Test). AzBio sentences are presented in quiet and in noise while enabling and disabling the custom features in Apple’s Accommodation settings. Listeners then complete a questionnaire targeting usability of the features and perceived benefit. Overall, listeners found the features easy to use and to be at least a little helpful, regardless of hearing status. Listeners with suspected or known hearing impairment reported slightly greater benefit than normal hearing listeners when listening in noise with the custom audio features. Headphone Accommodations in AirPods Pro may be an affordable option for an improved listening experience. [Work supported by Western Washington University.]

Validation of a clinical test of auditory emotion recognition

Currently, there are no accessible clinical tests that can be used to measure auditory emotion recognition. Experimental emotion recognition tasks usually involve many stimuli and take a lot of time to complete, making them unfeasible for use in a clinical setting. Prior research from our laboratory has measured the impact of various test factors on auditory emotion recognition, including the number of emotion categories, the number of stimuli per emotion category, the number of talkers, and using sentence versus word materials. In this study, we present a preliminary validation of a proposed audiotry emotion recognition test. Based on the results from our laboratory, the test consists of forty sentences (1 sentence × 10 talkers × 4 emotions) in order to maintain an appropriate test duration for a clinical setting. Listeners with normal hearing will complete the testing in quiet. Results will be compared with expectations informed by prior research. Performance and duration of the task will be measured, and standard deviation of scores among all participants will be assessed. Implications will be discussed, including the percentage correct of emotion recognition by normal hearing listeners.

Relating monaural and binaural envelope processing abilities to spatial release from masking

The difference in speech identification thresholds between colocated condition (when the target and the maskers are placed at the same location) and spatially separated condition (when target and the maskers are symmetrically separated) is quantified as Spatial Release from Masking (SRM). SRM is thought to be a combination of monaural and binaural advantages arising from spatially separating the target from the maskers. Monaural contributions are from the head shadow effect whereas the binaural contributions are from processing the interaural differences between the two ears. However, the exact contributions of the monaural and binaural advantage to SRM is unknown. Here, we present data on monaural and binaural envelope processing abilities and their relationship to SRM on a large cohort of young normal hearing listeners. Monaural envelope processing ability was measured using the envelope regularity discrimination task (Moore et al., 2019). Sensitivity to ITD-envelopes was used to quantify binaural envelope processing ability. SRM was measured using coordinate response measure sentences. The relationship between SRM, envelope regularity index, and ITD thresholds along with the monaural and binaural envelope processing abilities to SRM will be discussed.

The effect of explicit and implicit voice training on speech-on-speech intelligibility and listening effort

Listening to familiar voices might improve intelligibility of target speech in multiple-talker situations. In addition to personally familiar voices, voice training—through implicit exposure or explicit learning of a previously unheard voice—can improve speech intelligibility. However, there is no consensus on which method is more effective. We investigated the effect of explicit and implicit voice training on speech-on-speech perception and listening effort (pupillometry), among normal hearing listeners. There was no significant difference in speech intelligibility performance between trained and untrained voices, with either voice training method. However, an interaction between voice training method and target-to-masker ratio (TMR) on accuracy scores showed that the benefit of increased TMR on accuracy scores was significantly larger when voice training was implicit compared to explicit. Pupillometry results showed that explicit voice training significantly reduced listening effort for most disadvantageous TMR (−6dB), but not for more advantageous TMRs (0 and + 6 dB), and not for implicitly trained voices. Our results may imply that explicit voice training is more effective than implicit voice training in reducing listening effort. Still, implicit voice training, perhaps via procedural learning, might be more beneficial on the performance level when TMR becomes more advantageous.

Lateralization of interaural time differences with mixed rates of stimulation in bilateral cochlear implant listeners.

While listeners with bilateral cochlear implants (BiCIs) are able to access information in both ears, they still struggle to perform well on spatial hearing tasks when compared to normal hearing listeners. This performance gap could be attributed to the high stimulation rates used for speech representation in clinical processors. Prior work has shown that spatial cues, such as interaural time differences (ITDs), are best conveyed at low rates. Further, BiCI listeners are sensitive to ITDs with a mixture of high and low rates. However, it remains unclear whether mixed-rate stimuli are perceived as unitary percepts and spatially mapped to intracranial locations. Here, electrical pulse trains were presented on five, interaurally pitch-matched electrode pairs using research processors, at either uniformly high rates, low rates, or mixed rates. Eight post-lingually deafened adults were tested on perceived intracranial lateralization of ITDs ranging from 50 to 1600 μs. Extent of lateralization depended on the location of low-rate stimulation along the electrode array: greatest in the low- and mixed-rate configurations, and smallest in the high-rate configuration. All but one listener perceived a unitary auditory object. These findings suggest that a mixed-rate processing strategy can result in good lateralization and convey a unitary auditory object with ITDs.

Portable automated rapid testing: Validation of automated testing on listeners from India

Portable Automated Rapid Testing (PART) is an iPad application (https://braingamecenter.ucr.edu/games/p-a-r-t/) capable of measuring various psychoacoustic thresholds (speech on speech masking, temporal, spectral, and spectrotemporal modulation detection, temporal gap detection, frequency modulation tasks, and pure tone detection in noise) in an automated and rapid format using commercially available headphones. The app has been validated previously in native speakers of English and an adapted version of the app has been validated in young normal hearing listeners from Mexico. Here, we present psychoacoustic threshold data for a large cohort of younger college going listeners from India whose native language is not English but are proficient in English. The thresholds obtained from this group will be compared against previously published thresholds based on native speakers of English. It is hypothesized that there will not be any significant differences in thresholds between listeners from India and the thresholds published in the literature. These results will give us the required evidence to start using this freely available app to measure reliable thresholds of various central auditory processing measures in non-native speakers of English who are proficient in the language as well.

Long-lag identity priming in the absence of long-lag morphological priming: evidence from Mandarin tone alternation

The present study tested whether listeners hearing one form of a morpheme activate other forms of the same morpheme. Listeners performed lexical decisions while hearing Mandarin monosyllables; crucially, critical targets could be primed by related syllables that occurred 18–52 trials earlier (long-lag priming). The use of long-lag priming ensures that any facilitation effects are due to morphological relatedness and not to semantic or form relationships, which do not prime lexical decisions at long lags. Across three experiments (total N = 458), we consistently found that lexical decisions were primed when the same pronunciation of a morpheme occurred as prime and target (e.g., shiL – shiL) but were not primed when two different variants of the same morpheme occurred as prime and target (e.g., shiR – shiL, where both of these syllables are potential pronunciations of the same morpheme). In other words, we observed identity priming but not morphological priming, unlike other long-lag priming experiments, which almost invariably observe intramodal morphological priming if they test it. This surprising finding suggests that there are boundary conditions on the elicitation of long-lag morphological priming effects.

Comparable Encoding, Comparable Perceptual Pattern: Acoustic and Electric Hearing.

Perception with electric neuroprostheses is sometimes expected to be simulated using properly designed physical stimuli. Here, we examined a new acoustic vocoder model for electric hearing with cochlear implants (CIs) and hypothesized that comparable speech encoding can lead to comparable perceptual patterns for CI and normal hearing (NH) listeners. Speech signals were encoded using FFT-based signal processing stages including band-pass filtering, temporal envelope extraction, maxima selection, and amplitude compression and quantization. These stages were specifically implemented in the same manner by an Advanced Combination Encoder (ACE) strategy in CI processors and Gaussian-enveloped Tones (GET) or Noise (GEN) vocoders for NH. Adaptive speech reception thresholds (SRTs) in noise were measured using four Mandarin sentence corpora. Initial consonant (11 monosyllables) and final vowel (20 monosyllables) recognition were also measured. Naïve NH listeners were tested using vocoded speech with the proposed GET/GEN vocoders as well as conventional vocoders (controls). Experienced CI listeners were tested using their daily-used processors. Results showed that: 1) there was a significant training effect on GET vocoded speech perception; 2) the GEN vocoded scores (SRTs with four corpora and consonant and vowel recognition scores) as well as the phoneme-level confusion pattern matched with the CI scores better than controls. The findings suggest that the same signal encoding implementations may lead to similar perceptual patterns simultaneously in multiple perception tasks. This study highlights the importance of faithfully replicating all signal processing stages in the modeling of perceptual patterns in sensory neuroprostheses. This approach has the potential to enhance our understanding of CI perception and accelerate the engineering of prosthetic interventions. The GET/GEN MATLAB program is freely available at https://github.com/BetterCI/GETVocoder.

Improving Auditory Filter Estimation by Incorporating Absolute Threshold and a Level-dependent Internal Noise.

Auditory filter (AF) shape has traditionally been estimated with a combination of a notched-noise (NN) masking experiment and a power spectrum model (PSM) of masking. However, there are several challenges that remain in both the simultaneous and forward masking paradigms. We hypothesized that AF shape estimation would be improved if absolute threshold (AT) and a level-dependent internal noise were explicitly represented in the PSM. To document the interaction between NN threshold and AT in normal hearing (NH) listeners, a large set of NN thresholds was measured at four center frequencies (500, 1000, 2000, and 4000 Hz) with the emphasis on low-level maskers. The proposed PSM, consisting of the compressive gammachirp (cGC) filter and three nonfilter parameters, allowed AF estimation over a wide range of frequencies and levels with fewer coefficients and less error than previous models. The results also provided new insights into the nonfilter parameters. The detector signal-to-noise ratio () was found to be constant across signal frequencies, suggesting that no frequency dependence hypothesis is required in the postfiltering process. The ANSI standard "Hearing Level-0dB" function, i.e., AT of NH listeners, could be applied to the frequency distribution of the noise floor for the best AF estimation. The introduction of a level-dependent internal noise could mitigate the nonlinear effects that occur in the simultaneous NN masking paradigm. The new PSM improves the applicability of the model, particularly when the sound pressure level of the NN threshold is close to AT.

Temporal Cues in the Judgment of Music Emotion for Normal and Cochlear Implant Listeners.

Several studies have established that Cochlear implant (CI) listeners rely on the tempo of music to judge the emotional content of music. However, a re-analysis of a study in which CI listeners judged the emotion conveyed by piano pieces on a scale from happy to sad revealed a weak correlation between tempo and emotion. The present study explored which temporal cues in music influence emotion judgments among normal hearing (NH) listeners, which might provide insights into the cues utilized by CI listeners. Experiment 1 was a replication of the Vannson et al. study with NH listeners using rhythmic patterns of piano created with congas. The temporal cues were preserved while the tonal ones were removed. The results showed (i) tempo was weakly correlated with emotion judgments, (ii) NH listeners' judgments for congas were similar to CI listeners' judgments for piano. In Experiment 2, two tasks were administered with congas played at three different tempi: emotion judgment and a tapping task to record listeners' perceived tempo. Perceived tempo was a better predictor than the tempo, but its physical correlate, mean onset-to-onset difference (MOOD), a measure of the average time between notes, yielded higher correlations with NH listeners' emotion judgments. This result suggests that instead of the tempo, listeners rely on the average time between consecutive notes to judge the emotional content of music. CI listeners could utilize this cue to judge the emotional content of music.

Speech Denoising and Compensation for Hearing Aids Using an FTCRN-Based Metric GAN

Hearing aids aims to improve speech intelligibility for hearing impaired patients to levels comparable to those for normal hearing listeners. However, the interference of environmental noises greatly increase the difficulty of hearing loss compensation. Most related research only focuses on one aspect of noise reduction and hearing loss compensation. In this letter, we propose a metric generative adversarial framework based on a frequency-time convolution recurrent network for joint noise reduction and hearing loss compensation. The audiogram is extended along the frequency axis to form embedded features. A metric discriminator is introduced and the optimization of the generator is guided by an evaluation score related to hearing loss compensation. Additional perceptual-based losses are set to stabilize optimization. Experimental results show that the proposed method can better reduce noise and compensate for hearing loss compared with other algorithms.

BPACE: A Bayesian, Patient-Centered Procedure for Matrix Speech Tests in Noise.

Matrix sentence tests in noise can be challenging to the listener and time-consuming. A trade-off should be found between testing time, listener's comfort and the precision of the results. Here, a novel test procedure based on an updated maximum likelihood method was developed and implemented in a German matrix sentence test. It determines the parameters of the psychometric function (threshold, slope, and lapse-rate) without constantly challenging the listener at the intelligibility threshold. A so-called "credible interval" was used as a mid-run estimate of reliability and can be used as a termination criterion for the test. The procedure was evaluated and compared to a STAIRCASE procedure in a study with 20 cochlear implant patients and 20 normal hearing participants. The proposed procedure offers comparable accuracy and reliability to the reference method, but with a lower listening effort, as rated by the listeners ( points on a 10-point scale). Test duration can be reduced by 1.3 min on average when a credible interval of 2 dB is used as the termination criterion instead of testing 30 sentences. Particularly, normal hearing listeners and well performing, cochlear implant users can benefit from shorter test duration. Although the novel procedure was developed for a German test, it can easily be applied to tests in any other language.

Performance in an Audiovisual Selective Attention Task Using Speech-Like Stimuli Depends on the Talker Identities, But Not Temporal Coherence.

Audiovisual integration of speech can benefit the listener by not only improving comprehension of what a talker is saying but also helping a listener select a particular talker's voice from a mixture of sounds. Binding, an early integration of auditory and visual streams that helps an observer allocate attention to a combined audiovisual object, is likely involved in processing audiovisual speech. Although temporal coherence of stimulus features across sensory modalities has been implicated as an important cue for non-speech stimuli (Maddox et al., 2015), the specific cues that drive binding in speech are not fully understood due to the challenges of studying binding in natural stimuli. Here we used speech-like artificial stimuli that allowed us to isolate three potential contributors to binding: temporal coherence (are the face and the voice changing synchronously?), articulatory correspondence (do visual faces represent the correct phones?), and talker congruence (do the face and voice come from the same person?). In a trio of experiments, we examined the relative contributions of each of these cues. Normal hearing listeners performed a dual task in which they were instructed to respond to events in a target auditory stream while ignoring events in a distractor auditory stream (auditory discrimination) and detecting flashes in a visual stream (visual detection). We found that viewing the face of a talker who matched the attended voice (i.e., talker congruence) offered a performance benefit. We found no effect of temporal coherence on performance in this task, prompting an important recontextualization of previous findings.

Acoustic deprivation modulates central gain in human auditory brainstem and cortex

Beyond reduced audibility, there is convincing evidence that the auditory system adapts according to the principles of homeostatic plasticity in response to a hearing loss. Such compensatory changes include modulation of central auditory gain mechanisms. Earplugging is a common experimental method that has been used to introduce a temporary, reversible hearing loss that induces changes consistent with central gain modulation. In the present study, young, normal-hearing adult participants wore a unilateral earplug for two weeks, during which we measured changes in the acoustic reflex threshold (ART), loudness perception, and cortically-evoked (40 Hz) auditory steady-state response (ASSR) to assess potential modulation in central gain with reduced peripheral input. The ART decreased on average by 8 to 10 dB during the treatment period, with modest increases in loudness perception after one week but not after two weeks of earplug use. Significant changes in both the magnitude and hemispheric laterality of source-localized cortical ASSR measures revealed asymmetrical changes in stimulus-driven cortical activity over time. The ART results following unilateral earplugging are consistent with the literature and suggest that homeostatic plasticity is evident in the brainstem. The novel findings from the cortical ASSR in the present study indicates that reduced peripheral input induces adaptive homeostatic plasticity reflected as both an increase in central gain in the auditory brainstem and reduced cortical activity ipsilateral to the deprived ear. Both the ART and the novel use of the 40-Hz ASSR provide sensitive measures of central gain modulation in the brainstem and cortex of young, normal hearing listeners, and thus may be useful in future studies with other clinical populations.

Interaural speech asymmetry predicts bilateral speech intelligibility but not listening effort in adults with bilateral cochlear implants.

Bilateral cochlear implants (BiCIs) can facilitate improved speech intelligibility in noise and sound localization abilities compared to a unilateral implant in individuals with bilateral severe to profound hearing loss. Still, many individuals with BiCIs do not benefit from binaural hearing to the same extent that normal hearing (NH) listeners do. For example, binaural redundancy, a speech intelligibility benefit derived from having access to duplicate copies of a signal, is highly variable among BiCI users. Additionally, patients with hearing loss commonly report elevated listening effort compared to NH listeners. There is some evidence to suggest that BiCIs may reduce listening effort compared to a unilateral CI, but the limited existing literature has not shown this consistently. Critically, no studies to date have investigated this question using pupillometry to quantify listening effort, where large pupil sizes indicate high effort and small pupil sizes indicate low effort. Thus, the present study aimed to build on existing literature by investigating the potential benefits of BiCIs for both speech intelligibility and listening effort. Twelve BiCI adults were tested in three listening conditions: Better Ear, Poorer Ear, and Bilateral. Stimuli were IEEE sentences presented from a loudspeaker at 0° azimuth in quiet. Participants were asked to repeat back the sentences, and responses were scored by an experimenter while changes in pupil dilation were measured. On average, participants demonstrated similar speech intelligibility in the Better Ear and Bilateral conditions, and significantly worse speech intelligibility in the Poorer Ear condition. Despite similar speech intelligibility in the Better Ear and Bilateral conditions, pupil dilation was significantly larger in the Bilateral condition. These results suggest that the BiCI users tested in this study did not demonstrate binaural redundancy in quiet. The large interaural speech asymmetries demonstrated by participants may have precluded them from obtaining binaural redundancy, as shown by the inverse relationship between the two variables. Further, participants did not obtain a release from effort when listening with two ears versus their better ear only. Instead, results indicate that bilateral listening elicited increased effort compared to better ear listening, which may be due to poor integration of asymmetric inputs.

Factors underlying masking release by voice-gender differences and spatial separation cues in multi-talker listening environments in listeners with and without hearing loss.

Voice-gender differences and spatial separation are important cues for auditory object segregation. The goal of this study was to investigate the relationship of voice-gender difference benefit to the breadth of binaural pitch fusion, the perceptual integration of dichotic stimuli that evoke different pitches across ears, and the relationship of spatial separation benefit to localization acuity, the ability to identify the direction of a sound source. Twelve bilateral hearing aid (HA) users (age from 30 to 75 years) and eleven normal hearing (NH) listeners (age from 36 to 67 years) were tested in the following three experiments. First, speech-on-speech masking performance was measured as the threshold target-to-masker ratio (TMR) needed to understand a target talker in the presence of either same- or different-gender masker talkers. These target-masker gender combinations were tested with two spatial configurations (maskers co-located or 60° symmetrically spatially separated from the target) in both monaural and binaural listening conditions. Second, binaural pitch fusion range measurements were conducted using harmonic tone complexes around a 200-Hz fundamental frequency. Third, absolute localization acuity was measured using broadband (125-8000 Hz) noise and one-third octave noise bands centered at 500 and 3000 Hz. Voice-gender differences between target and maskers improved TMR thresholds for both listener groups in the binaural condition as well as both monaural (left ear and right ear) conditions, with greater benefit in co-located than spatially separated conditions. Voice-gender difference benefit was correlated with the breadth of binaural pitch fusion in the binaural condition, but not the monaural conditions, ruling out a role of monaural abilities in the relationship between binaural fusion and voice-gender difference benefits. Spatial separation benefit was not significantly correlated with absolute localization acuity. In addition, greater spatial separation benefit was observed in NH listeners than in bilateral HA users, indicating a decreased ability of HA users to benefit from spatial release from masking (SRM). These findings suggest that sharp binaural pitch fusion may be important for maximal speech perception in multi-talker environments for both NH listeners and bilateral HA users.

Spatial cues on normal hearing and cochlear implant simulation with different coding strategies

Cochlear implant users are known to have limited access to spatial cues. This study investigated the perception of spatial cues in normal-hearing listeners and cochlear implant simulation users. Perception of spatial cues is assessed for performance in determining the direction of the sound and understanding the speech. The results show that cochlear implant simulation users still have access to spatial cues, just like normal- hearing listeners. Normal-hearing listeners and cochlear implant simulation users can perceive spatial cues in ILD and ITD. Both can accurately identify the direction of the sound (slope ≈ 1.00 and of set ≈ 0.00°). Cochlear implant simulation users can understand sentences as well as normal-hearing listeners (PCW = 113.64 rau) by using the coding strategy SPEAK in all channels or CIS with channel above 8. Perception of spatial cues in normal-hearing listeners and cochlear implant users can be improved by listening with two ears and spatially separating the target-masker position. The largest improvement in spatial cue perception was obtained from the head shadow effect (normal-hearing (NH) = 12.96, cochlear implant simulation users (CI) = 59.02), followed by binaural summation (NH = 5.72, CI = 19, 86) and binaural squelch (NH = 3.76, CI = 7.66).

Engaging effort improves efficiency during word recognition in cochlear implant users

Cochlear Implant (CI) users must cope with the degraded spectral input received through their device. This reduced quality leads to changes in how words are recognized: lexical access is delayed, leading to differences in competition between lexical candidates. CI users also report increased effort and fatigue during language processing, but effort is not clearly related to improved accuracy. We investigated the role that listening effort plays in the dynamics of word recognition. We related lexical competition and listening effort in 77 post-lingually deaf CI users with Visual World Paradigm and pupillometry tasks. Subjects also completed measures of peripheral auditory function (spectral ripple discrimination and temporal modulation detection). We used the difference in pupil size during the recognition of spoken and written words to isolate effort for spoken word recognition. Difference in pupil size predicted efficiency in the spoken word recognition task, over and above age and peripheral fidelity. That is, CI users who engage more effort were faster to recognize words and showed lexical competition similar to normal hearing listeners. This interacted with spectral resolution: better discrimination offsets the need to engage effort. This suggests that listening effort can be engaged to improve efficiency during word recognition.

The possible range of interaural cross correlation after cochlear implant processing

Normal hearing listeners rely on their binaural auditory system to combine signals from both ears into single auditory objects, which aids source segregation and sound localization. The ability to combine signals from the two ears is influenced by interaural symmetry - the similarity of the place of stimulation along the left and right cochlea—and the interaural cross-correlation (ICC) of the signal, calculated as the peak correlation between the signal for the two ears across unilateral temporal offsets. The ability of bilateral cochlear implant (CI) users to combine signals from the two ears can be worse than that of NH listeners. This is partly attributed to decreases in interaural symmetry related to factors such as differences in electrode array insertion depth. A secondary effect of interaural asymmetry is that it can result in reduced ICC at interaurally symmetric locations, mediated by aspects of CI processing. This study aims to investigate how CI processing and interaural asymmetry affect the ICC available to CI users for interaurally symmetric locations, using electrodograms recorded from a CI processor placed on a Knowles Electronics Manikin for Acoustic Research (KEMAR). Inferences on how ICC is altered with interaural asymmetry for CI users will be discussed.

Speech understanding in diffuse steady noise in typically hearing and hard of hearing listeners.

Spatial cues can facilitate segregation of target speech from maskers. However, in clinical practice, masked speech understanding is most often evaluated using co-located speech and maskers (i.e., without spatial cues). Many hearing aid centers in France are equipped with five-loudspeaker arrays, allowing masked speech understanding to be measured with spatial cues. It is unclear how hearing status may affect utilization of spatial cues to segregate speech and noise. In this study, speech reception thresholds (SRTs) for target speech in “diffuse noise” (target speech from 1 speaker, noise from the remaining 4 speakers) in 297 adult listeners across 9 Audilab hearing centers. Participants were categorized according to pure-tone-average (PTA) thresholds: typically-hearing (TH; ≤ 20 dB HL), mild hearing loss (Mild; >20 ≤ 40 dB HL), moderate hearing loss 1 (Mod-1; >40 ≤ 55 dB HL), and moderate hearing loss 2 (Mod-2; >55 ≤ 65 dB HL). All participants were tested without aided hearing. SRTs in diffuse noise were significantly correlated with PTA thresholds, age at testing, as well as word and phoneme recognition scores in quiet. Stepwise linear regression analysis showed that SRTs in diffuse noise were significantly predicted by a combination of PTA threshold and word recognition scores in quiet. SRTs were also measured in co-located and diffuse noise in 65 additional participants. SRTs were significantly lower in diffuse noise than in co-located noise only for the TH and Mild groups; masking release with diffuse noise (relative to co-located noise) was significant only for the TH group. The results are consistent with previous studies that found that hard of hearing listeners have greater difficulty using spatial cues to segregate competing speech. The data suggest that speech understanding in diffuse noise provides additional insight into difficulties that hard of hearing individuals experience in complex listening environments.