Outcomes after cochlear implantation for patients with single-sided deafness, including those with recalcitrant Ménière's disease

Menière's disease

Menière's disease (MD) is a chronic multifactorial disorder of the inner ear characterized by episodic vestibular symptoms associated with sensorineural hearing loss, tinnitus, and aural pressure. Epidemiologic and genomic evidence supports a genetic susceptibility with multiple biochemical pathways involved, including the endocrine system, innate immune response, and autonomic nervous system. Allergens, infectious agents, vascular events, or genetic factors could modify inner-ear homeostasis and trigger MD. The diagnosis of MD is based on clinical criteria and requires the observation of an episodic vertigo syndrome associated with low- to medium-frequency sensorineural hearing loss and fluctuating aural symptoms (hearing loss, tinnitus, and/or fullness) in the affected ear. Headache is also found during the attacks and bilateral involvement is found in 25-40% of cases. Audiologic and vestibular assessment is recommended to monitor the clinical course. The treatment of MD is symptomatic to obtain relief of vestibular episodes and preventive to limit hearing loss progression. Treatment options include sodium restriction, betahistine, intratympanic gentamicin, or steroids and eventually surgery, such as cochlear implantation.

Simultaneous cochlear implantation and labyrinthectomy for advanced Ménière's disease

Background:

Patients with Ménière's disease can develop unaidable sensorineural hearing loss. Cochlear implantation has recently been utilised in this group with favourable results. A more challenging group are those with intractable vertigo, and they have traditionally posed a significant management dilemma.

Case report:

Two female patients with unaidable hearing and recurrent incapacitating vertigo attacks despite conservative management underwent simultaneous labyrinthectomy and cochlear implantation. There was complete resolution of vertigo in both patients. Speech perception in quiet conditions and the ability to hear in background noise improved considerably.

Conclusion:

Surgical labyrinthectomy is effective for the elimination of vertigo in Ménière's disease patients. The major disadvantage in the past was loss of residual hearing. Cochlear implantation is now an option in these patients. The benefits of simultaneous labyrinthectomy with cochlear implantation include the prevention of implantation of a fibrosed or ossified cochlea, a decrease in the duration of deafness, and a single operative procedure.

A Series of Case Studies of Tinnitus Suppression With Mixed Background Stimuli in a Cochlear Implant

PURPOSE

Background sounds provided by a wearable sound playback device were mixed with the acoustical input picked up by a cochlear implant speech processor in an attempt to suppress tinnitus.

METHOD

First, patients were allowed to listen to several sounds and to select up to 4 sounds that they thought might be effective. These stimuli were programmed to loop continuously in the wearable playback device. Second, subjects were instructed to use 1 background sound each day on the wearable device, and they sequenced the selected background sounds during a 28-day trial. Patients were instructed to go to a website at the end of each day and rate the loudness and annoyance of the tinnitus as well as the acceptability of the background sound. Patients completed the Tinnitus Primary Function Questionnaire (Tyler, Stocking, Secor, & Slattery, 2014) at the beginning of the trial.

RESULTS

Results indicated that background sounds were very effective at suppressing tinnitus. There was considerable variability in sounds preferred by the subjects.

CONCLUSION

The study shows that a background sound mixed with the microphone input can be effective for suppressing tinnitus during daily use of the sound processor in selected cochlear implant users.

Cochlear implantation for patients with single-sided deafness or asymmetrical hearing loss: a systematic review of the evidence

OBJECTIVE

A systematic review of the literature to evaluate the clinical outcome of cochlear implantation for patients with single-sided deafness (SSD) or asymmetrical hearing loss (AHL).

DATA SOURCES

We searched the PubMed, Embase, Cochrane Library, and CINAHL databases from their inception up to December 10, 2013 for SSD or AHL and cochlear implantation or their synonyms.

STUDY SELECTION

In total, 781 articles were retrieved, of which 15 satisfied the eligibility criteria. Our outcomes of interest were speech perception in noise, sound localization, quality of life (QoL), and tinnitus.

DATA EXTRACTION

Critical appraisal showed that six studies reported on less than five patients or that they carried a low directness of evidence or a high risk of bias. Therefore, we extracted the data of nine studies (n = 112). Patient numbers, age, duration of deafness, classification of deafness, pure tone audiometry, follow-up duration, and outcome measurements were extracted from all nine articles.

DATA SYNTHESIS

Because of large heterogeneity between studies, we were not able to pool data in a meta-analysis. We therefore summarized the results of the studies specified per outcome.

CONCLUSION

There are no high-level-of-evidence studies concerning cochlear implantation in patients with SSD or AHL. Current literature suggests important benefits of cochlear implantation regarding sound localization, QoL, and tinnitus. Varying results were reported for speech perception in noise, possibly caused by the large clinical heterogeneity between studies. Larger and high-quality studies are certainly warranted.

The impact of cochlear implantation on speech understanding, subjective hearing performance, and tinnitus perception in patients with unilateral severe to profound hearing loss

OBJECTIVES

This study aimed to determine the impact of cochlear implantation on speech understanding in noise, subjective perception of hearing, and tinnitus perception of adult patients with unilateral severe to profound hearing loss and to investigate whether duration of deafness and age at implantation would influence the outcomes. In addition, this article describes the auditory training protocol used for unilaterally deaf patients.

DESIGN

This is a prospective study of subjects undergoing cochlear implantation for unilateral deafness with or without associated tinnitus.

METHODS

Speech perception in noise was tested using the Bamford-Kowal-Bench speech-in-noise test presented at 65 dB SPL. The Speech, Spatial, and Qualities of Hearing Scale and the Abbreviated Profile of Hearing Aid Benefit were used to evaluate the subjective perception of hearing with a cochlear implant and quality of life. Tinnitus disturbance was measured using the Tinnitus Reaction Questionnaire. Data were collected before cochlear implantation and 3, 6, 12, and 24 months after implantation.

RESULTS

Twenty-eight postlingual unilaterally deaf adults with or without tinnitus were implanted. There was a significant improvement in speech perception in noise across time in all spatial configurations. There was an overall significant improvement on the subjective perception of hearing and quality of life. Tinnitus disturbance reduced significantly across time. Age at implantation and duration of deafness did not influence the outcomes significantly.

CONCLUSION

Cochlear implantation provided significant improvement in speech understanding in challenging situations, subjective perception of hearing performance, and quality of life. Cochlear implantation also resulted in reduced tinnitus disturbance. Age at implantation and duration of deafness did not seem to influence the outcomes.

Cochlear Implantation and Single-sided Deafness: A Systematic Review of the Literature

Introduction Current data show that binaural hearing is superior to unilateral hearing, specifically in the understanding of speech in noisy environments. Furthermore, unilateral hearing reduce onés ability to localize sound.

Objectives This study provides a systematic review of recent studies to evaluate the outcomes of cochlear implantation in patients with single-sided deafness (SSD) with regards to speech discrimination, sound localization and tinnitus suppression.

Data Synthesis We performed a search in the PubMed, Cochrane Library and Lilacs databases to assess studies related to cochlear implantation in patients with unilateral deafness. After critical appraisal, eleven studies were selected for data extraction and analysis of demographic, study design and outcome data.

Conclusion Although some studies have shown encouraging results on cochlear implantation and SSD, all fail to provide a high level of evidence. Larger studies are necessary to define the tangible benefits of cochlear implantation in patients with SSD.

Tinnitus Suppression by Intracochlear Electrical Stimulation in Single-Sided Deafness: A Prospective Clinical Trial - Part I

Cochlear implantation is a viable treatment option for tinnitus, but the underlying mechanism is yet unclear. Is the tinnitus suppression due to the reversal of the assumed maladaptive neuroplasticity or is it the shift in attention from the tinnitus to environmental sounds and therefore a reduced awareness that reduces tinnitus perception? In this prospective trial, 10 patients with single-sided deafness were fitted with a cochlear implant to investigate the effect of looped intracochlear electrical stimulation (i.e. stimulation that does not encode environmental sounds) on tinnitus, in an effort to find optimal stimulation parameters. Variables under investigation were: amplitude (perceived stimulus loudness), anatomical location inside the cochlea (electrode/electrodes), amplitude modulation, polarity (cathodic/anodic first biphasic stimulation) and stimulation rate. The results suggest that tinnitus can be reduced with looped electrical stimulation, in some cases even with inaudible stimuli. The optimal stimuli for tinnitus suppression appear to be subject specific. However, medium-to-loud stimuli suppress tinnitus significantly better than soft stimuli, which partly can be explained by the masking effect. Although the long-term effects on tinnitus would still have to be investigated and will be described in part II, intracochlear electrical stimulation seems a potential treatment option for tinnitus in this population.

Cochlear implantation and single-sided deafness

PURPOSE OF REVIEW

Recently, more patients with single-sided deafness (SSD) have been undergoing cochlear implantation. We review recent studies and case reports to provide an overview of the efficacy of cochlear implants to rehabilitate patients with SSD with regards to sound localization, speech discrimination, and tinnitus suppression.

RECENT FINDINGS

There are a growing number of studies evaluating the effect of cochlear implantation for rehabilitation of the deficits associated with SSD over the past several years as more centers offer this treatment modality to patients with SSD. Although individual studies have few patients and are underpowered, the vast majority report improvement in sound localization, speech understanding in quiet and noise, and tinnitus. In some cases, the outcomes with cochlear implant appear superior to those achieved with other devices, including contralateral routing of sound devices and osseointegrated implants.

SUMMARY

Although cochlear implant is not a Food and Drug Administration-approved treatment for SSD, several recent studies show improvements in speech understanding, sound localization, and tinnitus. Because of the low number of cases, it is difficult to conclusively compare outcomes achieved with cochlear implants and those provided by other devices. However, on the basis of encouraging early results and the unique ability to restore binaural sound processing, a growing number of centers offer cochlear implants as treatment for SSD. Forthcoming studies will help define outcome expectations in different populations.

Cochlear implantation: a biomechanical prosthesis for hearing loss

Cochlear implants are a medical prosthesis used to treat sensorineural deafness, and one of the greatest advances in modern medicine. The following article is an overview of cochlear implant technology. The history of cochlear implantation and the development of modern implant technology will be discussed, as well as current surgical techniques. Research regarding expansion of candidacy, hearing preservation cochlear implantation, and implantation for unilateral deafness are described. Lastly, innovative technology is discussed, including the hybrid cochlear implant and the totally implantable cochlear implant.

Release from informational masking in a monaural competing-speech task with vocoded copies of the maskers presented contralaterally

Single-sided deafness prevents access to the binaural cues that help normal-hearing listeners extract target speech from competing voices. Little is known about how listeners with one normal-hearing ear might benefit from access to severely degraded audio signals that preserve only envelope information in the second ear. This study investigated whether vocoded masker-envelope information presented to one ear could improve performance for normal-hearing listeners in a multi-talker speech-identification task presented to the other ear. Target speech and speech or non-speech maskers were presented unprocessed to the left ear. The right ear received no signal, or either an unprocessed or eight-channel noise-vocoded copy of the maskers. Presenting the vocoded maskers contralaterally yielded significant masking release from same-gender speech maskers, albeit less than in the unprocessed case, but not from opposite-gender speech, stationary-noise, or modulated-noise maskers. Unmasking also occurred with as few as two vocoder channels and when an attenuated copy of the target signal was added to the maskers before vocoding. These data show that delivering masker-envelope information contralaterally generates masking release in situations where target-masker similarity impedes monaural speech-identification performance. By delivering speech-envelope information to a deaf ear, cochlear implants for single-sided deafness have the potential to produce a similar effect.