Confirmatory factor analysis of the Tinnitus Impact Questionnaire using data from patients seeking help for tinnitus alone or tinnitus combined with hyperacusis.

A confirmatory factor analysis (CFA) of the Tinnitus Impact Questionnaire (TIQ) was performed. In contrast to commonly used tinnitus questionnaires, the TIQ is intended solely to assess the impact of tinnitus by not including items related to hearing loss or tinnitus loudness. This was a psychometric study based on a retrospective cross-sectional analysis of clinical data. Data were available for 155 new patients who had attended a tinnitus and hyperacusis clinic in the UK within a five-month period and had completed the TIQ. The mean age was 54 years (standard deviation = 14 years). The TIQ demonstrated good internal consistency, with Cronbach's α = 0.84 and McDonald's ω = 0.89. CFA showed that two items of the TIQ had low factor loadings for both one-factor and two-factor models and their scores showed low correlations with scores for other items. Bi-factor analysis gave a better fit, indicated by a relative chi-square (χ2) of 18.5, a Root-Mean Square Error of Approximation (RMSEA) of 0.103, a Comparative Fit Index (CFI) of 0.97, a Tucker Lewis Index (TLI) of 0.92, and a Standardized Root-Mean Residual (SPMR) of 0.038. Total TIQ scores were moderately correlated with scores for the Visual Analogue Scale of effect of tinnitus on life and the Screening for Anxiety and Depression-Tinnitus questionnaire, supporting the convergent validity of the TIQ. The TIQ score was not correlated with the pure-tone average hearing threshold, indicating discriminant validity. A multiple-causes multiple-indicator (MIMIC) model showed no influences of age, gender or hearing status on TIQ item scores. The TIQ is an internally consistent tool. CFA suggests a bi-factor model with sufficient unidimensionality to support the use of the overall TIQ score for assessing the impact of tinnitus. TIQ scores are distinct from the impact of hearing impairment among patients who have tinnitus combined with hearing loss.

A Preliminary Analysis of the Clinical Effectiveness of Audiologist-Delivered Cognitive Behavioral Therapy Delivered via Video Calls for Rehabilitation of Misophonia, Hyperacusis, and Tinnitus.

PURPOSE: Cognitive behavioral therapy (CBT) is a key intervention for management of misophonia, hyperacusis, and tinnitus. The aim of this study was to perform a preliminary analysis comparing the scores for self-report questionnaires before and after audiologist-delivered CBT via video calls for adults with misophonia, hyperacusis, or tinnitus or a combination of these. METHOD: This was a retrospective cross-sectional study. The data for 37 consecutive patients who received CBT for misophonia, hyperacusis, or tinnitus from a private institute in the United Kingdom were analyzed. Self-report questionnaires taken as part of routine care were as follows: 4C Questionnaires for tinnitus, hyperacusis, and misophonia (4C-T, 4C-H, and 4C-M, respectively), Tinnitus Impact Questionnaire (TIQ), Hyperacusis Impact Questionnaire (HIQ), Misophonia Impact Questionnaire (MIQ), Sound Sensitivity Symptoms Questionnaire (SSSQ), and Screening for Anxiety and Depression in Tinnitus (SAD-T). Responses were also obtained to other questionnaires related to tinnitus, hyperacusis, insomnia, and anxiety and mood disorders. A linear mixed-model method was used to assess the changes in response to the questionnaires pretreatment and posttreatment. RESULTS: Pretreatment-posttreatment comparisons showed that scores for the 4C-T, 4C-H, 4C-M, TIQ, HIQ, MIQ, SSSQ, and SAD-T improved, with effect sizes of 1.4, 1.2, 1.3, 2.6, 0.9, 0.7, 0.9, and 1.4, respectively (all p < .05). CONCLUSIONS: This preliminary analysis suggests that CBT via video calls may be effective in reducing the impact of misophonia, hyperacusis, and tinnitus. However, this study did not have a control group, so its results need to be interpreted with caution.

Development of New Open-Set Speech Material for Use in Clinical Audiology with Speakers of British English.

BACKGROUND: The Chear open-set performance test (COPT), which uses a carrier phrase followed by a monosyllabic test word, is intended for clinical assessment of speech recognition, evaluation of hearing-device performance, and the fine-tuning of hearing devices for speakers of British English. This paper assesses practice effects, test-retest reliability, and the variability across lists of the COPT. METHOD: In experiment 1, 16 normal-hearing participants were tested using an initial version of the COPT, at three speech-to-noise ratios (SNRs). Experiment 2 used revised COPT lists, with items swapped between lists to reduce differences in difficulty across lists. In experiment 3, test-retest repeatability was assessed for stimuli presented in quiet, using 15 participants with sensorineural hearing loss. RESULTS: After administration of a single practice list, no practice effects were evident. The critical difference between scores for two lists was about 2 words (out of 15) or 5 phonemes (out of 50). The mean estimated SNR required for 74% words correct was -0.56 dB, with a standard deviation across lists of 0.16 dB. For the participants with hearing loss tested in quiet, the critical difference between scores for two lists was about 3 words (out of 15) or 6 phonemes (out of 50).

Sensitivity of Methods for Diagnosing Noise-Induced Hearing Loss in Cases of Exposures Including Intense Low-Frequency Noise.

Exposure to intense low-frequency sounds, for example inside tanks and armoured vehicles, can lead to noise-induced hearing loss (NIHL) with a variable audiometric pattern, including low- and mid-frequency hearing loss. It is not known how well existing methods for diagnosing NIHL apply in such cases. Here, the audiograms of 68 military personnel (mostly veterans) who had been exposed to intense low-frequency noise (together with other types of noise) and who had low-frequency hearing loss (defined as a pure-tone average loss at 0.25, 0.5 and 1 kHz ≥20 dB) were used to assess the sensitivity of three diagnostic methods: the method of Coles, Lutman and Buffin, denoted CLB, which depends on the identification of a notch or bulge in the audiogram near 4 kHz, and two methods specifically intended for diagnosing NIHL sustained during military service, the rM-NIHL method, which depends on the identification of a notch or bulge in the audiogram near 4 kHz and/or a hearing loss at high frequencies greater than expected from age alone, and the MLP(18) method based on a multi-layer perceptron. The proportion of individuals receiving a positive diagnosis for either or both ears, which provides an approximate measure of sensitivity, was 0.40 for the CLB method, 0.79 for the rM-NIHL method and 1.0 for the MLP(18) method. It is concluded that the MLP(18) method is suitable for diagnosing NIHL sustained during military service whether or not the exposure includes intense low-frequency sounds.

The Cambridge aided loudness profile (CALP): item choices and data for unaided listening by young and older normal-hearing listeners and older hearing-impaired listeners.

OBJECTIVE: To develop an improved version of the profile of aided loudness (PAL), intended for assessment of the appropriateness of the loudness of everyday sounds. DESIGN: Initially, 16 participants with a range of ages and degrees of hearing loss indicated whether they encountered each situation described in the PAL and how specific they considered the description to be. Based on the responses, most situations from the PAL were eliminated and new situations were introduced, giving the Cambridge Aided Loudness Profile (CALP). The CALP was administered to 80 young and 22 older participants with normal hearing, who rated the loudness of each situation and satisfaction with this loudness (as for the original PAL). Satisfaction was strongly negatively correlated with loudness, suggesting that satisfaction was largely based on loudness. The CALP was then administered to 32 new young normal-hearing participants and 49 older participants with hearing loss, most of whom used hearing aids, who rated loudness and the appropriateness of loudness. RESULTS: Some situations were rated as loud but appropriate in loudness, indicating that the CALP can distinguish these aspects. CONCLUSIONS: The CALP questions were understood by all participants. The CALP may be useful for assessing the appropriateness of loudness.

Confirmatory factor analysis of the Hyperacusis Impact Questionnaire, Sound Sensitivity Symptoms Questionnaire, and Screening for Anxiety and Depression in Tinnitus, including preliminary analyses of the parent versions for use with children.

BACKGROUND: We previously reported the results of exploratory factor analysis (EFA) of the Hyperacusis Impact Questionnaire (HIQ), the Sound Sensitivity Symptoms Questionnaire (SSSD) and the Screening for Anxiety and Depression in Tinnitus (SAD-T). Confirmatory Factor Analysis (CFA) is necessary to confirm the latent constructs determined using EFA. CFA should use different samples but with similar characteristics to those used for EFA. PURPOSE: The aim was to use CFA to confirm latent constructs derived using EFA of the HIQ, SSSQ and SAD-T. We further evaluated the psychometric properties of parent versions of these questionnaires (indicated by -P), which are intended for use with children. RESEARCH DESIGN: This was a retrospective cross-sectional study. STUDY SAMPLE: Data for 323 consecutive adults and 49 children who attended a Tinnitus and Hyperacusis Therapy Clinic in the UK within a six-month period were included. DATA COLLECTION AND ANALYSIS: Data were collected retrospectively from the records of patients held at the audiology department. CFA with the weighted least-squares mean and variance-adjusted estimator was applied to assess the previously proposed factor structures of the HIQ, SSSQ and SAD-T. The internal consistency of the scales was assessed via Cronbach's alpha (α). The items of the HIQ, SSSQ and SAD-T were tested for measurement invariance regarding age and gender using the multiple indicator multiple cause (MIMIC) model. RESULTS: All questionnaires showed good to excellent internal consistency, with α = 0.93 for the HIQ, 0.87 for the SSSQ, and 0.91 for the SAD-T. The parent versions showed acceptable to good internal consistency, with α = 0.88 for the HIQ-P, 0.71 for the SSSQ-P, and 0.86 for the SAD-T-P. CFA showed that the HIQ, SSSQ, and SAD-T were all one-factor questionnaires and the factors generally were similar to those obtained for the EFA. The MIMIC model showed that all three questionnaires can be considered as measurement invariant, with scores similar across genders and ages. CONCLUSIONS: The HIQ, SSSQ and SAD-T are internally consistent one-factor questionnaires that can be used in clinical and research settings to assess the impact of hyperacusis, the severity of sound sensitivity symptoms, and to screen for anxiety and depression symptoms. Future studies should further explore the psychometric properties of the parent versions of the HIQ and SSSQ and SAD-T.

Sixty Years of Frequency-Domain Monaural Speech Enhancement: From Traditional to Deep Learning Methods.

Frequency-domain monaural speech enhancement has been extensively studied for over 60 years, and a great number of methods have been proposed and applied to many devices. In the last decade, monaural speech enhancement has made tremendous progress with the advent and development of deep learning, and performance using such methods has been greatly improved relative to traditional methods. This survey paper first provides a comprehensive overview of traditional and deep-learning methods for monaural speech enhancement in the frequency domain. The fundamental assumptions of each approach are then summarized and analyzed to clarify their limitations and advantages. A comprehensive evaluation of some typical methods was conducted using the WSJ + Deep Noise Suppression (DNS) challenge and Voice Bank + DEMAND datasets to give an intuitive and unified comparison. The benefits of monaural speech enhancement methods using objective metrics relevant for normal-hearing and hearing-impaired listeners were evaluated. The objective test results showed that compression of the input features was important for simulated normal-hearing listeners but not for simulated hearing-impaired listeners. Potential future research and development topics in monaural speech enhancement are suggested.

Psychometric Evaluation of the Misophonia Impact Questionnaire (MIQ) Using a Clinical Population of Patients Seeking Help for Tinnitus, Hyperacusis and/or Misophonia.

BACKGROUND: Misophonia is a decreased tolerance of certain sounds related to eating noises, lip smacking, sniffing, breathing, clicking sounds, and tapping. While several validated self-report misophonia questionnaires exist, none focus solely on the impact of misophonia on the patient's life. Additionally, there are no available validated pediatric self-report measures of misophonia. Therefore, a tool was needed to assess the impact of misophonia on both adult and pediatric patients. PURPOSE: To evaluate the psychometric properties of the 8-item Misophonia Impact Questionnaire (MIQ). RESEARCH DESIGN: This was a retrospective cross-sectional study. STUDY SAMPLE: Patients who attended the Tinnitus and Hyperacusis Therapy Specialist Clinic (THTSC) in the UK seeking help for tinnitus, hyperacusis and/or misophonia (n = 256). A subsample of children aged 16 years or younger (n=15) was included for preliminary analyses of a version of the MIQ to be filled in by a parent (MIQ-P). DATA COLLECTION AND ANALYSIS: Data were collected retrospectively from the records of patients held at the audiology department. These included demographic data, audiological measures and self-report questionnaires taken as part of routine care. Descriptive statistics and psychometric analyses were conducted. The MIQ was analyzed for item difficulty, factor structure, reliability, and construct validity. RESULTS: Confirmatory factor analysis revealed that a one-factor model for the MIQ gave an excellent fit and its estimated reliability was excellent, with Cronbach's α = 0.94. The total MIQ scores were highly correlated with scores for the Hyperacusis Impact Questionnaire (HIQ) and Sound Sensitivity Symptoms Questionnaire (SSSQ). MIQ scores were not significantly correlated with scores for the Tinnitus Impact Questionnaire (TIQ) or average hearing thresholds. Preliminary data from the sub-sample indicated excellent internal consistency for the MIQ-P, with Cronbach's α = 0.92. CONCLUSIONS: The MIQ is a promising questionnaire for assessing the impact of misophonia. Future studies should focus on establishing test/re-test reliability, identifying clinically significant change in MIQ scores, defining the severity of misophonia impact categories, and further exploring the psychometric properties of the MIQ-P.

Effects of hearing loss, age, noise exposure, and listening skills on envelope regularity discrimination.

The envelope regularity discrimination (ERD) test assesses the ability to discriminate irregular from regular amplitude modulation (AM). The measured threshold is called the irregularity index (II). It was hypothesized that the II at threshold should be almost unaffected by the loudness recruitment that is associated with cochlear hearing loss because the effect of recruitment is similar to multiplying the AM depth by a certain factor, and II values depend on the amount of envelope irregularity relative to the baseline modulation depth. To test this hypothesis, the ERD test was administered to 60 older adults with varying degrees of hearing loss, using carrier frequencies of 1 and 4 kHz. The II values for the two carrier frequencies were highly correlated, indicating that the ERD test was measuring a consistent characteristic of each subject. The II values at 1 and 4 kHz were not significantly correlated with the audiometric thresholds at the corresponding frequencies, consistent with the hypothesis. The II values at 4 kHz were significantly positively correlated with age. There was an unexpected negative correlation between II values and a measure of noise exposure. This is argued to reflect the confounding effects of listening skills.

An association between auditory responsiveness of children and duration of entertainment screen time in the early years of life.

OBJECTIVE: To examine whether the responsiveness of young children to simple sounds was associated with entertainment screen time (EST), opportunities for social interaction, and social and communication skills. DESIGN: Parents completed a questionnaire covering, for years one and two, the number of times the child met with other children; the number of words the child spoke; and the daily amount of EST. Social, attention and communication skills were assessed. STUDY SAMPLE: Participants were 118 children, aged 15 to 46 months. They were initially assessed behaviourally using simple sounds. Children who responded to such sounds were denoted the Responsive group. Children who did not were assessed using familiar songs and denoted the Unresponsive group. RESULTS: The two groups did not differ significantly in mean age or the number of opportunities to meet other children. The Unresponsive group had significantly fewer words than the Responsive group at 12 and 24 months and had significantly higher EST than the Responsive group for years 1 and 2. The Unresponsive group showed lower social, attention and communication skills than the Responsive group. CONCLUSIONS: High EST was associated with poorer auditory and social skills. Hence, it may be wise to limit the EST of young children.

Exploiting individual differences to assess the role of place and phase locking cues in auditory frequency discrimination at 2 kHz.

The relative role of place and temporal mechanisms in auditory frequency discrimination was assessed for a centre frequency of 2 kHz. Four measures of frequency discrimination were obtained for 63 normal-hearing participants: detection of frequency modulation using modulation rates of 2 Hz (FM2) and 20 Hz (FM20); detection of a change in frequency across successive pure tones (difference limen for frequency, DLF); and detection of changes in the temporal fine structure of bandpass filtered complex tones centred at 2 kHz (TFS). Previous work has suggested that: FM2 depends on the use of both temporal and place cues; FM20 depends primarily on the use of place cues because the temporal mechanism cannot track rapid changes in frequency; DLF depends primarily on temporal cues; TFS depends exclusively on temporal cues. This led to the following predicted patterns of the correlations of scores across participants: DLF and TFS should be highly correlated; FM2 should be correlated with DLF and TFS; FM20 should not be correlated with DLF or TFS. The results were broadly consistent with these predictions and with the idea that frequency discrimination at 2 kHz depends partly or primarily on temporal cues except for frequency modulation detection at a high rate.

Diagnosing Noise-Induced Hearing Loss Sustained During Military Service Using Deep Neural Networks.

The diagnosis of noise-induced hearing loss (NIHL) is based on three requirements: a history of exposure to noise with the potential to cause hearing loss; the absence of known causes of hearing loss other than noise exposure; and the presence of certain features in the audiogram. All current methods for diagnosing NIHL have involved examination of the typical features of the audiograms of noise-exposed individuals and the formulation of quantitative rules for the identification of those features. This article describes an alternative approach based on the use of multilayer perceptrons (MLPs). The approach was applied to databases containing the ages and audiograms of individuals claiming compensation for NIHL sustained during military service (M-NIHL), who were assumed mostly to have M-NIHL, and control databases with no known exposure to intense sounds. The MLPs were trained so as to classify individuals as belonging to the exposed or control group based on their audiograms and ages, thereby automatically identifying the features of the audiogram that provide optimal classification. Two databases (noise exposed and nonexposed) were used for training and validation of the MLPs and two independent databases were used for evaluation and further analyses. The best-performing MLP was one trained to identify whether or not an individual had M-NIHL based on age and the audiogram for both ears. This achieved a sensitivity of 0.986 and a specificity of 0.902, giving an overall accuracy markedly higher than for previous methods.

Evaluation of deep marginal feedback cancellation for hearing aids using speech and music.

Speech and music both play fundamental roles in daily life. Speech is important for communication while music is important for relaxation and social interaction. Both speech and music have a large dynamic range. This does not pose problems for listeners with normal hearing. However, for hearing-impaired listeners, elevated hearing thresholds may result in low-level portions of sound being inaudible. Hearing aids with frequency-dependent amplification and amplitude compression can partly compensate for this problem. However, the gain required for low-level portions of sound to compensate for the hearing loss can be larger than the maximum stable gain of a hearing aid, leading to acoustic feedback. Feedback control is used to avoid such instability, but this can lead to artifacts, especially when the gain is only just below the maximum stable gain. We previously proposed a deep-learning method called DeepMFC for controlling feedback and reducing artifacts and showed that when the sound source was speech DeepMFC performed much better than traditional approaches. However, its performance using music as the sound source was not assessed and the way in which it led to improved performance for speech was not determined. The present paper reveals how DeepMFC addresses feedback problems and evaluates DeepMFC using speech and music as sound sources with both objective and subjective measures. DeepMFC achieved good performance for both speech and music when it was trained with matched training materials. When combined with an adaptive feedback canceller it provided over 13 dB of additional stable gain for hearing-impaired listeners.

Assessing mechanisms of frequency discrimination by comparison of different measures over a wide frequency range.

It has been hypothesized that auditory detection of frequency modulation (FM) for low FM rates depends on the use of both temporal (phase locking) and place cues, depending on the carrier frequency, while detection of FM at high rates depends primarily on the use of place cues. To test this, FM detection for 2 and 20 Hz rates was measured over a wide frequency range, 1-10 kHz, including high frequencies for which temporal cues are assumed to be very weak. Performance was measured over the same frequency range for a task involving detection of changes in the temporal fine structure (TFS) of bandpass filtered complex tones, for which performance is assumed to depend primarily on the use of temporal cues. FM thresholds were better for the 2- than for the 20-Hz rate for center frequencies up to 4 kHz, while the reverse was true for higher center frequencies. For both FM rates, the thresholds, expressed as a proportion of the center frequency, were roughly constant for center frequencies from 6 to 10 Hz, consistent with the use of place cues. For the TFS task, thresholds worsened progressively with increasing frequency above 4 kHz, consistent with the weakening of temporal cues.

The Effectiveness of Unguided Internet-Based Cognitive Behavioral Therapy for Tinnitus for Patients with Tinnitus Alone or Combined with Hyperacusis and/or Misophonia: A Preliminary Analysis.

BACKGROUND: In the UK, audiologist-delivered cognitive behavioral therapy (CBT) is a key intervention to alleviate the distress caused by tinnitus and its comorbid hyperacusis. However, the availability of face-to-face CBT is limited, and such therapy involves significant costs. CBT provided via the internet provides a potential solution to improve access to CBT for tinnitus. PURPOSE: The aim was to perform a preliminary assessment of the effect of a specific program of non-guided internet-based CBT for tinnitus, denoted iCBT(T), in alleviating the problems caused by tinnitus alone or tinnitus combined with hyperacusis. RESEARCH DESIGN: This was a retrospective cross-sectional study. STUDY SAMPLE: The data for 28 people with tinnitus who completed the iCBT(T) program and answered a series of questions about their tinnitus and hearing status were included in the study. Twelve patients reported also having hyperacusis (including five also with misophonia). DATA COLLECTION AND ANALYSIS: The iCBT(T) program has seven self-help modules. Anonymous data were collected retrospectively from patients' answers to the questions in the iCBT(T) initial and final assessment modules. Questionnaires administered within the iCBT(T) program were: 4C Tinnitus Management Questionnaire (4C), Screening for Anxiety and Depression in Tinnitus (SAD-T), and the CBT Effectiveness Questionnaire (CBT-EQ). RESULTS: Responses to the 4C showed a significant improvement from pre- to post-treatment, with a medium effect size. The mean improvement was similar for those with and without hyperacusis. Responses to the SAD-T questionnaire also showed a significant improvement from pre- to post-treatment with a medium effect size. The improvement was significantly greater for participants with tinnitus alone than for participants who also had hyperacusis. For both the 4C and the SAD-T, the improvements were not significantly related to age or gender. Participants' views of the effectiveness of the iCBT(T) program were assessed using the CBT-EQ. The mean score was 50 out of a maximum of 80, indicating moderately high effectiveness. CBT-EQ scores did not differ for those with and without hyperacusis. CONCLUSIONS: Based on this preliminary analysis, the iCBT(T) program showed promising result in improving the ability to manage tinnitus and decreasing symptoms of anxiety and depression. Future studies with larger samples and control group(s) are required to further assess various aspects of this program.

The effect of recreational noise exposure on amplitude-modulation detection, hearing sensitivity at frequencies above 8 kHz, and perception of speech in noise.

Psychoacoustic and speech perception measures were compared for a group who were exposed to noise regularly through listening to music via personal music players (PMP) and a control group without such exposure. Lifetime noise exposure, quantified using the NESI questionnaire, averaged ten times higher for the exposed group than for the control group. Audiometric thresholds were similar for the two groups over the conventional frequency range up to 8 kHz, but for higher frequencies, the exposed group had higher thresholds than the control group. Amplitude modulation detection (AMD) thresholds were measured using a 4000-Hz sinusoidal carrier presented in threshold-equalizing noise at 30, 60, and 90 dB sound pressure level (SPL) for modulation frequencies of 8, 16, 32, and 64 Hz. At 90 dB SPL but not at the lower levels, AMD thresholds were significantly higher (worse) for the exposed than for the control group, especially for low modulation frequencies. The exposed group required significantly higher signal-to-noise ratios than the control group to understand sentences in noise. Otoacoustic emissions did not differ for the two groups. It is concluded that listening to music via PMP can have subtle deleterious effects on speech perception, AM detection, and hearing sensitivity over the extended high-frequency range.

A comparison of interaural asymmetry, audiogram slope, and psychometric measures of tinnitus, hyperacusis, anxiety and depression for patients with unilateral and bilateral tinnitus.

OBJECTIVE: To evaluate differences in tinnitus impact, hyperacusis and hearing threshold level (HTL) between patients with unilateral and bilateral tinnitus. For patients with unilateral tinnitus, to compare audiological variables for the tinnitus ear and the non-tinnitus ear. To assess whether the presence of unilateral tinnitus increases the likelihood of interaural hearing asymmetry (relative to bilateral tinnitus) that warrants referral for an MRI scan. DESIGN: Retrospective cross-sectional. STUDY SAMPLE: Data regarding HTLs and responses to self-report questionnaires were collected from the records of 311 patients attending a tinnitus clinic. RESULTS: 38.5% had unilateral tinnitus and the ears with tinnitus had higher HTLs and greater HTL slopes than the ears without tinnitus. There was no significant difference in tinnitus impact and hyperacusis between patients with unilateral and bilateral tinnitus. 40% of patients with unilateral tinnitus and 13% of patients with bilateral tinnitus had a between-ear difference in HTL ≥15 dB at two adjacent frequencies (2AF15 asymmetry). Unilateral tinnitus increased the risk of 2AF15 asymmetry by a factor of 4.4. CONCLUSIONS: Unilateral tinnitus increases the risk of having interaural asymmetry in HTLs that warrants referral for an MRI scan.

Age-related changes in auditory temporal processing assessed using forward masking.

One of the main complaints of older adults is difficulty understanding speech in noise. For older adults with audiometric thresholds within the normal range this difficulty may partly reflect deficits in temporal processing. The purpose of this study was to evaluate the effect of age on the rate of recovery from forward masking. There were seven young participants (four females; mean age 26 years) and seven older participants (six females; mean age 62 years) with normal audiometric thresholds, designated YNH and ONH groups. Signal frequencies of 500, 1000, 2000, and 4000 Hz were used. The level of the 20-ms signal was fixed at 15 dB SL for each participant and frequency. The 200-ms masker was a band of noise centered at the signal frequency with a bandwidth equal to the center frequency. The masker level was varied to determine the masker-to-signal ratio (MSR) required for threshold for masker-signal intervals (MSIs) of 5, 10, 20, 30, and 50 ms. The MSRs were smaller for the ONH group than for the YNH group, perhaps indicating lower processing efficiency for the former. Importantly, there was a significant interaction between MSI and the group. The change in MSR with increasing MSI was greater for the YNH than for the ONH group, indicating poorer temporal resolution for the latter.