scholarly journals New Protocol for Auditory Brainstem Implant Positioning

2021 ◽  
Vol 9 (5) ◽  
pp. 01-07
Author(s):  
Sheila Veronese ◽  
Marco Cambiaghi ◽  
Andrea Sbarbati
Keyword(s):  
Cochlear Nucleus ◽  
Electrode Array ◽  
Auditory Brainstem ◽  
New Method ◽  
Average Charge ◽  
Stimulation Protocol ◽  
Channel Interaction ◽  
Auditory Brainstem Implant ◽  
Implant Positioning ◽  
Saturation Effects

Background: Surgery for applying the auditory brainstem implant is an otoneurosurgery that requires careful intraoperative monitoring to optimize the placement of the electrode paddle. This study aimed to validate a new method capable of increasing the accuracy of electrode array placement, reducing channel interaction, electrical artefacts, and saturation effects, and providing the largest number of electrodes that can be activated with the lowest possible electric charge. Materials and methods: Thirty-six subjects aged between 1.42 and 69.92 years were tested during surgery for auditory brainstem implantation. We recorded auditory electrical responses of the brainstem using the implant supplier's suggested stimulation protocol and the new protocol. Results: Saturations effects and electric artefacts were noticed respectively in 81.85% and 53.25% of recordings using implant supplier's method, while in 70.34% and 24.75% of recordings using the new method, with a percentage variation of 11.51% and 28.50%. Considering the amount of charge required to activate the electrodes, with the implant supplier's method an average charge of 14 nC was needed, while with the new protocol an average charge of 8 nC was necessary. Conclusions: The new method improves the coupling between the auditory brainstem implant and the surface of the cochlear nucleus.

scholarly journals Measurements of the local evoked potential from the cochlear nucleus in patients with an auditory brainstem implant and its implication to auditory perception and audio processor programming

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0249535
Author(s):  
Lutz Gärtner ◽  
Thomas Lenarz ◽  
Andreas Büchner
Keyword(s):  
Cochlear Nucleus ◽  
Auditory Perception ◽  
False Positive Rate ◽  
Electrode Array ◽  
Compound Action Potential ◽  
Auditory Brainstem ◽  
Auditory Brainstem Implant ◽  
Evoked Compound Action Potential ◽  
Positive Rate ◽  
Fitting In

The measurement of the electrically evoked compound action potential (ECAP) in cochlear implant (CI) patients is widely used to provide evidence of a functioning electrode-nerve interface, to confirm proper location of the electrode array and to program the sound processor. In patients with an auditory brainstem implant (ABI), a likewise versatile measurement would be desirable. The ECAP measurement paradigm “Alternating Polarity” was utilized to record responses via the implanted ABI electrode array placed on the cochlear nucleus. Emphasizing on the different location of stimulation and recording, these responses are called local evoked potentials (LEP). LEP measurements were conducted during the clinical routine in 16 ABI patients (12 children and 4 adults), corresponding to 191 electrode contacts. A retrospective analysis of these data revealed, that LEP responses were observed in 64.9% of all measured electrode contacts. LEP responses predicted auditory perception with a sensitivity of 90.5%. False-positive rate was 33.7%. Objective LEP thresholds were highly significantly (p < 0.001) correlated both to behavioral thresholds (Pearson’s r = 0.697) and behavioral most comfortable levels (r = 0.840). Therefore, LEP measurements have the potential to support fitting in ABI patients.

Multichannel auditory brainstem implant: update on performance in 61 patients

2002 ◽  
Vol 96 (6) ◽  
pp. 1063-1071 ◽  
Author(s):  
Steven R. Otto ◽  
Derald E. Brackmann ◽  
William E. Hitselberger ◽  
Robert V. Shannon ◽  
Johannes Kuchta
Keyword(s):  
Cochlear Nucleus ◽  
Electrode Array ◽  
Neurofibromatosis Type ◽  
Auditory Brainstem ◽  
Surgical Removal ◽  
Content Type ◽  
Auditory Brainstem Implant ◽  
Vs Removal ◽  
Fine Print

Object. Neurofibromatosis Type 2 (NF2) has typically resulted in deafness after surgical removal of bilateral vestibular schwannomas (VSs). Cochlear implants are generally ineffective for this kind of deafness because of the loss of continuity in the auditory nerve after tumor removal. The first auditory brainstem implant (ABI) in such a patient was performed in 1979 at the House Ear Institute, and this individual continues to benefit from electrical stimulation of the cochlear nucleus complex. In 1992, an advanced multichannel ABI was developed and a series of patients with NF2 received this implant to study the safety and efficacy of the device. Methods. At the time of first- or second-side VS removal, patients received an eight-electrode array applied to the surface of the cochlear nucleus within the confines of the lateral recess of the fourth ventricle. The device was activated approximately 6 weeks after implantation, and patients were tested every 3 months for the 1st year after the initial stimulation, and annually thereafter. The protocol included a comprehensive battery of psychophysical and speech perception tests. Conclusions. The multichannel ABI proved to be effective and safe in providing useful auditory sensations in most patients with NF2. The ABI improved patients' ability to communicate compared with the lipreading-only condition, it allowed the detection and recognition of many environmental sounds, and in some cases it provided significant ability to understand speech by using just the sound from the ABI (with no lipreading cues). Its performance in most patients has continued to improve for up to 8 years after implantation.

The Auditory Brainstem Implant

2019 ◽  
pp. 758-770
Author(s):  
Robert V. Shannon
Keyword(s):  
Surgical Technique ◽  
Cochlear Nucleus ◽  
Meta Analysis ◽  
Auditory Brainstem ◽  
Auditory Information ◽  
Speech Understanding ◽  
Auditory Neurons ◽  
Auditory Brainstem Implant ◽  
The Brain ◽  
Implanted Device

The auditory brainstem implant (ABI) is a surgically implanted device to electrically stimulate auditory neurons in the cochlear nucleus complex of the brainstem in humans to restore hearing sensations. The ABI is similar in function to a cochlear implant, but overall outcomes are poorer. However, recent applications of the ABI to new patient populations and improvements in surgical technique have led to significant improvements in outcomes. While the ABI provides hearing benefits to patients, the outcomes challenge our understanding of how the brain processes neural patterns of auditory information. The neural pattern of activation produced by an ABI is highly unnatural, yet some patients achieve high levels of speech understanding. Based on a meta-analysis of ABI surgeries and outcomes, a theory is proposed of a specialized sub-system of the cochlear nucleus that is critical for speech understanding.

Adult Auditory Brainstem Implant Outcomes and Three-Dimensional Electrode Array Position on Computed Tomography

2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Dana Egra-Dagan ◽  
Isabeau van Beurden ◽  
Samuel R. Barber ◽  
Christine L. Carter ◽  
Mary E. Cunnane ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Electrode Array ◽  
Auditory Brainstem ◽  
Auditory Brainstem Implant ◽  
Array Position

Topographic anatomy of the cochlear nuclear region at the floor of the fourth ventricle in humans

1999 ◽  
Vol 91 (3) ◽  
pp. 466-476 ◽  
Author(s):  
Ralf Quester ◽  
Roland Schröder
Keyword(s):  
Surgical Approach ◽  
Cochlear Nucleus ◽  
Fourth Ventricle ◽  
Auditory Brainstem ◽  
Nuclear Surface ◽  
Content Type ◽  
Auditory Brainstem Implant ◽  
Ventral Cochlear Nucleus ◽  
Small Series ◽  
Fine Print

Object. The development of appropriate methods to stimulate the dorsal and ventral cochlear nucleus by means of an auditory brainstem implant in patients with acquired bilateral anacusis requires a detailed topoanatomical knowledge both of the location and extension of the nuclear surface in the fourth ventricle and lateral recess and of its variability. The goal of this study was to provide that information. Anatomically, it is possible to use a midline surgical approach to the fourth ventricle rather than the translabyrinthine and suboccipital routes of access used hitherto. This is especially useful if severe scarring, which occurs as a result of tumor removal in the cerebellopontine angle, make the orientation and placement of an auditory brainstem implant via a lateral surgical approach difficult. There have been only a few studies, involving single cases and small series of patients, in which the focus was the exact extension of the cochlear nuclei, whose microsurgically relevant position in relation to the surface structures is not known in detail.Methods. Landmarks that are important for the placement of an auditory brainstem implant through the fourth ventricle were examined and measured in a large series of 28 formalin-fixed human brainstems. In all cases, these examinations were supplemented by addition of a histological section series. For the first time values of unfixed fresh brainstem tissue were determined. Anatomical features are discussed with regard to their possible neurosurgical relevance, taking into account inter- and intraindividual variability.Conclusions. The midline approach would provide an opportunity to stimulate the whole area of the dorsal as well as the ventral cochlear nucleus with an auditory brainstem implant.

Auditory Brainstem Implant (ABI): New Frontiers in Adults and Children

2005 ◽  
Vol 133 (1) ◽  
pp. 126-138 ◽  
Author(s):  
Vittorio Colletti ◽  
Marco Carner ◽  
Veronica Miorelli ◽  
Maurizio Guida ◽  
Liliana Colletti ◽  
...  
Keyword(s):  
Electrode Array ◽  
Neurofibromatosis Type ◽  
Auditory Brainstem ◽  
Cochlear Nerve ◽  
Auditory Brainstem Responses ◽  
Closed Set ◽  
Sentence Recognition ◽  
Auditory Brainstem Implant ◽  
Open Set ◽  
Cochlear Nerve Aplasia

Previous studies have considered only patients with neurofibromatosis type 2 (NF2) older than 12 years as candidates for an auditory brainstem implant (ABI). Our study expands the potential criteria to include both children and adult subjects with other cochlear or cochlear nerve malfunctions who either would not benefit at all from a cochlear implant (eg, cochlear nerve aplasia or avulsion) or whose benefit was or would be severely compromised (eg, cochlear ossification, cochlear fracture). STUDY DESIGN: In our department, over the period from April 1997 to September 2002, 29 patients, 20 adults and 9 children, were fitted with ABIs. Their ages ranged from 14 months to 70 years. Thirteen subjects had tumors, 10 NF2 and 3 solitary vestibular schwannoma, and 16 patients had a variety of nontumor (NT) cochlear or cochlear nerve diseases. A retrosigmoid-transmeatal approach was used in T and a retrosigmoid approach in NT 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 (EABRs). RESULTS: Correct implantation was achieved in all patients. No complications were observed due to implantation surgery or related to ABI activation or long-term use. Auditory sensations were induced in all patients with various numbers of electrodes (from 5 to 15). Different pitch sensations were identifiable with different electrode stimulation. Closed-set word recognition, open-set sentence recognition, and speech tracking scores achieved by the patients are reported in detail. The auditory performance of the patients showed significantly better outcomes than controls (Multicentric European clinical investigations on ABI with NF2). CONCLUSION: We have shown that the indications for the ABI can be extended to include NT patients with severe cochlear and/or cochlear nerve abnormalities. The degree of auditory benefit varies as a function of the underlying pathological conditions, with NT subjects exhibiting significantly better outcomes than the T patients.

The multichannel auditory brainstem implant: how many electrodes make sense?

2004 ◽  
Vol 100 (1) ◽  
pp. 16-23 ◽  
Author(s):  
Johannes Kuchta ◽  
Steven R. Otto ◽  
Robert V. Shannon ◽  
William E. Hitselberger ◽  
Derald E. Brackmann
Keyword(s):  
Electrode Array ◽  
Neurofibromatosis Type ◽  
Auditory Brainstem ◽  
Sound Effect ◽  
Content Type ◽  
Sentence Recognition ◽  
Auditory Brainstem Implant ◽  
Retrospective Clinical Study ◽  
Wide Range ◽  
Fine Print

Object. Development of multichannel auditory brainstem implant (ABI) systems has been based in part on the assumption that audiological outcome can be optimized by increasing the number of available electrodes. In this paper the authors critically analyze this assumption on the basis of a retrospective clinical study performed using the Nucleus 22 ABI surface electrode array. Methods. The perceptual performances of 61 patients with neurofibromatosis Type 2 were tested approximately 6 weeks after an eight-electrode ABI had been implanted. Of eight implanted electrodes 5.57 ± 2.57 (mean ± standard deviation [SD] provided auditory sensations when stimulated. Electrodes were deactivated when stimulation resulted in significant nonauditory side effects or no auditory sensation at all, and also when they failed to provide distinctive pitch sensations. The mean (± SD) scores for patients with ABIs were the following: sound-only consonant recognition, 20.4 ± 14.3 (range 0–65%); vowel recognition, 28.8 ± 18% (range 0–67%); Monosyllable Trochee Spondee (MTS) word recognition 41.1 ± 25.3% (range 0–100%); and sentence recognition, 5.3 ± 11.4% (range 0–64%). Performance in patients in whom between one and three electrodes provided auditory sensation was significantly poorer than that in patients with between four and eight functional electrodes in the vowel, MTS word, and City University of New York (CUNY) sentence recognition tests. The correlation between performance and electrode number did not reach the 0.05 level of significance with respect to the sound effect, consonant, and MTS stress-pattern recognition tests, probably because a satisfactory performance in these tests can be obtained only with temporal cues, that is, without any information about the frequency of the sounds. In the MTS word and the CUNY sentence recognition tests, performance was optimal in the patients with eight functional electrodes. Although all top performers had more than three functional auditory electrodes, no further improvement (asymptotic performance) was seen in those with five or more active electrodes in the consonant, vowel, and sound effect recognition tests. Conclusions. A minimum of three spectral channels, programmed in the appropriate individual tonotopic order seem to be required for satisfactory speech recognition in most patients with ABI. Due to the limited access to the tonotopic frequency gradient of the cochlear nucleus with surface stimulation, patients with ABI do not receive a wide range of spectral cues (frequency information) with multielectrode (> 5) surface arrays.

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