Gap Detection Thresholds Research Articles

Tests of human auditory temporal resolution: Simulations of Bayesian threshold estimation for auditory gap detection.

In an attempt to develop tests of auditory temporal resolution using gap detection, we conducted computer simulations of Zippy Estimation by Sequential Testing (ZEST), an adaptive Bayesian threshold estimation procedure, for measuring gap detection thresholds. The results showed that the measures of efficiency and precision of ZEST changed with the mean and standard deviation (SD) of the initial probability density function implemented in ZEST. Appropriate combinations of mean and SD values led to efficient ZEST performance; i.e., the threshold estimates converged to their true values after 10 to 15 trials.

Relationship between-channel gap detection thresholds and speech perception in older adults

Relationship between-channel gap detection thresholds and speech perception in older adults

Central Auditory Processing Abilities in Children with Non-Syndromic Cleft Lip/and Palate-a Behavioural Study.

The present study aimed to assess the central auditory processing abilities and working memory in children with non-syndromic cleft lip and palate (NSCLP) and to compare with the developed normative and craniofacially normal peers. Sixteen NSCLP children aged 7 to 12 years and fifteen craniofacially normal peers were recruited in this study. Speech perception in noise Kannada (SPIN-K), gap detection threshold (GDT), dichotic consonant-vowel (DCV), and masking level difference (MLD) tests were administered to assess various central auditory processing abilities. Working memory abilities were assessed by using forward-digit span and backward-digit span tests. The results showed significant differences in SPIN-K, dichotic CV, GDT, forward digit, and backward digit span scores between children with NSCLP and craniofacially normal peers. Thus, it can be concluded from the present study that children with NSCLP have a risk of developing auditory processing deficits. To conclude, assessment of central auditory processing abilities in children with NSCLP is recommended.

Peripheral Neural Synchrony in Postlingually Deafened Adult Cochlear Implant Users.

This paper reports a noninvasive method for quantifying neural synchrony in the cochlear nerve (i.e., peripheral neural synchrony) in cochlear implant (CI) users, which allows for evaluating this physiological phenomenon in human CI users for the first time in the literature. In addition, this study assessed how peripheral neural synchrony was correlated with temporal resolution acuity and speech perception outcomes measured in quiet and in noise in postlingually deafened adult CI users. It tested the hypothesis that peripheral neural synchrony was an important factor for temporal resolution acuity and speech perception outcomes in noise in postlingually deafened adult CI users. Study participants included 24 postlingually deafened adult CI users with a Cochlear™ Nucleus® device. Three study participants were implanted bilaterally, and each ear was tested separately. For each of the 27 implanted ears tested in this study, 400 sweeps of the electrically evoked compound action potential (eCAP) were measured at four electrode locations across the electrode array. Peripheral neural synchrony was quantified at each electrode location using the phase-locking value (PLV), which is a measure of trial-by-trial phase coherence among eCAP sweeps/trials. Temporal resolution acuity was evaluated by measuring the within-channel gap detection threshold (GDT) using a three-alternative, forced-choice procedure in a subgroup of 20 participants (23 implanted ears). For each ear tested in these participants, GDTs were measured at two electrode locations with a large difference in PLVs. For 26 implanted ears tested in 23 participants, speech perception performance was evaluated using consonant-nucleus-consonant (CNC) word lists presented in quiet and in noise at signal to noise ratios (SNRs) of +10 and +5 dB. Linear Mixed effect Models were used to evaluate the effect of electrode location on the PLV and the effect of the PLV on GDT after controlling for the stimulation level effects. Pearson product-moment correlation tests were used to assess the correlations between PLVs, CNC word scores measured in different conditions, and the degree of noise effect on CNC word scores. There was a significant effect of electrode location on the PLV after controlling for the effect of stimulation level. There was a significant effect of the PLV on GDT after controlling for the effects of stimulation level, where higher PLVs (greater synchrony) led to lower GDTs (better temporal resolution acuity). PLVs were not significantly correlated with CNC word scores measured in any listening condition or the effect of competing background noise presented at an SNR of +10 dB on CNC word scores. In contrast, there was a significant negative correlation between the PLV and the degree of noise effect on CNC word scores for a competing background noise presented at an SNR of +5 dB, where higher PLVs (greater synchrony) correlated with smaller noise effects on CNC word scores. This newly developed method can be used to assess peripheral neural synchrony in CI users, a physiological phenomenon that has not been systematically evaluated in electrical hearing. Poorer peripheral neural synchrony leads to lower temporal resolution acuity and is correlated with a larger detrimental effect of competing background noise presented at an SNR of 5 dB on speech perception performance in postlingually deafened adult CI users.

The Directional Effects of Marker Frequencies on Across-Channel Temporal Gap Detection Tasks: An Experimental Study

Plain Language SummaryGap detection tests are essential while performing hearing assessments that are aimed to tap central auditory processing abilities. Different varieties of gap detection tests are evaluated for their sensitivity, and across-channel gap detection is noted to have high potential to detect central auditory processing disorders. However, any variations in the stimulus frequencies would impact the results of gap detection thresholds. Present study would enlighten the reader with the impact of such variations in stimuli on the outcome gap detection measures. The result of the study indicates when the two marker frequencies are close in nature (one-octave difference), then the order of their presentation did not change the outcome measures significantly. But, when the two marker frequencies are wide in nature (two-octave difference), then the order of their presentation changed the outcome measures significantly. The measured gap detection thresholds are better if high-frequency segment presented initially followed by the low frequency. Further, the study also provides valuable discussions on the results obtained. The study would add necessary understanding and precautions about the stimulus while using gap detection measures.

Age-related changes in gap detection thresholds in adult cochlear-implant users: Effects of stimulus level and electrode-to-neural interface

Aging is associated with reduced sensitivity to brief temporal gaps in auditory stimuli. Although gap detection is a relative strength among late-deafened cochlear-implant users, aging and electrode-to-neural interface (ENI) factors may contribute to temporal processing difficulties. Because aging may negatively impact perception particularly at very low and very high input levels, we hypothesized larger gap detection thresholds (GDTs) at poor-ENI electrodes and an interaction between age and level such that GDT improvement with increased level would be less evident in older listeners. GDTs were measured on three electrodes selected to span a range of good-to-poor ENI based on electrically-evoked compound action potential amplitude growth or threshold sensitivity to increased pulse rate. GDTs were assessed using constant-amplitude single-electrode 1000-pps pulse trains presented at 40/60/80/100% dynamic range. In preliminary data (N = 4), GDTs averaged 3 ms at 100%DR and 40 ms at 40%DR. Listeners with better average ENI metrics displayed better GDTs. Within-subject, an advantage for best-ENI electrode over poorer-ENI electrodes was evident only at low levels. Finding an interaction between age and level such that temporal processing is impaired at both low and high (but not mid) levels for older listeners may help elucidate the contributions of peripheral versus central factors.

Investigation of central auditory processing performance in individuals with and without stuttering

BackgroundDifferences in core auditory processing abilities, such as sound timing, frequency discrimination, auditory perception, and auditory memory, have been suggested in stutterers, despite the fact that the precise origin of stuttering is not entirely understood. It is suggested that these differences may play a role in the development of stuttering. The aim of our study is to assess the temporal central auditory processing performance in individuals with stuttering and compare it to individuals without stuttering to uncover potential differences stuttering and compare it to individuals without stuttering to reveal potential differences. MethodIn current study, a total of 60 right-handed participants between the ages of 8 and 17 were included, divided into two balanced groups based on age, education, and gender: individuals with stuttering (n = 30) and individuals without stuttering (n = 30). All participants underwent the Frequency Pattern Test, Duration Pattern Test, and Gaps-In-Noise test. ResultsIndividuals who stutter showed lower performance in the gap detection threshold and the percentage of total correct gap identification parameters of the Frequency Pattern Test, Duration Pattern Test, and Gaps-In-Noise test compared to fluent speakers. ConclusionsThe findings indicate a potential relationship between stuttering and central auditory processing. In this context, incorporating central auditory processing measures into the assessment and therapy processes for stuttering may enhance the likelihood of obtaining more accurate results.

Assessment of Central Auditory Processing in Children Using a Novel Tablet-Based Platform: Application for Low- and Middle-Income Countries.

Evaluate whether a portable, tablet-based central auditory processing (CAP) test system using native language training videos and administered by minimally trained community health workers can produce CAP results comparable to previously published norms. Our secondary aim was to determine subject parameters that influence test results. Cross-sectional study. Community-based settings in Chontales, Nicaragua, New Hampshire, and Florida. English- and/or Spanish-speaking children and adolescents (n = 245; average age, 12.20 yr; range, 6-18 yr). Completion of the following tests with responses comparable to published norms: Pure-tone average (PTA), gap detection threshold (GDT), fixed-level frequency threshold, masking level difference (MLD), Hearing in Noise Test (HINT), Dichotic Digits Test (DDT), and Frequency Pattern Recognition (FPR) test. GDT, HINT, and DDT had comparable results to previously published normative values. MLD and FPR results differed compared with previously published normative values. Most CAP tests (MLD, GDT, HINT) results were independent of age and PTA (p = 0.1-0.9). However, DDT was associated with age and PTA (p < 0.0001). Pediatric CAP testing can be successfully completed in remote low- and middle- income country environments using a tablet-based platform without the presence of an audiologist. Performance on DDT improved with age but deteriorated with hearing loss. Further investigation is warranted to assess the variability of FPR.

Speech intelligibility and its relation to auditory temporal processing in Czech and Swiss German subjects with and without tinnitus.

Previous studies have shown that levels for 50% speech intelligibility in quiet and in noise differ for different languages. Here, we aimed to find out whether these differences may relate to different auditory processing of temporal sound features in different languages, and to determine the influence of tinnitus on speech comprehension in different languages. We measured speech intelligibility under various conditions (words in quiet, sentences in babble noise, interrupted sentences) along with tone detection thresholds in quiet [PTA] and in noise [PTAnoise], gap detection thresholds [GDT], and detection thresholds for frequency modulation [FMT], and compared them between Czech and Swiss subjects matched in mean age and PTA. The Swiss subjects exhibited higher speech reception thresholds in quiet, higher threshold speech-to-noise ratio, and shallower slope of performance-intensity function for the words in quiet. Importantly, the intelligibility of temporally gated speech was similar in the Czech and Swiss subjects. The PTAnoise, GDT, and FMT were similar in the two groups. The Czech subjects exhibited correlations of the speech tests with GDT and FMT, which was not the case in the Swiss group. Qualitatively, the results of comparisons between the Swiss and Czech populations were not influenced by presence of subjective tinnitus. The results support the notion of language-specific differences in speech comprehension which persists also in tinnitus subjects, and indicates different associations with the elementary measures of auditory temporal processing.

Binaural advantages in sound temporal information processing by neurons in the rat inferior colliculus.

Previous studies on the advantages of binaural hearing have long been focused on sound localization and spatial stream segregation. The binaural advantages have also been observed in speech perception in reverberation. Both human speech and animal vocalizations contain temporal features that are critical for speech perception and animal communication. However, whether there are binaural advantages for sound temporal information processing in the central auditory system has not been elucidated. Gap detection threshold (GDT), the ability to detect the shortest silent interval in a sound, has been widely used to measure the auditory temporal resolution. In the present study, we determined GDTs of rat inferior collicular neurons under both monaural and binaural hearing conditions. We found that the majority of the inferior collicular neurons in adult rats exhibited binaural advantages in gap detection, i.e., better neural gap detection ability in binaural hearing conditions compared to monaural hearing condition. However, this binaural advantage in sound temporal information processing was not significant in the inferior collicular neurons of P14-21 and P22-30 rats. Additionally, we also observed age-related changes in neural temporal acuity in the rat inferior colliculus. These results demonstrate a new advantage of binaural hearing (i.e., binaural advantage in temporal processing) in the central auditory system in addition to sound localization and spatial stream segregation.

Peripheral neural status and auditory temporal resolution in cochlear implant users

Auditory temporal resolution is important for understanding speech with a cochlear implant (CI). The aim of this study was to determine the relative contributions of peripheral neural synchrony and peripheral neural survival to perceptual temporal resolution in CI users. To date, study participants included 8 post-lingually deafened adult CI users. All participants used Cochlear™ Nucleus® devices in their test ears. For each implanted ear tested in each participant, auditory temporal resolution, neural synchrony, and neural survival were evaluated at multiple electrode locations along the array. Auditory temporal resolution was estimated using single-channel, psychophysical gap detection thresholds (GDTs), peripheral neural synchrony was estimated using the phase-locking value (PLV), and peripheral neural survival was estimated using the sensitivity of the electrically-evoked compound action potential to changes in interphase gap (i.e., IPG effect). After adjusting for multiple comparisons, our preliminary results indicated that GDT was significantly correlated with the PLV but not with the IPG effect. The PLV and the IPG effect were not significantly correlated. These preliminary results suggested that the degree of peripheral neural synchrony appeared to play a more important role in determining auditory temporal resolution than peripheral neural survival. [Work supported by NIH: 1R01 DC016038, 1R01 DC017846, R21 DC019458]

Explaining the deterioration of the relative timing accuracy for across-channel by a simple mathematical model

The perceptual simultaneity range, within which two asynchronous pure tones are perceived to start simultaneously, and the gap detection threshold are known to be wide when the frequency separation of the tones is large. It is generally said that the accuracy of the relative timing for different frequency channels deteriorates. However, there is no clear explanation of why such deteriorations are necessary. This study aimed to show that a simple mathematical model leads to the deterioration of relative timing accuracy for two tones with different frequencies. As a result of the calculations, the model simulated the deterioration of the perceptual simultaneity range not only with the increase of the frequency separation but also with the decrease of the frequency region of two tones. The model also simulated the behavior of the gap detection threshold for two different frequencies (across-channel) with its asymmetric deterioration. Further, the model simulated the behavior of the gap detection threshold for two identical frequencies (within-channel). These results suggest that one simple mathematical model may explain the mechanisms underlying perceptual simultaneity, within-channel gap detection, and between-channel gap detection for two tones.

The Effect of Hemodialysis on Spectral and Temporal Processing Abilities and Speech Perception in Noise among Individuals with Chronic Kidney Disease

Introduction: The effect of chronic kidney disease (CKD) on hearing is well documented in the literature. Several studies have investigated the effect of hemodialysis on the peripheral auditory system among individuals with CKD. However, studies investigating the effect of hemodialysis on speech perception and auditory processing abilities are limited. The present study investigated the effect of hemodialysis on few auditory processing abilities and speech perception in noise among adults with CKD. Methods: A total of 25 adults with CKD undergoing hemodialysis regularly participated in the study. Spectral ripple discrimination threshold (SRDT), gap detection threshold (GDT), amplitude-modulation detection threshold (AMDT), and speech recognition threshold in noise (SRTn) were measured before and after hemodialysis. Paired samples “t” test was carried out to investigate the effect of hemodialysis on thresholds. Results: Results showed a significant improvement for SRDT, GDT, AMDT, and SRTn after hemodialysis among individuals with CKD. Discussion: Hemodialysis showed a positive effect on speech perception in noise and auditory processing abilities among individuals with CKD.

Keep your finger on the pulse: Better rate perception and gap detection with vibrotactile compared to visual stimuli

Important characteristics of the environment can be represented in the temporal pattern of sensory stimulation. In two experiments, we compared accuracy of temporal processing by different modalities. Experiment 1 examined binary categorization of rate for visual (V) or vibrotactile (T) stimulus pulses presented at either 4 or 6 Hz. Inter-pulse intervals were either constant or variable, perturbed by random Gaussian variates. Subjects categorized the rate of T pulse sequences more accurately than V sequences. In V conditions only, subjects disproportionately tended to mis-categorize 4-Hz pulse rates, for all but the most variable sequences. In Experiment 2, we compared gap detection thresholds across modalities, using the same V and T pulses from Experiment 1, as well as with bimodal (VT) pulses. Visual gap detection thresholds were larger (3times ) than tactile thresholds. Additionally, performance with VT stimuli seemed to be nearly completely dominated by their T components. Together, these results suggest (i) that vibrotactile temporal acuity surpasses visual temporal acuity, and (ii) that vibrotactile stimulation has considerable, untapped potential to convey temporal information like that needed for eyes-free alerting signals.

Does Binaural Stimulation Enhance Temporal Processing in Young Children?

Background and objective Temporal processing abilities help perceive signal changes over time. Efficient temporal processing is necessary for pitch perception, voice identification, and speech perception. It plays a significant role in language development. Internal redundancy of the central auditory nervous plays a role in processing sensory information. There is a need to gain more insights into the maturation of neural hardwiring that supports binaural temporal processing at a young age. The purpose of the present study was to evaluate the difference between monaural and binaural temporal processing in children aged 7-11 years. Methods Temporal processing was assessed using gap detection and temporal modulation transfer function (TMTF) tests. The tests were administered in 40 typically developing children with normal clinical auditory sensitivity. The maximum likelihood procedure (MLP), a MATLAB toolbox, was employed to deliver the stimulus. A multivariate analysis followed by post hoc analysis was performed to analyze the data. Results There was a significant difference between binaural and monoaural stimulation in children aged 7-11 years. However, there was no statistically significant difference between the right and left ears for gap detection threshold (GDT) and TMTF across all test frequencies. Conclusion Based on our findings, binaural stimulation enhances temporal processing in young children.

Relationships Between the Auditory Nerve's Ability to Recover From Neural Adaptation, Cortical Encoding of and Perceptual Sensitivity to Within-channel Temporal Gaps in Postlingually Deafened Adult Cochlear Implant Users.

As a step toward identifying the origin of the across-electrode variation in within-channel gap detection thresholds (GDTs) measured in individual cochlear implant (CI) users, this study assessed the relationships between the auditory nerve's (AN's) ability to recover from neural adaptation, cortical encoding of and perceptual sensitivity to within-channel temporal gaps in postlingually deafened adult CI users. Study participants included 11 postlingually deafened adults with Cochlear Nucleus devices, including three bilaterally implanted participants. In each of the 14 ears tested, recovery from neural adaptation of the AN was measured using electrophysiological measures of the electrically evoked compound action potential at up to four electrode locations. The two CI electrodes in each ear showing the largest difference in the speed of adaptation recovery were selected for assessing within-channel temporal GDT. GDTs were measured using both psychophysical and electrophysiological procedures. Psychophysical GDTs were evaluated using a three-alternative, forced-choice procedure, targeting 79.4% correct on the psychometric function. Electrophysiological GDTs were measured using the electrically evoked auditory event-related potential (eERP) evoked by temporal gaps embedded in electrical pulse trains (i.e., the gap-eERP). Objective GDT was defined as the shortest temporal gap that could evoke a gap-eERP. Related-samples Wilcoxon Signed Rank test was used to compare psychophysical GDTs and objective GDTs measured at all CI electrode locations. It was also used to compare psychophysical GDTs and objective GDTs measured at the two CI electrode locations with different speeds or amounts of adaptation recovery of the AN. A Kendall Rank correlation test was used to assess the correlation between GDTs measured at the same CI electrode location using psychophysical or electrophysiological procedures. Objective GDTs were significantly larger than those measured using psychophysical procedures. There was a significant correlation between objective and psychophysical GDTs. GDTs could not be predicted based on the amount or the speed of adaptation recovery of the AN. Electrophysiological measures of the eERP evoked by temporal gaps can potentially be used to assess within-channel GDT in CI users who cannot provide reliable behavioral responses. The difference in adaptation recovery of the AN is not the primary factor accounting for the across-electrode variation in GDT in individual CI users.

Test-retest Reliability of Various Psychoacoustic Tests in Psycon Application

Background and Aim: Psychoacoustics includes studying the perceived effects of changes in sound intensity, temporal, and frequency aspects that are critical for speech perception. Psycon is one such software used in studies to assess psychoacoustic abilities. Psycon has the potential for wide clinical applications in psychoacoustic research and relies on Auditory syntaX (AUX), a program designed specifically to handle auditory signals. The current study aimed to determine the test-retest reliability of the Psycon application for differential sensitivity measures of frequency, intensity, duration and silence. Methods: The study included 39 participants with normal hearing sensitivity. Psychoacoustic measures, namely, gap detection threshold, duration discrimination threshold, difference limen of intensity, and difference limen of frequency, were used to assess test-retest reliability. The test-retest reliability of all measures was checked in two separate sessions within one day. Results: The reliability of each measure was measured using Cronbach’s alpha. Test-retest reliability of various psychoacoustic tests measured with Psycon ranges from good to excellent. difference limen of frequency had the highest reliability, followed by duration discrimination thresholds, difference limen of intensity, and gap detection thresholds. Conclusion: Psycon appears to be a reliable tool for assessing different psychoacoustic abilities. Keywords: Psycon; psychoacoustics; reliability; difference limen; perception

Gap Detection in Pairs of Ultrasound Mid-air Vibrotactile Stimuli

Ultrasound mid-air haptic (UMH) devices are a novel tool for haptic feedback, capable of providing localized vibrotactile stimuli to users at a distance. UMH applications largely rely on generating tactile shape outlines on the users’ skin. Here we investigate how to achieve sensations of continuity or gaps within such two-dimensional curves by studying the perception of pairs of amplitude-modulated focused ultrasound stimuli. On the one hand, we aim to investigate perceptual effects that may arise from providing simultaneous UMH stimuli. On the other hand, we wish to provide perception-based rendering guidelines for generating continuous or discontinuous sensations of tactile shapes. Finally, we hope to contribute toward a measure of the perceptually achievable resolution of UMH interfaces. We performed a user study to identify how far apart two focal points need to be to elicit a perceptual experience of two distinct stimuli separated by a gap. Mean gap detection thresholds were found at 32.3-mm spacing between focal points, but a high within- and between-subject variability was observed. Pairs spaced below 15 mm were consistently (&gt;95%) perceived as a single stimulus, while pairs spaced 45 mm apart were consistently (84%) perceived as two separate stimuli. To investigate the observed variability, we resort to acoustic simulations of the resulting pressure fields. These show a non-linear evolution of actual peak pressure spacing as a function of nominal focal point spacing. Beyond an initial threshold in spacing (between 15 and 18 mm), which we believe to be related to the perceived size of a focal point, the probability of detecting a gap between focal points appears to linearly increase with spacing. Our work highlights physical interactions and perceptual effects to consider when designing or investigating the perception of UMH shapes.

The Relative Contribution of Cochlear Synaptopathy and Reduced Inhibition to Age-Related Hearing Impairment for People With Normal Audiograms.

Older people often show auditory temporal processing deficits and speech-in-noise intelligibility difficulties even when their audiogram is clinically normal. The causes of such problems remain unclear. Some studies have suggested that for people with normal audiograms, age-related hearing impairments may be due to a cognitive decline, while others have suggested that they may be caused by cochlear synaptopathy. Here, we explore an alternative hypothesis, namely that age-related hearing deficits are associated with decreased inhibition. For human adults (N = 30) selected to cover a reasonably wide age range (25-59 years), with normal audiograms and normal cognitive function, we measured speech reception thresholds in noise (SRTNs) for disyllabic words, gap detection thresholds (GDTs), and frequency modulation detection thresholds (FMDTs). We also measured the rate of growth (slope) of auditory brainstem response wave-I amplitude with increasing level as an indirect indicator of cochlear synaptopathy, and the interference inhibition score in the Stroop color and word test (SCWT) as a proxy for inhibition. As expected, performance in the auditory tasks worsened (SRTNs, GDTs, and FMDTs increased), and wave-I slope and SCWT inhibition scores decreased with ageing. Importantly, SRTNs, GDTs, and FMDTs were not related to wave-I slope but worsened with decreasing SCWT inhibition. Furthermore, after partialling out the effect of SCWT inhibition, age was no longer related to SRTNs or GDTs and became less strongly related to FMDTs. Altogether, results suggest that for people with normal audiograms, age-related deficits in auditory temporal processing and speech-in-noise intelligibility are mediated by decreased inhibition rather than cochlear synaptopathy.

Within- and across-frequency temporal processing and speech perception in cochlear implant users.

Cochlear implant (CI) recipient's speech perception performance is highly variable and is influenced by temporal processing abilities. Temporal processing is commonly assessed using a behavioral task that requires the participant to detect a silent gap with the pre- and post-gap stimuli of the same frequency (within-frequency gap detection) or of different frequencies (across-frequency gap detection). The purpose of the study was to evaluate behavioral and electrophysiological measures of within- and across-frequency temporal processing and their correlations with speech perception performance in CI users. Participants included 11 post-lingually deafened adult CI users (n = 15 ears; Mean Age = 50.2 yrs) and 11 age- and gender-matched normal hearing (NH) individuals (n = 15 ears; Mean Age = 49.0 yrs). Speech perception was assessed with Consonant-Nucleus-Consonant Word Recognition (CNC), Arizona Biomedical Sentence Recognition (AzBio), and Bamford-Kowal-Bench Speech-in-Noise Test (BKB-SIN) tests. Within- and across-frequency behavioral gap detection thresholds (referred to as the GDTwithin and GDTacross) were measured using an adaptive, two-alternative, forced-choice procedure. Cortical auditory evoked potentials (CAEPs) were elicited using within- and across-frequency gap stimuli under four gap duration conditions (no gap, GDT, sub-threshold GDT, and supra-threshold GDT). Correlations among speech perception, GDTs, and CAEPs were examined. CI users had poorer speech perception scores compared to NH listeners (p < 0.05), but the GDTs were not different between groups (p > 0.05). Compared to NH peers, CI users showed increased N1 latency in the CAEPs evoked by the across-frequency gap stimuli (p < 0.05). No group difference was observed for the CAEPs evoked by the within-frequency gap (p > 0.05). Three CI ears showing the longest GDTwithin also showed the poorest performance in speech in noise. The within-frequency CAEP increased in amplitude with the increase of gap duration; while the across-frequency CAEP displayed a similar amplitude for all gap durations. There was a significant correlation between speech scores and within-frequency CAEP measures for the supra-threshold GDT condition, with CI users with poorer speech performance having a smaller N1-P2 amplitude and longer N1 latency. No correlations were found among GDTacross, speech perception, and across-frequency CAEP measures. Within- and across-frequency gap detection may involve different neural mechanisms. The within-frequency gap detection task can help identify CI users with poor speech performance for rehabilitation. The within-frequency CAEP is a better predictor for speech perception performance than the across-frequency CAEP.