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Objectives: Auditory brainstem implants (ABIs) may be the only opportunity for patients with NF2 to regain some sense of hearing sensation. However, only a very small number of individuals achieved open-set speech understanding and high sentence scores. Suboptimal placement of the ABI electrode array over the cochlear nucleus may be one of main factors for poor auditory performance. In the current study, we present a method of awake craniotomy to assist with ABI placement., Methods: Awake surgery and hearing test via the retrosigmoid approach were performed for vestibular schwannoma resections and auditory brainstem implantations in four patients with NF2. Auditory outcomes and complications were assessed postoperatively., Results: Three of 4 patients who underwent awake craniotomy during ABI surgery received reproducible auditory sensations intraoperatively. Satisfactory numbers of effective electrodes, threshold levels and distinct pitches were achieved in the wake-up hearing test. In addition, relatively few electrodes produced non-auditory percepts. There was no serious complication attributable to the ABI or awake craniotomy., Conclusions: It is safe and well tolerated for neurofibromatosis type 2 (NF2) patients using awake craniotomy during auditory brainstem implantation. This method can potentially improve the localization accuracy of the cochlear nucleus during surgery.

Conclusions: Even though sound perception may be limited after treatment with an auditory brainstem implant (ABI), it provides benefits and should be selectively offered to patients. Importantly the patients must be motivated, given reasonable expectations of outcome and offered long-term rehabilitation with a considerable 'learn to listen' period with the implant device., Objectives: To describe the clinical experiences and results of 24 ABI surgeries performed in Uppsala University Hospital between 1993 and 2013., Methods: Most patients (n = 20) suffered from neurofibromatosis type 2 (NF2); a few patients (n = 4) were paediatric non-NF2 patients. The files were searched for information on the presurgery size of the vestibular schwannoma, whether the patient had undergone gamma knife treatment, the surgical approach, the side effects of the surgery and of the use of the implant, the electrode activation pattern and implant use, and categories of auditory performance (CAP) score., Results: Our results show that many patients greatly benefited from an ABI, and most of the patients used their implants even though the hearing improvements usually consisted of awareness of surrounding sounds and improved lip-reading. No severe side effects were observed from implant stimulation.

Conclusions: New technological developments will most probably improve the efficiency of auditory brainstem implantation (ABI). Meanwhile, cochlear implantation in patients who have undergone prior reductive surgery, and who have maintained a positive electric stimulation, is an excellent alternative for rehabilitating complete and bilateral hearing loss in patients with neurofibromatosis type 2 (NF2). Auditory results are far better than those reported after ABI. Long-term follow-up will be necessary to demonstrate the validity of this strategy., Objectives: ABIs restore some degree of auditory perception in NF2 patients with bilateral and complete hearing loss, but results are often inadequate for maintaining social and professional activities. The aim of this study was to report the results of auditory rehabilitation by cochlear implantation in three cases of NF2., Patients and Methods: This was a retrospective study undertaken in a tertiary referral center. The first patient had undergone previous surgery for a left grade III vestibular schwannoma (VS) and then underwent irradiation for a right grade I VS. Two years after irradiation, he suddenly lost his remaining hearing. Electric promontory stimulation was positive and cochlear implantation was performed. The second patient had undergone surgery for a left grade III VS and followed for a right grade II VS. She suddenly lost her remaining hearing. A cytoreductive surgery was performed and the cochlear nerve was preserved. Postoperative electric stimulation was positive. She was then implanted with a cochlear implant. The third patient presented with a right stage III and a left stage I VS. She first underwent a subtotal removal of the left VS with immediate cochlear implantation. She then underwent removal of the right VS stage III with no possible preservation of the cochlear nerve., Results: All three patients had excellent postoperative speech performance and were back to work 3 months after implantation. Imaging follow-ups at 4, 2, and 1 year, respectively, do not show any evolution of the tumor.

Conclusion: This preliminary study demonstrates the development of hearing ability and shows that there is a significant improvement in some cognitive parameters related to selective visual/spatial attention and to fluid or multisensory reasoning, in children fitted with auditory brainstem implantation (ABI). The improvement in cognitive paramenters is due to several factors, among which there is certainly, as demonstrated in the literature on a cochlear implants (CIs), the activation of the auditory sensory canal, which was previously absent. The findings of the present study indicate that children with cochlear or cochlear nerve abnormalities with associated cognitive deficits should not be excluded from ABI implantation., Objectives: The indications for ABI have been extended over the last 10 years to adults with non-tumoral (NT) cochlear or cochlear nerve abnormalities that cannot benefit from CI. We demonstrated that the ABI with surface electrodes may provide sufficient stimulation of the central auditory system in adults for open set speech recognition. These favourable results motivated us to extend ABI indications to children with profound hearing loss who were not candidates for a CI. This study investigated the performances of young deaf children undergoing ABI, in terms of their auditory perceptual development and their non-verbal cognitive abilities., Patients and Methods: In our department from 2000 to 2006, 24 children aged 14 months to 16 years received an ABI for different tumour and non-tumour diseases. Two children had NF2 tumours. Eighteen children had bilateral cochlear nerve aplasia. In this group, nine children had associated cochlear malformations, two had unilateral facial nerve agenesia and two had combined microtia, aural atresia and middle ear malformations. Four of these children had previously been fitted elsewhere with a CI with no auditory results. One child had bilateral incomplete cochlear partition (type II); one child, who had previously been fitted unsuccessfully elsewhere with a CI, had auditory neuropathy; one child showed total cochlear ossification bilaterally due to meningitis; and one child had profound hearing loss with cochlear fractures after a head injury. Twelve of these children had multiple associated psychomotor handicaps. The retrosigmoid approach was used in all children. Intraoperative electrical auditory brainstem responses (EABRs) and postoperative EABRs and electrical middle latency responses (EMLRs) were performed. Perceptual auditory abilities were evaluated with the Evaluation of Auditory Responses to Speech (EARS) battery - the Listening Progress Profile (LIP), the Meaningful Auditory Integration Scale (MAIS), the Meaningful Use of Speech Scale (MUSS) - and the Category of Auditory Performance (CAP). Cognitive evaluation was performed on seven children using the Leiter International Performance Scale - Revised (LIPS-R) test with the following subtests: Figure ground, Form completion, Sequential order and Repeated pattern., Results: No postoperative complications were observed. All children consistently used their devices for >75% of waking hours and had environmental sound awareness and utterance of words and simple sentences. Their CAP scores ranged from 1 to 7 (average =4); with MAIS they scored 2-97.5% (average =38%); MUSS scores ranged from 5 to 100% (average =49%) and LIP scores from 5 to 100% (average =45%). Owing to associated disabilities, 12 children were given other therapies (e.g. physical therapy and counselling) in addition to speech and aural rehabilitation therapy. Scores for two of the four subtests of LIPS-R in this study increased significantly during the first year of auditory brainstem implant use in all seven children selected for cognitive evaluation.

The primary aim of the auditory brainstem implant (ABI), an investigational device, is to restore auditory sensations in neurofibromatosis-2 patients deafened by bilateral acoustic neuroma surgery. An electrode is placed on the dorsal cochlear nucleus after the tumor is removed through the translabyrinthine approach. This procedure was performed on 18 patients: 13 were completely deafferentated after bilateral tumor removal and had received the ABI during surgery on the second-sided tumor; 5 were implanted at first-sided tumor removal. Three of these 5 patients had usable hearing remaining on the side of the second acoustic neuroma and were stimulated only during laboratory sessions. All patients had tinnitus. We used a questionnaire to assess the effects of brainstem stimulation on this symptom. Of the 18 patients, one early patient deceased, and one patient with no follow-up was not included in this study. Six patients who were unable to use the ABI because of temporary hardware problems or side effects from electrical stimulation were also excluded. Thus, we studied 10 patients. Of 7 patients who used their implant daily, 6 reported noticeable tinnitus reduction; the ABI had no effect in the remaining case. Of 3 recently implanted patients who used this implant only during laboratory testing, one patient reported complete suppression of tinnitus, one described worse tinnitus, and one reported no effect.

With the aim of preserving hearing, 20 acoustic neurinomas in 17 patients with neurofibromatosis 2 were intentionally submitted to an incomplete (80%) tumour removal. In 12 cases this was an operation on the last hearing ear with total deafness of the contralateral ear. If an auditus existed in both ears the better hearing ear was selected for the primary intervention. Early audiological controls evidenced residual hearing in 19 of the 20 cases operated on by the enlarged middle fossa approach, which was utilized inspite of the tumour diameters being between 1 and 6 cm in the cerebello-pontine angle. The oncologic and functional follow-up over 1 to 7 years showed different patterns of slow progression of hearing loss and of persistent auditory function over 2 to 7 years. Facial nerve function was excellent in 16 of the 18 controlled cases. Continued CT or MRT imaging revealed no signaling in 2 cases, constant tumour sizes in 10 cases and slow progression in 3 cases. With regard to the importance of an auditory communication in the younger adult, the described treatment modality appears to be the first choice method.