Cochlear implant and tinnitus-a meta-analysis

Current understanding of subjective tinnitus in adults

PURPOSE

An up-to-date overview of epidemiology, etiology and pathophysiological mechanisms, diagnostic and evaluation methods, current treatment status and future directions of subjective tinnitus in adults.

METHODS

Review of current evidence-based literature on subjective tinnitus in adults.

RESULTS

The prevalence of subjective tinnitus in the adult population is estimated to be around 14%, and it tends to increase with age. Subjective tinnitus is a complex condition with multiple factors contributing to its origin. However, the exact causes and underlying mechanisms remain unknown. Potential causes may include hearing loss, dysfunction in the somatosensory system, and auditory cortical dysfunction, although severe underlying pathology is rare. Currently, diagnosis primarily relies on patient self-reported medical history and physician-based clinical assessment due to the lack of objective testing. Various treatment and management options have been proposed, but their effectiveness varies, and there is no universally agreed-upon treatment option.

CONCLUSIONS

Tinnitus is a complex and heterogeneous disease with a high incidence rate and a tendency to increase with age. A holistic perspective is needed to understand the generation, perception, and emotional responses to tinnitus. Diagnosis requires a comprehensive assessment based on medical history and relevant examinations, identification of concurrent psychosomatic comorbidities, and active pursuit of objective diagnostic methods. At the same time, on the basis of existing treatment plans and combining emerging technologies, we will develop new personalized, precise, and combined treatment plans.

Active TriCROS: A Simultaneous Stimulation With a (Bi)CROS System and a Hearing Aid in the Worst Ear for Severely Asymmetrical Hearing Loss

OBJECTIVE

Severely asymmetrical hearing loss (SAHL) is characterized by a moderately severe or severe hearing loss in one side and normal or mildly impaired controlateral hearing in the other. The Active tri-CROS combines the Contralateral Routing-of-Signal System (CROS, or BiCROS if the best ear is stimulated) and the stimulation of the worst ear by an in-the-canal hearing aid. This study aims to evaluate the benefit of the Active tri-CROS for SAHL patients.

STUDY DESIGN

This retrospective study was conducted from September 2019 to December 2020.

SETTING

Ambulatory, tertiary care.

PATIENTS

Patients were retrospectively included if they had received the Active tri-CROS system after having used a CROS or BiCROS system for SAHL for at least 3 years.

MAIN OUTCOME MEASURES

Audiometric gain, signal-to-noise ratio, spatial localization, and the Abbreviated Profile of Hearing Aid Benefit and Tinnitus Handicap Inventory questionnaires were performed before equipment and after a month with the system.

RESULTS

Twenty patients (mean, 62 yr old) with a mean of 74.3 ± 8.7 dB HL on the worst ear were included. The mean tonal hearing gain on the worst ear was 20 ± 6 dB. Signal-to-noise ratio significantly rose from 1.43 ± 3.9 to 0.16 ± 3.4 dB ( p = 0.0001). Spatial localization was not significantly improved. The mean Tinnitus Handicap Inventory test score of the eight patients suffering from tinnitus rose from 45.5 ± 18.5 to 31 ± 25.2 ( p = 0.016).

CONCLUSIONS

The Active tri-CROS system is a promising new therapeutically solution for SAHL.

Tinnitus: Clinical Insights in Its Pathophysiology-A Perspective

Tinnitus, the perception of sound without a corresponding external sound source, and tinnitus disorder, which is tinnitus with associated suffering, present a multifaceted clinical challenge due to its heterogeneity and its incompletely understood pathophysiology and especially due to the limited therapeutic options. In this narrative review, we give an overview on various clinical aspects of tinnitus including its heterogeneity, contributing factors, comorbidities and therapeutic pathways with a specific emphasis on the implications for its pathophysiology and future research directions. Tinnitus exhibits high perceptual variability between affected individuals (heterogeneity) and within affected individuals (temporal variability). Hearing loss emerges as predominant risk factor and the perceived pitch corresponds to areas of hearing loss, supporting the compensatory response theory. Whereas most people who have tinnitus can live a normal life, in 10-20% tinnitus interferes severely with quality of life. These patients suffer frequently from comorbidities such as anxiety, depression or insomnia, acting as both risk factors and consequences. Accordingly, neuroimaging studies demonstrate shared brain networks between tinnitus and stress-related disorders shedding light on the intricate interplay of mental health and tinnitus. The challenge lies in deciphering causative relationships and shared pathophysiological mechanisms. Stress, external sounds, time of day, head movements, distraction, and sleep quality can impact tinnitus perception. Understanding these factors provides insights into the interplay with autonomic, sensory, motor, and cognitive processes. Counselling and cognitive-behavioural therapy demonstrate efficacy in reducing suffering, supporting the involvement of stress and anxiety-related networks. Hearing improvement, especially through cochlear implants, reduces tinnitus and thus indirectly validates the compensatory nature of tinnitus. Brain stimulation techniques can modulate the suffering of tinnitus, presumably by alteration of stress-related brain networks. Continued research is crucial for unravelling the complexities of tinnitus. Progress in management hinges on decoding diverse manifestations, identifying treatment-responsive subtypes, and advancing targeted therapeutic approaches.

Electrical Ear Canal Stimulation as a Therapeutic Approach for Tinnitus-A Proof of Concept Study

Background: Tinnitus-the perception of sound despite the absence of an external source-can be a debilitating condition for which there are currently no pharmacological remedies. Our proof of concept study focused on the immediate effects of non-invasive electrical stimulation through the ear canal on loudness and tinnitus-induced distress. In addition, we aimed to identify variables that may affect the simulation outcomes. Methods: Sixty-six patients (29 women and 37 men, mean age 54.4 ± 10.4) with chronic tinnitus were recruited to the tertiary referral hospital between December 2019 and December 2021. They underwent 10 min of electrical stimulation through the ear canal for three consecutive days. Visual analog scales measured loudness and tinnitus-induced distress immediately before and after stimulation. Results: After three days of electrical stimulation, tinnitus loudness decreased in 47% of patients, 45.5% reported no change, and 7.6% reported worsening. Tinnitus severity decreased in 36.4% of cases, 59.1% of patients reported no change, and 4.5% reported worsening. Women responded positively to therapy earlier than men. In addition, tinnitus distress decreased in patients with compensated tinnitus but not in those with uncompensated tinnitus. Finally, patients with bilateral tinnitus improved earlier than those with unilateral tinnitus, and the age of the patients did not influence the stimulation results. Conclusions: Our proof of concept study confirms the potential of non-invasive electrical stimulation of the ear as a promising screening approach to identifying patients for more advanced electrostimulation treatment, such as an extracochlear anti-tinnitus implant. These findings have practical implications for tinnitus management, offering hope for improved patient care.

Interventions against hearing loss as an integral component of successful tinnitus therapy

Tinnitus very often develops from acute or chronic hearing loss, mainly inner ear deafness. The frequency of the tinnitus mostly corresponds to the frequency range of the hearing loss and is enhanced by down-regulation of inhibition in the central auditory pathway for these frequencies, in addition to focused attention and enhanced arousal for the disturbing sound. Therefore, interventions to improve hearing such as mid-ear surgery or-more often-electronic devices including hearing aids or cochlear implants (CI) are important for the treatment of tinnitus. In this review, the current German S3 guideline "Chronic tinnitus" and recent literature are discussed.

Changes in Tinnitus Characteristics and Residual Inhibition following Cochlear Implantation: A Prospective Analysis

This study aims to explore the effect of cochlear implantation on tinnitus perception. A prospective study was conducted on 72 adult hearing-impaired patients to evaluate tinnitus perception before and after cochlear implantation, using standardized tinnitus questionnaires (the tinnitus sample case-history questionnaire, tinnitus functional index (TFI), and tinnitus handicap inventory (THI)). A large variety of demographic and hearing- and implant-related data was collected from patient hospital records to explore possible associations with the implantation effect. The prevalence of tinnitus complaints before implantation was 58.3%. The temporary induction or aggravation of tinnitus immediately after surgery was noted in 20% and 46.7% of patients, respectively. When evaluated 3 months after implantation, 60% of tinnitus patients experienced a clinically significant reduction in their complaints; most of the improvements were experienced immediately after activation of the implant. Only the scores for TFI and THI at baseline were found to be significantly correlated with a reduction in TFI scores after implantation. In 80% of tinnitus patients, the tinnitus remained suppressed for some time after taking off the device. The large subset of patients with residual inhibition supports the involvement of central pathophysiological processes in implantation effects on tinnitus, which are explored in this paper.

[Interventions against hearing loss are an integral component of successful tinnitus therapy. German version]

Tinnitus very often develops from acute or chronic hearing loss, mainly inner ear deafness. The frequency of the tinnitus mostly corresponds to the frequency range of the hearing loss and is enhanced by down-regulation of inhibition in the central auditory pathway for these frequencies, in addition to focused attention and enhanced arousal for the disturbing sound. Therefore, interventions to improve hearing such as mid-ear surgery or-more often-electronic devices including hearing aids or cochlear implants (CI) are important for the treatment of tinnitus. In this review, the current German S3 guideline "Chronic tinnitus" and recent literature are discussed.

Early effects of very early cochlear implant activation on tinnitus

BACKGROUND

Cochlear implantation (CI) has long been the standard of care for patients with severe-to-profound hearing impairment. Yet the benefits of CI extend far beyond speech understanding, with mounting recent literature supporting its role in tinnitus abatement. However, those studies have uniformly analyzed the effects of tinnitus after the traditional 3-4 weeks waiting period between CI surgery and device activation. As many clinics are shifting these waiting intervals to become shorter (in some cases within 24 hours, little is known about tinnitus abatement very early in the postoperative period. The aim of this study was to compare preoperative and postoperative tinnitus handicaps in this unique but growing population of very early-activated patients.

METHODS

Twenty-seven adults with severe-to-profound hearing impairment with chronic tinnitus (>6 months) were included. Patients with concomitant psychiatric disorders were excluded. All patients were implanted with the same array and were switched on within 24 hours after the surgery. Tinnitus Handicap Inventory (THI) was recorded preoperatively, immediately after activation at 24 hours postoperatively, at 1 week, 2 weeks, and I month after activation. Wilcoxon signed-rank test was used to compare values between preoperative assessment and respective fitting sessions.

RESULTS

Mean THI 24 hours after implantation increased in comparison to that assessed preoperatively (77.6 vs 72.5, p = 0.001). By 1 week after surgery, the THI had decreased to 54.9 ( p < 0.001). This trend continued and was statistically significant at 2 weeks (36.0, p < 0.001) and 1 month (28.5, p < 0.001).

CONCLUSION

On average, most patients with tinnitus will note a significant improvement in their tinnitus handicap when activated within 24 hours of CI. However, tinnitus does increase between surgery and 24 hours, most likely reflecting not only intracochlear changes, but modulation of the entire auditory pathway. Following this early rise, the tinnitus continues to abate over the following month. Patients with tinnitus may benefit from early activation, although should be counseled that they may experience an exacerbation during the very early postoperative period.

Cochlear implant in tinnitus management

PURPOSE OF REVIEW

To evaluate whether cochlear implantation can mitigate tinnitus perception and its discomfort among patients with severe-to-profound hearing loss, in order to provide an answer on a possible treatment for a health condition with high prevalence and impact on quality of life.

RECENT FINDINGS

Tinnitus can develop after peripheral hearing loss and is associated with altered auditory processing. It does not only involve auditory structures but also aberrant neural activity and interaction with other regions of the Central Nervous System associated with emotion, attention, anguish, memory and motor activity.

SUMMARY

Recent studies investigated the changes in tinnitus perception among patients who underwent cochlear implantation and demonstrated a postoperative decrease. Hence, patients with severe-to-profound sensorineural hearing loss and tinnitus are likely to benefit from cochlear implantation.

Effects of auditory rehabilitation with cochlear implant on tinnitus prevalence and distress, health-related quality of life, subjective hearing and psychological comorbidities: Comparative analysis of patients with asymmetric hearing loss (AHL), double-sided (bilateral) deafness (DSD), and single-sided (unilateral) deafness (SSD)

Introduction

Auditory rehabilitation with a cochlear implant (CI), in many cases, positively impacts tinnitus. However, it is unclear if the tinnitus-related benefit of CI is equal for patients with various indications for CI. Therefore, this study aimed to determine differences in tinnitus prevalence and distress, health-related quality of life, subjective hearing, perceived stress, and psychological comorbidities between patients diagnosed with asymmetric hearing loss (AHL), single-sided (unilateral) deafness (SSD), and double-sided (bilateral) deafness (DSD) before and six months after cochlear implantation.

Methods

One hundred-one CI candidates were included in this prospective study (39 AHL patients, 23 DSD patients, and 39 SSD patients). The patients completed questionnaires measuring tinnitus distress, health-related quality of life, subjective hearing, perceived stress, and psychological comorbidities before and 6 months after CI.

Results

The prevalence of tinnitus in the entire cohort (80.2% before CI) decreased 6 months after CI to 71.3%. The DSD group had the lowest tinnitus prevalence at both time points. The degree of tinnitus-induced distress decreased significantly in all three groups after CI. Differences in quality of life, subjective hearing, and psychological comorbidities between the groups at the study onset disappeared after CI. Significant correlations existed between anxiety, depression, and tinnitus distress in AHL and SSD but not in DSD patients before and after CI.

Discussion

Our results demonstrate significant differences between the three groups of CI candidates, which might affect the implantation outcome. These differences suggest a need for personalized psychological counseling during the auditory rehabilitation process, focusing on anxiety and depressive symptoms for SSD and AHL patients.

A Spectrum of Intraoperative and Postoperative Complications of Cochlear Implants: A Critical Review

A cochlear implant is a neuroprosthetic, electrical device that is developed for the treatment of patients who have sensory hearing loss. It directly stimulates the hearing nerve by bypassing the injured or damaged sensory receptors, the hair cells. This implant is directly placed in the inner ear. It is an electronic device which is proved to be very useful in patients with sensorineural hearing loss. This implant consists of a speech processor (externally present), which takes up the sound; transforms it into digital signals, and then internal components take it to convert it into electrical energy, which stimulates auditory nerves, and the brain perceives it and hears it as a sound. This is one of the most successful surgeries, which happens very frequently nowadays. Although, many complications are mostly associated with this implant. This paper deals with the preoperative, operative, and postoperative complications associated with cochlear implant surgery. That includes tinnitus, Meniere's disease, unilateral hearing loss, musical ear syndrome, infections; flap necrosis, facial nerve palsy, improper electrode placement, magnet displacement; failure and re-implantation, cholesteatoma, and pneumocephalus. These are just a few of the complications; there are much more complications which are associated with cochlear implants.

Clinical practice guideline: Chronic tinnitus—diagnosis and treatment

BACKGROUND

Chronic tinnitus is a commonly occurring symptom of the auditory system. Epidemiological studies assume a lifetime prevalence in men and women of 3.5% for chronic tinnitus requiring treatment. Almost 25% of all Germans have experienced at least one episode of tinnitus. No causal therapy is yet available, but numerous treatment strategies are being pursued. Rigorous scientific assessment of these procedures is essential.

METHODS

For this exhaustive revision of the German clinical practice guideline, the literature in the medical databases PubMed and Cochrane Library, including existing guidelines from various countries, was systematically searched using keywords on the topic of chronic tinnitus. On the basis of the revised guideline, a separate guideline was written in language accessible to patients.

RESULTS

Chronic tinnitus is often associated with hearing loss, but the mental distress caused by the ear noise is another crucial element. Apart from expert counseling, the recommended treatment comprises psychotherapeutic interventions, particularly cognitive behavioral therapy (with effect sizes of 0.54 to 0.91 for reduction of the tinnitus-related distress), and measures to improve the hearing. There is insufficient evidence regarding the effects of drug treatment, sound and music therapy, and neuromodulation (magnetic stimulation or electrostimulation).

CONCLUSION

Alongside thorough and sound diagnosis and counseling, the principal treatment options for chronic tinnitus are specific cognitive behavioral therapy and expert psychotherapeutic interventions on an individual or group basis. Future-preferably interdisciplinary-research should evaluate the long-term effects of the treatment options, with particular attention to psychosomatic comorbidity.

Tinnitus suppression with electrical stimulation in adults: long-term follow-up

Objectives

To investigate the long-term effects of cochlear implants as a treatment for patients with severe to profound neurosensory loss associated with severe tinnitus.

Methods

Prospective study in 17 adult patients with severe to profound sensorineural hearing loss associated with severe tinnitus, indicated with a Tinnitus Handicap Inventory (THI) score ≥ 58%, and hyperacusis. Measures were made on hearing, tinnitus, hyperacusis and quality of life up to 5 years after activation of the sound processor of the cochlear implant. It was evaluated by using the disyllabic test, THI, visual analogue scale and Glasgow Benefit Inventory questionnaire.

Results

60 months after cochlear implantation, improvements in loudness and discomfort of tinnitus, speech discrimination and hyperacusis were observed. Subjects perceive an important subjective benefit upon receiving the cochlear implant.

Conclusions

Cochlear implants can be used as treatment for patients with severe to profound sensorineural hearing loss associated with severe tinnitus and hyperacusis with long-term benefits on quality of life and lasting relief of tinnitus.

Using Extracochlear Multichannel Electrical Stimulation to Relieve Tinnitus and Reverse Tinnitus-Related Auditory-Somatosensory Plasticity in the Cochlear Nucleus

OBJECTIVES

Tinnitus has no reliable cure but may be significantly relieved by the usage of cochlear implants. However, not all tinnitus patients necessitate cochlear implantation that can impair hearing. This study was to investigate whether a novel extracochlear electrical stimulation (EES) strategy could relieve tinnitus of guinea pigs without hearing impairment, and the roles of auditory-somatosensory plasticity in the cochlear nucleus in the tinnitus relief.

MATERIALS AND METHODS

We used a novel four-electrode extracochlear implant to electrically stimulate the cochlea of tinnitus guinea pigs. Tinnitus was assessed by the gap-prepulse inhibition of the acoustic startle reflex (GPIAS) ratios and the tinnitus index. The plasticity of auditory and somatosensory innervation in the different subdivisions of cochlear nucleus was evaluated by immunostaining of vesicular glutamate transporter 1 (VGLUT1) and VGLUT2, respectively.

RESULTS

The EES induced significant decreases of GPIAS ratios and the tinnitus index of tinnitus guinea pigs, indicating reductions of tinnitus behavioral manifestations. Meanwhile, the EES reversed the abnormal auditory-somatosensory innervation in the cochlear nucleus of tinnitus animals but did not change the hearing and the numbers of inner hair cell synapses.

CONCLUSIONS

This study demonstrated that the novel EES strategy could effectively relieve tinnitus without impairment to hearing and cochlear structure of tinnitus animals. The reversal of tinnitus-related auditory-somatosensory plasticity in the cochlear nucleus was correlated with the tinnitus relief induced by the EES.