Auditory brainstem implant in posttraumatic cochlear nerve avulsion

Patients aged over 12 years with neurofibromatosis type 2 are considered candidates for an auditory brainstem implant (ABI). This study extends the indication criteria of ABI to subjects with profound hearing loss due to damaged cochleas and/or cochlear nerves (CNs) following head injuries. In our department, over the period from April 1997 to November 2002, 32 patients, 23 adults and 9 children, were fitted with ABIs. Their ages ranged from 14 months to 70 years. These patients were suffering from a variety of tumor (13 subjects) and nontumor CN or cochlear diseases (19 subjects). Six patients, 5 adults and 1 child, had profound hearing loss following head injury. Their mean age was 25 years (range: 16-48 years). Five were male and 1 female. The retrosigmoid approach was used in all 6 patients. The electrode array was inserted into the lateral recess of the fourth ventricle and correct electrode positioning was monitored with the aid of electrically evoked auditory brainstem responses and neural response telemetry. Correct implantation was achieved in all patients. No complications were observed due to implantation surgery or related to ABI activation and stimulation of the cochlear nuclei. At activation, an average of 9.8 electrodes (range 5-13) were switched on without side effects. One to 6 electrodes were activated in the following sessions after time periods ranging from 2 to 16 months. All patients achieved auditory-alone-mode closed-set word recognition scores ranging from 40 to 100%; 3 had auditory-alone-mode open-set sentence recognition scores of 60-100%; 2 of these even had speech-tracking performance scores of 38 and 43 words, respectively, showing an ability to engage in normal conversation and converse over the phone. The present study demonstrates that the ABI is a useful rehabilitation instrument in subjects with damaged cochleas and/or CN avulsion following head injury who are unamenable or poorly responsive to auditory rehabilitation using cochlear implants.     

Abnormal timing delays in auditory brainstem responses evoked by bilateral cochlear implant use in children.

HYPOTHESIS: A period of unilateral implant use before bilateral implantation affects timing of brainstem processes measured by the electrically evoked auditory brainstem response (EABR). BACKGROUND: EABR latencies decrease with unilateral implant use potentially disrupting binaural timing cues important in auditory brainstem processing of bilateral input. METHODS: EABRs were evoked by electrical pulses from the left, right, and both implants simultaneously in 3 groups of children. All were initially implanted at ages younger than 3 years and had the following: 1) a long delay (>2 yr [n = 16]), 2) a short delay (<1 yr [n = 15]), or 3) no delay (n = 15) between left and right ear implantation. Responses were recorded on the first day of bilateral implant use and 3 and 9 months thereafter. RESULTS: Relative to responses evoked in the experienced ear, the naive ear showed prolonged latency in both the EABR peaks and the binaural difference response. After 3 and 9 months of bilateral implant use, the relative prolongation decreased in the long and short delay groups, but significant differences persisted in the former. No clear differences in latencies evoked by the left versus right implant were found at any time point in children receiving bilateral implants simultaneously. CONCLUSION: Results suggest potential disruptions to binaural brainstem processing based on timing cues in children receiving a second cochlear implant after more than 2 years of unilateral implant use that persist through at least the first 9 months of bilateral implant use.     

Auditory localization abilities in bilateral cochlear implant recipients.

OBJECTIVE: To quantify binaural advantage for auditory localization in the horizontal plane by bilateral cochlear implant (CI) recipients. Also, to determine whether the use of dual microphones with one implant improves localization. METHODS: Twenty subjects from the UK multicenter trial of bilateral cochlear implantation with Nucleus 24 K/M device were recruited. Sound localization was assessed in an anechoic room with an 11-loudspeaker array under four test conditions: right CI, left CI, binaural CI, and dual microphone. Two runs were undertaken for each of five stimuli (speech, tones, noise, transients, and reverberant speech). Order of conditions was counterbalanced across subjects. RESULTS: Mean localization error with bilateral implants was 24 degrees compared with 67 degrees for monaural implant and dual microphone conditions (chance performance is 65 degrees). Normal controls average 2 to 3 degrees in similar conditions. Binaural performance was significantly better than monaural performance for all subjects, for all stimulus types, and for different sound sources. Only small differences in performance with different stimuli were observed. CONCLUSIONS: Bilateral cochlear implantation with the Nucleus 24 device provides marked improvement in horizontal plane localization abilities compared with unilateral CI use for a range of stimuli having different spectral and temporal characteristics. Benefit was obtained by all subjects, for all stimulus types, and for all sound directions. However, binaural performance was still worse than that obtained by normal hearing listeners and hearing aid users with the same methodology. Monaural localization performance was at chance. There is no benefit for localization with dual microphones.     

Auditory brainstem implant as a salvage treatment after unsuccessful cochlear implantation.

OBJECTIVE: The present article investigates on an individual basis the performance achieved with the auditory brainstem implant in patients who had been treated unsuccessfully with a cochlear implant. STUDY DESIGN: An intrasubject comparison between results achieved with the cochlear implant and the auditory brainstem implant is reported. SETTING: Tertiary referral care. PATIENTS: Five subjects were fitted with an auditory brainstem implant in our department because of the poor results achieved with cochlear implants. Two were children, one with bilateral cochlear nerve aplasia and one suffering from auditory neuropathy. Three were adults with complete cochlear ossification. INTERVENTION: A retrosigmoid approach was used in all subjects. Electrically evoked auditory brainstem responses and neural response telemetry were used to monitor electrode positioning. RESULTS: No complications were observed due to implantation surgery or related to activation or long-term use of the auditory brainstem implant. Auditory sensations were induced in all patients with varying numbers of electrodes (from 9-16). In all three adults, the cochlear implant did not allow either word/sentence discrimination or speech tracking, whereas the auditory brainstem implant permitted discrimination of two- or three-syllable words with scores from 85 to 100%. In the two adults with a follow-up of 5 and 6 months after auditory brainstem implant activation, the open-set sentence recognition scores (auditory-only mode) were 70% and 100%, respectively, and the speech-tracking scores were 27 and 40 words/min, respectively. One patient with a follow-up of only 3 months scored 0% in both sentence recognition and speech tracking. The two children who had achieved no hearing ability with the cochlear implant were already able to detect sounds and words as early as 2 months after activation of the auditory brainstem implant and are showing progressive improvement in their performance. CONCLUSION: Auditory brainstem implantation may be a very powerful rehabilitative treatment after cochlear implant failure. The possibility of using the auditory brainstem implant as first-choice therapy in some categories of deaf patients (e.g., subjects with auditory neuropathy or cochlear ossification) who are currently treated with cochlear implantation is discussed.     

Auditory performance of children with cochlear ossification and partial implant insertion.

The management of the profoundly deaf child with a cochlear implant poses a special challenge, particularly when total ossification of the cochlea is present. In this setting, insertion of an electrode array into a child's cochlea is often difficult. Our experience supports the feasibility of partial insertion of a multichannel implant into the basal turn of an ossified cochlea. Five children with ossified cochleae who had undergone partial implantation of a multichannel electrode were compared with the performance of matched controls who had full insertion of multichannel implants. No dramatic differences were detected during a 6- to 18-month follow-up period on selected test measures. These preliminary results suggest that active electrode number may exert a limited effect on performance with a cochlear implant. Drilling out the basal turn of an ossified cochlea in conjunction with partial insertion of a multichannel implant appears to be an acceptable surgical and rehabilitational alternative for placement of a cochlear implant prosthesis in children with complete cochlear ossification.     

Psychological change following 18 months of cochlear implant use.

Consecutive recipients of multichannel cochlear implants participated in preimplant as well as 9-month and 18-month psychological evaluations. Before receiving a cochlear implant, psychological tests indicated that the implant recipients were more depressed, suspicious, socially isolated, lonely, and socially anxious than was the general population. After 18 months of implant use, there was a significant reduction in depression, loneliness, social anxiety, social isolation, and suspiciousness. These changes in psychological state did not correlate with improved performance on audiological measures. The data suggest that although cochlear implants can have a positive effect on the emotional and behavioral status of persons with acquired postlingual profound deafness, the psychological outcome of implants is not simply a function of the audiological benefit assessed with standardized speech-based audiological tests.     

Auditory verbal habilitation is associated with improved outcome for children with cochlear implant

Objectives: To study the impact of (re)habilitation strategy on speech-language outcomes for early, cochlear implanted children enrolled in different intervention programmes post implant.

Methods: Data relate to a total of 130 children representing two pediatric cohorts consisting of 94 and 36 subjects, respectively. The two cohorts had different speech and language intervention following cochlear implantation, i.e. standard habilitation vs. auditory verbal (AV) intervention. Three tests of speech and language were applied covering language areas of receptive and productive vocabulary and language understanding.

Results: Children in AV intervention outperformed children in standard habilitation on all three tests of speech and language. When effect of intervention was adjusted with other covariates children in AV intervention still had higher odds at performing at age equivalent speech and language levels.

Conclusion: Compared to standard intervention, AV intervention is associated with improved outcome for children with CI. Based on this finding, we recommend that all children with HI should be offered this intervention and it is, therefore, highly relevant when National boards of Health and Social Affairs recommend basing the habilitation on principles from AV practice. It should be noted, that a minority of children use spoken language with sign support. For this group it is, however, still important that educational services provide auditory skills training.     

Sequential bilateral cochlear implant: results in children and adolescents

IntroductionThe use of the bilateral cochlear implants can promote the symmetrical development of the central auditory pathways, thus benefiting the development of auditory abilities and improving sound localization and the ability of auditory speech perception in situations of competitive noise.ObjectiveTo evaluate the ability of speech perception in children and adolescents using sequential bilateral cochlear implants, considering the association of these variables: age at surgery, time of device use and interval between surgeries.MethodsA total of 14 individuals between 10 and 16 years of age, who demonstrated surgical indication for the use of sequential bilateral cochlear implants as intervention in the auditory habilitation process, were assessed. The speech perception ability was assessed through sentence lists constructed in the Portuguese language, presented in two situations: in silence, with fixed intensity of 60 dB SPL, and in competitive noise, with a signal-to-noise ratio of +15 dB. The evaluation was performed under the following conditions: unilateral with the first activated cochlear implant, unilateral with the second activated cochlear implant and bilateral with both devices activated.ResultsThe results of the speech perception tests showed better performance in both silence and in noise for the bilateral cochlear implant condition when compared to the 1st cochlear implant and the 2nd cochlear implant alone. A worse result of speech perception was found using the 2nd cochlear implant alone. No statistically significant correlation was found between age at the surgical procedure, interval between surgeries and the time of use of the 2nd cochlear implant, and the auditory speech perception performance for all assessed conditions. The use of a hearing aid prior to the 2nd cochlear implant resulted in benefits for auditory speech perception with the 2nd cochlear implant, both in silence and in noise.ConclusionThe bilateral cochlear implant provided better speech perception in silence and in noise situations when compared to the unilateral cochlear implant, regardless of the interval between surgeries, age at the surgical procedure and the time of use of the 2nd cochlear implant. Speech perception with the 1st cochlear implant was significantly better than with the 2nd cochlear implant, both in silence and in noise. The use of the hearing aid prior to the 2nd cochlear implant influenced speech perception performance with the 2nd cochlear implant, both in silence and in noise.     

听觉脑干置入用于双侧听神经瘤全聋患者的听力康复(附1例报告)

目的：探讨听觉脑干置入（ABI）用于双侧听神经瘤全聋患者的听力康复。方法：对1例双侧听神经瘤全聋患者，在经乙状窦枕下径路切除第2侧听神经瘤时，同期将12道听觉脑干装置的电极阵置入第4脑室的侧隐窝内，术中行第Ⅶ、Ⅸ脑神经监测，并且记录电刺激脑干诱发电位，以确定和校正电极位置。术后2个月开通电极并作调试。结果：术后头颅X线侧位片示电极位置正确，术后开通调试发现电刺激12个电极均能引起听觉反应，无一电极引起非听觉反应。结论：多道ABI能让双侧听神经瘤全聋患者产生有意义的听觉。术中电极阵准确地置入到脑干耳蜗核是手术成功的关键。     

Auditory steady-state response in cochlear implant patients

Introduction and objective

Auditory steady state responses to continuous amplitude modulated tones at rates between 70 and 110 Hz, have been proposed as a feasible alternative to objective frequency specific audiometry in cochlear implant subjects. The aim of the present study is to obtain physiological thresholds by means of auditory steady-state response in cochlear implant patients (Clarion HiRes 90K), with acoustic stimulation, on free field conditions and to verify its biological origin.

双侧人工耳蜗植入研究进展

人工耳蜗植入目前是极重度感音神经性聋的最有效的治疗方法,双耳听力植入开始于上世纪90年代。尽管其存在费用、手术风险、患者远期期待、双侧植入设备整合等问题,双侧耳蜗植入越来越被广为接受,被耳科专家所推荐。相比单侧植入,双耳植入可显著提高声音定位能力,减小头影效应,明显改善在安静和噪声下的听力和言语理解能力,有助于获得更自然的声音感受,促进听觉言语和音乐欣赏能力的发展,更快的重建言语功能。双侧耳蜗植入带来的听觉刺激可以更好的促进听觉通路和皮层的协调发育。     

Auditory brainstem implant in a child with severely ossified cochlea

OBJECTIVE: The hearing outcome after implanting a severely ossified cochlea has always been less satisfactory than implanting a patent one. The aim of our study is to present a case where brainstem implantation was successfully performed as an alternative to cochlear implantation in a child with bilateral severe ossification of the cochlea. STUDY DESIGN: Case presentation. This study was conducted at Gruppo Otologico, Rome, Italy, a private referral center for neurotology and skull base surgery. METHODS: The subject of our study was a 12-year-old female child with postmeningitic deafness and bilaterally ossified cochleae. This case is the first brainstem implantation performed at our center with the indication of severe ossification of the cochlea. RESULTS: Successful brainstem implantation of a device was carried out, and the hearing of the patient was restored to the degree that she can freely use the telephone after 8 months of implantation. CONCLUSION: Although more cases are needed before establishing the exact outcome of brainstem implantation in cases of deafness in the presence of severe bilateral cochlear ossification, preliminary results show the superiority of brainstem implants to conventional or even customized cochlear implants.     

Auditory brainstem implant in postmeningitis totally ossified cochleae

Introduction: An auditory brainstem implant (ABI) is an option for auditory rehabilitation in patients with totally ossified cochleae who cannot receive a conventional cochlear implant.

Objective: To evaluate the outcomes in audiometry and speech perception tests after the implantation of an ABI via the extended retrolabyrinthine approach in patients with postmeningitis hearing loss.

Materials and methods: Ten patients, including children and adults, with postmeningitis hearing loss and bilateral totally ossified cochleae received an ABI in a tertiary center from 2009 to 2015. The extended retrolabyrinthine approach was performed in all the patients by the same surgeons. A statistical analysis compared pure tonal averages and speech perception tests before and at least 12 months after the ABI activation.

Results: Eight patients (80%) showed improvements in tonal audiometry and the word and vowel perception tests after an average follow-up of 3.3 years. Two patients recognized up to 40% of the closed-set sentences without lip-reading. Two patients had no auditory response.

Conclusions: The ABI improved hearing performance in audiometry and speech perception tests in cases of postmeningitis hearing loss. The extended retrolabyrinthine approach is a safe surgical option for patients with postmeningitis hearing loss and bilateral totally ossified cochleae.     

Positron emission tomography in cochlear implant and auditory brainstem implant recipients

Positron emission tomography (PET) imaging was used to evaluate the brain's response to auditory stimulation, including speech. Five cases of adults illustrate the utility of PET to illuminate auditory processing with cochlear or brainstem implants. Subjects showed varying degrees of success in processing speech, which was reflected in the resulting PET images. Functional speech processing was associated with activation in areas classically associated with speech processing. In one patient who did not achieve functional speech processing, activation in frontal regions suggests that the subject used other cognitive strategies to assist auditory processing. Learning outcomes: As a result of this activity, the participant will be introduced to the principles of PET and the application of this technology to deaf patients who have received an implanted auditory prosthesis.