Normal Hearing Tinnitus Research Articles

Sound-Evoked Neural Activity in Normal-Hearing Tinnitus: Effects of Frequency and Stimulated Ear Side.

Tinnitus is a common phantom auditory percept believed to be related to plastic changes in the brain due to hearing loss. However, tinnitus can also occur in the absence of any clinical hearing loss. In this case, since there is no hearing loss, the mechanisms that drive plastic changes remain largely enigmatic. Previous studies showed subtle differences in sound-evoked brain activity associated with tinnitus in subjects with tinnitus and otherwise normal hearing, but the results are not consistent across studies. Here, we aimed to investigate these differences using monaural rather than binaural stimuli. Sound-evoked responses were measured using functional magnetic resonance imaging (MRI) in participants with and without tinnitus. All participants had clinically normal audiograms. The stimuli were pure tones with frequencies between 353 and 8000 Hz, presented monaurally. A Principal Component Analysis (PCA) of the response in the auditory cortex revealed no difference in tonotopic organization, which confirmed earlier studies. A GLM analysis showed hyperactivity in the lateral areas of the bilateral auditory cortex. Consistent with the tonotopic map, this hyperactivity mainly occurred in response to low stimulus frequencies. This may be related to hyperacusis. Furthermore, there was an interaction between stimulation side and tinnitus in the parahippocampus. This may reflect an interference between tinnitus and spatial orientation.

Tinnitus and Cochlear Functions in Hearing Impaired and Normal Hearing Individuals

Background: In order to determine the pathophysiology of tinnitus and deciding on treatment, the function of peripheral hearing organs is very important. Objective: To evaluate the cochlear functions in tinnitus patients with or without hearing-loss(HL). Methods: Participants with tinnitus were divided into two groups; 16 participants with accompanying HL were included in the first study group (SG-I), and 15 participants without HL were included in the second group (SG-II). 21 normal-hearing subjects without tinnitus included as control group(CG). Tinnitus discomfort levels was determined with Tinnitus Handicap Inventory(THI). Besides pure-tone audiometry, Otoacoustic Emissions, to evaluate cochlear functions and to decide dead regions (DR), Threshold Equalizing Noise-(TEN) was used. Results: The threshold-shift was observed with TEN in subjects in SG-I and these levels were statistically different from SG-II and CG. There were both threshold-shift and DR in SG-II according to TEN. TEOAEs did not differ between SG-II and CG. The DPOAE results for SG-II showed significant decreases in emission amplitudes at 6 & 8 kHz. Conclusion: While Tinnitus patients with HL can be evaluated with conventional tests, evaluating patients with normal hearing tinnitus with additional tests such as OAE and TEN allows us to get more precise results on the functions of peripheral hearing organs.

Behavioural and Electrophysiological Evaluation of Loudness Growth in Clinically Normal Hearing Tinnitus Patients with and without Hyperacusis

Introduction: The common mechanism of tinnitus, hyperacusis, and loudness perception is hypothesized to be related to central gain. Although central gain increases with attempts to compensate hearing loss, reduced input can also be observed in those with clinically normal hearing. This study aimed to evaluate the loudness growth function of tinnitus patients with and without hyperacusis using behavioural and electrophysiological methods. Methods: The study consists of three groups with a total of 60 clinically normal hearing subjects, including the control group (10 men and 10 women; mean age 39.8, SD 11.8 years), tinnitus group (10 men and 10 women; mean age 40.9, SD 12.2 years), and hyperacusis group (also have tinnitus) (7 men and 13 women; mean age 38.7, SD 14.6 years). Loudness discomfort levels (LDLs), categorical loudness scaling (CLS), and cortical auditory evoked potentials were used for the evaluation of loudness growth. N1-P2 component amplitudes and latencies were measured. Results: LDL results of 500, 1,000, 2,000, 4,000, and 8,000 Hz showed a significant difference between the hyperacusis group and the other two groups (p < 0.001). In the loudness scale test performed with 500 Hz and 2,000 Hz narrow-band noise (NBN) stimulus, a significant difference was observed between the hyperacusis group and the other two groups in the “medium,” “loud,” and “very loud” categories (p < 0.001). In the cortical examination performed with 500 Hz and 2,000 Hz NBN stimulus at 40, 60, and 80 dB nHL intensities, no significant difference was observed between the groups in the N1, P2 latency, and N1-P2 peak-to-peak amplitude. Conclusion: Although the hyperacusis group is significantly different between groups in behavioural tests, the same cannot be said for electrophysiological tests. In our attempt to differentiate tinnitus and hyperacusis with electrophysiological tests over the loudness growth function, N1 and P2 responses were not seen as suitable methods. However, it appears to be beneficial to use CLS in addition to LDLs in behavioural tests.

Study of auditory brainstem response in tinnitus patients with normal hearing

Introduction: Tinnitus is often associated with hearing loss, but it may occur in patients with normal hearing. However, normal hearing thresholds do not exclude cochlear damage.Tinnitus may be initiated by abnormal activity from the peripheral auditory system, but its progress and maintenance is due to the central nervous system involvement. For that reason, Auditory Brainstem Response (ABR) may contribute to clarify the origin of tinnitus.Aim: The aim of this study is to evaluate the ABR waveform amplitude and latencies in tinnitus patients with normal hearing to explore the origin of tinnitus.Results: Auditory brainstem response, recorded using ipsilateral rarefaction click stimuli at 80 dBnHL in 10 normal hearing tinnitus adult patients and 10 matching controls, showed that Wave I amplitude was significantly reduced in the study group when compared to control group. The V/I amplitude ratio was significantly higher in the study group compared to control group. The absolute latency of wave I was significantly increased in the study group compared to control group. Interpeak I-V latency was significantly decreased in the study group compared to control group.Conclusion: Tinnitus sufferers with normal audiometric thresholds might show ABR amplitude changes indicative of cochlear synaptopathy (reduced wave I amplitude) and compensated central responses (no reduction in wave V amplitude). The increased responsiveness of central regions might lead to tinnitus generation secondry to increased spontaneous activity.

Otoacoustic emissions and contralateral suppression in tinnitus sufferers with normal hearing

BackgroundThe general consensus on the role of hearing loss in generating tinnitus is not relevant in tinnitus patients with normal hearing thresholds. One source of tinnitus may be related to damage to outer hair cells (OHC) of the cochlea. If the OHC of the human cochlea are to be involved in the generation of tinnitus, testing of Otoacoustic emissions (OAE) could provide a reliable means of recording OHC dysfunction. We investigated the role of OHC and cochlear efferent system in tinnitus development in normal hearing ears through studying of Distortion Product Otoacoustic Emissions (DPOAE) and Transient Evoked Otoacoustic Emissions (TEOAE) amplitudes, contralateral suppression amplitudes and suppression value in 15 normal hearing tinnitus patients and 15 control subjects.ResultsMean f2 DPOAE amplitudes and contralateral suppression were significantly lower in tinnitus group compared to controls for all frequencies from 1001 to 6348 Hz. Suppression values of DPOAEs revealed lower but not significant difference between tinnitus and control groups for all frequencies except 1587 and 6348 Hz. TEOAE amplitudes and contralateral suppression were significantly lower in tinnitus groups for all frequencies from 1000 to 4000 Hz compared to the control group. Suppression value of TEOAEs revealed no significant difference between the two groups for all frequencies except 3000 and 4000 Hz were significantly lower in the tinnitus group compared to the control group.ConclusionsNormal hearing manifested by pure tone audiometry in non-vascular tinnitus sufferers does not exclude OHC and/or cochlear efferent pathology.

Clinical management of tinnitus

Aim: Tinnitus is defined as the perception of sound or sounds without any external audible source. Unknown ethiopathological mechanisms with lack of standardized protocol in symptom evaluation, causes difficulties in clinical management. Therefore, we aimed to evaluate the efficacy of magnesium, misoprostol and lidocaine treatments in patients with tinnitus.Material and Methods: The 58 tinnitus cases, were evaluated retrospectively. A total number of 40 patients who were able to comply with the scheduled therapy were received two staged therapy. As first line therapy, 20 patients with sensorineural hearing loss and acoustic trauma history were received oral magnesium, while remaining 20 cases without hearing loss were received oral misoprostol. Tinnitus handicap inventory (THI) was applied to all patients before and one month after the therapy. As second line therapy, 1.5mg/kg intravenous lidocaine was administered to the patients who had ineffective treatment results according to the THI.Results: The 40 patients included in this study were 10 female (25%), and 30 male (75%) and the mean age of all patients was 41,47 years. In both magnesium and misoprostol group, the mean scores of post-treatment THI were significantly lower than pre-treatment THI scores (p-values=0,001 and 0,007, respectively). No statistically significant difference was found between pre - and post treatment scores of the THI in lidocaine group.Conclusion: In present study, it was demonstrated that magnesium treatment is effective on tinnitus cases with acoustic trauma and misoprostol is effective on normal hearing tinnitus group, whereas intravenous lidocaine treatment was not found to be effective in tinnitus.

Speech-in-noise recognition examined in individuals with normal hearing sensitivity and tinnitus using behavioral and brain imaging methods

Although we know tinnitus can cause concentration problems, its contribution to communication difficulties has not been well-studied. In a series of experiments, we have investigated Speech-in-noise (SiN) performance, in those with tinnitus and normal hearing sensitivity using a variety of methods, including behavioral, otoacoustic emissions, structural MRI and in a proposed study, ERP/ EEG. We found that tinnitus patients with normal hearing sensitivity did not have a general speech-in-noise deficit (Tai and Husain, JARO, 2018). Instead, our findings indicated that the tinnitus group performed significantly worse only under the 5-dB signal-to-noise ratio (SNR) condition. Additionally, the SiN performance in tinnitus patients was found to be significantly correlated with the perceptual factors related to tinnitus, such as perceived loudness, and was worse in the left ear. We are currently investigating (1) how the left ear appears to be more affected in tinnitus by using structural MRI and (2) whether there is any correlation between tinnitus pitch and consonant recognition. For both the latter studies, we are also contrasting the normal hearing tinnitus group with a hearing loss tinnitus group and other control groups.

Auditory Related Resting State fMRI Functional Connectivity in Tinnitus Patients: Tinnitus Diagnosis Performance.

The purpose of the present study was to investigate functional connectivity in tinnitus patients with and without hearing loss, and design the tinnitus diagnosis performance by resting state functional magnetic resonance imaging (rs-fMRI). Nineteen volunteers with normal hearing without tinnitus, 18 tinnitus patients with hearing loss, and 11 tinnitus patients without hearing loss were enrolled in this study. The subjects were evaluated with rs-fMRI, and region of interests (ROIs) based correlation analyses were performed using the CONN toolbox version 16 and SPM version 8. The correlation coefficients from individual level results were converted into beta values. With a beta threshold of more than 0.2, 91% of all possible connections between auditory-related ROIs (Heschl's gyrus, planum temporale, planum polare, operculum, insular cortex, superior temporal gyrus) in the control group remained intact, whereas 83 and 66% of such connections were present in the hearing loss and the normal-hearing tinnitus group. However, between non-auditory-related ROIs, the rates of intact connections at a beta threshold of more than 0.2 were 17% in the control group, and 16 and 15% in the tinnitus groups. When resting state fMRI positive is defined as less than 9% of all possible connections between auditory-related ROIs with a beta threshold of more than 0.7, the sensitivity and specificity of tinnitus diagnosis is 86 and 74%, respectively. The associations between auditory-related networks are weakened in tinnitus patients, even if they have normal hearing. It is possible that rs-fMRI can be a tool for objective examination of tinnitus, by focusing the auditory-related areas.

Autobiographical Memory Specificity in Patients with Tinnitus Versus Patients with Depression and Normal Controls

Several studies show that patients with depression and post-traumatic stress disorder respond with fewer specific autobiographical memories in a cued memory task (i.e. the autobiographical memory test; AMT) compared to healthy controls. One previous study found this phenomenon among tinnitus patients as well (Andersson, Ingerholt, & Jansson, 2003). The aim of this study was to replicate the previous study with an additional control group of depressed patients and memory errors as measured with the AMT as an additional outcome. We included 20 normal hearing tinnitus patients, 20 healthy controls and 20 persons diagnosed with clinical depression. The AMT was administered together with self-report measures of depression, anxiety and tinnitus distress. Both the tinnitus and depression groups differed from the healthy control group in that they reported fewer specific autobiographical memories. There were, however, differences between the tinnitus and depression groups in terms of the errors made on the AMT. The depression group had more overgeneral memories than the normal control group, whereas the tinnitus group did not differ from the control group on this memory error. The tinnitus group had more semantic associations and non-memories than the other two groups, suggesting that executive functioning may play a role for the tinnitus group when completing the AMT. Clinical and theoretical implications of the findings are discussed.

Does Tinnitus Distress Depend on Age of Onset?

ObjectivesTinnitus is the perception of a sound in the absence of any physical source of it. About 5–15% of the population report hearing such a tinnitus and about 1–2% suffer from their tinnitus leading to anxiety, sleep disorders or depression. It is currently not completely understood why some people feel distressed by their tinnitus, while others don't. Several studies indicate that the amount of tinnitus distress is associated with many factors including comorbid anxiety, comorbid depression, personality, the psychosocial situation, the amount of the related hearing loss and the loudness of the tinnitus. Furthermore, theoretical considerations suggest an impact of the age at tinnitus onset influencing tinnitus distress.MethodsBased on a sample of 755 normal hearing tinnitus patients we tested this assumption. All participants answered a questionnaire on the amount of tinnitus distress together with a large variety of clinical and demographic data.ResultsPatients with an earlier onset of tinnitus suffer significantly less than patients with an onset later in life. Furthermore, patients with a later onset of tinnitus describe their course of tinnitus distress as more abrupt and distressing right from the beginning.ConclusionWe argue that a decline of compensatory brain plasticity in older age accounts for this age-dependent tinnitus decompensation.

Acceptance and Commitment Therapy versus Tinnitus Retraining Therapy in the treatment of tinnitus: A randomised controlled trial

The study compared the effects of Acceptance and Commitment Therapy (ACT) with Tinnitus Retraining Therapy (TRT) on tinnitus impact in a randomised controlled trial. Sixty-four normal hearing subjects with tinnitus were randomised to one of the active treatments or a wait-list control (WLC). The ACT treatment consisted of 10 weekly 60 min sessions. The TRT treatment consisted of one 150 min session, one 30 min follow-up and continued daily use of wearable sound generators for a recommended period of at least 8 h/day for 18 months. Assessments were made at baseline, 10 weeks, 6 months and 18 months. At 10 weeks, results showed a superior effect of ACT in comparison with the WLC regarding tinnitus impact (Cohen’s d = 1.04), problems with sleep and anxiety. The results were mediated by tinnitus acceptance. A comparison between the active treatments, including all assessment points, revealed significant differences in favour of ACT regarding tinnitus impact (Cohen’s d = 0.75) and problems with sleep. At 6 months, reliable improvement on the main outcome measure was found for 54.5% in the ACT condition and 20% in the TRT condition. The results suggest that ACT can reduce tinnitus distress and impact in a group of normal hearing tinnitus patients.

The Analysis of Hearing of Tinnitus Patients

Objective To investigate the necessity to test the hearing of patients whose initial symptom is tinnitus with pure tone audiometer. Methods To analyze the results of pure tone audiometer of 218 tinnitus patients.Results Among 218 cases of tinnitus patients,a total of 123 patients with abnormal hearing,among 95 cases of patients with normal hearing, except for 50 cases of tinnitus, no other cause of disease. Conclusion Among the normal hearing tinnitus patients, we should do further hearing test for them if they are not identified a clear cause of disease,such as auditory brainstem response,otoacoustic emission and other necessary checks to clear the reasons for tinnitus or the position of the unusual auditory system. It is important for early diagnosis and treatment of tinnitus. But the pure-tone audiometer should be a routine examination when tinnitus patients come for the first visit. Key words: Tinnitus; Hearing test; Otoacoustic emissions

Clinical characteristics and audiological significance of spontaneous otoacoustic emissions in tinnitus patients with normal hearing

To define the clinical and audiological features of normal-hearing tinnitus patients with spontaneous otoacoustic emissions, and to evaluate the role of spontaneous otoacoustic emissions in tinnitus generation. Thirty-two patients with spontaneous otoacoustic emissions were compared with 29 patients without spontaneous otoacoustic emissions, regarding clinical and audiological aspects. The mean age of the study group subjects was significantly lower, and they experienced the kindling effect less frequently than the control group. The mean tinnitus handicap inventory score of the study group was considerably higher than that of the controls, although the difference was not statistically significant. The study group had significantly quieter tinnitus, and higher transient evoked and distortion product otoacoustic emission responses, compared with the control group. Normal-hearing tinnitus patients with spontaneous otoacoustic emissions have different clinical and audiological characteristics, compared with those without spontaneous otoacoustic emissions. Appropriate evaluation and treatment should be considered at an early stage in these patients.

Neuro-otological findings in tinnitus patients with normal hearing

Tinnitus is usually associated with hearing loss, and patients with tinnitus and normal hearing are unusual. Neuro-otological findings have not previously been described in tinnitus patients with normal hearing. To analyse neuro-otological examination results from a group of tinnitus patients with normal hearing. Seventeen normal-hearing tinnitus patients seen over a 10-year period were retrospectively evaluated. Their results were compared with those of a control group of 17 normal subjects without tinnitus. The main neuro-otological finding in the tinnitus patients was caloric test abnormality: a unilateral canal paresis was present in 15 of the 17 patients. Caloric tests were normal in 15 of the 17 control subjects. We may infer from these results that tinnitus could be the only clinical manifestation of a cochlear - and presumably cochleo-vestibular - lesion, and that unilateral canal paresis may be the only abnormal finding on neuro-otological examination.

Quantitative analysis of cochlear active mechanisms in tinnitus subjects with normal hearing sensitivity: multiparametric recording of evoked otoacoustic emissions and contralateral suppression

Aim of this study was to investigate the possible role played by outer hair cells and cochlear efferent system functionality when tinnitus develops in normal hearing ears. A multiparametric approach was used, entailing recording and analysis of a set of otoacoustic emissions (OAEs): distortion product (DPOAEs), transient evoked (TEOAEs) and efferent-mediated TEOAE suppression in the presence of contralateral acoustic stimulation (CAS). Fifty-four subjects with normal hearing sensitivity participated in the study. Twenty-three suffered from chronic subjective tinnitus whereas thirty-one did not have tinnitus and acted as control subjects. DPOAEs were measured with eliciting tones of frequency ratio 1.22 and intensity 65 and 55dB SPL in the frequency range 0.5-8kHz. TEOAEs were recorded with the 'linear' protocol using clicks at 60dB peak SPL both in the absence and in the presence of CAS at two different intensities. DPOAE amplitude, TEOAE amplitude, and TEOAE suppression were analysed as relevant parameters. Significantly reduced DPOAE amplitude in the frequency range 1.5-8kHz, lower TEOAE amplitude, and slightly decreased TEOAE suppression were measured in tinnitus subjects compared to non-tinnitus controls. In particular, 74% of tinnitus subjects exhibited abnormal DPOAEs, 13% had abnormal TEOAEs, whereas abnormal TEOAE suppression was found in 9% of patients. Overall, the present work revealed the presence of abnormal OAEs, in particular at higher frequencies, in tinnitus subjects with normal hearing sensitivity. A minor (i.e., sub-clinical) outer hair cell dysfunction, particularly in high-frequency cochlear regions, might thus be assumed in normal hearing tinnitus subjects. In order to better put in light the possible role played by outer hair cells in low-frequency cochlear regions, or by the cochlear efferent system, additional analyses would be needed.

Characteristics of DPOAE audiogram in tinnitus patients

To investigate cochlear activity in tinnitus, the DPOAE (distortion product otoacoustic emission) audiograms (DP-gram) of tinnitus patients were measured. Nine tinnitus patients (15 ears) with normal hearing and 55 tinnitus patients (75 ears) with hearing impairment were included in this study. Significant decreases in DPOAE amplitude over a limited frequency range were observed in 93.3% of the normal hearing tinnitus group and in 96% of the hearing-impaired tinnitus group. The averaged DP-gram of the normal hearing tinnitus group was significantly different from that of the normal subjects (repeated-measures ANOVA, P<0.01). These results imply that tinnitus may be evaluated objectively by DPOAE.