Single-sided Deafness Patients Research Articles

A Quantitative Electroencephalography Study on Cochlear Implant-Induced Cortical Changes in Single-Sided Deafness with Tinnitus.

The mechanism of tinnitus suppression after cochlear implantation (CI) in single-sided deafness (SSD) is not fully understood. In this regard, by comparing pre- and post-CI quantitative electroencephalography (qEEG), we explored cortical changes relevant to tinnitus improvement. In SSD patients who underwent CI, qEEG data were collected: (1) before CI, (2) 6 months post-operatively with CI-on, and (3) 30 min after CI-off and source-localized cortical activity/functional connectivity analyses were performed. Compared to the pre-operative baseline, the CI-on condition demonstrated significantly decreased activity in the right auditory- and orbitofrontal cortices (OFC) for the delta frequency band as well as decreased connectivity between the auditory cortex/posterior cingulate cortex for the delta/beta2 bands. Meanwhile, compared to the CI-off condition, the CI-on condition displayed decreased activity in the right auditory cortices/OFC for the delta band, and in bilateral auditory cortices, left inferior frontal cortex/OFC for the gamma band. However, qEEG analyses showed no significant differences between the CI-off and baseline conditions. CI induced overall decreased cortical activity and functional connectivity. However, judging from no differences between the CI-off and baseline conditions, CI-induced cortical activity and functional connectivity changes are not by cortical plastic changes, but by dynamic peripheral reafferentation.

Baha implant as a hearing solution for single-sided deafness after retrosigmoid approach for the vestibular schwannoma: surgical results.

Skull base tumors and, in particular, vestibular schwannoma (VS) are among the etiological reasons for single-sided deafness (SSD). Patients with SSD have problems in understanding speech in a noisy environment and cannot localize the direction of sounds. Baha is one of the most frequently used systems for SSD compensation. Out of 38 patients with SSD after retrosigmoid removal of VS who underwent testing with Baha softband, 16 were satisfied and were indicated for Baha implantation. Two surgical approaches have been used-the Nijmegen linear incision technique with subdermal thinning (Group I, implant BI300) and fast surgery technique without subdermal thinning (Group II, implant BIA400). The duration of the surgery, the implant stability measured by Ostell, and skin or soft tissue reactions in long range follow-up were evaluated and compared between Group I and II. There was a difference in duration of surgery, in Group II procedures averaged significantly faster (p > 0.001). In both groups, there was a similar trend of the gradual increase of implant stability. In the Group I and II, there was comparable rate of the skin or soft tissue reactions grade 0, I, II, or III. We have proved Baha to be a suitable possibility for SSD patients after the removal of VS, regardless of the approach. After the retrosigmoid approach to the VS, the key step of Baha implantation must be to reach intact healthy bone to avoid implantation into scar tissue.

Etiology of single-sided deafness and asymmetrical hearing loss

Conclusions: The present study revealed that various etiologies are involved in single-sided deafness (SSD), and that the cause of SSD and asymmetrical hearing loss (AHL) differed greatly between congenital/early-onset cases and adult cases. Clarification of the etiology is the first step toward providing appropriate intervention.Objectives: The study aimed to clarify the etiology of SSD and AHL patients.Methods: The etiology of a total of 527 SSD or AHL patients who visited Shinshu University Hospital between 2006 and 2016 were analyzed by imaging as well as serological tests for mumps virus, and CMV DNA testing.Results: In our cohort of congenital/early-onset SSD (n = 210), the most prevalent cause in children was cochlear nerve deficiency (43.7%; 87 of 199 patients undergoing CT and/or MRI), followed by CMV infection, mumps infection, anomalies of the inner ear, ANSD, and other rare etiologies. In contrast, half of the adult SSD patients presented with idiopathic sensorineural hearing loss, followed by various types of otitis media, cerebellopontine angle tumor and other rare etiologies.

Contralateral electrically-evoked suppression of transient evoked otoacoustic emissions in single-sided deaf patients

Contralateral electrically-evoked suppression of transient evoked otoacoustic emissions in single-sided deaf patients

Cochlear implant treatment of patients with single-sided deafness or asymmetric hearing loss. German version

The rehabilitation of patients with single-sided deafness (SSD) or asymmetric hearing loss can be achieved with conventional (bilateral) contralateral routing of signals ((Bi)CROS) hearing aids ((Bi)CROS-HA, (Bi)CROS), bone-anchored hearing systems (BAHS) or cochlear implants (CI). To date, only small case series have been published on treatment outcomes in SSD patients after CI surgery and there are only afew comparative studies evaluating rehabilitation outcomes. The aim of this study was to provide evidence of successful treatment of SSD and asymmetric hearing loss with aCI compared to the untreated monaural hearing condition and the BAHS and (Bi)CROS treatment options in alarge number of patients. In asingle-centre study, 45patients with SSD and 40patients with asymmetric hearing loss were treated with aCI after careful evaluation for CI candidacy. Monaural speech comprehension in noise and localisation ability were examined with (Bi)CROS-HA and BAHS devices (on atest rod) both preoperatively and at 12months after CI switch-on. At the same intervals, subjective evaluation of hearing ability was conducted using the Speech, Spatial and Qualities of Hearing Scale (SSQ). This report presents the first evidence of successful binaural rehabilitation with CI in arelatively large patient cohort and the advantages over (Bi)CROS and BAHS in smaller subgroups, thus confirming the indication for CI treatment. Moreover, patients with long-term acquired deafness (>10years) show a benefit from the CI comparable to that observed in patients with shorter-term deafness.

Functional Result After Cochlear Implantation in Children and Adults With Single-sided Deafness.

Patients with single-sided deafness (SSD) suffer from reduced binaural hearing (i.e., sound localization and speech in noise discrimination). Cochlear implantation has recently been introduced for patients with SSD, as an alternative to hearing devices that employ contralateral routing of the signal. Application to children has also been started. We retrospectively analyze a case series of 4 children and 17 adults with SSD, treated with cochlear implantation. The outcome of adult patients was compared with a control group of 27 patients with bilateral profound hearing loss using a cochlear implant. During 12 months, the mean speech recognition score increased from 30 to 41% for monosyllabic words in adults, and from 58 to 89% for multisyllabic numbers. The cochlear implant (CI) improved hearing in noise in all SSD patients, as was demonstrated by a significant improvement of the speech reception threshold in different speech and noise configurations. Sound localization-correlated angle detection error improved with CI use at every time point. The maximum word recognition score for monosyllabic words in quiet correlated with the logarithm of the duration of deafness; improvement of the speech reception threshold and RMS angle detection error by the CI did not. All SSD patients benefitted from the CI in different hearing situations. Patients with SSD for a long period can improve after cochlear implantation.

Cochlear Implantation Improves Spatial Release From Masking and Restores Localization Abilities in Single-sided Deaf Patients.

Adult patients with acquired single-sided deafness (SSD) benefit from binaural hearing after cochlear implantation (CI). To spatially separate the signal of interest from noise is of utmost importance for the speech understanding in challenging listening situations. This ability, however, largely depends on binaural hearing. CI in acquired SSD restores hearing on the deaf ear. This study intended to test, if this is accompanied by a restoration of binaural functions of the auditory system. Eleven CI users with SSD and normal hearing to mild sensorineural hearing loss in the contralateral ear participated in this study. Speech reception thresholds (SRT) were obtained using the Oldenburg Sentence Test (OLSA) sentence test in competing two talker babble noise. To evaluate spatial release from masking, seven spatial configurations of speech and noise were used in a free field setup: noise originated from 0 degree, ±45 degrees and ±90 degrees incidence angles, whereas speech was either presented from the front or ±90 degrees. In addition, localization ability in the frontal horizontal plane was assessed with a 1 s Comité Consultatif International Téléphonique et Télégraphique (CCITT) noise stimulus using an array of nine equally spaced loudspeakers. All tests were conducted in acoustic normal hearing ear alone (AH) and aided conditions. In conditions with spatially separated signal and noise sources, significant benefit of the aided over the AH condition was observed, even when noise was presented from the AH side. Localization ability significantly improved in the aided condition. The present data demonstrates that spatial release from masking can be restored in patients with SSD using a cochlear implant.

The effects of cochlear implantation in Japanese single-sided deafness patients: five case reports

Conclusion Cochlear implantation (CI) for Japanese single-sided deafness patients resulted in improved speech perception, increased sound localization accuracy, and reduced tinnitus handicap. Objectives This study reports results for five adult SSD cases with CI, focusing on the benefits they obtained in terms of speech recognition, sound localization, and tinnitus handicap. Methods Five Japanese patients meeting the eligibility criteria were included in this study. All patients were implanted with a fully inserted MED-EL Concerto FLEX28® implant (MED-EL, Innsbruck, Austria). Speech perception outcomes in noise, as well as sound localization and tinnitus disturbance, were assessed pre-surgically and at 1, 3, 6, and 12 months after CI activation. Results The Japanese monosyllable test score in noise improved gradually after implantation. In some cases, speech perception ability appeared unstable, particularly in the first 1–6 months after implantation. The sound localization ability showed marked improvement in all cases, with the disturbance to daily life caused by tinnitus also decreasing in all cases from the early post-operative period.

Sensitivity of the cochlear nerve to acoustic and electrical stimulation months after a vestibular labyrinthectomy in guinea pigs

Single-sided deafness patients are now being considered candidates to receive a cochlear implant. With this, many people who have undergone a unilateral vestibular labyrinthectomy for the treatment of chronic vertigo are now being considered for cochlear implantation. There is still some concern regarding the potential efficacy of cochlear implants in these patients, where factors such as cochlear fibrosis or nerve degeneration following unilateral vestibular labyrinthectomy may preclude their use. Here, we have performed a unilateral vestibular labyrinthectomy in normally hearing guinea pigs, and allowed them to recover for either 6 weeks, or 10 months, before assessing morphological and functional changes related to cochlear implantation. Light sheet fluorescence microscopy was used to assess gross morphology throughout the entire ear. Whole nerve responses to acoustic, vibrational, or electrical stimuli were used as functional measures. Mild cellular infiltration was observed at 6 weeks, and to a lesser extent at 10 months after labyrinthectomy. Following labyrinthectomy, cochlear sensitivity to high-frequency acoustic tone-bursts was reduced by 16 ± 4 dB, vestibular sensitivity was almost entirely abolished, and electrical sensitivity was only mildly reduced. These results support recent clinical findings that patients who have received a vestibular labyrinthectomy may still benefit from a cochlear implant.

Outer ear canal sound pressure and bone vibration measurement in SSD and CHL patients using a transcutaneous bone conduction instrument

The intraoperative and postoperative objective functional assessment of transcutaneous bone conduction implants is still a challenge. Here we compared intraoperative Laser-Doppler-vibrometry (LDV, Polytec Inc.) to measure vibration of the bone close to the implant to Outer Ear Canal Sound Pressure Level (OEC-SPL) measurements. Twelve single sided deafness (SSD) patients with contralateral intact ossicular chains and eight bilateral conductive hearing loss (CHL) patients were included in the study. SSD patients had a minor average air-bone-gap (ABG) of 0.4 ± 0.4 dB (0.5, 1, 2, 4 kHz mean value (MV) ± standard deviation (SD)) on the contralateral side where a normal transmission between cochlea and the tympanic membrane can be assumed. CHL patients had an impaired middle ear transmission with a mean ABG of 46.0 ± 7.9 dB (MV±SD). Vibration and OEC-SPL responses could reliably be recorded with a minimal signal-to-noise ratio of at least 12 dB.Average OEC-SPL on the contralateral side and intraoperative vibration measurements were strongly correlated in SSD (r2 = 0.75) and CHL (r2 = 0.86) patients. The correlation in individual results between OEC-SPL and vibration measurements was weak, indicating some underlying inter-individual variability. The high correlation of average responses showed that OEC-SPL are closely linked to bone vibration, although both cannot be equivalently used for intraoperative testing due to the high variability in individual results. On the other hand, OEC-SPL provides an easy and affordable measurement tool to monitor stability and functionality postoperatively using individual reference measurements.We observed no significant differences (t-test, p < 0.05) by comparing results from contralateral OEC-SPL in twelve SSD and eight CHL patients at frequencies between 0.5 and 8 kHz. This implies that the part of the measured sound pressure in the ear canal originating from the cochlea and emitted by the tympanic is not dominant and OEC-SPL is mainly due to vibration of the external ear-canal walls as the only other pathway of BC sound to reach the ear canal. In addition, the transcranial attenuation (contralateral outer ear canal sound pressure divided by ipsilateral) was compared to previous studies measuring vibration by LDV and accelerometer. The trend in the average transcranial attenuation in patients was similar to previous studies measuring the OEC-SPL with less than 5 dB difference.

Single-Sided Deafness: The Effect of Cochlear Implantation on Quality of Life, Quality of Hearing, and Working Performance

Aims: To evaluate the effect of a cochlear implant (CI) on quality of life (QoL), quality of hearing (QoH), and working performance in patients with single-sided deafness (SSD). Methods: Using specific questionnaires, we measured QoL, QoH, and working performance in 7 SSD patients scheduled for CI surgery of the affected ear. Sound localization and speech perception in noise were also assessed. All questionnaires and tests were performed before the CI surgery and at 6 and 12 months after CI activation. Results: The QoL, QoH, sound localization, and speech perception in noise had improved statistically significantly after CI surgery. Communication with co-workers became easier, and the patients were less fatigued after the working day. Conclusions: CI clearly improves QoL, QoH, and working performance in patients with SSD.

Bone-anchored hearing implants in single-sided deafness patients: Long-term use and satisfaction by gender.

To examine the long-term satisfaction and possible effects of gender in patients with single-sided deafness (SSD) who underwent bone-anchored hearing implant (BAHI) surgery. Retrospective case-control study. All (n = 145) consecutive SSD patients fitted with a BAHI between January 2001 and October 2011 were asked to complete a questionnaire consisting of the Abbreviated Profile of Hearing Aid Benefit (APHAB), the Communication Profile for the Hearing Impaired (CPHI), and the SSD questionnaire. Twenty-three of the 135 responding patients (17%) reported discontinuation of the device over an average follow-up time of 61.7 months. No significant differences were found in the degree of disability or coping between men and women, according to the APHAB and CPHI scores. Improvement in quality of life and appreciation of the BAHI were not affected by gender, age, directional hearing ability, and handling of the device. The appearance of the device positively affected their appreciation. At the mean follow-up time of 117 months, 69.2% was using their BAHI. In the domains background noise, reverberant surroundings, and aversion to sounds, the mean APHAB scores were significantly changed at 3 months, 1 year, and 10 years after implantation. Our study examined the results of BAHI use in SSD patients over a relatively long follow-up period, with an average of 5 years. The majority of users (83%) were satisfied with the device. No significant gender differences were in terms of reported appreciation, hearing disability, or coping with a BAHI. 3b.

CINGLE-trial: cochlear implantation for siNGLE-sided deafness, a randomised controlled trial and economic evaluation.

BackgroundIndividuals with single-sided deafness (SSD) have problems with speech perception in noise, localisation of sounds and with communication and social interaction in their daily life. Current treatment modalities (Contralateral Routing of Sound systems [CROS] and Bone Conduction Devices [BCD]) do not restore binaural hearing. Based on low level of evidence studies, CROS and BCD do not improve speech perception in noise or sound localisation. In contrast, cochlear implantation (CI) may overcome the limitations of CROS and BCD, as binaural input can be restored. Promising results have previously been achieved on speech perception in noise, sound localisation, tinnitus and quality of life.Methods and designA single-center Randomised Controlled Trial (RCT) was designed to compare all treatment strategies for SSD. One hundred and twenty adult single-sided deaf patients (duration of deafness >3 months and maximum 10 years; pure tone average at 0.5, 1, 2, 4 kHz, deaf ear: threshold equal to or more than 70 dB, better ear: threshold of maximum 30 dB) will be included in this trial and randomised to CI, ‘first BCD, then CROS’ or ‘first CROS, then BCD’-groups. After the trial period, patients in the two latter groups may choose with which treatment option they continue. Outcomes of interest are speech perception in noise, sound localization, tinnitus and quality of life. These outcomes will be measured during a baseline visit and at follow up visits, which will take place at 6, 12, 18, 24, 36, 48 and 60 months after onset of treatment. Furthermore, an economic evaluation will be performed and adverse events will be monitored.DiscussionThis RCT allows for a comparison between the two current treatment modalities for single-sided deafness and a new promising treatment strategy, CI, on a range of health outcomes: speech perception in noise, sound localization, tinnitus and quality of life. Additionally, we will be able to answer the question if the additional costs of CI are justified by increased benefits, when compared to current treatment strategies. This study will inform health policy makers with regard to reimbursement of CI.Trial registrationNetherlands Trial Register (www.trialregister.nl): NTR4580.

Cochlear Implantation in Children with Single-Sided Deafness: Does Aetiology and Duration of Deafness Matter?

For adult patients with single-sided deafness (SSD), treatment with a cochlear implant (CI) is well established as an acceptable and beneficial hearing rehabilitation method administered routinely in clinical practice. In contrast, for children with SSD, CI has been applied less often to date, with the rationale to decide either on a case-by-case basis or under the realm of clinical research. The aim of our clinical study was to evaluate the longitudinal benefits of CI for a group of children diagnosed with SSD and to compare their outcomes with respect to patient characteristics. Evaluating a pool of paediatric SSD patients presenting for possible CI surgery revealed that the primary aetiology of deafness was congenital cochlear nerve deficiency. A subgroup of children meeting the CI candidacy criteria for the affected ear (the majority with acquired hearing loss) were enrolled in the study. Preliminary group results suggest substantial improvements in speech comprehension in noise and in the ability to localise sound, which was demonstrated through objective and subjective assessments after CI treatment for the group, with results varying from patient to patient. Our study shows a trend towards superior outcomes for children with acquired hearing loss and a shorter duration of hearing loss compared to congenitally deafened children who had a longer duration of SSD. This indicates an interactive influence of the age at onset, aetiology and duration of deafness upon the restoration of binaural integration and the overall benefits of sound stimulation to two ears after CI treatment. Continued longitudinal investigation of these children and further studies in larger groups may provide more guidance on the optimal timing of treatment for paediatric patients with acquired and congenital SSD.

Interaural Level Difference Cues Determine Sound Source Localization by Single-Sided Deaf Patients Fit with a Cochlear Implant

In this report, we used filtered noise bands to constrain listeners' access to interaural level differences (ILDs) and interaural time differences (ITDs) in a sound source localization task. The samples of interest were listeners with single-sided deafness (SSD) who had been fit with a cochlear implant in the deafened ear (SSD-CI). The comparison samples included listeners with normal hearing and bimodal hearing, i.e. with a cochlear implant in 1 ear and low-frequency acoustic hearing in the other ear. The results indicated that (i) sound source localization was better in the SSD-CI condition than in the SSD condition, (ii) SSD-CI patients rely on ILD cues for sound source localization, (iii) SSD-CI patients show functional localization abilities within 1-3 months after device activation and (iv) SSD-CI patients show better sound source localization than bimodal CI patients but, on average, poorer localization than normal-hearing listeners. One SSD-CI patient showed a level of localization within normal limits. We provide an account for the relative localization abilities of the groups by reference to the differences in access to ILD cues.

The sound of a cochlear implant: Lessons learned from unilaterally deaf patients fit with a cochlear implant

Starting about 10 years ago in Europe, patients who had one normally hearing ear and one deafened ear were fitted with cochlear implants in an effort to suppress tinnitus in the deafened ear. That effort was very successful. More recently, single sided deaf patients without tinnitus have been implanted in an effort to improve health-related quality of life. This effort, too, has been successful. This patient population, with one normal hearing ear and one implanted ear, offers an unprecedented window into the sound quality of a cochlear implant. That is, these patients can tell us whether a candidate stimulus presented to the normally hearing ear sounds like the stimulus presented to the cochlear implant. In this talk, we describe our efforts to reproduce the sound of a cochlear implant.

Mitigation of Informational Masking in Individuals With Single-Sided Deafness by Integrated Bone Conduction Hearing Aids

To confirm an increased susceptibility to informational masking among individuals with single-sided deafness (SSD). To demonstrate a reduction in informational masking when SSD is treated with an integrated bone conduction hearing aid (IBC). To identify the acoustic cues that contribute to IBC-aided masking release. To determine the effects of device experience on the IBC advantage. Informational masking was evaluated with the coordinate-response measure. Participants performed the task by reporting color and number coordinates that changed randomly within target sentences. The target sentences were presented in free field accompanied by zero to three distracting sentences. Target and distracting sentences were spoken by different talkers and originated from different source locations, creating two sources of information for auditory streaming. Susceptibility to informational masking was inferred from the error rates of unaided SSD patients relative to normal controls. These baseline measures were derived by testing inexperienced IBC users without the device on the day of their initial fitting. The benefits of IBC-aided listening were assessed by measuring the aided performance of users who had at least 3 months' device experience. The acoustic basis of the listening advantage was isolated by correlating response errors with the voice pitch and location of distracting sentences. The effects of learning on cue effectiveness were evaluated by comparing the error rates of experienced and inexperienced users. Unaided SSD participants (inexperienced users) performed as well as normal controls when tested without distracting sentences but produced significantly higher error rates when tested with distracting sentences. Most errors involved responding with coordinates that were contained in distracting sentences. This increased susceptibility to informational masking was significantly reduced when experienced IBC users were tested with the device. The listening advantage was most strongly correlated with the availability of voice pitch cues, although performance was also influenced by the location of distracting sentences. Directional asymmetries appear to be dictated by location-dependent cues that are derived from the distinctive transmission characteristics of IBC stimulation. Experienced users made better use of these cues than inexperienced users. These results suggest that informational masking is a significant source of communication impairment among individuals with SSD. Despite the lateralization of auditory function, unaided SSD subjects experience informational masking when distractors occur in either the deaf or normal spatial hemifield. Restoration of aural sensitivity in the deaf hemifield with an IBC enhances speech intelligibility under complex listening conditions, presumably by providing additional sound-segregation cues that are derived from voice pitch and spatial location. The optimal use of these cues is not immediate, but a significant listening advantage is observed after 3 months of unstructured use.

Expanded selection criteria in adult cochlear implantation

Cochlear implantation has become the standard procedure for restoring substantial hearing in the profoundly deaf. The excellent performance of most of the CI recipients coupled with the rapid evolution of implant technology lead to a distinct expansion in selection criteria for CI. These changes in candidacy primarily include patients with (1) moderate preoperative speech recognition with hearing aids, (2) significant residual hearing, (3) single-sided deafness, and (4) geriatric patients. Many of these patients’ conditions were regarded as a clear contraindication to CI only a few years ago. In this article an overview of the current and new aspects of candidacy for cochlear implantation is provided.

Re

To the Editor Dr. Snapp eloquently recognizes many of the problems and difficulties raised with respect to patient expectations in the rehabilitation of single-sided deafness (SSD) using bone-anchored implants (BAIs). She rightly asserts that “clinicians must be clear in identifying what the implant system will be able to accomplish for the patient.” She also observes that “BAIs are merely a means to provide access to sound arriving at the deaf ear” and that “BAIs do not overcome the loss of localization ability for these patients.” Unfortunately, by presenting an article that focuses upon speech-in-noise testing, she risks suggesting that this is a handicap that can be effectively treated with BAIs. Although she has been able to show a significant reduction in signal-to-noise ratio loss using the BAI, it is important to recognize the artificiality of the test used and the particularly favorable protocol chosen. In this context, the QuickSIN test is more a test of the lifting of the head-shadow than of speech comprehension in noise characterized by binaural squelch and sophisticated interhemispheric “top-down” auditory processing. By presenting noise to the hearing ear and speech to the implanted ear, the researchers have demonstrated the aided benefit seen in other studies (1–4) without seeing the aided handicap imposed by the BAI if noise—rather than signal—is presented to the implanted ear. This handicap—the introduction of unwanted and distracting noise—emphasizes that the BAI is a “means to provide access to sound arriving at the deaf ear” whether that be “good” sound or “bad.” There can be no doubt that a significant number of patients with SSD derive benefit from BAIs and the relief from the head-shadow they offer. This benefit, however, is not due to improved speech-in-noise comprehension as it is perceived by binaurally hearing individuals, as it is not due to improved sound localization: such benefits are only seen when a physiological and anatomically bilateral auditory pathway is reestablished, as is possible in a proportion of patients with SSD. Initial studies of cochlear implantation (CI) suggest that this may be feasible (5–7). The study by Arndt et al. (6)—the first to compare BAI and CI for this indication—reports improved subjective and objective outcomes with CI and does not find any negative impact arising from noise being presented to the aided ear. Experience of cochlear implantation in SSD is promising but limited, and further research is required. We would advocate a protocol using auditory scene analysis (8), which considers the ways that auditory objects are identified and perceived in the environment to investigate any benefits of true binaural hearing in rehabilitated SSD patients. If cochlear implantation proves effective in this regard, it might be time to move away from the partial solutions offered by BAIs toward a more radical form of rehabilitation in those selected cases who feel sufficiently handicapped by SSD. Thomas Peter Cutlack Martin, FRCS (ORL-HNS) Skull Base Fellow ENT Department Addenbrooke’s Hospital Hill’s Road Cambridge, U.K. David Baguley, Ph.D. Audiology Department Addenbrooke’s Hospital Hill’s Road Cambridge, U.K.

Neural substrates predicting improvement of tinnitus after cochlear implantation in patients with single-sided deafness

Notwithstanding successful reduction of tinnitus after cochlear implantation (CI) in patients with single-sided deafness (SSD) in recent studies, neither the exact mechanism of suppression nor the predictors of the amount of improvement are fully understood yet. We collected quantitative electroencephalography (qEEG) data from nine SSD patients who underwent CI for tinnitus management. By correlating the degree of improvement in tinnitus intensity and tinnitus-related distress with preoperative source-localized qEEG findings and comparing qEEG findings of patients with marked improvement after CI with those with relatively slight improvement with regard to source-localized activity complimented by connectivity analysis, we attempted to find preoperative predictors of tinnitus improvement. Our results showed increased activities of the auditory cortex (AC), posterior cingulate cortex (PCC) and increased functional connectivity between the AC and PCC as negative prognostic factors for the reduction of tinnitus intensity after CI in patients with SSD. Also, relatively increased activity of the right dorsolateral prefrontal cortex and decreased connectivity between distress-related areas such as the orbitofrontal cortex/parahippocampus and sensory-perception areas such as the AC/precuneus were found in patients with relatively slight improvement in tinnitus-related distress as compared with those with marked improvement. The current study suggests that preoperative cortical oscillations can be applied to predict post-CI tinnitus reduction in patients with SSD.