External Acoustic Stimulus Research Articles

Electrophysiological auditory measures to identify potential cortical markers of tinnitus

Tinnitus, or the perception of a sound in the absence of an external acoustic stimulus, is a common condition that cannot yet be objectively diagnosed. Current diagnostic tests of tinnitus consist of case history and behavioral measures that rely on subjective responses. This study examined electrophysiological measures, specifically the auditory late response (ALR), mismatch negativity (MMN), and P300 as potential neural biomarkers of tinnitus in both a tinnitus and non-tinnitus control group while utilizing the pitch-matched tinnitus frequencies as the test stimuli. Results of this study found differences in MMN amplitudes and area under the curve, and in P300 topographic maps between tinnitus and control subjects. The differences in MMN responses across groups suggest that dysfunctional processing of acoustic stimuli located near the tinnitus frequency in individuals with tinnitus manifests as soon as 200 ms after initial onset of the stimulus. In addition, results from a global field power analysis and differences in spatial distributions on topographical maps indicate that deficits persist through higher levels of cortical processing. A secondary goal of this study was to determine if electrophysiological measures correlated with reported tinnitus severity on questionnaires. This analysis indicated that P2 latency was a significant predictor of Tinnitus Reaction Questionnaire, Tinnitus Handicap Inventory, and percent of the time participant’s tinnitus was considered bothersome, suggesting that this measure could potentially be used to assess the efficacy of treatment programs for tinnitus.

High-frequency audiometry in the diagnosis of tinnitus

BackgroundSubjective tinnitus is an unpleasant perception of sound without any external acoustic stimulus. It can be manifested in the form of various phantom sounds, which most often resemble ringing, whistling, squeaking, noise, chirping, or buzzing. The sounds are heard solely by the sufferer and can occur in the middle of the head, but also in the ears—on one or both sides.AimThe aim of the study was to evaluate the hearing capacity based on audiometric threshold measurements in the frequency range of 0.125–16 kHz in patients with tinnitus. In addition, we investigated the following questions:Can high-frequency audiometry be useful in the diagnosis of tinnitus?Does hearing loss occur in an increasingly wide frequency range with age compared to the control group?Can tinnitus be considered the first symptom of the onset of high-frequency hearing loss?MethodsThe study included 99 patients, all of whom underwent pure-tone audiometry (PTA) and extended high-frequency audiometry (HFA) in the ranges of 0.125–8 kHz and 8–16 kHz, respectively. In each patient (excluding the control group), tinnitus was characterized in terms of its frequency and intensity.Results and conclusionThe study concluded that tinnitus may be a symptom indicating the presence of high-frequency hearing loss as hearing loss occurs in an increasingly wider frequency range with age, so HFA should be a routine audiological test in patients with tinnitus.

A Scoping New Revolution for Tinnitus Management: A Neuromonics Narrative Review.

With a prevalence ranging from 16-21%, tinnitus is an irking neurological disorder, manifesting as the perception of a roar of cacophony without an external acoustic stimulus. Although tinnitus is a non-life-threatening symptom, tinnitus's negative repercussions, such as personality disturbances and social withdrawal, are daunting concerns despite a gamut of conventional and emerging treatment options. Tinnitus management is still a critical challenge that provides opportunities for clinicians, ENT (Ear/eye, nose and throat) physicians, and other specialists such as audiologists, psychiatrists, and psychologists. Among the new treatment modalities, Neuromonics tinnitus treatment (NTT) draws special attention in tinnitus management due to its mounting success rate. Nonetheless, unlike in developed countries like Australia, the United States, and the United Kingdom, the scanty awareness of NTT among Indian ENT specialists is a titanic setback for care providers. Because of this backdrop, this review emphasized the current perspectives on tinnitus management and the underlying principles and clinical efficacy of NTT. The challenges for tinnitus management can be met and reduced by suppressing tinnitus through motivation, counseling, cochlear implant, and psychotherapy.

Herbal medicines in the treatment of tinnitus: An updated review.

Tinnitus is perception of sound in the absence of an apparent external acoustic stimulus. The condition is prevalent in adults, especially the elderly (≥65years), and may be associated with cognitive function decline and significantly impacts on the quality of life, heralding difficulties in managing this challenging disorder. Interventions for tinnitus have been varied. However, drugs have not yet been approved for the treatment of tinnitus and there is no pharmacotherapy recommended by existing guidelines. Still, herbal medicines are used for the treatment of tinnitus in many countries, especially Gingko (G.) biloba. In the current updated literature review, we evaluated the efficacy of herbal medicines in the treatment of tinnitus by reviewing the evidence of relevant randomized controlled trials. The authors also highlight some of the issues in clinical trials of herbal medicines given that currently available evidence on herbal medicines for tinnitus is overall of insufficient quality and the conclusions from existing trials are conflicting. Nevertheless, there is a clear and urgent need for safe and effective pharmacotherapy of tinnitus.

Towards an Acoustic Geometry in Slightly Viscous Fluids

We explore the behaviour of barotropic and irrotational fluids with a small viscosity under the effect of first-order acoustic perturbations. We discuss, following the extant literature, the difficulties in gleaning an acoustic geometry in the presence of viscosity. In order to obviate various technical encumbrances, when viscosity is present, for an extraction of a possible acoustic geometry, we adopted a method of double perturbations, whereby dynamical quantities such as the velocity field and potential undergo a perturbation both in viscosity and in an external acoustic stimulus. The resulting perturbation equations yield a solution which can be interpreted in terms of a generalised acoustic geometry, over and above the one known for inviscid fluids.

Evaluation of stress and cognitive skills in individuals with tinnitus complaints

Background/Aim: The sense of sound in the absence of external acoustic stimuli is known as subjective tinnitus, or phantom tinnitus. The purpose of this study was whether tinnitus complaints have an impact on perceived stress and cognitive skills like attention and memory. Methods: This prospective case-control study comprised 60 healthy volunteers between the ages of 18 and 25, all of whom had normal hearing. Using the G*Power program, it was established that a minimum of 50 people should be worked with an 80 percent power and a 5% margin of error. The study group consisted of 30 people with tinnitus complaints in their daily lives, whereas the control group consisted of the remaining people. Tinnitus Handicap Inventory and Perceived Stress Scale were applied to the participants within the scope of the working hypotheses. In terms of cognitive skills, the Stroop Test Form was applied to evaluate selective attention, focused attention and disruptive effects, and the Visual Auditory Digit Sequence Test Form was applied to evaluate short-term memory and working memory skills. The findings were analyzed with the SPSS program. Type 1 error level is determined as 5%. Results: According to Tinnitus Handicap Inventory, tinnitus complaint of all individuals in the study group is very mild. The statistically significant differences were found between the perceived stress level, Stroop and Visual Auditory Digit Sequence Test scores between people with and without tinnitus complaints. The poorer performance was observed in the group with tinnitus complaint. (P=0.037, P=0.017, P=0.010). No statistically significant relationship was found between perceived stress level, tinnitus and cognitive skills (P=0.067, P=0.160, P=0.208). Conclusion: Tinnitus is becoming a more common cause of health problems, sometimes coupled by psychological stress, and it affects cognitive skills. The study adds to the knowledge regarding the use of cognitive tests as a supplemental measurement in the evaluation of tinnitus and the impact of tinnitus on daily cognitive abilities.

Considerations on tinnitus retraining therapy and transcranial magnetic stimulation

Introduction. Tinnitus is a subjective perception of sound in the absence of an external acoustic stimulus. It has negative behavioral feelings associated, e.g., depression, insomnia, difficulty of concentration, anxiety, irritability, and panic. The feelings impact negatively on the social and economic life of individuals. Empirical data suggest that disorders in the auditory cortex and its neural pathways give rise to abnormal spontaneous activations associated with tinnitus. Understanding the causes remains challenging. However, the current hypothesis suggests that clusters of neural networks and subnetworks are involved in tinnitus generation. Central dynamic neuroplasticity induced by a peripheral loss of auditory input can cause tinnitus noise. To date, there is no widespread consensus about the most effective therapy for treating tinnitus. Objective. To reflect on two tinnitus therapies: Tinnitus Retraining Therapy (TRT) and Transcranial Magnetic Stimulation (TMS). Method. A narrative review. Explicit and systematic criteria were not adopted in searching for the theoretical framework. Results. TMS is promising compared to TRT because TMS acts on tinnitus neural mechanisms. TRT is effective on a behavioral level since it relieves mild and moderate tinnitus' negative feelings. Conclusion. TRT does not advance on the neural source, but only on the tinnitus perception. TMS acts directly on the neural causes. Both therapies have limitations and can work for some patients. However, the effect of TMS seems more efficient, although transient.

The balance between Bayesian inference and default mode determines the generation of tinnitus from decreased auditory input: A volume entropy-based study.

Along with phantom pain, tinnitus, a phantom auditory perception occurring in the absence of an external acoustic stimulus, is one of the most representative phantom perceptions that develops in subjects with decreased peripheral sensory input. Although tinnitus is closely associated with peripheral hearing loss (HL), it remains unclear why only some individuals with HL develop tinnitus. In this study, we investigated the differences between 65 HL with tinnitus (HL‐T) and 104 HL with no tinnitus (HL‐NT) using a resting‐state electroencephalography data‐based volume entropy model of the brain network, by comparing the afferent node capacities, that quantify the contribution of each node to the spread of information, of all Brodmann areas. While the HL‐T group showed increased information flow in areas involved in Bayesian inference (the left orbitofrontal cortex, the left subgenual anterior cingulate cortex, and the left ventrolateral prefrontal cortex) and auditory memory storage (the right hippocampus/parahippocampus), the HL‐NT group showed increased afferent node capacity in hub areas of the default mode network (DMN; the right posterior cingulate cortex and the right medial temporal gyrus). These results suggest that the balance of activity between the Bayesian inferential network (updating missing auditory information by retrieving auditory memories from the hippocampus/parahippocampus) and DMN (maintaining the “silent status quo”) determines whether phantom auditory perception occurs in a brain with decreased peripheral auditory input.

Chronic tinnitus- a challenge for both the patient and the clinician

Background: Tinnitus is defined as the perception of sound in the absence of a corresponding external acoustic stimulus. It is a common problem that markedly impairs the quality of life of about 1% of the general population. Materials and Methods: We selectively reviewed the pertinent literature to provide an overview of the current treatment options for chronic tinnitus. Tinnitus is the perception of sound without external stimulation. It can greatly affect a patient’s physical and psychological quality of life. Clinical history taking is directed at eliciting whether symptoms have a pulsatile or nonpulsatile quality, whether symptoms are unilateral or bilateral, and whether there is associated hearing loss. For tinnitus that is pulsatile or unilateral, referral to an otolaryngologist is recommended, as these qualities might be associated with more serious underlying conditions. Most patients with tinnitus can be managed with reassurance, conservative measures, and hearing aids if substantial hearing loss exists. Conclusion: Family physicians play the primary role in managing patients with tinnitus and are well situated to address both the physiologic and the psychological manifestations. As tinnitus is very common, helping patients cope with the symptoms through conservative measures and reassurance can prove to have the best outcomes. Keywords: Tinnitus, Hearing loss, Quality of life.

Lidocaine injections to the otic ganglion for the treatment of tinnitus-A pilot study.

Tinnitus is defined as the perception of noise without an external acoustic stimulus. Due to the heterogeneity of tinnitus, no treatment has proven equally beneficial to every single of these patients. Previous studies have shown that trigeminal input can interfere with the perception of tinnitus. Therefore, we aimed to explore the therapeutic potential of lidocaine injections in trigeminal structures. We conducted a pilot study with 19 participants to explore feasibility and tolerability of this approach. The intervention consisted of three injections of lidocaine in the anatomical area of the trigeminal ganglion and the ganglion oticum via an oral approach corresponding to the affected side of tinnitus. We performed an assessment that included the Mini-TQ, CGII, and numeric rating scales of tinnitus loudness and severity at different time points over a follow-up period of 12 weeks. In addition to changes of subjective tinnitus complaints, potential adverse events were documented. Patients were treated at the Centre of Otorhinolaryngology in Traunstein, Germany, and data were analyzed at the University of Regensburg, Germany. We did not observe any relevant side effects. There was a significant reduction of tinnitus distress (Mini-TQ, Tinnitus severity) and loudness (measured subjectively) over time. Our pilot data suggests that lidocaine injections targeting trigeminal structures may be able to reduce tinnitus complaints. Future studies should investigate the effects of lidocaine injections in placebo-controlled trials in an extended sample size to further explore the potential benefits of this therapeutic approach on tinnitus.

Tinnitus, Use and Evaluation of Sound Therapy, Current Evidence and Area of Future Tinnitus Research.

Tinnitus is one of the otologic symptoms seen in persons with ear pathologies. It is defined as an acoustic sensation in the ear without a corresponding external acoustic stimulus. Tinnitus is said to be generated from the higher auditory centres because of reduced feedback from the peripheral or neural component but can be an outcome of irritation at different levels of the auditory system. Several treatment modalities have been tried in the management of tinnitus, either as a single treatment or as part of combination therapy. They range from lifestyle or dietary modification, medications, surgery, to Tinnitus Retraining Therapy (TRT), use of sound generating devices, hearing aids and cochlear implants. Current literature has shown that the prevalence of tinnitus is highly variable and reflects the difference in symptom criteria and patient selection for the various treatment modalities. This variability is also visible in the outcomes of cases where the various treatment modalities have been used. In the presence of an augmented hearing, the brain can focus on the meaningful sound generated externally while suppressing or even aborting the tinnitus. Future tinnitus research needs to apply the highest level of randomization and blinding, in line with the high subjectivity of tinnitus and the possibility of a response with control. The natural sequence of tinnitus is characterized by the conditioning or habituation and possible gradual attenuation of symptom, this implies that there is a limit to which the benefits observed was due to our intervention rather than a natural process of this symptom.

Auditory Neural Plasticity in Tinnitus Mechanisms and Management.

Tinnitus, which is the perception of sound in the absence of a corresponding external acoustic stimulus, including change of hearing and neural plasticity, has become an increasingly important ailment affecting the daily life of a considerable proportion of the population and causing significant burdens for both the affected individuals and society as a whole. Here, we briefly review the epidemiology and classification of tinnitus, and the currently available treatments are discussed in terms of the available evidence for their mechanisms and efficacy. The conclusion drawn from the available evidence is that there is no specific medication for tinnitus treatment at present, and tinnitus management might provide better solutions. Therapeutic interventions for tinnitus should be based on a comprehensive understanding of the etiology and features of individual cases of tinnitus, and more high quality and large-scale research studies are urgently needed to develop more efficacious medications.

P1495 Suddenly haunted by a turbulent heart beat in the right ear. Post-traumatic monolateral pulsatile tinnitus caused by cervical arteriovenous malformation: colour-Doppler ultrasound and angio-CT find

Abstract Funding Acknowledgements No financial disclosure to be added INTRODUCTION Tinnitus, the perceived sensation of sound in absence of corresponding external acoustic stimulus, has a prevalence of 15% among adults [1]; it may impair quality of life in about 1-2% of cases. When pulsatile, objective and synchronous with heart beat, it may be secondary to vascular abnormalities [2]; in some patients a post-traumatic pathogenesis ( head and neck) has been reported, with a prevalence up to 10% . CASE REPORT We report the case of a 28 year old male patient with a history of a right side pulsatile tinnitus occurred three days after head trauma. Described as "hearing heart beat in the right ear as a turbulent sound", it corresponded with an audible bruit and palpable fremitus in latero-cervical region. History was negative for medical or surgical comorbidities as laboratory investigation; color Doppler ultrasound revealed an external carotid artery collateral- internal jugular vein fistula, resulting in a pulsatile turbulent flow, synchronic with heart beat. Angio-CT scan of epiaortic vessels confirmed findings in the context of occipital articulation, near jugular foramen. Patient postponed further investigations for personal reasons. DISCUSSION Vascular post-traumatic lesions may cause post-traumatic pulsatile tinnitus. Symptom onset may be delayed from several days up to twelve weeks after trauma and it can be a sign of life-threatening disorders such as carotid cavernous fistulas, arteriovenous malformations, and carotid dissections [3 ] . Clinical management includes basic diagnostic steps ( history, assessment of tinnitus severity, clinical ear examination, audiological and a neurovascular examination [2] . CT and MR with angiography, following colour-Doppler ultrasound , are used to determine the anatomical cause of vascular pulsatile tinnitus and to study surrounding structures. Angiography may be helpful for diagnosis and treatment planning [4]. CONCLUSIONS Pulsatile tinnitus may occur after head and neck trauma, may affect quality of life and can be caused by live-threatening lesions. Arteriovenous fistulae between carotid artery branches and jugular vein may be treatable anatomical cause of symptoms, and have to be considered in differential diagnosis . Abstract P1495 Figure. Pulsatile tinnitus:Imaging and Pathology

Molecular Aspects of Melatonin Treatment in Tinnitus: A Review.

Tinnitus is a hearing disorder characterized by the perception of sound without external acoustic stimuli, which is caused by damage to the auditory system in response to excessive levels of noise, ototoxic agents and aging. Neural plasticity, oxidative/nitrosative stress and apoptosis play important roles in the pathogenesis of tinnitus. The expression of neural plasticity related to excessive glutamatergic neurotransmission leads to generation of abnormal sound in one's ears or head. Furthermore, hyperactivation and over-expression of NMDA receptors in response to excessive release of glutamate contribute to the calcium overload in the primary auditory neurons and subsequent cytotoxicity. Reactive oxygen/nitrogen species are endogenously produced by different type of cochlear cells under pathological conditions, which cause direct damage to the intracellular components and apoptotic cell death. Cochlear hair-cell death contributes to the progressive deafferentation of auditory neurons, which consequently leads to the aberrant activity in several parts of the auditory pathway. Therefore, targeting neural plasticity, oxidative/nitrosative stress, apoptosis and autophagy may ameliorate tinnitus. Melatonin is an endogenously produced indoleamine synchronizing circadian and circannual rhythms. Based on laboratory studies indicating the protective effect of melatonin against cochlear damage induced by acoustic trauma and ototoxic agents, and also clinical studies reporting the ability of melatonin to minimize the severity of tinnitus, melatonin is suggested to be a treatment option for the patient with tinnitus. Herein, we describe the ameliorative effect of melatonin on tinnitus, focusing on neural plasticity, oxidative/nitrosative stress, apoptotsis and autophagy.

Research progress of idiopathic tinnitus

SummaryIdiopathic tinnitus is a spontancous sense of hearing under neither external acoustic or electric stimuli,and is one of the common symptoms of otorhinolaryngology. At present，the clinical stages and classification of tinnitus vary among different countries. The examination of tinnitus is also multifaceted, including audiology, imaging, psychology and other tests to find tinnitus for the purpose. There are many treatments for tinnitus, including etiological treatment, counseling, cognitive behavioral therapy, tinnitus masking therapy, tinnitus therapy, hearing aids, cochlear implants, drug therapy, repetitive transcranial magnetic stimulation, electrical stimulation and so on.The above treatment methods have not reached a consensus on the efficacy of tinnitus. In recent years, some technology innovations based on sound have produced personalized treatment schemes for different types of tinnitus,which will inevitably become a hot topic in future research.

Proposal of conditional random inter-stimulus interval method for unconstrained enclosure based GPIAS measurement systems.

Gap prepulse inhibition of acoustic startle (GPIAS) method has been used effectively for the objective assessment of tinnitus in animals. Among two types of enclosures for the GPIAS, the unconstrained type carries less risk of animal death due to the absence of binding stress in the enclosure, and lack of need for alteration to animal size variation as it grows. However, animals' voluntary movements, which have no relation to the startles evoked by acoustic stimuli, are problematic, as they cannot be excluded in the case of the unconstrained enclosure based GPIAS measurement system. In order to discount voluntary movements which are not associated with external acoustic stimuli, we propose the conditional random inter-stimulus interval (CR ISI) method for unconstrained enclosure based GPIAS measurement. With the proposed ISI method, the unconstrained enclosure based acoustic startle response measurement system has been implemented in this paper. As a result, the effectiveness of the proposed CR ISI method has been verified and compared with those of conventional ISI methods through animal experiments using SD-rats. The experimental results showed that abnormal startle responses and invalid GPIAS values caused by motion were prevented when our proposed CR ISI method was applied to our implemented system. It was also verified that our proposed CR ISI method is advantageous in reducing the total experimental time for acquiring normal startle responses and valid GPIAS values, compared to conventional ISI methods, since our proposed CR ISI can begin the acoustic stimulation only when the animal gets stable and motionless.

Voltage readout from a piezoelectric intracochlear acoustic transducer implanted in a living guinea pig

The ability to measure the voltage readout from a sensor implanted inside the living cochlea enables continuous monitoring of intracochlear acoustic pressure locally, which could improve cochlear implants. We developed a piezoelectric intracochlear acoustic transducer (PIAT) designed to sense the acoustic pressure while fully implanted inside a living guinea pig cochlea. The PIAT, fabricated using micro-electro-mechanical systems (MEMS) techniques, consisted of an array of four piezoelectric cantilevers with varying lengths to enhance sensitivity across a wide frequency bandwidth. Prior to implantation, benchtop tests were conducted to characterize the device performance in air and in water. When implanted in the cochlea of an anesthetized guinea pig, the in vivo voltage response from the PIAT was measured in response to 80–95 dB sound pressure level 1–14 kHz sinusoidal acoustic excitation at the entrance of the guinea pig’s ear canal. All sensed signals were above the noise floor and unaffected by crosstalk from the cochlear microphonic or external electrical interference. These results demonstrate that external acoustic stimulus can be sensed via the piezoelectric voltage response of the implanted MEMS transducer inside the living cochlea, providing key steps towards developing intracochlear acoustic sensors to replace external or subcutaneous microphones for auditory prosthetics.

Pathophysiology of Subjective Tinnitus: Triggers and Maintenance.

Tinnitus is the conscious perception of a sound without a corresponding external acoustic stimulus, usually described as a phantom perception. One of the major challenges for tinnitus research is to understand the pathophysiological mechanisms triggering and maintaining the symptoms, especially for subjective chronic tinnitus. Our objective was to synthesize the published literature in order to provide a comprehensive update on theoretical and experimental advances and to identify further research and clinical directions. We performed literature searches in three electronic databases, complemented by scanning reference lists from relevant reviews in our included records, citation searching of the included articles using Web of Science, and manual searching of the last 6 months of principal otology journals. One-hundred and thirty-two records were included in the review and the information related to peripheral and central mechanisms of tinnitus pathophysiology was collected in order to update on theories and models. A narrative synthesis examined the main themes arising from this information. Tinnitus pathophysiology is complex and multifactorial, involving the auditory and non-auditory systems. Recent theories assume the necessary involvement of extra-auditory brain regions for tinnitus to reach consciousness. Tinnitus engages multiple active dynamic and overlapping networks. We conclude that advancing knowledge concerning the origin and maintenance of specific tinnitus subtypes origin and maintenance mechanisms is of paramount importance for identifying adequate treatment.

Is tinnitus an early voice of masked hypertension? High masked hypertension rate in patients with tinnitus

ABSTRACTObjectives: Tinnitus is hearing a sound without any external acoustic stimulus. There are some clues of hypertension can cause tinnitus in different ways. The aim of the study was to evaluate the relationship between tinnitus and masked hypertension including echocardiographic parameters and severity of tinnitus.Methods: This study included 88 patients with tinnitus of at least 3 months duration and 85 age and gender-matched control subjects. Tinnitus severity index was used to classify the patients with tinnitus. After a complete medical history, all subjects underwent routine laboratory examination, office blood pressure measurement, hearing tests and ambulatory blood pressure monitoring. Masked hypertension is defined as normal office blood pressure measurement and high ambulatory blood pressure level.Results: Baseline characteristics in patients and controls were similar. Prevalence of masked hypertension was significantly higher in patients with tinnitus than controls (18.2% vs 3.5%, p = 0.002). Office diastolic BP (76 ± 8.1 vs. 72.74 ± 8.68, p = 0.01), ambulatory 24-H diastolic BP (70.2 ± 9.6 vs. 66.9 ± 6.1, p = 0.07) and ambulatory daytime diastolic BP (73.7 ± 9.5 vs. 71.1 ± 6.2, p = 0.03) was significantly higher in patients with tinnitus than control group. Tinnitus severity index in patients without masked hypertension was 0 and tinnitus severity index in patients with masked hypertension were 2 (1–5).Conclusion: This study demonstrated that masked hypertension must be kept in mind if there is a complaint of tinnitus without any other obvious reason.

Bi-modal stimulation in the treatment of tinnitus: a study protocol for an exploratory trial to optimise stimulation parameters and patient subtyping

IntroductionTinnitus is the perception of sound in the absence of a corresponding external acoustic stimulus. Bimodal neuromodulation is emerging as a promising treatment for this condition. The main objectives of...