Association of Auditory Steady State Responses with Perception of Temporal Modulations and Speech in Noise

The purpose of this study was to evaluate the accuracy with which auditory steady-state response (ASSR) and tone burst auditory brain stem response (ABR) thresholds predict behavioral thresholds, using a within-subjects design. Because the spectra of the stimuli used to evoke the ABR and the ASSR differ, it was hypothesized that the predictive accuracy also would differ, particularly in subjects with steeply sloping hearing losses. ASSR and ABR thresholds were recorded in a group of 14 adults with normal hearing, 10 adults with flat, sensorineural hearing losses, and 10 adults with steeply sloping, high-frequency, sensorineural hearing losses. Evoked-potential thresholds were recorded at 1, 1.5, and 2 kHz and were compared with behavioral, pure-tone thresholds. The predictive accuracy of two ABR protocols was evaluated: Blackman-gated tone bursts and linear-gated tone bursts presented in a background of notched noise. Two ASSR stimulation protocols also were evaluated: 100% amplitude-modulated (AM) sinusoids and 100% AM plus 25% frequency-modulated (FM) sinusoids. The results suggested there was no difference in the accuracy with which either ABR protocol predicted behavioral threshold, nor was there any difference in the predictive accuracy of the two ASSR protocols. On average, ABR thresholds were recorded 3 dB closer to behavioral threshold than ASSR thresholds. However, in the subjects with the most steeply sloping hearing losses, ABR thresholds were recorded as much as 25 dB below behavioral threshold, whereas ASSR thresholds were never recorded more than 5 dB below behavioral threshold, which may reflect more spread of excitation for the ABR than for the ASSR. In contrast, the ASSR overestimated behavioral threshold in two subjects with normal hearing, where the ABR provided a more accurate prediction of behavioral threshold. Both the ABR and the ASSR provided reasonably accurate predictions of behavioral threshold across the three subject groups. There was no evidence that the predictive accuracy of the ABR evoked using Blackman-gated tone bursts differed from the predictive accuracy observed when linear-gated tone bursts were presented in conjunction with notched noise. Similarly, there was no evidence that the predictive accuracy of the AM ASSR differed from the AM/FM ASSR. In general, ABR thresholds were recorded at levels closer to behavioral threshold than the ASSR. For certain individuals with steeply sloping hearing losses, the ASSR may be a more accurate predictor of behavioral thresholds; however, the ABR may be a more appropriate choice when predicting behavioral thresholds in a population where the incidence of normal hearing is expected to be high.

The number of commercially available evoked potential systems implementing multiple-frequency auditory steady-state response (ASSR) techniques has increased over the last several years. The majority of data in the multiple-frequency ASSR literature have been obtained using time-domain averaging and Fast Fourier Transform (FFT) techniques with F-test statistical analysis. Another commercially available analysis method has been introduced using an adaptive filtering algorithm called the Fourier Linear Combiner (FLC). No previous investigation has evaluated the performance of the FLC method, nor compared the two techniques. In addition, there is a need for evaluation of clinical protocols for ASSR testing using these available commercial systems that balance time efficiency and accuracy in estimating threshold. (1) To determine whether ASSR thresholds, the relationship between ASSR and behavioral thresholds, and clinical test time are affected by the ASSR analysis method when comparing two commercially available systems for multiple-frequency ASSR. (2) To investigate the use of clinical ASSR test protocols of varying recording length, and the effect on accuracy and time efficiency, using these two commercially available analysis methods. RESEARCH DESIGN AND STUDY SAMPLE: ASSR threshold searches were completed on a group of 20 normal-hearing and 20 hearing-impaired adult participants using two different analysis methods, FFT and FLC, under separate, independent, tests as well under simultaneous recording conditions. Three experiments were completed: (1) independent assessment of ASSR thresholds using the FFT and FLC methods separately, (2) simultaneous recording of ASSR for both the FFT and FLC method, and (3) an automated threshold search protocol using the FLC method. Variables analyzed for Experiments 1 and 3 included ASSR thresholds, the difference between ASSR and behavioral threshold, and total test time. For Experiment 2, the number of detected ASSRs per method, the agreement between methods, and the time per detected ASSR were evaluated. ASSR thresholds and the relationship between ASSR and behavioral thresholds were found to be in line with those reported in the literature for multiple-frequency ASSR for both the FLC and FFT methods. ASSR thresholds were found to be significantly higher for the FLC method for the low frequencies, but not for the high frequencies, when tested independently. Correlations between ASSR and behavioral thresholds, however, were found to be the same across methods. Overall, it did not appear that either analysis method held an advantage in terms of accuracy or overall test time in independent comparisons using the protocol implemented in the current study. The time benefits of an automated protocol were significant, although with compromised test accuracy. The results of this study suggest critical clinical decision making is a necessary part of the ASSR protocol in order to decrease false positive and false negative responses and to increase overall efficiency.

To improve understanding of normal responses in infants by comparing air conduction (AC) and bone conduction (BC) auditory thresholds using both the auditory steady state response (ASSR) and behavioral testing methods in normal-hearing infants (6 to 18 months of age) and adults. At present, there are no correction factors available for estimating BC behavioral thresholds from BC ASSR thresholds, which is a barrier to clinical implementation of the ASSR. In addition, previous studies have reported infant-adult differences in AC and BC sensitivity, which suggest a "maturational" air-bone gap (ABG) that is not attributable to a conductive pathology; no study has yet compared AC and BC thresholds for either ASSR or behavioral methods in the same individuals. The objectives of the present study are: (1) to compare BC thresholds between methods and provide the initial step toward positing correction factors to predict BC behavioral thresholds, (2) to directly compare AC and BC thresholds to provide an accurate estimate of the maturational ABG, (3) to determine preliminary normal levels for BC and AC ASSRs to exponentially amplitude modulated stimuli, and (4) to investigate infant-adult differences in AC and BC thresholds using ASSRs and behavioral assessment tools. Participants were 23 infants (6.5 to 19.0 months of age) and 12 adults (17 to 50 years of age) with normal hearing. Thresholds were estimated at 500, 1000, 2000, and 4000 Hz using air- and bone-conducted stimuli for ASSRs and behavioral testing. The ASSR stimuli were exponential envelope modulated (amplitude modulation [AM]) at modulation frequencies of 78, 85, 93, and 101 Hz for 500, 1000, 2000, and 4000 Hz, respectively, presented simultaneously. Frequency-modulated (warble tone) stimuli were used for behavioral testing for both infants and adults, respectively. All stimuli were calibrated in dB HL. Thresholds were compared across frequency and between stimulus presentation modes, between age groups and assessment method. Normal levels for AC and BC ASSRs to AM stimuli were also calculated. The findings indicated that BC thresholds were, on average, 7 to 16 dB poorer for ASSR compared with visual reinforcement audiometry (VRA), but varied widely across infants. For infants, mean ABGs of 14 to 17 dB were found for low-frequency ASSR thresholds but mean ABGs for VRA thresholds were less than 10 dB. The preliminary normal levels for ASSR AM stimuli at 500, 1000, 2000, and 4000 Hz, respectively, were: (i) AC: 30, 30, 20, and 20 dB HL, and (ii) BC: 20, 20, 30, and 30 dB HL. There was a tendency for infant and adult ASSR thresholds to differ for BC, but not for AC. Behavioral thresholds for AC and BC were similar between infants and adults and across frequency. Infant-adult and AC-BC threshold differences are greater for ASSRs compared with behavioral measures. The results support the presence of a clinically significant maturational ABG in the low frequencies for infant ASSRs but not for VRA. The findings also show a significant offset between BC ASSR and BC VRA thresholds and large intersubject variability.

Background In the literature, the effect of chronic kidney disease on the peripheral auditory system has been well documented. But studies investigating the effect of chronic kidney disease on speech perception and auditory processing abilities are limited. Aims/objectives The present study investigated the effect of chronic kidney disease on different auditory processing tasks and speech perception in noise among adults. Material and methods A total of 28 adults participated in the study. Group 1 included 14 individuals with chronic kidney disease undergoing hemodialysis, and Group 2 included 14 individuals with no known kidney complications. Amplitude modulation detection threshold, gap detection threshold, spectral ripple discrimination threshold, and speech recognition threshold in noise were measured. Independent samples t-test was carried out to investigate whether mean thresholds are significantly different between groups. Results Results showed poorer gap detection threshold, amplitude modulation detection threshold, spectral ripple discrimination threshold, and speech recognition threshold in noise among individuals with chronic kidney disease compared to individuals with no known kidney complications. Conclusions The present study showed poorer auditory processing and speech perception abilities in 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.

Even though many patients undergoing auditory steady-state response (ASSR) testing have some degree of hearing loss, some have normal hearing and ASSR often overestimates the behavioral thresholds in this group. In most commercial ASSR systems such as Chartr EP, a default correction factor is applied to compensate for this difference. Little is known, however, as how the correction factor compensates for the difference between ASSR and pure tone audiometry (PTA) thresholds as a function of carrier or modulation frequency (MF) in a commercial ASSR system. Our goal is to evaluate this relationship. Twenty-four normal hearing adults were examined for both PTA and ASSR (Chartr EP system, GN Otometrics). ASSR thresholds were obtained at three MFs (20, 40, and 80Hz). The difference scores were obtained by subtracting PTA from ASSR thresholds at each frequency for each subject. The corrected ASSR thresholds, then, were compared with the PTA thresholds across MFs and carrier frequencies. The default correction factors in the ASSR equipment differed significantly from the difference scores at all MFs and carrier frequencies (n = 24, p < 0.005). The correlation between corrected ASSR and PTA thresholds at most MFs and carrier frequencies were medium to poor. At most MFs and carrier frequencies, the default correction factors defined by the manufacturer do not compensate for the difference between ASSR and PTA thresholds in normal hearing adults. The use of the default correction factors in Chartr EP system for the normal hearing adults needs special considerations.

Conclusion: The correlations between behavioral and auditory steady-state response (ASSR) thresholds were significant at 500, 1000, 2000, and 4000 Hz. ASSR presented high sensitivity and specificity in the detection of residual hearing in cochlear implant candidates when compared with warble-tone audiometry. Objectives: To assess residual hearing in cochlear implant candidates by comparing the electrophysiological thresholds obtained in dichotic single-frequency ASSR with behavioral thresholds at 500, 1000, 2000, and 4000 Hz. Methods: This was a comparative study between ASSR and warble-tone audiometry thresholds in 40 cochlear implant candidates (80 ears) before cochlear implantation with bilateral severe-to-profound sensorineural hearing loss. Results: Thresholds were obtained in 62.5% of all frequencies evaluated in warble-tone audiometry and in 63.1% in the ASSR. ASSR sensitivity was 96% and specificity was 91.6%. Mean differences between behavioral and ASSR thresholds did not reach significance at any frequencies. Strong correlations between behavioral and ASSR thresholds were observed in 500, 1000, and 2000 Hz and moderate in 4000 Hz, with correlation coefficients varying from 0.65 to 0.81. On 90% of occasions, ASSR thresholds were acquired within 10 dB of behavioral thresholds.

Recent work has investigated the use of electric stimuli to evoke auditory steady state response (ASSR) in cochlear implant (CI) users. While more control can be exerted using electric stimuli, acoustic stimuli present natural listening environment for CI users. However, ASSR using acoustic stimuli in the presence of a CI could lead to artifacts. Five experiments investigated the presence and characteristics of CI-artifacts during sound-field ASSR using amplitude modulated (AM) stimulus (carrier frequency: 2 kHz; modulation frequency: 82.031 Hz). Experiment 1 investigated differences between 10 normal hearing (NH) and 10 CI participants in terms of ASSR amplitude versus intensity and onset phase versus intensity. Experiment 2 explored similar relationships for an implant-in-a-box. Experiment 3 investigated correlations between electrophysiological ASSR thresholds (ASSRe) and behavioral thresholds to the AM stimulus (BTAM) for the NH and CI groups. Mean threshold differences (ASSRe-BTAM) were computed for each group and group differences were studied. Experiment 4 investigated the presence of transducer-related artifacts using masking. Experiment 5 investigated the effect of manipulation of intensity and external components of the CI on the ASSR. Overall, results of this study provide the first comprehensive description of the characteristics of CI-artifacts during sound-field ASSR. Implications for future research to further characterize CI-artifacts, thereby leading to strategies to minimize them are discussed.

Different methods of producing the auditory steady state response (ASSR) are used to test dolphin hearing, but each method affects the resulting ASSR threshold. Since behavioral thresholds are often desired, this study, using common ASSR methods, compared differences between ASSR and behavioral hearing thresholds in five dolphins. Sinusoidal amplitude modulated (SAM) tones or tone pip trains were presented to the dolphins through a contact transducer while they were in air or partially submerged under water. Underwater behavioral hearing thresholds were obtained with pure tone stimuli on the same days as ASSR testing. Independent of the test medium, SAM tone stimuli yielded thresholds that consistently overestimated (i.e., were higher than) behavioral thresholds. Tone pip trains consistently underestimated thresholds when presented in air, and while they underestimated thresholds at lower test frequencies, they overestimated thresholds at higher test frequencies when presented under water. The mean differences between ASSR and behavioral thresholds were almost always lower when using tone pip train stimuli, but were exaggerated up to -47 dB when testing frequencies just above the upper-frequency limit of hearing. Knowing the relationship between ASSR and behavioral thresholds enables better approximations of behavioral thresholds in dolphins for which only ASSR thresholds exist.

Background Verification of the hearing level in the malinger workers is a long-standing problem. Otolaryngologists and audiologists are often called upon to evaluate the auditory thresholds of workers who file claims for compensation as a result of noise-induced hearing loss. Although objective diagnostic methods tend to dominate modern medical science, behavioral pure-tone audiometry (PTA) remains the golden standard for identifying hearing threshold levels. A number of auditory-evoked potential techniques have been implemented for this purpose over the past three decades. The most widely used of these techniques has been the auditory brainstem response (ABR) and more recently another auditory-evoked potential, the auditory steady-state response (ASSR). We also used old techniques such as postauricular myogenic potential and late cortical-evoked potential P100 as an alternative technique for objective audiometry. Rationale Integration of different objective hearing tests is deficient in the literature on high-risk adult population. Objectives To implement an objective protocol for assessing hearing in adult patients and for those difficult to test by routine PTA in Suez Canal Authority. Materials and methods This study was designed as a case–control study to collect and analyze data from September 2012 to be finished on June 2014. Sixty adult patients divided into two groups: those suffering from normal hearing and those suffering from sensorineural hearing loss. All patients in this research were submitted to the following: full history taking and otologic examination; basic audiological evaluations (PTA, speech audiometry and immittacemetry); tone burst ABR recorded using 500, 1000, 2000, and 4000 Hz stimulus; and ASSR stimulus using carrier frequencies 500, 1000, 2000, and 4000 Hz; postauricular myogenic potential response using 1000 and 4000 Hz; and late cortical-evoked potential P100 using 1000, 2000, and 4000 Hz. Results In the normal hearing group, ASSR and ABR thresholds are closer to PTA thresholds than posterior auricular muscle (PAM) thresholds, the difference decrease with increasing frequency being closer at 4000 Hz than 500 Hz results. In the study group ASSR and ABR thresholds are approximated to PTA thresholds but still the ASSR thresholds are closer to PTA thresholds than ABR thresholds and PAM threshold but much higher in the case of P100. In the study group, ABR and ASSR thresholds show the best level of prediction of PTA thresholds. We found that the mean difference between all test and pure-tone thresholds had a tendency to be smaller with increasing frequency in both groups. However, the mean difference in the study group was statistically significantly lower than the control group. There are statistically significant positive correlation between PTA threshold and both ABR and ASSR threshold at all frequencies. A statistically significant correlation was found only at 1000 Hz in PAM test and a statistically significant correlation was found only at 1000 and 2000 Hz in P100 test. Conclusion ASSR is more accurate at higher frequencies, making ASSR more suitable in accessing auditory thresholds in patients with noise-induced hearing loss.

The auditory steady state response (ASSR) is an auditory evoked potential (AEP) that can be used to objectively estimate hearing sensitivity in individuals with normal hearing sensitivity and with various degrees and configurations of sensorineural hearing loss (SNHL). For this reason, many audiologists want to learn more about the stimulus and recording parameters used to successfully acquire this response, as well as information regarding how accurately this response predicts behavioral thresholds across various clinical populations. The scientific goal is to create a tutorial on the ASSR for doctor of audiology (Au.D.) students and audiologists with limited (1-5 yr) clinical experience with AEPs. This tutorial is needed because the ASSR is unique when compared to other AEPs with regard to the type of terminology used to describe this response, the types of stimuli used to record this response, how these stimuli are delivered, the methods of objectively analyzing the response, and techniques used to calibrate the stimuli. A second goal is to provide audiologists with an understanding of the accuracy with which the ASSR is able to estimate pure tone thresholds in a variety of adult and pediatric clinical populations. This tutorial has been organized into various sections including the history of the ASSR, unique terminology associated with this response, the types of stimuli used to elicit the response, two common stimulation methods, methods of objectively analyzing the response, technical parameters for recording the ASSR, and the accuracy of ASSR threshold prediction in the adult and pediatric populations. In each section of the manuscript, key terminology/concepts associated with the ASSR are bolded in the text and are also briefly defined in a glossary found in the appendix. The tutorial contains numerous figures that are designed to walk the reader through the key concepts associated with this response. In addition, several summary tables have been included that discuss various topics such as the effects of single versus multifrequency stimulation techniques on the accuracy of estimating behavioral thresholds via the ASSR; differences, if any, in monaural versus binaural ASSR thresholds; the influence of degree and configuration of SNHL on ASSR thresholds; test-retest reliability of the ASSR; the influence of neuro-maturation on ASSR thresholds; and the influence of various technical factors (i.e., oscillator placement, coupling force, and the number of recording channels) that affect bone conducted ASSRs. Most researchers agree that, in the future, ASSR testing will play an important role in clinical audiology. Therefore, it is important for clinical audiologists and Au.D. students to have a good basic understanding of the technical concepts associated with the ASSR, a knowledge of optimal stimulus and recording parameters used to accurately record this response, and an appreciation of the current role and/or limitations of using the ASSR to estimate behavioral thresholds in infants with various degrees and configurations of hearing loss.

The inclusion of the auditory steady-state response (ASSR) into test-batteries for objective audiometry has allowed for clinical comparisons with the most widely used procedure, the auditory brainstem response (ABR). The current study describes ASSR and ABR thresholds for a group of infants and young children with various types and degrees of hearing loss. A sample of 48 subjects (23 female) with a mean age of 2.8+/-1.9 years SD were assessed with a comprehensive test-battery and classified according to type and degree of hearing loss. Thresholds were determined with a broadband click-evoked ABR and single frequency ASSR evoked with continuous tones (0.25-4 kHz) amplitude modulated (67-95 Hz). Mean difference scores (+/-SD) between the ABR and high frequency ASSR thresholds were 9.8 (+/-11), 3.6 (+/-12) and 10.5 (+/-12) dB at 1, 2 and 4 kHz, respectively. An ASSR mean threshold for 2-4 and 1-4 kHz compared to the ABR threshold revealed an average difference of 7 (+/-9) and 7.9 (+/-8) dB, respectively. The overall correlation between the ABR and ASSR thresholds was highest for the mean ASSR thresholds of 2-4 and 1-4 kHz (r=0.92 for both conditions). Correlations between the ABR and individual ASSR frequencies were slightly less (0.82-0.86). The average of the 2-4 kHz ASSR thresholds correlated best with the click-evoked ABR for all categories of hearing loss except for the sensorineural hearing loss category for which the 1-4 kHz ASSR average was better correlated to ABR thresholds. Findings demonstrate the reliability of verifying high frequency ASSR thresholds with a click-evoked ABR as an important cross-check in infants for whom behavioural audiometry may not be possible.

Objective: To compare the results of auditory steady-state response (ASSR) and click auditory brainstem response (click ABR) among infants and young children tested at the Ear Unit of a Tertiary General Hospital.&#x0D; &#x0D; Methods:&#x0D; Design: Cross-sectional Study&#x0D; Setting: Tertiary General Hospital&#x0D; Population: Within-subject comparisons of click auditory brainstem response (click ABR) thresholds and auditory steady-state response (ASSR) thresholds among 55 infants and young children, 2 months to 35 months of age referred to the Ear Unit for electrophysiologic hearing assessment.&#x0D; Results: Click ABR showed strong positive correlation to all frequencies and averages of ASSR. Highest correlation was noted with the average of 1-4 kHz ASSR results with Pearson r = 0.89 (Spearman r=0.80), the average of 2-4 kHz had strong positive correlation r = 0.88 (0.79). Correlation was consistently strong through all ASSR frequencies (0.5 kHz at r=0.86 (0.74), 1 kHz at r=0.88 (0.78), 2 kHz at r=0. 87 (0.79), 4 kHz at r=0.85 (0.76)). Average differences of click ABR and ASSR thresholds were 8.2±12.9dB at 0.5 kHz, 8.6±12.6dB at 1 kHz, 5.3±11.8dB at 2 kHz and 7.8±13.4dB at 4 kHz. Among patients with no demonstrable waveforms by click ABR with maximal click stimulus, a large percentage presented with ASSR thresholds. Of these, 80.5% (33 of 41) had measurable results at 0.5 kHz with an average of 107.3±11.1dB, 85.4% (35 of 41) at 1 kHz with an average of 110.5±11.8dB, 73.2% (30 of 41) at 2 kHz with an average of 111.2±11.1dB and 63.4% (26 of 41) at 4 kHz with and average of 112.2±8.21dB. Auditory steady-state response results were comparable to auditory brainstem response results in normal to severe hearing loss, and provided additional information necessary for complete audiologic assessment especially among patients with severe to profound hearing loss wherein click ABR showed no responses. Up to 85.4% of patients that would have been noted to have no waveforms by click ABR still demonstrated measurable thresholds by ASSR&#x0D; &#x0D; Conclusion: Our study suggests that ASSR may be the best available tool for assessing children with severe to profound hearing loss, and is a comparably effective tool in overall hearing assessment for patients requiring electrophysiological testing. The advantages of ASSR over click ABR include: 1) detection of frequency-specific thresholds and; 2) the detection of hearing loss thresholds beyond the limits of click ABR.&#x0D; &#x0D; &#x0D; Key words: Auditory Steady-State Response, ASSR, Auditory Brainstem-Evoked Response, ABR, Hearing Thresholds, Electrophysiologic Testing&#x0D;

For estimating behavioral hearing thresholds, auditory steady state response (ASSR) can be reliably evoked by stimuli at low and high modulation frequencies (MFs). In this regard, little is known regarding ASSR thresholds evoked by stimuli at different MFs in female and male participants. In fact, recent data suggest that 40-Hz ASSR is influenced by estrogen level in females. Hence, the aim of the present study was to determine the effect of gender and MF on ASSR thresholds in young adults. Twenty-eight normally hearing participants (14 males and 14 females) were enrolled in this study. For each subject, ASSR thresholds were recorded with narrow-band chirps at 500, 1,000, 2,000, and 4,000 Hz carrier frequencies (CFs) and at 40 and 90 Hz MFs. Two-way mixed ANOVA (with gender and MF as the factors) revealed no significant interaction effect between factors at all CFs (p > 0.05). The gender effect was only significant at 500 Hz CF (p < 0.05). At 500 and 1,000 Hz CFs, mean ASSR thresholds were significantly lower at 40 Hz MF than at 90 Hz MF (p < 0.05). Interestingly, at 2,000 and 4,000 Hz CFs, mean ASSR thresholds were significantly lower at 90 Hz MF than at 40 Hz MF (p < 0.05). The lower ASSR thresholds in females might be due to hormonal influence. When recording ASSR thresholds at low MF, we suggest the use of gender-specific normative data so that more valid comparisons can be made, particularly at 500 Hz CF.

Speech understanding in noise is comparatively more problematic for older listeners with and without hearing loss, and age-related changes in temporal resolution might be associated with reduced speech recognition in complex noise. The purpose of this study was to investigate the effects of aging on temporal processing and speech perception in noise for normal-hearing (NH) and cochlear-implant (CI) listeners. All participants completed three experimental procedures: (1) amplitude modulation (AM) detection thresholds, (2) sentence recognition in quiet, and (3) speech recognition in steady or modulating noise. Four listener groups participated in the study: 11 younger (≤ 30 yr old, YNH) listeners and 12 older (> 60 yr old, ONH) listeners with NH and 7 younger (< 55 yr old, YCI) and 6 older (> 60 yr old, OCI) CI users. CI listeners have been wearing their device either monaurally or binaurally at least 1 yr. For speech recognition testing, there were eight listening conditions in noise (4 modulation frequencies × 2 signal-to-noise ratios) and one in quiet for each listener. For modulation detection testing, a broadband noise with a duration of 500 msec served as the stimuli at three temporal modulation frequencies of 2, 4, and 8 Hz, which were used to modulate the noise in the speech recognition experiment. We measured AM detection thresholds using a two-interval, two-alternative, forced-choice adaptive procedure. We conducted a series of analysis of variance tests to examine the effect of aging on each test result and measured the correlation coefficient between speech recognition in noise and modulation detection thresholds. Although older NH and CI listeners performed similar to the younger listeners with the same hearing status for sentence recognition in quiet, there was a significant aging effect on speech recognition in noise. Regardless of modulation frequency and signal-to-noise ratio, speech recognition scores of the older listeners were poorer than those of the younger listeners when hearing status was matched. We also found a significant effect of aging on AM detection at each modulating frequency and a strong correlation between speech recognition in modulating noise and AM detection thresholds at 2 and 4 Hz. Regardless of differences in hearing status, the degree and pattern of aging effect on auditory processing of the NH listener groups were similar to those of the CI listener groups. This result suggests that age-related declines in speech understanding are likely multifactorial, including peripheral and central factors. Although the age cutoff of the current older age group was 10 yr less than in previous studies (Dubno et al, 2002; Lin et al, 2011), we still found the age-related differences on two auditory tasks. This study extends the knowledge of age-related auditory perception difficulties to CI listeners.