[Chronic tinnitus: An interplay between somatic and psychological factors]

Chronic tinnitus is a common, sometimes highly distressing phenomenon that can be triggered and maintained by an interplay of physical and psychological factors. Partnering with clinical psychology and psychosomatic medicine, modern otolaryngology integrates both medical (e.g., hearing loss) and psychological influences (e.g., interactions between biographical experiences, personality traits, subjective evaluation of intrapsychic and interpersonal stimuli, emotional states, and intrapsychic or interpersonal emotion regulation strategies). Both groups of variables can influence the intensity and course of chronic tinnitus symptomatology both directly and indirectly, whereby the quality and relative degrees of psychological and physical components in a person's self-experience can fluctuate. With this in mind, the present article distinguishes between chronic tinnitus symptomatology with or without hearing loss-and strongly advocates for an integrated understanding of the symptomatology within a holistic psychological frame of reference. After a brief introduction to the principles of psychosomatic medicine and psychotherapy, the article discusses psychological case conceptualization using a vulnerability-stress-coping (VSC) model as an example, outlines clinical aspects and diagnostics of chronic tinnitus symptomatology, and concludes with a conceptualization of chronic tinnitus-related distress as a function of person-centered VSC interactions.

Cortical and subcortical gray matter changes in patients with chronic tinnitus sustaining after vestibular schwannoma surgery

Tinnitus is attributed to partial sensory deafferentation resulting in a central maladaptive neuroplasticity. Unfortunately, the agent of deafferentation is usually unknown or irreversible. In patients with unilateral vestibular schwannoma (VS), however, the auditory nerve is affected by a benign tumor. Hence, removal of the tumor can cease the tinnitus. In turn, sustaining complaints after surgery indicate cortical neuroplasticity. The present study is a cross sectional study which aims to track cortical structural changes by surface-based morphometry in 46 VS patients with sustained (i.e. centralized) or ceased (i.e. peripheral) tinnitus after surgery. A volumetric analysis of cortical and subcortical gray matter (GM) anatomy was performed on preoperative high-resolution MRI and related to the presence of hearing impairment, pre- and/or postoperative tinnitus. Patients with sustained (i.e. chronic) tinnitus showed an increased GM volume of the bilateral caudate nucleus, the contralateral superior colliculus, the middle frontal and middle temporal gyrus, the fusiform gyrus as well as the ipsilateral pars orbitalis when compared to those patients in whom tinnitus ceased postoperatively. Chronic tinnitus in VS patients is associated with characteristic structural changes in frontal, temporal and subcortical areas. Notably, a significant GM change of the caudate nucleus was detected providing further support for the striatal gaiting model of tinnitus.

Mean platelet volume and neutrophil to lymphocyte ratio in patients with tinnitus: a case-control study

INTRODUCTION

Different theories have been proposed on the etiology of tinnitus, including metabolic and audiologic causes. We suggest that mean platelet volume and neutrophil to lymphocyte ratio levels change in tinnitus, indicating microcirculatory disturbance and inflammatory process in the etiopathogenesis of tinnitus.

OBJECTIVES

We aimed to evaluate the mean platelet volume and neutrophil to lymphocyte ratio in patients with tinnitus in comparison to healthy controls.

METHODS

Retrospective case-control study. Two-hundred and eighty-seven patients aged 18-59 years and diagnosed with tinnitus in the Ear, Nose, and Throat Clinic between December 2014 and May 2017 (patient group) and 275 healthy individuals who applied for a hearing screening within the same time period (control group). Demographics, concomitant diseases, laboratory results, and audiometric data were recorded. Mean platelet volume and neutrophil to lymphocyte ratio were the outcome measures. Patients with hearing loss due to presbycusis or another reasons, and patients with anatomical disorders in the external and middle ear were excluded from the study by using physical examinations, pure audio audiometry results and radiological imaging. The upper age limit was set at 59 to exclude presbycusis patients.

RESULTS

The ratio of female patients was higher in patient group than control group (58.5%, n=168 vs. 49.4%, n=127; respectively; p=0.033). The mean age of patient group was significantly higher than those of control group (44.89±10.96 years and 38.37±10.65 years, respectively; p=0.001). The percentage of subjects with high mean platelet volume level was significantly higher in patient group than control group (9.4%, n=27, and 3.1%, n=8 respectively; p=0.008). The mean neutrophil to lymphocyte ratio was higher in patients with tinnitus than control group (1.95±1.02 and 1.67±0.57, p=0.012). A neutrophil to lymphocyte ratio level of 2.17 and above is associated with 1.991 times higher risk of tinnitus (odds ratio=1.99, 95% confidence interval 1.31-3.02).

CONCLUSION

High mean platelet volume and neutrophil to lymphocyte ratio values are associated with idiopathic tinnitus, suggesting the role of vascular pathologies in etiology of tinnitus. Tinnitus may be a sign of underlying systemic or local disorders. Therefore, patients with tinnitus should undergo detailed evaluation including hematological indices.

Investigation of the effect of cochlear implantation on tinnitus, and its associated factors

Background: Many studies have focused on the suppressive effects of cochlear implants (CIs) on loudness of tinnitus.Aims/objective: This study aimed to examine the effects of CIs and their activation on changes in loudness and tinnitus and explore other factors associated with this effect.Material and methods: We recruited 26 CI recipients according to specific criteria. Participants asked to complete tinnitus questionnaires, while the CI was kept on and at 30 min after the CI was turned off. Tinnitus improvement after CI was tested using Wilcoxon signed rank tests, and correlation was tested using Spearman's rank correlation coefficients and multiple linear regression.Results: After CI, tinnitus reduced from 62% to 46%. Total and partial reduction in tinnitus was seen in 76% subjects with pre-CI tinnitus. However, 6% of the subjects had tinnitus since birth, and none showed worsening tinnitus. The average THI score while the CI on was significantly lower than that CI off.Conclusions: Post-CI tinnitus improvement was seen in 76% of those with pre-CI tinnitus; however, the low risk of new or aggravating tinnitus should be considered, and reasonable expectations for tinnitus reduction should be built into the pre-CI assessment.

Neurofeedback for tinnitus: study protocol for a randomised controlled trial assessing the specificity of an alpha/delta neurofeedback training protocol in alleviating both sound perception and psychological distress in a cohort of chronic tinnitus sufferers

BACKGROUND

Tinnitus is a particularly common condition and can have debilitating psychological consequences for certain people. Although several interventions have been helpful in teaching individuals to better cope with tinnitus, no cure exists at present. Neurofeedback is an emerging treatment modality in tinnitus. Previous studies, utilising an alpha/delta training protocol, have shown promise. However, they were characterised by small sample sizes and a lack of neurofeedback control conditions. Therefore, the aim of this study is to investigate whether an alpha/delta neurofeedback training protocol, compared to beta/theta neurofeedback or a diary control group, is effective in reducing not only the tinnitus sound perception but also the psychological symptoms associated with the condition.

METHODS

The study is designed as a three-armed randomised controlled trial. Participants are randomly assigned to a) an established neurofeedback protocol for tinnitus (alpha/delta training), b) an active control group (beta/theta training) or c) a diary control group. In the 4-week intervention period, participants in both neurofeedback groups undergo 10 sessions, whereas participants in the diary control group complete a bi-weekly diary. The primary outcomes are between group differences in tinnitus sound perception change, as measured with the Tinnitus Magnitude Index (TMI), and changes in tinnitus distress, measured with the Tinnitus Handicap Inventory (THI), 4 weeks after the start of the intervention. Secondary outcome measures include changes in tinnitus distress, sleep quality, depressive symptoms and whether neurofeedback leads to specific power changes in the trained frequency bands.

DISCUSSION

This is the first randomised controlled trial examining the efficacy of an alpha/delta neurofeedback training protocol in reducing tinnitus sound perception and the distress associated with the condition. Compared to former studies, the present study is designed to assess both the specificity of an alpha/delta neurofeedback training protocol by including an active comparator and beta/theta neurofeedback training, in addition to controlling for placebo effects by the inclusion of a diary control group. This study aims to contribute to an understanding of the influences of both specific and non-specific effects in neurofeedback treatment for tinnitus.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03550430. Registered on 27 May 2018.

Postoperative Tinnitus after Vestibular Schwannoma Surgery: A Neglected Entity

Background

This prospective study analyzes the factors responsible for pre and postoperative persistent tinnitus following vestibular schwannoma (VS) surgery and discusses the possible etiopathogenetic mechanisms.

Materials and Methods

Sixty-seven consecutive patients with unilateral VS operated via the retrosigmoid-suboccipital approach were included in the study. The Cochlear nerve, often unidentifiable from the tumor capsule, was resected during the surgery. Tinnitus Handicap Inventory (THI) score assessed the severity of pre and postoperative tinnitus.

Result

Twenty-eight (41%) patients had preoperative tinnitus. Out of those 28 patients, 24(85%) had significantly improvement in postoperative THI score. In 15 of the 24 patients, tinnitus subsided completely. In 3 of the 28 (10%) patients, THI scores were unaltered, and in 1 of the 28 (3.5%) patients, THI scores worsened. In 39 (58.2%) patients without preoperative tinnitus, 4 (10%) developed a new-onset postoperative tinnitus. Patients with severe sensory neural hearing loss (SNHL) had significantly higher incidence of postoperative persistent tinnitus (PPT) (P = 0.00) compared to those with mild-to-moderate SNHL. Patients with profound SNHL, however, had a much lower incidence of PPT (P = 0.007; odds ratio = 0. 0.077; 95% CI: 0.009-0.637). Large (P = 0.07) and giant schwannomas (P = 0.03) VS had an increased risk of PPT. Patients with PPT further analyzed with brain stem auditory evoked response (BAER) showed normal contralateral waveform.

Conclusion

Assessment of tinnitus is mandatory during the management of VS as there are high chances (nearly 46%) of PPT. Preoperative tinnitus, linked to the degree of SNHL (higher incidence in severe SNHL compared to mild-to-moderate/profound SNHL), is dependent on an intact cochlear nerve functioning. However, PPT is dependent on other mechanisms (brain stem/ipsilateral cochlear nuclei compression, and cortical reorganization) as it persists despite cochlear nerve resection.

Effect of statins on hearing function and subjective tinnitus in hyperlipidemic patients

INTRODUCTION

It is known that hyperlipidemia reduces hearing functions. In this study, we aimed to study the effect of antihyperlipidemic drugs on hearing functions and tinnitus.

METHODS

Eighty-four patients aged 18 to 84, who were diagnosed with hyperlipidemia and started treatment with the statin group (atorvastatin 20 mg and 40 mg, rosuvastatin 10 mg and 20 mg, and simvastatin 20 mg) of antihyperlipidemic drugs, were included in this study. All patients underwent pure-tone audiometry before starting treatment with antihyperlipidemic drugs. Patients with tinnitus were evaluated by Tinnitus Severity Index and Visual Analogue Scale. In the 6th month of therapy, otologic examination, pure-tone audiometry and tinnitus evaluation of the patients were repeated.

RESULTS

No significant difference was found in the pure-tone averages of the patients before and after statin use (p > 0.05). However, it was found in the audiometry that, after statin use, all drugs caused to statistically significant decrease in the hearing thresholds at 6000 Hertz (p < 0.05). Also, a strong increase was found in the Speech Discrimination percentages after treatment in patients using rosuvastatin 10 mg (p = 0.022). A significant decrease was found in the tinnitus frequency, duration, severity and degree of annoyance in patients using rosuvastatin 10 mg and 20 mg (p < 0.05).

CONCLUSION

Statin group of drugs can have a positive effect on the hearing functions and subjective tinnitus. In particular, it is seen that rosuvastatin group of statins has a more notable effect on tinnitus. It was considered that further studies with larger patient groups are needed.

Changes in tinnitus after vestibular schwannoma surgery

We designed a prospective study to evaluate changes in tinnitus after vestibular schwannoma (VS) surgery. Subjects included 41 patients who were diagnosed with a VS and underwent translabyrinthine microsurgery (TLM) between January 2015 and May 2016. All patients underwent related examinations and were asked to answer the Tinnitus Handicap Inventory (THI) scale and a visual analog scale (VAS) of tinnitus severity both pre- and postoperatively. Of the 41 patients, 31 (75.6%) suffered from tinnitus before surgery. Microsurgery was associated with an overall decrease in tinnitus (p < 0.001). There was a significant improvement in THI and VAS scores after surgery (p = 0.001 and p = 0.005, respectively). The decrease in THI scores in the low-frequency group was significantly larger than that of the mid- and high-frequency groups after surgery (p = 0.034 and p = 0.001, respectively). The loudness of tinnitus decreased significantly after surgery (p = 0.031). Tinnitus in patients with VS improved after TLM. Patients with mid-/high-frequency tinnitus and louder tinnitus preoperatively seemed to have a worse prognosis than those with low-frequency and quieter tinnitus.

Eye movement desensitization and reprocessing as a treatment for tinnitus

OBJECTIVES/HYPOTHESIS

To determine the effectiveness of eye movement desensitization and reprocessing (EMDR) as a treatment for tinnitus.

STUDY DESIGN

Single-site prospective interventional clinical trial at a university hospital in the United Kingdom.

METHODS

Participants were provided with tEMDR. This is a bespoke EMDR protocol that was developed specifically to treat individuals with tinnitus. Participants received a maximum of 10 sessions of tEMDR. Outcome measures including tinnitus questionnaires and mood questionnaires were recorded at baseline, discharge, and at 6 months postdischarge.

RESULTS

Tinnitus Handicap Inventory and Beck Depression Inventory scores demonstrated a statistically significant improvement at discharge after EMDR intervention (P = .0005 and P = .0098, respectively); this improvement was maintained at 6 months postdischarge. There was also a moderate but not significant (P = .0625) improvement in Beck Anxiety Inventory scores.

CONCLUSIONS

This study has demonstrated that the provision of tEMDR has resulted in a clinically and statistically significant improvement in tinnitus symptoms in the majority of those participants who took part. Furthermore, the treatment effect was maintained at 6 months after treatment ceased. This study is of particular interest, as the study protocol was designed to be purposefully inclusive of a diverse range of tinnitus patients. However, as a small uncontrolled study, these results do not consider the significant effects of placebo and therapist interaction. Larger high-quality studies are essential for the verification of these preliminary results.

LEVEL OF EVIDENCE

4 Laryngoscope, 129:2384-2390, 2019.

Sensory neurologic disorders: Tinnitus

Tinnitus is the sensation of hearing a sound with no external auditory stimulus present. It is a public health issue correlated with multiple comorbidities and precipitating factors such as noise exposure, military service, and traumatic brain injury, migraine, insomnia, small vessel disease, smoking history, stress exposure, anxiety, depression, and socioeconomic status. Clinical experience and a recent literature review point at tinnitus as a neuropsychiatric condition involving both auditory and nonauditory cortical areas of the brain and affecting brain-auditory circuitry. In fact, brain-ear connections have been highlighted in different models. Forward management of this disorder should take this body of research into consideration as tinnitus remains a challenging condition to evaluate and treat with current management protocols still symptomatic at best. With a better understanding of the etiologic factors and comorbidities of tinnitus, additional research trials and new therapeutic approaches could see the light to tackle this public health disability bringing hope to patients and doctors.

Postoperative Tinnitus After Vestibular Schwannoma Surgery Depends on Preoperative Tinnitus and Both Pre- and Postoperative Hearing Function

Objective

Tinnitus is one of the most common symptoms before and/or after the surgical removal of a vestibular schwannoma (VS) affecting almost half of the patients. Although there is increasing evidence for the association of hearing impairment and VS-associated tinnitus, the effect of hearing deterioration due to surgery and its relation to the postoperative tinnitus (postTN) is poorly investigated. This knowledge, however, might (i) enlighten the pathophysiology of VS-associated tinnitus (i.e., peripheral or central origin) and (ii) improve preoperative patient counseling. The aim of this study was to understand the predisposition factors for a postTN in relation to hearing outcome after surgery.

Methods

This retrospective study analyzed the presence of tinnitus in 208 patients with unilateral VS before and after surgical removal. A binomial logistic regression was performed to ascertain the effect of pre- and postoperative hearing as well as age, gender, tumor side, and size, and intraoperative cochlear nerve resection (CNR) on the likelihood of postoperative VS-associated tinnitus.

Results

Preoperative tinnitus was the strongest predictor of postTN. In addition, deterioration of functional hearing was increasing, while functional deafferentation (i.e., postoperative hearing loss) of non-functional hearing was reducing the risk of postTN. At the same time, patients with no preoperative tinnitus but complete hearing loss had the lowest risk to suffer from postTN. Patient age, gender, tumor side, and size as well as CNR played a subordinate role.

Conclusion

While the presence of preoperative tinnitus was the strongest predictor of postTN, there is a distinct relationship between hearing outcome and postTN depending on the preoperative situation. Functional or anatomical deafferentation due to surgical tumor removal does not prevent postTN per se.

Predictors of Preoperative Tinnitus in Unilateral Sporadic Vestibular Schwannoma

Objective

Nearly two-thirds of patients with vestibular schwannoma (VS) are reporting a significantly impaired quality of life due to tinnitus. VS-associated tinnitus is attributed to an anatomical and physiological damage of the hearing nerve by displacing growth of the tumor. In contrast, the current pathophysiological concept of non-VS tinnitus hypothesizes a maladaptive neuroplasticity of the central nervous system to a (hidden) hearing impairment resulting in a subjective misperception. However, it is unclear whether this concept fits to VS-associated tinnitus. This study aims to determine the clinical predictors of VS-associated tinnitus to ascertain the compatibility of both pathophysiological concepts.

Methods

This retrospective study includes a group of 478 neurosurgical patients with unilateral sporadic VS evaluated preoperatively regarding the occurrence of ipsilateral tinnitus depending on different clinical factors, i.e., age, gender, tumor side, tumor size (T1–T4 according to the Hannover classification), and hearing impairment (Gardner–Robertson classification, GR1–5), using a binary logistic regression.

Results

61.8% of patients complain about a preoperative tinnitus. The binary logistic regression analysis identified male gender [OR 1.90 (1.25–2.75); p = 0.002] and hearing impairment GR3 [OR 1.90 (1.08–3.35); p = 0.026] and GR4 [OR 8.21 (2.29–29.50); p = 0.001] as positive predictors. In contrast, patients with large T4 tumors [OR 0.33 (0.13–0.86); p = 0.024] and complete hearing loss GR5 [OR 0.36 (0.15–0.84); p = 0.017] were less likely to develop a tinnitus. Yet, 60% of the patients with good clinical hearing (GR1) and 25% of patients with complete hearing loss (GR5) suffered from tinnitus.

Conclusion

These data are good accordance with literature about non-VS tinnitus indicating hearing impairment as main risk factor. In contrast, complete hearing loss appears a negative predictor for tinnitus. For the first time, these findings indicate a non-linear relationship between hearing impairment and tinnitus in unilateral sporadic VS. Our results suggest a similar pathophysiology in VS-associated and non-VS tinnitus.

Auditory Brainstem Responses in Tinnitus: A Review of Who, How, and What?

The auditory brainstem response (ABR) in tinnitus subjects has been extensively investigated over the last decade with the hopes of finding possible abnormalities related to the pathology. Despite this effort, the use of the ABR for tinnitus diagnosis or as an outcome measure is under debate. The present study reviewed published literature on ABR and tinnitus. The authors searched PubMed, MedLine, Embase, PsycINFO, and CINAHL, and identified additional records through manually searching reference lists and gray literature. There were 4,566 articles identified through database searching and 151 additional studies through the manual search (4,717 total): 2,128 articles were removed as duplicates, and 2,567 records did not meet eligibility criteria. From the final 22 articles that were included, ABR results from 1,240 tinnitus subjects and 664 control subjects were compiled and summarized with a focus on three main areas: the participant characteristics, the methodology used, and the outcome measures of amplitude and/or latency of waves I, III, and V. The results indicate a high level of heterogeneity between the studies for all the assessed areas. Amplitude and latency differences between tinnitus and controls were not consistent between studies. Nevertheless, the longer latency and reduced amplitude of wave I for the tinnitus group with normal hearing compared to matched controls was the most consistent finding across studies. These results support the need for greater stratification of the tinnitus population and the importance of a standardized ABR method to make comparisons between studies possible.

A Study of Brainstem Auditory Evoked Responses in Normal Hearing Patients with Tinnitus

Tinnitus is thought to be an auditory phenomenon resulting from spontaneous neuronal activity somewhere along the auditory pathway either in the peripheral or central auditory system. The neural abnormalities underlying tinnitus are largely unknown. This study analysis the auditory brainstem responses in normal hearing patients with tinnitus. This study consisted of 100 patients divided into two groups. Group I (Control): 50 Normal hearing patients without tinnitus. Group II (Study): 50 Normal hearing patients complaining of tinnitus. Both groups were submitted to full audiological history taking, otological examination, basic audiologic evaluation and Auditory brainstem responses (ABR) followed by calculation of the absolute latencies of wave I, III and V and interpeak latencies between waves I-III, III-V and I-V. In the study group 20 patients showed abnormal results in at least 1 of the 6 parameters evaluated. The results of absolute latencies of wave I, III and V showed significant prolongation, but the interpeak latencies of waves I-III, III-V and I-V were not significantly prolonged when compared with control group. Our study data showed that there are changes in the central pathways in the study group. The significance of these changes must be investigated with further audiological and neurological tests. We also understand that ABR has to be included in the work up of tinnitus patients whose hearing is within normal parameters.

Does attempt at hearing preservation microsurgery of vestibular schwannoma affect postoperative tinnitus?

Background. The aim of this study was to analyze the effect of vestibular schwannoma microsurgery via the retrosigmoid-transmeatal approach with special reference to the postoperative tinnitus outcome. Material and Methods. A prospective study was performed in 89 consecutive patients with unilateral vestibular schwannoma indicated for microsurgery. Patient and tumor related parameters, pre- and postoperative hearing level, intraoperative findings, and hearing and tinnitus handicap inventory scores were analyzed. Results. Cochlear nerve integrity was achieved in 44% corresponding to preservation of preoperatively serviceable hearing in 47% and useful hearing in 21%. Main prognostic factors of hearing preservation were grade/size of tumor, preoperative hearing level, intraoperative neuromonitoring, tumor consistency, and adhesion to neurovascular structures. Microsurgery led to elimination of tinnitus in 66% but also new-onset of the symptom in 14% of cases. Preservation of useful hearing and neurectomy of the eighth cranial nerve were main prognostic factors of tinnitus elimination. Preservation of cochlear nerve but loss of preoperative hearing emerged as the main factor for tinnitus persistence and new onset tinnitus. Decrease of THI scores was observed postoperatively. Conclusions. Our results underscore the importance of proper pre- and intraoperative decision making about attempt at hearing preservation versus potential for tinnitus elimination/risk of new onset of tinnitus.

Suppression and facilitation of auditory neurons through coordinated acoustic and midbrain stimulation: investigating a deep brain stimulator for tinnitus

OBJECTIVE

The inferior colliculus (IC) is the primary processing center of auditory information in the midbrain and is one site of tinnitus-related activity. One potential option for suppressing the tinnitus percept is through deep brain stimulation via the auditory midbrain implant (AMI), which is designed for hearing restoration and is already being implanted in deaf patients who also have tinnitus. However, to assess the feasibility of AMI stimulation for tinnitus treatment we first need to characterize the functional connectivity within the IC. Previous studies have suggested modulatory projections from the dorsal cortex of the IC (ICD) to the central nucleus of the IC (ICC), though the functional properties of these projections need to be determined.

APPROACH

In this study, we investigated the effects of electrical stimulation of the ICD on acoustic-driven activity within the ICC in ketamine-anesthetized guinea pigs.

MAIN RESULTS

We observed ICD stimulation induces both suppressive and facilitatory changes across ICC that can occur immediately during stimulation and remain after stimulation. Additionally, ICD stimulation paired with broadband noise stimulation at a specific delay can induce greater suppressive than facilitatory effects, especially when stimulating in more rostral and medial ICD locations.

SIGNIFICANCE

These findings demonstrate that ICD stimulation can induce specific types of plastic changes in ICC activity, which may be relevant for treating tinnitus. By using the AMI with electrode sites positioned with the ICD and the ICC, the modulatory effects of ICD stimulation can be tested directly in tinnitus patients.

The neuropsychiatry of tinnitus: a circuit-based approach to the causes and treatments available

Patients presenting with tinnitus commonly have neuropsychiatric symptoms with which physicians need to be familiar. We provide an overview of tinnitus, including its types and pathophysiology. We discuss how recent methods such as transcranial magnetic stimulation, positron emission tomography, MRI, magnetoencephalography and quantitative EEG improve our understanding of the pathophysiology of tinnitus and connect tinnitus to the neuropsychiatric symptoms. We then explain why treatment of the tinnitus patient falls within the purview of neuropsychiatry. Psychiatric problems such as depression, anxiety and personality disorders are discussed. We also discuss how stress, headache, cognitive processing speed and sleep disturbance are associated with tinnitus. Finally, we provide a brief overview of treatment options and discuss the efficacy of various medications, including benzodiazepines, antidepressants, antipsychotics and mood-stabilising agents, and various non-pharmacological treatment options, such as cognitive behavioural therapy, habituation therapy and acupuncture. We also discuss how brain stimulation therapies are being developed for the treatment of tinnitus. In conclusion, a review of the literature demonstrates the varied neuropsychiatric manifestations of tinnitus. Imaging studies help to explain the mechanism of the association. However, more research is needed to elucidate the neurocircuitry underlying the association.

Change in tinnitus after treatment of vestibular schwannoma: microsurgery vs. gamma knife radiosurgery

PURPOSE

Tinnitus is a very common symptom of vestibular schwannoma, present in 45 to 80% of patients. We evaluated changes in tinnitus after translabyrinthine microsurgery (TLM) or gamma knife radiosurgery (GKS).

MATERIALS AND METHODS

Among 78 patients with vestibular schwannoma who underwent TLM or GKS at Severance Hospital from 2009-2012, 46 patients with pre- or postoperative tinnitus who agreed to participate were enrolled. Pure tone audiometry, tinnitus handicap inventory (THI), visual analogue scale (VAS) scores for loudness, awareness, and annoyance were measured before and after treatment. Changes of THI and VAS were analysed and compared according to treatment modality, tumour volume, and preoperative residual hearing.

RESULTS

In the TLM group (n=27), vestibulocochlear nerves were definitely cut. There was a higher rate of tinnitus improvement in TLM group (52%) than GKS group (16%, p=0.016). The GKS group had a significantly higher rate of tinnitus worsening (74%) than TLM group (11%, p<0.001). Mean scores of THI and VAS scores significantly decreased in the TLM group in contrast to significant increases in the GKS group. Tumor volume and preoperative hearing did not affect the changes in THI or VAS.

CONCLUSION

GKS can save vestibulocochlear nerve continuity but may damage the cochlea, cochlear nerve and can cause worsening tinnitus. In cases where hearing preservation is not intended, microsurgery with vestibulocochlear neurectomy during tumor removal can sometimes relieve or prevent tinnitus.

Anatomical study of the central myelin portion and transitional zone of the vestibulocochlear nerve

BACKGROUND

The aim of this study was to evaluate gross and microscopic anatomical features of the vestibulocochlear nerve or eighth cranial nerve (CNVIII) from fresh cadavers, especially the nerve's central myelin portion (CMP) and transitional zone (TZ), and to consider any pathological implications.

METHODS

Six fresh cadavers were used to examine the CNVIII. Its cisternal length from brainstem to internal auditory meatus was measured. Longitudinal sections were stained to make following measurements: the diameter where the nerve enters the brainstem, the diameter where the TZ begins, the distance to the most distal part of TZ from the brainstem, and the depth of the TZ. The volume of the CMP was calculated as well.

RESULTS

The cisternal length of ten CNVIIIs measured between 14.2 and 19.2 mm (16.48 ± 1.78 mm). The thickness where the CNVIII enters the brainstem was between 1.21 and 3.16 mm (2.31 ± 0.68 mm); the thickness where the TZ begins was between 1.07 and 2.21 mm (1.44 ± 0.38 mm); the distance of the most distal part of the TZ from the brainstem was between 9.28 and 13.84 mm (11.50 ± 1.56 mm); the depth of the TZ was between 0.56 and 1.28 mm (0.81 ± 0.27 mm). The volume of the CMP was between 17.34 and 53.87 mm(3) (33.98 ± 13.74 mm(3)). The measurements were compared to trigeminal, facial, glossopharyngeal and vagus nerves. CNVIII was the nerve with the longest CMP.

CONCLUSIONS

The measurements showed that the CMP of CNVIII was very long. The implication of this length in the dysfunctional syndromes of this nerve, its propensity to harbor schwannomas, which most frequently arise at the porus of the auditory meatus, and the vulnerability to damages are discussed.

Prognosis of tinnitus after acoustic neuroma surgery--surgical management of postoperative tinnitus

OBJECTIVE

Tinnitus is a bothersome symptom for patients with acoustic neuroma. We studied the possibility of surgical control of postoperative tinnitus associated with acoustic neuroma.

METHODS

Postoperative changes and prognosis of tinnitus were studied in 367 patients treated surgically via a lateral suboccipital retrosigmoid approach.

RESULTS

Postoperative prognosis of tinnitus was as follows: resolved in 20%, improved in 22%, unchanged in 35%, changed in 10%, and worsened in 14% of 290 patients who had preoperative tinnitus, and no tinnitus in 78% and appeared in 22% of 77 patients without preoperative tinnitus. Prognosis of postoperative tinnitus was influenced by age, tumor size, preoperative hearing acuity, types of preoperative hearing disturbance, and conditions of the cochlear nerve after tumor resection. Worse prognosis of postoperative tinnitus in the preoperative tinnitus group was found in younger patients, smaller tumor size, better preoperative hearing function, and normal or retrocochlear type of hearing disturbance. Regarding the conditions of the cochlear nerve after tumor resection, prognosis of tinnitus was significantly worse in the group of anatomically preserved cochlear nerve without useful hearing than in the group of cut cochlear nerve.

CONCLUSIONS

Deciding whether to cut the cochlear nerve during acoustic neuroma surgery by referring to a flowchart, we proposed in cases where hearing preservation is not intended or judged less possible contributes to controlling postoperative tinnitus. However, regardless of whether the cochlear nerve was cut intraoperatively, tinnitus remained unchanged in 37% of patients, suggesting that their tinnitus originates in the brainstem or post-brainstem pathways before surgery, and it is considered difficult to control postoperative tinnitus in these cases.

Vascular compression of the cochlear nerve and tinnitus: a pathophysiological investigation

OBJECTIVE

Chronic microvascular compressions of the eighth nerve induce a slowing down of signal transmission in the auditory nerve, electrophysiologically characterized by IPL I-III prolongation.

METHODS

The authors hypothesize this is compensated by an active slowing down of signal transmission of the contralateral input at the level of the brainstem, characterized by contralateral IPL III-V prolongation.

RESULTS

Differences between ipsilateral and contralateral IPL I-III and IPL III-V are analyzed before and after microvascular decompression. ABR diagnostic criteria for microvascular compression are ipsilateral IPL I-III prolongation or ipsilateral peak II decrease + ipsilateral IPL I-III prolongation. With IPL I-III as diagnostic criterion, unlike preoperatively the difference between the ipsi- and contralateral IPL I-III is significant postoperatively. When using the stricter diagnostic criterion of IPL I-III + peak II, there is a preoperative significant difference between ipsi- and contralateral IPL I-III, but postoperatively the difference between the ipsi- and contralateral IPL I-III is not significant.

CONCLUSIONS

Preoperatively, there is a marginal significant difference between the ipsi- and contralateral IPL III-V, which disappears postoperatively.

Cochlear changes in presbycusis with tinnitus

OBJECTIVES

The pathophysiology of tinnitus is obscure and its treatment is therefore elusive. Significant progress in this field can only be achieved by determining the mechanisms of tinnitus generation, and thus, histopathologic findings of the cochlea in presbycusis with tinnitus become crucial. We revealed the histopathologic findings of the cochlea in subjects with presbycusis and tinnitus.

MATERIAL AND METHODS

The subjects were divided into 2 groups, presbycusis with tinnitus (tinnitus) group and presbycusis without tinnitus (control) group, with each group comprising 8 temporal bones from 8 subjects. We quantitatively analyzed the number of spiral ganglion cells, loss of cochlear inner and outer hair cells, and areas of the stria vascularis and spiral ligament.

RESULTS

There was a significantly greater loss of outer hair cells in the tinnitus group compared with the control group in the basal and upper middle turns. The stria vascularis was more atrophic in the tinnitus group compared with the control group in the basal turn.

CONCLUSIONS

Tinnitus is more common in patients with presbycusis who have more severe degeneration of outer hair cells and stria vascularis.

Comparison of auditory electrophysiological responses in normal-hearing patients with and without tinnitus

Introduction:

Tinnitus is a disturbing symptom and is often the main reason for otology referral. It is usually associated with hearing loss of varying aetiology, and is thought to begin in the cochlea, with later abnormal central activity. We hypothesise that tinnitus without hearing loss may be caused by central and subcortical abnormalities and altered outer hair cell function.

Aim:

To compare the auditory brainstem responses, middle latency responses and otoacoustic emissions in normal-hearing individuals with and without tinnitus.

Methodology:

The audiological test results of 25 normal hearing subjects with tinnitus (age 18–45 years) were determined, and compared with those of a control group.

Results:

A statistically significant difference was found between study group tinnitus ears vs control group ears, as regards wave I latency prolongation, shortening of wave V and absolute I–III and I–V interpeak latency, enlargement of wave Na and Pa amplitude, and distortion product and transient evoked otoacoustic emission signal-to-noise ratios. There was no statistically significant difference between unilateral vs bilateral tinnitus ears.

Conclusion:

The pathogenesis and optimum management of tinnitus are still unclear. It often occurs with primary ear disease, usually associated with hearing loss, but may occur in patients with normal hearing. Observed changes in auditory brainstem and middle latency responses indicate central auditory alterations. Tinnitus involves both peripheral and central activity, and complete audiological and neurophysiological investigation is required. Management should be based on both audiological and neurophysiological findings.

Results of TRT after eighteen months: Our experience

The aim of this study was to evaluate the efficacy of TRT in patients suffering from tinnitus. The tinnitus disorder affects about 10-15% of the population and, in one person out of a hundred, it is a disabling disorder. TRT treatment is based on Jastreboff's neurophysiological model. TRT consists of two parts: counselling, and sound therapy by means of dedicated hearing aids and sound generators. It proved to be useful to reduce the symptoms related to tinnitus. Jastreboff's structured interviews were proposed to a sample of 51 patients with tinnitus belonging to the I-II-III-IV classes according to Jastreboff. These patients were treated for 18 months. Sixty-eight percent of patients reported a reduction in the symptoms related to tinnitus, such as sleep disturbance, problems in concentration, and inability to relax. A percentage (64.7%) of patients thought that their quality of life was improved. Patients who had suffered from tinnitus for less than one year achieved significantly better results than patients who had suffered for a longer period of time. TRT is an effective tool in the treatment of tinnitus.

The mechanisms of tinnitus: perspectives from human functional neuroimaging

In this review, we highlight the contribution of advances in human neuroimaging to the current understanding of central mechanisms underpinning tinnitus and explain how interpretations of neuroimaging data have been guided by animal models. The primary motivation for studying the neural substrates of tinnitus in humans has been to demonstrate objectively its representation in the central auditory system and to develop a better understanding of its diverse pathophysiology and of the functional interplay between sensory, cognitive and affective systems. The ultimate goal of neuroimaging is to identify subtypes of tinnitus in order to better inform treatment strategies. The three neural mechanisms considered in this review may provide a basis for TI classification. While human neuroimaging evidence strongly implicates the central auditory system and emotional centres in TI, evidence for the precise contribution from the three mechanisms is unclear because the data are somewhat inconsistent. We consider a number of methodological issues limiting the field of human neuroimaging and recommend approaches to overcome potential inconsistency in results arising from poorly matched participants, lack of appropriate controls and low statistical power.

Subjective idiopathic tinnitus and palliative care: a plan for diagnosis and treatment

This article integrates the highlights of the authors' clinical experiences derived from existing protocols for tinnitus diagnosis and treatment with the evolving discipline of palliation medicine. Specifically, it demonstrates how the inclusion of principles of palliation medicine contributes to the efficacy of treatment.

Tinnitus: characteristics, causes, mechanisms, and treatments

Tinnitus-the perception of sound in the absence of an actual external sound-represents a symptom of an underlying condition rather than a single disease. Several theories have been proposed to explain the mechanisms underlying tinnitus. Tinnitus generators are theoretically located in the auditory pathway, and such generators and various mechanisms occurring in the peripheral auditory system have been explained in terms of spontaneous otoacoustic emissions, edge theory, and discordant theory. Those present in the central auditory system have been explained in terms of the dorsal cochlear nucleus, the auditory plasticity theory, the crosstalk theory, the somatosensory system, and the limbic and autonomic nervous systems. Treatments for tinnitus include pharmacotherapy, cognitive and behavioral therapy, sound therapy, music therapy, tinnitus retraining therapy, massage and stretching, and electrical suppression. This paper reviews the characteristics, causes, mechanisms, and treatments of tinnitus.

Acute high-intensity sound exposure alters responses of place cells in hippocampus

Overstimulation is known to activate neural plasticity in the auditory nervous system causing changes in function and re-organization. It has been shown earlier that overstimulation using high-intensity noise or tones can induce signs of tinnitus. Here we show in studies in rats that overstimulation causes changes in the way place cells of the hippocampus respond as rats search for rewards in a spatial maze. In familiar environments, a subset of hippocampal pyramidal neurons, known as place cells, respond when the animal moves through specific locations but are relatively silent in others. This place-field activity (i.e. location-specific firing) is stable in a fixed environment. The present study shows that activation of neural plasticity through overstimulation by sound can alter the response of these place cells. Rats implanted with chronic drivable dorsal hippocampal tetrodes (four microelectrodes) were assessed for stable single-unit place-field responses that were extracted from multiunit responses using NeuroExplorer computer spike-sorting software. Rats then underwent either 30 min exposure to a 4 kHz tone at 104 dB SPL or a control period in the same sound chamber. The place-field activity was significantly altered after sound exposure showing that plastic changes induced by overstimulation are not limited to the auditory nervous system but extend to other parts of the CNS, in this case to the hippocampus, a brain region often studied in the context of plasticity.

Tinnitus and inferior colliculus activity in chinchillas related to three distinct patterns of cochlear trauma

A longstanding hypothesis is that tinnitus, the perception of sound without an external acoustic source, is triggered by a distinctive pattern of cochlear hair cell (HC) damage and that this subsequently leads to altered neural activity in the central auditory pathway. This hypothesis was tested by assessing behavioral evidence of tinnitus and spontaneous neural activity in the inferior colliculus (IC) after unilateral cochlear trauma. Chinchillas were assigned to four cochlear treatment groups. Each treatment produced a distinctive pattern of HC damage, as follows: acoustic exposure (AEx): sparse low-frequency inner hair cell (IHC) and outer hair cell (OHC) loss; round window cisplatin (CisEx): pronounced OHC loss mixed with some IHC loss; round window carboplatin (CarbEx): pronounced IHC loss without OHC loss; control: no loss. Compared with controls, all experimental groups displayed significant and similar psychophysical evidence of tinnitus with features resembling a 1-kHz tone. Contralateral IC spontaneous activity was elevated in the AEx and CisEx groups, which showed increased spiking and increased cross-fiber synchrony. A multidimensional analysis identified a subpopulation of neurons more prevalent in animals with tinnitus. These units were characterized by high bursting, low ISI variance, and within-burst peak spiking of approximately 1,000/sec. It was concluded that cochlear trauma in general, rather than its specific features, leads to multiple changes in central activity that underpin tinnitus. Particularly affected was a subpopulation ensemble of IC neurons with the described unique triad of features.

Transient and distortion product evoked oto-acoustic emissions in normal hearing patients with and without tinnitus

Objective

To test the hypothesis that tinnitus begins with outer hair cell dysfunction by recording transient (TEOAE) and distortion product evoked (DPOAE) oto-acoustic emissions in patients with normal hearing with (study group, SG) and without tinnitus (control group, CG).

Study Design

Case control study.

Subjects and Methods

SG had 32 patients with pure tone thresholds below 25 dB in the 500 to 8000 Hz interval. CG had 37 age- and gender-matched patients with similar thresholds. All patients had normal tympanograms and stapedial reflexes. TEOAE were recorded with wide band click in continuous mode at 80-dB peak SPL. DPOAE were recorded with f1/f2 = 1.22 and intensities of 65 dB (f1) and 55 dB (f2) SPL.

Results

DPOAE were abnormal in 68.4% of SG and in 50% of CG ( P = 0.036). TEOAE were abnormal in 70.2% of SG and in 16.10% of CG ( P = 0.0001).

Conclusion

SG had significantly higher prevalence of abnormal TEOAE and DPOAE than CG.

Myofascial trigger point:a possible way of modulating tinnitus

In order to investigate whether myofascial trigger points can modulate tinnitus, as well as the association between tinnitus and myofascial trigger points, 94 individuals with and 94 without tinnitus, matched by age and gender, were analyzed by means of bilateral digital pressure of 9 muscles. Temporary modulation of tinnitus was frequently observed (55.9%) during digital pressure, mainly in the masseter. The rate of tinnitus modulation was significantly higher on the same side of the myofascial trigger point subject to examination in 6 out of 9 muscles. An association between tinnitus and the presence of myofascial trigger points was observed (p < 0.001), as well as a laterality association between the ear with the worst tinnitus and the side of the body with more myofascial trigger points (p < 0.001). Thus, this relationship could be explained not only by somatosensory-auditory system interactions but also by the influence of the sympathetic system.

Auditory cortex stimulation for tinnitus

Functional imaging techniques have demonstrated a relationship between the intensity of tinnitus and the degree of reorganization of the primary auditory cortex. Studies in experimental animals and humans have revealed that tinnitus is associated with a synchronized hyperactivity in the auditory cortex and proposed that the underlying pathophysiological mechanism is thalamocortical dysrhythmia; hence, decreased auditory stimulation results in decreased firing rate, and decreased lateral inhibition. Consequently, the surrounding brain area becomes hyperactive, firing at gamma band rates; this is considered a necessary precondition of auditory consciousness, and also tinnitus. Synchronization of the gamma band activity could possibly induce a topographical reorganization based on Hebbian mechanisms. Therefore, it seems logical to try to suppress tinnitus by modifying the tinnitus-related auditory cortex reorganization and hyperactivity. This can be achieved using neuronavigation-guided transcranial magnetic stimulation (TMS), which is capable of modulating cortical activity. If TMS is capable of suppressing tinnitus, the effect should be maintained by implanting electrodes over the area of electrophysiological signal abnormality on the auditory cortex. The results in the first patients treated by auditory cortex stimulation demonstrate a statistically significant tinnitus suppression in cases of unilateral pure tone tinnitus without suppression of white or narrow band noise. Hence, auditory cortex stimulation could become a physiologically guided treatment for a selected category of patients with severe tinnitus.

The dorsal cochlear nucleus as a participant in the auditory, attentional and emotional components of tinnitus

The dorsal cochlear nucleus (DCN) has been modeled in numerous studies as a possible source of tinnitus-generating signals. This hypothesis was originally developed on the basis of evidence that the DCN becomes hyperactive following exposure to intense noise. Since these early observations, evidence that the DCN is an important contributor to tinnitus has grown considerably. In this paper, the available evidence to date will be summarized. In addition, the DCN hypothesis of tinnitus can now be expanded to include possible involvement in other, non-auditory components of tinnitus. It will be shown by way of literature review that the DCN has direct connections with non-auditory brainstem structures, such as the locus coeruleus, reticular formation and raphe nuclei, that are implicated in the control of attention and emotional responses. The hypothesis will be presented that attentional and emotional disorders, such as anxiety and depression, which are commonly associated with tinnitus, may result from an interplay between these non-auditory brainstem structures and the DCN. Implicit in this hypothesis is that attempts to develop effective anti-tinnitus therapies are likely to benefit from a greater understanding of how the levels of activity in the DCN are influenced by different states of activation of these non-auditory brainstem structures and vice versa.

General review of tinnitus: prevalence, mechanisms, effects, and management

Tinnitus is an increasing health concern across all strata of the general population. Although an abundant amount of literature has addressed the many facets of tinnitus, wide-ranging differences in professional beliefs and attitudes persist concerning its clinical management. These differences are detrimental to tinnitus patients because the management they receive is based primarily on individual opinion (which can be biased) rather than on medical consensus. It is thus vitally important for the tinnitus professional community to work together to achieve consensus. To that end, this article provides a broad-based review of what is presently known about tinnitus, including prevalence, associated factors, theories of pathophysiology, psychological effects, effects on disability and handicap, workers' compensation issues, clinical assessment, and various forms of treatment. This summary of fundamental information has relevance to both clinical and research arenas.