Masking Level Research Articles

An Investigation of Feasibility and Safety of Bi-Modal Stimulation for the Treatment of Tinnitus: An Open-Label Pilot Study

ObjectivesTinnitus is the perception of sound in the absence of an external auditory stimulus. It is widely believed that tinnitus, in patients with associated hearing loss, is a neurological phenomenon primarily affecting the central auditory structures. However, there is growing evidence for the involvement of the somatosensory system in this form of tinnitus. For this reason it has been suggested that the condition may be amenable to bi‐modal stimulation of the auditory and somatosensory systems. We conducted a pilot study to investigate the feasibility and safety of a device that delivers simultaneous auditory and somatosensory stimulation to treat the symptoms of chronic tinnitus.MethodsA cohort of 54 patients used the stimulation device for 10 weeks. Auditory stimulation was delivered via headphones and somatosensory stimulation was delivered via electrical stimulation of the tongue. Patient usage, logged by the device, was used to classify patients as compliant or noncompliant. Safety was assessed by reported adverse events and changes in tinnitus outcome measures. Response to treatment was assessed using tinnitus outcome measures: Minimum Masking Level (MML), Tinnitus Loudness Matching (TLM), and Tinnitus Handicap Inventory (THI).ResultsThe device was well tolerated by patients and no adverse events or serious difficulties using the device were reported. Overall, 68% of patients met the defined compliance threshold. Compliant patients (N = 30) demonstrated statistically significant improvements in mean outcome measures after 10 weeks of treatment: THI (−11.7 pts, p < 0.001), TLM (−7.5dB, p < 0.001), and MML (−9.7dB, p < 0.001). The noncompliant group (N = 14) demonstrated no statistical improvements.ConclusionThis study demonstrates the feasibility and safety of a new bi‐modal stimulation device and supports the potential efficacy of this new treatment for tinnitus.

Neural Correlates of the Binaural Masking Level Difference in Human Frequency-Following Responses.

The binaural masking level difference (BMLD) is an auditory phenomenon where binaural tone-in-noise detection is improved when the phase of either signal or noise is inverted in one of the ears (SπNo or SoNπ, respectively), relative to detection when signal and noise are in identical phase at each ear (SoNo). Processing related to BMLDs and interaural time differences has been confirmed in the auditory brainstem of non-human mammals; in the human auditory brainstem, phase-locked neural responses elicited by BMLD stimuli have not been systematically examined across signal-to-noise ratio. Behavioral and physiological testing was performed in three binaural stimulus conditions: SoNo, SπNo, and SoNπ. BMLDs at 500Hz were obtained from 14 young, normal-hearing adults (ages 21-26). Physiological BMLDs used the frequency-following response (FFR), a scalp-recorded auditory evoked potential dependent on sustained phase-locked neural activity; FFR tone-in-noise detection thresholds were used to calculate physiological BMLDs. FFR BMLDs were significantly smaller (poorer) than behavioral BMLDs, and FFR BMLDs did not reflect a physiological release from masking, on average. Raw FFR amplitude showed substantial reductions in the SπNo condition relative to SoNo and SoNπ conditions, consistent with negative effects of phase summation from left and right ear FFRs. FFR amplitude differences between stimulus conditions (e.g., SoNo amplitude-SπNo amplitude) were significantly predictive of behavioral SπNo BMLDs; individuals with larger amplitude differences had larger (better) behavioral B MLDs and individuals with smaller amplitude differences had smaller (poorer) behavioral B MLDs. These data indicate a role for sustained phase-locked neural activity in BMLDs of humans and are the first to show predictive relationships between behavioral BMLDs and human brainstem responses.

The Effects of Compensatory Auditory Stimulation and High-Definition Transcranial Direct Current Stimulation (HD-tDCS) on Tinnitus Perception - A Randomized Pilot Study.

BackgroundTinnitus correlates with elevated hearing thresholds and reduced cochlear compression. We hypothesized that reduced peripheral input leads to elevated neuronal gain resulting in the perception of a phantom sound.ObjectiveThe purpose of this pilot study was to test whether compensating for this peripheral deficit could reduce the tinnitus percept acutely using customized auditory stimulation. To further enhance the effects of auditory stimulation, this intervention was paired with high-definition transcranial direct current stimulation (HD-tDCS).MethodsA randomized sham-controlled, single blind study was conducted in a clinical setting on adult participants with chronic tinnitus (n = 14). Compensatory auditory stimulation (CAS) and HD-tDCS were administered either individually or in combination in order to access the effects of both interventions on tinnitus perception. CAS consisted of sound exposure typical to daily living (20-minute sound-track of a TV show), which was adapted with compressive gain to compensate for deficits in each subject's individual audiograms. Minimum masking levels and the visual analog scale were used to assess the strength of the tinnitus percept immediately before and after the treatment intervention.ResultsCAS reduced minimum masking levels, and visual analog scale trended towards improvement. Effects of HD-tDCS could not be resolved with the current sample size.ConclusionsThe results of this pilot study suggest that providing tailored auditory stimulation with frequency-specific gain and compression may alleviate tinnitus in a clinical population. Further experimentation with longer interventions is warranted in order to optimize effect sizes.

Binaural Hearing Ability With Bilateral Bone Conduction Stimulation in Subjects With Normal Hearing: Implications for Bone Conduction Hearing Aids.

The purpose of this study is to evaluate binaural hearing ability in adults with normal hearing when bone conduction (BC) stimulation is bilaterally applied at the bone conduction hearing aid (BCHA) implant position as well as at the audiometric position on the mastoid. The results with BC stimulation are compared with bilateral air conduction (AC) stimulation through earphones. Binaural hearing ability is investigated with tests of spatial release from masking and binaural intelligibility level difference using sentence material, binaural masking level difference with tonal chirp stimulation, and precedence effect using noise stimulus. In all tests, results with bilateral BC stimulation at the BCHA position illustrate an ability to extract binaural cues similar to BC stimulation at the mastoid position. The binaural benefit is overall greater with AC stimulation than BC stimulation at both positions. The binaural benefit for BC stimulation at the mastoid and BCHA position is approximately half in terms of decibels compared with AC stimulation in the speech based tests (spatial release from masking and binaural intelligibility level difference). For binaural masking level difference, the binaural benefit for the two BC positions with chirp signal phase inversion is approximately twice the benefit with inverted phase of the noise. The precedence effect results with BC stimulation at the mastoid and BCHA position are similar for low frequency noise stimulation but differ with high-frequency noise stimulation. The results confirm that binaural hearing processing with bilateral BC stimulation at the mastoid position is also present at the BCHA implant position. This indicates the ability for binaural hearing in patients with good cochlear function when using bilateral BCHAs.

The role of compression in the simultaneous masker phase effect.

Peripheral compression is believed to play a major role in the masker phase effect (MPE). While compression is almost instantaneous, activation of the efferent system reduces compression in a temporally evolving manner. To study the role of efferent-controlled compression in the MPE, in experiment 1, simultaneous masking of a 30-ms 4-kHz tone by 40-ms Schroeder-phase harmonic complexes was measured with on- and off-frequency precursors as a function of masker phase curvature for two masker levels (60 and 90 dB sound pressure level). The MPE was quantified by the threshold range [min/max difference (MMD)] across the phase curvatures. For the 60-dB condition, the presence of on-frequency precursor decreased the MMD from 10 to 5 dB. Experiment 2 studied the role of the precursor on the auditory filter's bandwidth. The on-frequency precursor was found to increase the bandwidth, an effect incorporated in the subsequent modeling. A model of the auditory periphery including cochlear filtering and basilar membrane compression generally underestimated the MMDs. A model based on two-step compression, including compression of inner hair cells, accounted for the MMDs across precursor and level conditions. Overall, the observed precursor effects and the model predictions suggest an important role of compression in the simultaneous MPE.

Testing a computational model for detection of “real-world” sounds

Hoglund (et al., 2010) reported the ability of listeners to detect a recorded signal masked by nine different ambient sounds. Signals were selected from 410 recordings of two different helicopters; maskers were selected from nine outdoor field recordings from three different locations. Signal and masker levels were randomized from trial to trial in a 2I,2AFC adaptive procedure to produce psychometric functions. Signal-to-masker ratios (SNR) ranged from -22 to -4 dBA for 70% correct detections. The Hoglund et al. results were used to tune a network of non-linear oscillators to optimize its performance. To evaluate the model, recordings of three fixed-wing aircraft were obtained for use as signals in the same nine environmental backgrounds. Signal and masker recordings were pre-processed to ensure that overall RMS voltage measures reflected the sound pressure level measured in a flat-plate coupler at the headphone used by the listeners. Model predictions for complete psychometric functions were obtained before experimental results were available for comparison. This poster presents details of the pre-processing of signals and maskers, and of the adaptive, single-interval procedure used to obtain the SNR for P(C) = 66.5%, 75%, and 87.5% by 16 listeners. Good agreement was found between model predictions and listener performance. [Work supported by a SBIR grant from AFOSR.]

Effects of stimulus level and rate on psychophysical thresholds for interleaved pulse trains in cochlear implants.

This study examined channel interactions using interleaved pulse trains to assess masking and potential facilitative effects in cochlear-implant recipients using clinically relevant stimuli. Psychophysical thresholds were measured for two adjacent mid-array electrodes; one served as the masker and the other as the probe. Two rates representative of those found in present-day strategies were tested: 1700 and 3400 pulses per second per channel. Four masker levels ranging from sub-threshold to loud-but-comfortable were tested. It was hypothesized that low-level maskers would produce facilitative effects, shifting to masking effects at high levels, and that faster rates would yield smaller masking effects due to greater stochastic neural firing patterns. Twenty-nine ears with Cochlear or Advanced Bionics devices were tested. High-level maskers produced more masking than low-level maskers, as expected. Facilitation was not observed for sub-threshold or threshold-level maskers in most cases. High masker levels yielded reduced probe thresholds for two Advanced Bionics subjects. This was partly eliminated with a longer temporal offset between each masker-probe pulse pair, as was used with Cochlear subjects. These findings support the use of temporal gaps between stimulation of subsequent electrodes to reduce channel interactions.

Influence of noise on sensitivity to ripple shift and spacing in rippled-spectrum signals

The influence of noise on hearing thresholds of ripple shift and ripple spacing in rippled-spectrum signals was investigated in humans. The band-limited noises with rippled spectra were used as signals. The signal spectrum band was 1 octave wide, centered at 2 kHz, the ripple spacing was frequency proportional. With the ripple-shift test, the ripple density was 3.5 cycles per octave and ripple-shift threshold was measured. With the ripple-spacing test, ripple-spacing threshold was measured using a ripple reversal paradigm. A two-alternative forced-choice procedure was combined with adaptive stimulation procedure. Signal levels were 50 or 80 dB SPL. Masker levels varied from 30 to 100 dB SPL. Masked thresholds were obtained for five maskers centered at 0 (on-frequency masker), 0.5, 0.75, 1, and 1.25 oct below the signal (low-frequency maskers). Both on- and low-frequency maskers increased thresholds of both ripple shifts and ripple spacing. The effect of the on-frequency masker depended more on masker/signal ratio than on masker or signal SPL. Effects of low-frequency maskers decreased with increasing the frequency distance between the signal and masker, and its effects became more dependent on masker SPL than on masker/signal ratio.

Performance of children with mild or moderate sensory hearing loss on central auditory tests

Hearing is fundamental to the development of successful language skills. Deficits in hearing acuity and auditory processing (AP) can profoundly obstruct effective communication. Our study aimed to evaluate the performance of children with mild and moderate sensory hearing loss (HL) on central AP tests. The study included 50 children: 10 children with normal hearing who were used as controls; 20 children with mild sensory HL; and 20 children with moderate sensory HL. Both male and female children were equally represented. All children underwent otoscopic examination, pure tone audiometry, tympanometry, and acoustic reflex measurements. Questionnaires on central AP disorders, dyslexia, and attention deficit hyperactivity disorder were answered by the parents. Screening tests for AP abilities [pitch pattern sequence test, speech perception in noise (SPIN) right SPIN, left SPIN, dichotic digit test] were conducted. All children were then examined with the full versions of the previous tests in addition to auditory fusion test − revised, masking level difference test, binaural fusion test, competing sentence test, and low pass-filtered test. Arabic-version dyslexia assessment was carried out for those who failed the tests. The study revealed that children with mild and moderate HL who failed the screening tests also failed the full version tests, and when tested by the Arabic-version dyslexia assessment test, dyslexia was found as a comorbid condition.

Binaural processing in adults with a history of traumatic brain injury

An auditory processing deficit is a perceptual issue affecting how the central auditory nervous system understands and makes use of auditory information. Auditory processing deficits are typically associated with the pediatric population; however, anecdotal clinical evidence and the recent focus on central auditory effects of traumatic brain injury (TBI) suggests that auditory processing deficits may be prevalent among adults with a history of TBI. Individuals with symptoms of an auditory processing deficit often score within the normal range on standard clinical assessments. The objectiveof the current study, therefore, was to target measures of binaural processing to identify and characterize auditory processing deficits among adults with a history of TBI. Two groups were recruited: adults with a history of TBI and a control group. Binaural processing was measured with: 1) the Revised Speech Perception in Noise test measured in soundfield; 2) dichotic word recognition without and with low-pass filtering measured in the free recall and directed recall conditions; 3) the 500-Hz masking level difference; and 4) the Listening in Spatialized Noise Sentences Test. Results suggest that individuals with a history of TBI have lower than normal binaural performance.

Analysis of Masked Data in a Series System Subjected to Sources of Shocks Under Type I Progressive Hybrid Censoring

Abstract In this paper, we consider the statistical analysis of masked data based on the fatal shock model under type I progressive hybrid censoring. It is assumed that the time of shock follows Weibull distribution. Maximum-likelihood estimators for the unknown parameters are obtained by solving a one-dimensional optimization problem. Approximate maximum-likelihood estimators have been proposed based on a Taylor series expansion, and they have explicit expressions. In addition, the Bayesian approach, combined with Gibbs sampling, are developed based on the assumption that the shape parameter has a log-concave function, and for the given shape parameter, the scale parameters have Gamma-Dirichlet priors. Finally, Monte Carlo simulations are performed to compare the performances of the proposed methods under different progressive censoring schemes and masking levels.

A metric for predicting binaural speech intelligibility in stationary noise and competing speech maskers.

One criterion in the design of binaural sound scenes in audio production is the extent to which the intended speech message is correctly understood. Object-based audio broadcasting systems have permitted sound editors to gain more access to the metadata (e.g., intensity and location) of each sound source, providing better control over speech intelligibility. The current study describes and evaluates a binaural distortion-weighted glimpse proportion metric-BiDWGP-which is motivated by better-ear glimpsing and binaural masking level differences. BiDWGP predicts intelligibility from two alternative input forms: either binaural recordings or monophonic recordings from each sound source along with their locations. Two listening experiments were performed with stationary noise and competing speech, one in the presence of a single masker, the other with multiple maskers, for a variety of spatial configurations. Overall, BiDWGP with both input forms predicts listener keyword scores with correlations of 0.95 and 0.91 for single- and multi-masker conditions, respectively. When considering masker type separately, correlations rise to 0.95 and above for both types of maskers. Predictions using the two input forms are very similar, suggesting that BiDWGP can be applied to the design of sound scenes where only individual sound sources and their locations are available.

Manganese and Lipoflavonoid Plus(®) to Treat Tinnitus: A Randomized Controlled Trial.

Several tinnitus sufferers suggest that manganese has been helpful with their tinnitus. We tested this in a controlled experiment where participants were committed to taking manganese and Lipoflavonoid Plus(®) to treat their tinnitus. Randomized controlled trial. 40 participants were randomized to receive both manganese and Lipoflavonoid Plus(®) for 6 months, or Lipoflavonoid Plus(®) only (as the control). Pre- and postmeasures were obtained with the Tinnitus Handicap Questionnaire, Tinnitus Primary Functions Questionnaire, and tinnitus loudness and annoyance ratings. An audiologist performed the audiogram, the tinnitus loudness match, and minimal masking level. Twelve participants were dropped out of the study because of the side effects or were lost to follow-up. In the manganese group, 1 participant (out of 12) showed a decrease in the questionnaires, and another showed a decrease in the loudness and annoyance ratings. No participants from the control group (total 16) showed a decrease in the questionnaires ratings. Two participants in the control group reported a loudness decrement and one reported an annoyance decrement. We were not able to conclude that either manganese or Lipoflavonoid Plus(®) is an effective treatment for tinnitus.

"Measurement" of Tinnitus.

Chronic tinnitus is the persistent sensation of hearing a sound that exists only inside the head. The prevalence of tinnitus in adults in the United States is estimated at 10 to 15%. For about 20% of these individuals the tinnitus is significantly bothersome. Although myriad therapies for tinnitus are offered (often at significant cost), most are not evidence based. Difficulty in the assessment and further development of interventions for tinnitus stems from the limitations of techniques used to evaluate these interventions. Questionnaires are widely available to "measure" (tinnitus can only be indirectly measured) functional effects of tinnitus, such as difficulty sleeping and concentrating, and negative emotions such as anxiety, depression, and annoyance. Questionnaires have recently been documented for sensitivity to change in response to intervention (i.e., "responsiveness"). All of these questionnaires function well to assess the overall impact of tinnitus. The limitations mentioned pertain primarily to measures of tinnitus perception, which typically include the psychoacoustic measures of tinnitus loudness and pitch matches, tinnitus spectral content, minimum masking levels, and residual inhibition. These measures, which are obtained routinely in many clinics and as part of research studies, have not been validated for being diagnostic, prognostic, discriminative, or responsive. In order for these measures to become clinically meaningful, normative standards are needed, both for baseline measures and for repeated measures of tinnitus perception. Evidence-based intervention for tinnitus requires accurately measuring both the perception of, and reactions to, tinnitus.

Comparison of characteristics observed in tinnitus patients with unilateral vs bilateral symptoms, with both normal hearing threshold and distortion-product otoacoustic emissions

Conclusion: Tinnitus characteristics in normal-hearing patients differ between the groups with unilateral and bilateral complaints.Objectives: The study was to determine the differences between tinnitus characteristics observed in patients with unilateral vs bilateral symptoms and normal hearing threshold, as well as normal results of distortion-product otoacoustic emissions (DPOAEs).Method: The patients answered questions concerning tinnitus duration, laterality, character, accompanying symptoms, and circumstances of onset. The results of tympanometry, auditory brainstem responses, tinnitus likeness spectrum, minimum masking level (MML), and uncomfortable loudness level were evaluated. Records of 380 tinnitus sufferers were examined. Patients with abnormal audiograms and/or DPOAEs were excluded. The remaining 66 participants were divided into groups with unilateral and bilateral tinnitus.Results: Unilateral tinnitus in normal-hearing patients was diagnosed twice more frequently than bilateral. Tinnitus pitch was higher in the group with bilateral tinnitus (p < .001). MML was lower in unilateral tinnitus (p < .05). Mean age of patients was higher in the unilateral tinnitus group (p < .05). Mean tinnitus duration was longer (p < .05) and hypersensitivity to sound was more frequent (p < .05) in the bilateral tinnitus group. Repeated exposure to excessive noise was the most frequent cause in the bilateral tinnitus group.

EPV 17. Reduced tone detection contralateral to auditory cortex lesions in complex auditory scenes

Objective Unilateral structural lesions of auditory cortex are considered to produce little neurological deficits and no elevation of contralateral detection thresholds. Extinction contralateral to the lesion has been shown with dichotic tests ( Blaettner et al., 1989 , Biedermann et al., 2008 , Gutschalk et al., 2012 ). Here we tested if auditory detection is more generally reduced in the presence of competing sounds using multi-tone informational masking ( Durlach et al., 2003 ). Methods We studied 14 patients with auditory cortex lesions (6 left-, 8 right-hemispheric) and 25 control listeners. Targets were six isochronous pure tones of 100 ms duration and a repetition interval of 400 ms. Target tones were presented monaurally and the frequency within a target sequence was fixed at 846 Hz, 950 Hz or 1066 Hz. Four difficulty levels of multi-tone maskers were used, comprising 2, 4, 6 or 12 tones within each 400-ms interval. Half of the masker tones were presented to the left ear and the other half to the right ear. Tone frequencies were randomly drawn from the range 100–5000 Hz. Half an octave around the target tones was kept as protected region to minimize energetic masking. Tone onsets were random within each 400 ms time interval. Participants indicated after each sequence, whether an isochronous target was present or not. There were 36 target trials and 18 catch trials without target for each masker level. Results Detection, as measured with the sensitivity index d ′ , decreased with increasing number of masker tones for controls and patients. Patients showed reduced target detection in the ear contralateral to the lesion. In comparison to the controls, patients also showed reduced absolute detection. Since this effect was stronger for right-hemisphere patients, we further explored if residual neglect could contribute to the effect. When neglect was modelled as additional factor, the effect of reduced overall detection depending on auditory cortex lesions was not significant any more. However, the contralateral deficit remained significant. Conclusion These results show that competing sounds reduce auditory detection in patients with auditory cortex lesion. Even though the effect was smaller than expected, it may potentially cause hearing difficulties of patients in crowded environments. Since the effect was only significant in the ear contralateral to the lesion, it has to be discussed how closely the effect is related to extinction in dichotic tests.

Short-term visual deprivation can enhance spatial release from masking

This research aims to study the effect of short-term visual deprivation on spatial release from masking, a major component of the cocktail party effect that allows people to detect an auditory target in noise. The Masking Level Difference (MLD) test was administered on healthy individuals over three sessions: before (I) and after 90min of visual deprivation (II), and after 90min of re-exposure to light (III). A non-deprived control group performed the same tests, but remained sighted between sessions I and II. The non-deprived control group displayed constant results across sessions. However, performance in the MLD test was improved following short-term visual deprivation and performance returned to pre-deprivation values after light re-exposure. This study finds that short-term visual deprivation transiently enhances the spatial release from masking. These data suggest the significant potential for enhancing a process involved in the cocktail party effect in normally developing individuals and adds to an emerging literature on the potential to enhance auditory ability after only a brief period of visual deprivation.

Systematic review of outcome domains and instruments used in clinical trials of tinnitus treatments in adults.

BackgroundThere is no evidence-based guidance to facilitate design decisions for confirmatory trials or systematic reviews investigating treatment efficacy for adults with tinnitus. This systematic review therefore seeks to ascertain the current status of trial designs by identifying and evaluating the reporting of outcome domains and instruments in the treatment of adults with tinnitus.MethodsRecords were identified by searching PubMed, EMBASE CINAHL, EBSCO, and CENTRAL clinical trial registries (ClinicalTrials.gov, ISRCTN, ICTRP) and the Cochrane Database of Systematic Reviews. Eligible records were those published from 1 July 2006 to 12 March 2015. Included studies were those reporting adults aged 18 years or older who reported tinnitus as a primary complaint, and who were enrolled into a randomised controlled trial, a before and after study, a non-randomised controlled trial, a case-controlled study or a cohort study, and written in English. Studies with fewer than 20 participants were excluded.ResultsTwo hundred and twenty-eight studies were included. Thirty-five different primary outcome domains were identified spanning seven categories (tinnitus percept, impact of tinnitus, co-occurring complaints, quality of life, body structures and function, treatment-related outcomes and unclear or not specified). Over half the studies (55 %) did not clearly define the complaint of interest. Tinnitus loudness was the domain most often reported (14 %), followed by tinnitus distress (7 %). Seventy-eight different primary outcome instruments were identified. Instruments assessing multiple attributes of the impact of tinnitus were most common (34 %). Overall, 24 different patient-reported tools were used, predominantly the Tinnitus Handicap Inventory (15 %). Loudness was measured in diverse ways including a numerical rating scale (8 %), loudness matching (4 %), minimum masking level (1 %) and loudness discomfort level (1 %). Ten percent of studies did not clearly report the instrument used.ConclusionsOur findings indicate poor appreciation of the basic principles of good trial design, particularly the importance of specifying what aspect of therapeutic benefit is the main outcome. No single outcome was reported in all studies and there was a broad diversity of outcome instruments.PROSPERO registrationThe systematic review protocol is registered on PROSPERO (International Prospective Register of Systematic Reviews): CRD42015017525. Registered on 12 March 2015 revised on 15 March 2016.Electronic supplementary materialThe online version of this article (doi:10.1186/s13063-016-1399-9) contains supplementary material, which is available to authorized users.

Role of worry in patients with chronic tinnitus and sensorineural hearing loss: a preliminary study.

Tinnitus-related distress appears to be more strongly associated with multiple psychological factors than with any perceptual properties of tinnitus. Prior studies have not investigated the role of worry in tinnitus sufferers. Worry is a dispositional cognitive trait that involves a pervasive, non-specific, future-oriented proneness to fretting, which can foster negative affective states and catastrophic thinking about a specific trouble when the trouble is actual and present. We examined the relationship between worry and self-perceived anxiety and depressive symptoms and handicap in 54 outpatients with chronic tinnitus and sensorineural hearing loss who had been previously recruited for a randomized double-blind study on the efficacy of transmeatal low-level laser therapy for tinnitus. We measured the current anxiety and depressive symptoms with the State-Trait Anxiety Inventory Form Y-1/Self-evaluation Depression Scale, the handicap with the Tinnitus Handicap Inventory, and the proneness to worry with the Penn State Worry Questionnaire. For the psychoacoustic tinnitus measures, we considered the loudness match and the minimum masking level. We found that tinnitus-related anxiety and depressive symptoms and handicap were significantly associated with proneness to worry (linear regression models, p<0.01), whereas no associations were found with the psychoacoustic measures. This suggests the usefulness of worry assessment when managing chronic tinnitus in clinical practice. Early therapeutic interventions for reducing proneness to worry may facilitate better adaptation to tinnitus.

Discrimination of rippled spectra in background of maskers of different frequencies

Discrimination of rippled-spectrum signals in masking noise was investigated in normal listeners. The rippled-spectrum signal was 0.5-oct wide centered at 2 kHz. Simultaneous masker was a 0.5-oct wide noise centered below, on, or above the signal band (low-, on-, and high-frequency maskers, respectively). Discrimination of the signals was assessed by (i) threshold for discrimination of ripple spacing; (ii) threshold for discrimination of spectrum-pattern shift. The threshold dependence on the masker level was qualitatively different for the low- and on-frequency maskers. For the on-frequency masker, the masking effect primarily depended on the masker/signal ratio: the thresholds steeply increased at a ratio of 5 dB; no ripple pattern was discriminated at a ratio of 10 dB or higher. Alternatively, for the low-frequency masker, the masking effect primarily depended on the masker SPL: the threshold increased at a masker SPL of 70–80 dB; no ripple pattern was discriminated at a masker SPL of 100 dB. The high-frequency masker produced little effect. Hypothetically, the effect of the on-frequency masker appeared due to a decrease of ripple depth when the masker overlapped the signal, whereas the effect of the low-frequency masker appeared due to widening of the auditory filters at high sound levels.