Identification Accuracy of Safety-Relevant Environmental Sounds in Adult Cochlear Implant Users.

OBJECTIVE: Examine cochlear implant (CI) users' ability to identify safety-relevant environmental sounds, imperative for safety, independence, and personal well-being. METHODS: Twenty-one experienced adult CI users completed an Environmental Sound Identification (ESI) test consisting of 42 common environmental sounds, 28 of which were relevant to personal safety, along with 14 control sounds. Prior to sound identification, participants were shown sound names and asked to rate the familiarity and, separately, relevance to safety of each corresponding sound on a 1-5 scale. RESULTS: Overall ESI accuracy was 57% correct for the safety-relevant sounds and 55% correct for control sounds. Participants rated safety-relevant sounds as more important to safety and more familiar than the non-safety sounds. ESI accuracy significantly correlated with familiarity ratings. CONCLUSION: The present findings suggest mediocre ESI accuracy in postlingual adult CI users for safety-relevant and other environmental sounds. Deficits in the identification of these sounds may put CI listeners at increased risk of accidents or injuries and may require a specific rehabilitation program to improve CI outcomes. LEVEL OF EVIDENCE: 4 Laryngoscope, 133:2388-2393, 2023.

Recognition of Interrupted Speech, Text, and Text-Supplemented Speech by Older Adults: Effect of Interruption Rate.

PURPOSE: Studies of speech and text interruption indicate that the interruption rate influences the perceptual information available, from whole words at slow rates to subphonemic cues at faster interruptions rates. In young adults, the benefit obtained from text supplementation of speech may depend on the type of perceptual information available in either modality. Age commonly reduces temporal aspects of information processing, which may influence the benefit older adults obtain from text-supplemented speech across interruption rates. METHOD: Older adults were tested unimodally and multimodally with spoken and printed sentences that were interrupted by silence or white space at various rates. RESULTS: Results demonstrate U-shaped performance-rate functions for all modality conditions, with minimal performance around interruption rates of 2-4 Hz. Comparison to previous studies with younger adults indicates overall poorer recognition for interrupted materials by the older adults. However, as a group, older adults can integrate information between the two modalities to a similar degree as younger adults. Individual differences in multimodal integration were noted. CONCLUSION: Overall, these results indicate that older adults, while demonstrating poorer overall performance in comparison to younger adults, successfully combine distributed partial information across speech and text modalities to facilitate sentence recognition.

Perception of interrupted speech and text: Listener and modality factors.

Interrupted speech and text are used to measure processes of linguistic closure that are important for recognition under adverse backgrounds. The present study compared recognition of speech and text that had been periodically interrupted with matched amounts of silence or white space, respectively. Recognition thresholds were obtained for younger and older adults with normal or simulated/impaired hearing and correlated with recognition of speech-in-babble. Results demonstrate domain-general, age-related processes in linguistic closure affecting high context sentences and domain-specific, hearing-related processes in speech recognition affecting low context sentences. Text recognition captures domain-general linguistic processes in speech recognition susceptible to age-related effects.

Online Assessment of Speech Perception and Auditory Spectrotemporal Processing in Spanish-English Bilinguals.

PURPOSE: There is limited access to audiology services for the growing population of Spanish-English bilinguals in the United States. Online auditory testing can potentially provide a cost-effective alternative to in-person visits. However, even for bilinguals with high English proficiency, age of English acquisition may affect speech perception accuracy. This study used a comprehensive test battery to assess speech perception and spectrotemporal processing abilities in Spanish-English bilinguals and to evaluate susceptibility of different tests to effects of native language. METHOD: The online battery comprised three tests of speech in quiet (vowel and consonant identification and words in sentences), four tests of speech perception in noise (two for intelligibility and two for comprehension), and three tests of spectrotemporal processing (two tests of stochastically modulated pattern discrimination and one test of spectral resolution). Participants were 28 adult Spanish-English bilinguals whose English acquisition began either early (≤ 6 years old) or late (≥ 7 years old) and 18 English monolingual speakers. RESULTS: Significant differences were found in six of the 10 tests. The differences were most pronounced for vowel perception in quiet, speech-in-noise test, and two tests of speech comprehension in noise. Late bilinguals consistently scored lower than native English speakers or early bilinguals. In contrast, no differences between groups were observed for digits-in-noise or three tests of spectrotemporal processing abilities. CONCLUSION: The findings suggest initial feasibility of online assessment in this population and can inform selection of tests for auditory assessment of Spanish-English bilinguals.

A Longitudinal Comparison of Environmental Sound Recognition in Adults With Hearing Aids Before and After Cochlear Implantation.

Purpose The aims of this study were (a) to longitudinally assess environmental sound recognition (ESR) before and after cochlear implantation in a sample of postlingually deafened adults and (b) to assess the extent to which spectro-temporal processing abilities influence ESR with cochlear implants (CIs). Method In a longitudinal cohort study, 20 postlingually deafened adults were tested with hearing aids on the Familiar Environmental Sound Test-Identification and AzBio sentences in quiet pre-CI and 6 months post-CI. A subset of 11 participants were also tested 12 months post-CI. Pre-CI spectro-temporal processing was assessed using the Spectral-temporally Modulated Ripple Test. Results Average ESR accuracy pre-CI (M = 63.60%) was not significantly different from ESR accuracy at 6 months (M = 65.40%) or 12 months (M = 69.09%) post-CI. In 11 participants (55%), however, ESR improved following implantation by 10.91 percentage points, on average. Pre-CI ESR correlated moderately and significantly with pre-CI and 12-month post-CI AzBio scores, with a trend toward significance for AzBio performance at 6 months. Pre-CI spectro-temporal processing was moderately associated with ESR at 6 and 12 months post-CI but not with speech recognition post-CI. Conclusions The present findings failed to demonstrate an overall significant improvement in ESR following implantation. Nevertheless, more than half of our sample showed some degree of improvement in ESR. Several environmental sounds were poorly identified both before and after implantation. Spectro-temporal processing ability prior to implantation appears to predict postimplantation performance for ESR. These findings indicate the need for greater attention to ESR following cochlear implantation and for developing individualized targets for ESR rehabilitation. Supplemental Material https://doi.org/10.23641/asha.13876745.

Perception of Environmental Sounds in Cochlear Implant Users: A Systematic Review.

Objectives: Improved perception of environmental sounds (PES) is one of the primary benefits of cochlear implantation (CI). However, past research contains mixed findings on PES ability in contemporary CI users, which at times contrast with anecdotal clinical reports. The present review examined extant PES research to provide an evidence basis for clinical counseling, identify knowledge gaps, and suggest directions for future work in this area of CI outcome assessment. Methods: Six electronic databases were searched using medical subject headings (MeSH) and keywords broadly identified to reference CI and environmental sounds. Records published between 2000 and 2021 were screened by two independent reviewers in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement to identify studies that met the inclusion criteria. Data were subsequently extracted and evaluated according to synthesis without-meta-analysis (SWiM) guidelines. Results: Nineteen studies met the inclusion criteria. Most examined PES in post-lingually implanted adults, with one study focused on pre/perilingual adults. Environmental sound identification (ESI) in quiet using open- or closed-set response format was most commonly used in PES assessment, included in all selected studies. ESI accuracy in CI children (3 studies) and adults (16 studies), was highly variable but generally mediocre (means range: 31-87%). Only two studies evaluated ESI performance prospectively before and after CI, while most studies were cross-sectional. Overall, CI performance was consistently lower than that of normal-hearing peers. No significant differences in identification accuracy were reported between CI candidates and CI users. Environmental sound identification correlated in CI users with measures of speech perception, music and spectro-temporal processing. Conclusion: The findings of this systematic review indicate considerable limitations in the current knowledge of PES in contemporary CI users, especially in pre/perilingual late-implanted adults and children. Although no overall improvement in PES following implantation was found, large individual variability and existing methodological limitations in PES assessment may potentially obscure potential CI benefits for PES. Further research in this ecologically relevant area of assessment is needed to establish a stronger evidence basis, identify CI users with significant deficits, and improve CI users' safety and satisfaction through targeted PES rehabilitation.

Development of the Basic Auditory Skills Evaluation Battery for Online Testing of Cochlear Implant Listeners.

Purpose Cochlear implant (CI) performance varies considerably across individuals and across domains of auditory function, but clinical testing is typically restricted to speech intelligibility. The goals of this study were (a) to develop a basic auditory skills evaluation battery of tests for comprehensive assessment of ecologically relevant aspects of auditory perception and (b) to compare CI listeners' performance on the battery when tested in the laboratory by an audiologist or independently at home. Method The battery included 17 tests to evaluate (a) basic spectrotemporal processing, (b) processing of music and environmental sounds, and (c) speech perception in both quiet and background noise. The battery was administered online to three groups of adult listeners: two groups of postlingual CI listeners and a group of older normal-hearing (ONH) listeners of similar age. The ONH group and one CI group were tested in a laboratory by an audiologist, whereas the other CI group self-tested independently at home following online instructions. Results Results indicated a wide range in the performance of CI but not ONH listeners. Significant differences were not found between the two CI groups on any test, whereas on all but two tests, CI listeners' performance was lower than that of the ONH participants. Principal component analysis revealed that four components accounted for 82% of the variance in measured results, with component loading indicating that the test battery successfully captures differences across dimensions of auditory perception. Conclusions These results provide initial support for the use of the basic auditory skills evaluation battery for comprehensive online assessment of auditory skills in adult CI listeners.

Safety-relevant environmental sound identification in cochlear implant candidates and users.

OBJECTIVES/HYPOTHESIS: To compare the identification of safety-relevant environmental sounds between experienced cochlear implant (CI) users and CI candidates. STUDY DESIGN: Cross-sectional. METHODS: A sample of 19 adult, postlingually deaf CI candidates (CI-Cs), 47 experienced CI users (CI-Es), and a control group of 37 age-matched normal-hearing adults were assessed using the Familiar Environmental Sounds Test-Identification (FEST-I). A subset of 11 sounds relevant for safety were selected for analysis in the current study. RESULTS: Analysis of safety-relevant sound identification accuracy revealed no significant difference in safety-relevant environmental sound identification skills between CI-E and CI-C participants, with average scores of 68.1% and 67.9%, respectively. Both performed substantially lower than age-matched normal hearing adults (95.1%). A significant moderate negative correlation (-0.4) was found between safety-relevant sound accuracy and chronological age only in one group, the CI-E group (r = -0.4, P < .005). CONCLUSIONS: These findings fail to demonstrate superior performance in safety-relevant environmental sound identification among CI-Es compared with CI-Cs. Although preliminary, these findings suggest that identification of safety-relevant sounds is a significant area of weakness for both CI-Es and CI-Cs, both of whom may benefit from rehabilitation. LEVEL OF EVIDENCE: 4 Laryngoscope, 130:1547-1551, 2020.

Perceptual Organization of Interrupted Speech and Text.

Purpose: Visual recognition of interrupted text may predict speech intelligibility under adverse listening conditions. This study investigated the nature of the linguistic information and perceptual processes underlying this relationship. Method: To directly compare the perceptual organization of interrupted speech and text, we examined the recognition of spoken and printed sentences interrupted at different rates in 14 adults with normal hearing. The interruption method approximated deletion and retention of rate-specific linguistic information (0.5-64 Hz) in speech by substituting either white space or silent intervals for text or speech in the original sentences. Results: A similar U-shaped pattern of cross-rate variation in performance was observed in both modalities, with minima at 2 Hz. However, at the highest and lowest interruption rates, recognition accuracy was greater for text than speech, whereas the reverse was observed at middle rates. An analysis of word duration and the frequency of word sampling across interruption rates suggested that the location of the function minima was influenced by perceptual reconstruction of whole words. Overall, the findings indicate a high degree of similarity in the perceptual organization of interrupted speech and text. Conclusion: The observed rate-specific variation in the perception of speech and text may potentially affect the degree to which recognition accuracy in one modality is predictive of the other.

How does aging affect recognition of spectrally degraded speech?

OBJECTIVES/HYPOTHESIS: Cochlear implants (CIs) restore auditory sensation to patients with moderate-to-profound sensorineural hearing loss. However, the benefits to speech recognition vary considerably among patients. Advancing age contributes to this variability in postlingual adult CI users. Similarly, older individuals with normal hearing (NH) perform more poorly on tasks of recognition of spectrally degraded speech. The overarching hypothesis of this study was that the detrimental effects of advancing age on speech recognition can be attributed both to declines in auditory spectral resolution as well as declines in cognitive functions. STUDY DESIGN: Case-control study. METHODS: Speech recognition was assessed in CI users (in the clear) and NH controls (spectrally degraded using noise-vocoding), along with auditory spectral resolution using the Spectral-Temporally Modulated Ripple Test. Cognitive skills were assessed using nonauditory visual measures of working memory, inhibitory control, speed of lexical/phonological access, nonverbal reasoning, and perceptual closure. Linear regression models were tested for mediation to explain aging effects on speech recognition performance. RESULTS: For both groups, older age predicted poorer sentence and word recognition. The detrimental effects of advancing age on speech recognition were partially mediated by declines in spectral resolution and in some measures of cognitive function. CONCLUSIONS: Advancing age contributes to poorer recognition of degraded speech for CI users and NH controls through declines in both auditory spectral resolution and cognitive functions. Findings suggest that improvements in spectral resolution as well as cognitive improvements may serve as therapeutic targets to optimize CI speech recognition outcomes. LEVEL OF EVIDENCE: 3b Laryngoscope, 2018.

Environmental Sound Awareness in Experienced Cochlear Implant Users and Cochlear Implant Candidates.

OBJECTIVE: To determine if postlingually deaf adult cochlear implant (CI) users have better environmental sound awareness (ESA) compared with adult patients eligible for CIs who have not yet undergone implantation. STUDY DESIGN: Cross-sectional cohort study. SETTING: Tertiary referral center. PATIENTS: A group of 39 postlingually deaf adult patients who are experienced CI users (ECI), and a group of 20 postlingually deaf adult patients who are cochlear implant candidates (CIC) awaiting implantation. INTERVENTION: Cochlear implantation. MAIN OUTCOME MEASURE: Environmental sound awareness as measured by accuracy (percent correct) using the computerized, Familiar Environmental Sounds Test-Identification (FEST-I). RESULTS: There was no significant difference between ESA in our sample of ECI users versus CIC patients. The ECI users scored an average FEST-I accuracy of 59.9% (SD 14.3). In comparison, the CICs had an average FEST-I accuracy of 54.7% (SD 26.4). This difference was not statistically significant. CONCLUSIONS: Our findings suggest that, despite the commonly held notion that improved ESA may be a benefit of cochlear implantation, our sample of ECI users did not demonstrate superior performance compared with CICs.

Relating quality of life to outcomes and predictors in adult cochlear implant users: Are we measuring the right things?

OBJECTIVE: Current clinical outcome measures for adults receiving cochlear implants (CIs) consist of word and sentence recognition, primarily under quiet conditions. However, these measures may not adequately reflect patients' CI-specific quality of life (QOL). This study first examined traditional auditory-only speech recognition measures and other potentially relevant auditory measures as correlates of QOL in CI users. Second, scores on nonauditory tasks of language and cognition were examined as potential predictors of QOL. STUDY DESIGN: Twenty-five postlingually deafened adults with CIs were assessed. METHODS: Participants completed a validated CI-specific QOL measure (the Nijmegen Cochlear Implant Questionnaire) and were tested for word and sentence recognition in quiet, as well as sentence recognition in speech-shaped noise. Participants also completed assessments of audiovisual speech recognition, environmental sound identification, and a task of complex auditory verbal processing. Several nonauditory language and cognitive tasks were examined as potential predictors of QOL. RESULTS: Quality-of-life scores significantly correlated with scores for audiovisual speech recognition and recognition of complex sentences in quiet but not sentences in noise or isolated words. No significant correlations were obtained between QOL and environmental sound identification or complex auditory verbal processing. Quality-of-life subdomain scores were predicted by several nonauditory language and cognitive tasks as well as some patient characteristics. CONCLUSION: Postoperative measures of recognition of sentences in quiet and audiovisual sentence recognition correlate with CI-related QOL. Findings suggest that sentence recognition tasks are QOL-relevant outcomes but only explain a small fraction of the variability in QOL outcomes for this patient population. LEVEL OF EVIDENCE: 4. Laryngoscope, 128:959-966, 2018.

Linguistic masking release in young and older adults with age-appropriate hearing status.

Past studies of speech-on-speech masking in young adults (YA) indicate that the intelligibility of masked speech can improve if the target and masker speech are in different languages. Current work investigated whether a linguistic masking release is obtained in older adults (OA) with age-typical hearing abilities. Participants listened to English sentences in the presence of two-talker Spanish or English maskers. A similar masking release with Spanish-language maskers was obtained for OA and YA listeners, despite greater accuracy by YA listeners. In speech-on-speech masking, older listeners can thus improve speech intelligibility by utilizing nonenergetic linguistic differences between the target and masker speech.

The Relationship Between Environmental Sound Awareness and Speech Recognition Skills in Experienced Cochlear Implant Users.

HYPOTHESIS: 1) Environmental sound awareness (ESA) and speech recognition skills in experienced, adult cochlear implant (CI) users will be highly correlated, and, 2) ESA skills of CI users will be significantly lower than those of age-matched adults with normal hearing. BACKGROUND: Enhancement of ESA is often discussed with patients with sensorineural hearing loss as a potential benefit of implantation and, in some cases, ESA may be a major motivating factor. Despite its ecological validity and patients' expectations, ESA remains largely a presumed skill. The relationship between ESA and speech recognition is not well-understood. METHODS: ESA was assessed in 35 postlingually deaf, experienced CI users and a control group of 41 age-matched, normal hearing listeners using the validated, computerized familiar environmental sounds test-identification (FEST-I) and a diverse speech recognition battery. Demographic and audiological factors as well as nonverbal intelligence quotient (IQ)/nonverbal reasoning and spectral resolution were assessed. RESULTS: Six of the 35 experienced CI users (17%) demonstrated FEST-I accuracy within the range of the NH controls. Among CI users all correlations between FEST-I accuracy and speech recognition scores were strong. Chronological age at the time of testing, duration of deafness, spectral resolution, and nonverbal IQ/nonverbal reasoning were strongly correlated with FEST-I accuracy. Partial correlation analysis showed that correlations between FEST-I and speech recognition measures remained significant when controlling for the demographic and audiological factors. CONCLUSION: Our findings reinforce the hypothesis that ESA and speech perception share common underlying processes rather than reflecting truly separate auditory domains.

Toward a Nonspeech Test of Auditory Cognition: Semantic Context Effects in Environmental Sound Identification in Adults of Varying Age and Hearing Abilities.

OBJECTIVE: Sounds in everyday environments tend to follow one another as events unfold over time. The tacit knowledge of contextual relationships among environmental sounds can influence their perception. We examined the effect of semantic context on the identification of sequences of environmental sounds by adults of varying age and hearing abilities, with an aim to develop a nonspeech test of auditory cognition. METHOD: The familiar environmental sound test (FEST) consisted of 25 individual sounds arranged into ten five-sound sequences: five contextually coherent and five incoherent. After hearing each sequence, listeners identified each sound and arranged them in the presentation order. FEST was administered to young normal-hearing, middle-to-older normal-hearing, and middle-to-older hearing-impaired adults (Experiment 1), and to postlingual cochlear-implant users and young normal-hearing adults tested through vocoder-simulated implants (Experiment 2). RESULTS: FEST scores revealed a strong positive effect of semantic context in all listener groups, with young normal-hearing listeners outperforming other groups. FEST scores also correlated with other measures of cognitive ability, and for CI users, with the intelligibility of speech-in-noise. CONCLUSIONS: Being sensitive to semantic context effects, FEST can serve as a nonspeech test of auditory cognition for diverse listener populations to assess and potentially improve everyday listening skills.

The intelligibility of interrupted and temporally altered speech: Effects of context, age, and hearing loss.

Temporal constraints on the perception of interrupted speech were investigated by comparing the intelligibility of speech that was periodically gated (PG) and subsequently either temporally compressed (PGTC) by concatenating remaining speech fragments or temporally expanded (PGTE) by doubling the silent intervals between speech fragments. Experiment 1 examined the effects of PGTC and PGTE at different gating rates (0.5 -16 Hz) on the intelligibility of words and sentences for young normal-hearing adults. In experiment 2, older normal-hearing (ONH) and older hearing-impaired (OHI) adults were tested with sentences only. The results of experiment 1 indicated that sentences were more intelligible than words. In both experiments, PGTC sentences were less intelligible than either PG or PGTE sentences. Compared with PG sentences, the intelligibility of PGTE sentences was significantly reduced by the same amount for ONH and OHI groups. Temporal alterations tended to produce a U-shaped rate-intelligibility function with a dip at 2-4 Hz, indicating that temporal alterations interacted with the duration of speech fragments. The present findings demonstrate that both aging and hearing loss negatively affect the overall intelligibility of interrupted and temporally altered speech. However, a mild-to-moderate hearing loss did not exacerbate the negative effects of temporal alterations associated with aging.

Relationship between Auditory and Cognitive Abilities in Older Adults.

OBJECTIVE: The objective was to evaluate the association of peripheral and central hearing abilities with cognitive function in older adults. METHODS: Recruited from epidemiological studies of aging and cognition at the Rush Alzheimer's Disease Center, participants were a community-dwelling cohort of older adults (range 63-98 years) without diagnosis of dementia. The cohort contained roughly equal numbers of Black (n=61) and White (n=63) subjects with groups similar in terms of age, gender, and years of education. Auditory abilities were measured with pure-tone audiometry, speech-in-noise perception, and discrimination thresholds for both static and dynamic spectral patterns. Cognitive performance was evaluated with a 12-test battery assessing episodic, semantic, and working memory, perceptual speed, and visuospatial abilities. RESULTS: Among the auditory measures, only the static and dynamic spectral-pattern discrimination thresholds were associated with cognitive performance in a regression model that included the demographic covariates race, age, gender, and years of education. Subsequent analysis indicated substantial shared variance among the covariates race and both measures of spectral-pattern discrimination in accounting for cognitive performance. Among cognitive measures, working memory and visuospatial abilities showed the strongest interrelationship to spectral-pattern discrimination performance. CONCLUSIONS: For a cohort of older adults without diagnosis of dementia, neither hearing thresholds nor speech-in-noise ability showed significant association with a summary measure of global cognition. In contrast, the two auditory metrics of spectral-pattern discrimination ability significantly contributed to a regression model prediction of cognitive performance, demonstrating association of central auditory ability to cognitive status using auditory metrics that avoided the confounding effect of speech materials.

Predicting the timing of dynamic events through sound: Bouncing balls.

Dynamic information in acoustical signals produced by bouncing objects is often used by listeners to predict the objects' future behavior (e.g., hitting a ball). This study examined factors that affect the accuracy of motor responses to sounds of real-world dynamic events. In experiment 1, listeners heard 2-5 bounces from a tennis ball, ping-pong, basketball, or wiffle ball, and would tap to indicate the time of the next bounce in a series. Across ball types and number of bounces, listeners were extremely accurate in predicting the correct bounce time (CT) with a mean prediction error of only 2.58% of the CT. Prediction based on a physical model of bouncing events indicated that listeners relied primarily on temporal cues when estimating the timing of the next bounce, and to a lesser extent on the loudness and spectral cues. In experiment 2, the timing of each bounce pattern was altered to correspond to the bounce timing pattern of another ball, producing stimuli with contradictory acoustic cues. Nevertheless, listeners remained highly accurate in their estimates of bounce timing. This suggests that listeners can adopt their estimates of bouncing-object timing based on acoustic cues that provide most veridical information about dynamic aspects of object behavior.

Discrimination of Stochastic Frequency Modulation by Cochlear Implant Users.

BACKGROUND: Past work has shown that low-rate frequency modulation (FM) may help preserve signal coherence, aid segmentation at word and syllable boundaries, and benefit speech intelligibility in the presence of a masker. PURPOSE: This study evaluated whether difficulties in speech perception by cochlear implant (CI) users relate to a deficit in the ability to discriminate among stochastic low-rate patterns of FM. RESEARCH DESIGN: This is a correlational study assessing the association between the ability to discriminate stochastic patterns of low-rate FM and the intelligibility of speech in noise. STUDY SAMPLE: Thirteen postlingually deafened adult CI users participated in this study. DATA COLLECTION AND ANALYSIS: Using modulators derived from 5-Hz lowpass noise applied to a 1-kHz carrier, thresholds were measured in terms of frequency excursion both in quiet and with a speech-babble masker present, stimulus duration, and signal-to-noise ratio in the presence of a speech-babble masker. Speech perception ability was assessed in the presence of the same speech-babble masker. Relationships were evaluated with Pearson product-moment correlation analysis with correction for family-wise error, and commonality analysis to determine the unique and common contributions across psychoacoustic variables to the association with speech ability. RESULTS: Significant correlations were obtained between masked speech intelligibility and three metrics of FM discrimination involving either signal-to-noise ratio or stimulus duration, with shared variance among the three measures accounting for much of the effect. Compared to past results from young normal-hearing adults and older adults with either normal hearing or a mild-to-moderate hearing loss, mean FM discrimination thresholds obtained from CI users were higher in all conditions. CONCLUSIONS: The ability to process the pattern of frequency excursions of stochastic FM may, in part, have a common basis with speech perception in noise. Discrimination of differences in the temporally distributed place coding of the stimulus could serve as this common basis for CI users.