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B P Weber

Publications and source records attributed to B P Weber.

At least 19 recordsLinked to original sources
PubMed2003

Influence of EEG monitoring on intraoperative stapedius reflex threshold values in cochlear implantation in children.

BACKGROUND: Cochlear implantation is a widely used means of treating deafness and severe hearing disorders. The surgical procedure includes inserting the cochlear implant electrode array into the cochlea and embedding the corresponding signal receiver in the mastoid bone behind the ear. Postoperative fitting of the externally worn speech processor is very important for successful use of the cochlear implant. For this purpose, electrically elicited stapedius reflex threshold values can be used. However, stapedius reflex threshold values measured intraoperatively are influenced by anaesthetics. The goal of this retrospective study was to find out whether electroencephalogram (EEG) control of anaesthesia produces more reliable reflex threshold values as a basis for the fitting of the speech processor. METHODS: Three groups of children, after surgery for cochlear implantation, were analysed with regard to the magnitude of intraoperative electrically elicited stapedius reflex threshold values and their deviations from postoperatively determined maximum comfortable levels (group 1: methohexital/remifentanil with EEG monitoring, n = 10; group 2: isoflurane/fentanyl with EEG monitoring, n = 9; group 3: isoflurane/fentanyl without EEG monitoring, n = 11). RESULTS: Children with EEG monitoring had significantly lower electrically elicited stapedius reflex threshold values and also significantly lower differences between intraoperative stapedius reflex threshold values and postoperatively determined maximum comfortable levels. CONCLUSIONS: Electroencephalogram monitoring in cochlear implantation is of considerable value in controlling anaesthesia and improving speech processor fitting based on more reliable intraoperative neurophysiological data.

Analysis of Variance↗
PubMed2002

Measurement method for the assessment of transmission properties of implantable hearing aids.

Over the last five years the Symphonix Vibrant soundbridge (VSB), an implantable hearing device, has proven an effective alternative treatment modality for patients suffering from moderate to severe sensorineural hearing loss. The results from the majority of our 40 patients are very encouraging but reveal clinical variations in benefit influenced by the coupling of the transducer to the ossicular chain. This study describes a set-up for measuring the sound pressure level in the external auditory canal when the middle ear implant is activated. The reverse transfer function allows the transducer performance to be determined both intra- and postoperatively. The sound pressure level shows a strong correlation with the stapes footplate displacement and free-field audiometry.

Adult↗
PubMed2001

[Vibrant Sound Bridge System. A new kind hearing prosthesis for patients with sensorineural hearing loss. 2. Audiological results].

OBJECTIVE: Implantable hearing aids present a new treatment modality for patients suffering from sensorineural hearing loss. The functional gain obtained with the partially implantable Symphonix soundbridge system was evaluated in a clinical study. The audiological results achieved with n = 34 patients over a period of up to three years are presented in this second part of the publication. PATIENTS AND METHODS: 34 patients have received the Symphonix Vibrant soundbridge system since February 1997. The average age at implantation was 47.2 years (minimum: 18.9 years; maximum: 80.3 years). All patients have had several years of experience with hearing aids, which, however, provided insufficient functional gain or could not be fitted with a conventional hearing aid for medical reasons (such as auditory ear canal problems). All patients fulfilled the audiological selection criteria as they had bilateral moderate to severe sensorineural hearing loss. As a rule, the ear with poorer performance was implanted. All patients were fitted with the audio processor eight weeks after the implantation. The pure tone thresholds, the functional gain, the monosyllable and sentence understanding (Göttinger Sentence Test in quiet and noise) were preoperatively and postoperatively assessed. Standardized self-assessment questionnaires were used to evaluate the subjective benefit (PHAB) and the quality of hearing (HDSS) as compared to the preoperative situation. Further hearing tests were performed after four weeks, three, six, nine, twelve, eighteen, twenty-four and thirty-six months postoperatively. During the observation period of up to three years the audioprocessor was updated several times, most recently with the fully digital three-channel-system Vibrant D. The results obtained were documented. RESULTS: Postoperatively, the pure tone threshold with the soundbridge system switched off did not change significantly in the implanted ear. All patients had a functional gain that was either comparable to the gain achieved with hearing aids or better. In particular speech-related frequencies showed improved amplification. The free field speech recognition tests revealed higher scores in quiet and in noise. The patients commended the natural sound quality, the lack of feedback, the absence of occlusion and distortion, the improved speech understanding in noise and the favourable cosmetic appeal. Only two patients failed to achieve better results as compared to their performance with conventional hearing aids. No complications, such as a deterioration of hearing due to inner ear damage or a conductive hearing loss, were observed in the long-term. CONCLUSIONS: The Symphonix Vibrant Soundbridge is a new and promising treatment modality for patients suffering from moderate to severe sensorineural hearing loss. Further improvement of the good results can be expected with improved coupling of the transducer to the ossicular chain and further development of signal processing.

Adolescent↗
PubMed2001

The nucleus double array cochlear implant: a new concept for the obliterated cochlea.

OBJECTIVE: To increase the number of intracochlear electrodes that may be inserted into a totally obliterated cochlea, a special implant has been developed in collaboration with Cochlear Limited. This implant features two separate electrode carriers containing 11 and 10 active electrodes, respectively, as well as a reference electrode located on the receiver-stimulator package. The potential stimulation modes available with this device therefore include monopolar and bipolar stimulation, and stimulation between both arrays. SURGICAL TECHNIQUE: A cochleostomy anterior to the round window provides access to the basal turn (both the scala tympani and the scala vestibuli), and new built connective tissue and bone can be removed until the anterior wall of the basal turn is approached. A second cochleostomy is performed at the second turn caudal of the cochleariform process and 2 mm anterior of the oval window after removal of the incus. New tissue should also be removed if necessary. The two electrode carriers are then placed into the scala tympani of the basal and the scala vestibuli of the second turn, respectively. The remaining surgical procedure is identical with that used for cochlear implantation in patients without obliterated cochleas. PATIENTS: In this clinical study, 10 patients aged 32 to 66 years with an obliterated cochlea each received a double array cochlear implant. All patients had total obliteration of the basal turn either on preoperative imaging or during surgery. Intraoperatively, the second turn was not obliterated in only 4 of 10 patients. Postoperatively, a standard audiologic test battery was used to determine auditory improvement over time. POSTOPERATIVE RESULTS: All patients achieved significantly improved speech understanding when the additional apical electrode array was used, compared with the use of each electrode array independently. No complications occurred. CONCLUSION: In patients with a totally obliterated cochlea, the number of intracochlear electrodes can be increased by use of the Nucleus double array implant. As a result, patients achieve significantly better auditory results.

Adult↗
PubMed2000

New Clarion electrode with positioner: insertion studies.

A new straight thin electrode array (universal electrode) was designed to be used together with a positioner, which will place the electrode array at the medial wall (modiolus) of the cochlea. The study objectives were to demonstrate safety and ease of insertion, tissue trauma, electrode position, and depth for universal and standard electrodes in human temporal bones; to test functional properties in cats; and to determine the surgical procedure and electrophysiological benefits in a clinical study. The cadaver study demonstrated the ease of insertion for the universal electrode and the positioner without tissue damage. An average gain of insertion depth of 180 degrees was achieved with the positioner. Animal studies demonstrated a reduction in threshold of 6 dB for the electrical auditory brain stem response (EABR). Neither additional cochlear damage nor additional connective tissue formation was found. The intraoperative human study findings showed a marked reduction of threshold for both EABR and stapedius reflex thresholds. Impedances were increased. Plain x-rays demonstrated modiolus proximity of the electrode with the positioner. The new Clarion electrode with positioner is a relatively safe design for providing modiolus proximity. The electrophysiological benefits include reduction of threshold and power consumption.

Adult↗
PubMed1999

Safe electrical stimulation of the cochlear nerve at the promontory during functional magnetic resonance imaging.

The purpose of this study was to evaluate possibilities and technical risks for combining intended electrical stimulation of the cochlear nerve and functional magnetic resonance imaging (fMRI). Theoretical considerations and experiments indicate that fMRI can be performed safely during electrical stimulation. A nerve stimulator was developed with minimized length of electrical conductors, current limiting resistance, high inner impedance of a current source, radio frequency (RF)-shielding, and avoidance of ferromagnetic materials. This nerve stimulator transfers the optically encoded stimulating current signal via a fiber optic cable located near the area of stimulation. There, the optical signal drives an MRI-compatible current source. This set-up was tested with transtympanic electrical stimulation of the cochlear nerve at the promontory during an fMRI examination. No hazardous effects could be detected. The stimulation resulted in activation of the Heschl's gyrus. Compared to the conventional promontory testing this method may allow a more objective examination of cochlear implant candidates. Magn Reson Med 42:371-378, 1999.

Cochlear Nerve↗
PubMed1999

[The Nucleus Double Array Cochlear Implant: a new concept in obliterated cochlea].

AIM: In order to increase the number of intracochlear electrodes to be inserted into a totally obliterated cochlea a special implant has been developed in collaboration with Cochlear Ltd. The implant features two separate electrode carriers containing 11 and 10 active electrodes, respectively, and a reference electrode on the receiver stimulator package. The potential stimulation modes include monopolar and bipolar stimulation as well as stimulation between both arrays. SURGICAL TECHNIQUE: A cochleostomy at the round window provides access to the scala tympani. Newly formed bone is removed as far as the anterior portion of the basal turn. Care is taken to identify and preserve the osseous border of the cochlea. A second cochleostomy is performed immediately caudal to the cochleariform process after removal of the incus. New tissue can be removed here in the same way. The two electrode carriers are then placed into the first and the second turn respectively. The remaining procedure corresponds to the procedure for cochlear implantation in cases in which the cochlea is not obliterated. PATIENTS: For the purpose of a clinical study n = 10 patients aged between 32-66 years with an obliterated cochlea were fitted with a double array cochlear implant. All patients showed signs of total obliteration of the basal turn either in preoperative imaging or during surgery. Intraoperative inspection revealed that the second turn was not obliterated in 4 of 10 patients. POSTOPERATIVE RESULTS: Postoperatively, a standard test battery was used to determine auditory performance over a period of time. All patients achieved significantly better speech understanding due to the additional apical electrode array. No complications occurred. CONCLUSION: In cases involving an obliterated cochlea, the number of intracochlear electrodes can be increased with the double array implant. As a result, the patients achieve significantly better auditory results.

Adult↗
PubMed1999

Clinical results of the CLARION magnetless cochlear implant.

This paper reports initial results for the CLARION Multi-Strategy Cochlear Implant, presently under investigational study in Europe. A magnetless implantable cochlear stimulator (ICS) with an ear-mold-supported headpiece was designed in response to an increasing demand for a magnetic resonance imaging (MRI)-compatible cochlear implant. Surgical technique, accompanying magnetless headpiece, and MRI compatibility were evaluated in 11 deaf patients (ages 6 to 62 years) who were implanted with a magnetless Clarion implant. Because of the headset mechanics, the ICS was implanted closer behind the ear than a magnet-containing ICS. The ICS-MRI compatibility was investigated with 1.5- and 0.3-T MRI. Results showed that the surgery was relatively safe and easy to learn. The headset was stable and reliable. The MRI compatibility tests indicate that the ICS poses no contraindication for patients needing MRI. Overall, the results suggest that the Clarion magnetless cochlear implant is relatively safe and easy to implant, is MRI-compatible, and functions well with the ear-mold-supported headpiece.

Adult↗
PubMed1998

[The Vibrant Soundbridge System: a new kind of hearing aid for sensorineural hearing loss. 1: Function and initial clinical experiences].

INTRODUCTION: Patients suffering from moderate to severe cochlear hearing impairment can not be considered for cochlear implantation on account of their relatively good residual hearing. Conventional hearing aids, on the other hand, have considerable disadvantages which clearly limit the benefit for these patients, e.g. feedback, sound distortion, unfavorable conditions for frequency transfer, occlusion, and recurrent infections of the auditory canal. In addition, many patients complain about a poor speech intelligibility in noise. VIBRANT SOUNDBRIDGE HEARING PROSTHESIS: Implantable hearing aids offer a new approach for improved auditory rehabilitation. The Vibrant Soundbridge system is based on an electromagnetic system, which is linked directly to the intact ossicular chain. Due to the high sound quality and the high frequency characteristic this system is ideally suited for the above-mentioned patient group. The usual disadvantages of conventional hearing aids can be avoided. Externally visible is merely the audio processor, which is worn in the retroauricular area and covered by hair. This processor transfers data and power via magnetic attachment transcutaneously. PATIENT POOL: During a European multicenter clinical study, 19 patients were implanted at MHH since February 1997. No significant complications occurred. RESULTS: In all patients, postoperative unaided pure tone threshold was unaltered in comparison with the preoperative recordings. The use of the audio processor leads to a significant functional gain, particularly in the high frequencies. The patients report about undistorted hearing resulting in a better speech understanding even in situations with loud background noise. CONCLUSION: The preliminary results show a promising new approach to the use of hearing prostheses for patients suffering from moderate to severe sensorineural hearing loss.

Audiometry, Pure-Tone↗
PubMed1998

[Development and clinical testing of a non-magnetic cochlear implant. Preliminary experimental studies and surgical concept. Results in the first 10 patients].

BACKGROUND: To ensure good transmission of electromagnetic signals from the speech processor to the internal cochlear stimulator (ICS) in cochlear implants, exact alignment of the external transmitter coil over the receiver coil of the ICS is necessary. Usually this is achieved by two magnets: one implanted within the ICS, the other one integrated into the transmitter coil of the external headset. Although this principle works, there are some serious problems with the implanted magnet. The most serious of these is that it renders MRI studies potentially hazardous or impossible, or at least compromises image quality. METHOD AND RESULTS: We developed a method to eliminate the magnet. The method requires varying the implantation technique and using a special headset. The technique is easy to perform, and the headset is suitable for series production. Experience with our first patients revealed the coil alignment to be remarkably stable, even more than in patients with a cochlear implant equipped with a magnet. Results of the first ten patients are presented. DISCUSSION: Aside from eliminating the magnet, we attempted to optimize the acoustic properties of the headset. This resulted in design changes such as repositioning the microphone. Further improvements such as integration of telephone coils and special sockets to connect peripheral appliances can easily be implemented in our special headset.

Adult↗
PubMed1998

Magnetic resonance imaging compatibility testing of the Clarion 1.2 cochlear implant.

OBJECTIVE: This study aimed to investigate the compatibility of the Clarion 1.2 magnet-containing cochlear implant with a 1.5-tesla (T) and 0.3-T magnetic resonance imager. BACKGROUND: Cochlear implants restore functional hearing to patients with sensorineural deafness. With the rapidly increasing number of patients with cochlear implants, there is a need to investigate the implant's magnetic resonance imaging (MRI) compatibility. METHODS: The authors tested the potential torque and force on the metallic components of the implant, heating of the implant and surrounding tissue, unintentional output, implant damage, and image distortion. Tests were performed in both a 1.5-T and 0.3-T MRI. RESULTS: The torque experienced by the implant in the 1.5-T MRI (0.19 nm) was large enough that it could potentially cause implant movement in some patients. An acceptable amount of torque (0.04 nm) was found in the 0.3-T MRI. Image distortion occurred in the area directly around the implant with a radius of up to 60 mm in the 1.5-T MRI and 100 mm in the 0.3-T MRI. In both MRI units, there was no detectable temperature increase or unintentional output. There was no implant damage except that with worst-case conditions, the internal magnet was demagnetized by 78.5% with the 1.5-T unit and 3.36% with the 0.3-T unit. CONCLUSIONS: The authors recommend patients with cochlear implants avoid imaging in a 1.5-T MRI. The results suggest that the 0.3-T MRI poses little or no risks to patients with cochlear implants.

Cochlear Implantation↗
PubMed1998

Pediatric cochlear implantation in cochlear malformations.

OBJECTIVE: This study aimed to present relevant information about pediatric cochlear implantation in malformed cochleas based on the experience gathered with 12 implanted children. STUDY DESIGN: A retrospective analysis was performed. SETTING: All patients were diagnosed and implanted at the Medical University of Hannover. Medical check-ups were performed regularly. The rehabilitation concept was developed by the Cochlear Implant Center of Hannover. PATIENTS: All children were female and were between 2 and 13 years of age at the time of implantation, with the average age being 4 years and 2 months. Only patients who were younger than 14 years of age and implanted between September 1992 and October 1995 were evaluated. INTERVENTION: Diagnostic computed tomographic scans including three-dimensional reconstructions and magnetic resonance imaging images were performed. In all cases, Nucleus devices (Mini 22 or 20 + 2) were implanted. Medical University of Hannover standard surgical technique was used, although in most cases, facial nerve monitoring and electrically evoked auditory brain stem responses were additionally recorded. Total or partial obliteration of the middle ear had occurred in two cases. An anteroposterior approach was used four times. The implantation was followed by the standard rehabilitation procedure for children. RESULTS: No serious complications occurred. All children responded to acoustic stimuli and showed improvement in their speech production. However, one autistic child performed poorly, and for another child suffering from a CHARGE syndrome, results still are pending. CONCLUSIONS: Given suitable preconditions, cochlear implantation is feasible with an acceptable risk of complications. Implantation appears to be beneficial in most cases with cochlear malformations provided that eighth nerve and cochlear lumen are present.

Adolescent↗
PubMed1997

Complications of cochlear implant surgery in children.

OBJECTIVE: To evaluate the intraoperative problems and postoperative complications in children receiving cochlear implants. STUDY DESIGN: A retrospective analysis of the clinical records of 366 children, aged 1 to 14 years, who had received cochlear implants. RESULTS: Intraoperatively, obliteration of the cochlea occurred in 66 patients, cochlear dysplasia in 8, and CSF leakage in 7, and nearly 5% of patients had signs of infection in the mucosa of the middle ear. Postoperatively, early complications occurred in 1% to 2.5% of patients: flap complications, electrode dislocation, facial nerve problems, and incorrect insertion of the electrode. Delayed complications included otitis media and stimulation of the facial nerve. CONCLUSION: Proper preparation of the implantation site, experienced and well-trained surgeons, and awareness of the operative and postoperative risks are necessary.

Adolescent↗
PubMed1997

Malformations in cochlear implant patients.

OBJECTIVE: To report on cochlear implantation in children with bony inner ear malformations. PATIENTS: 30 children with bony inner ear malformations who have received cochlear implants. INTERVENTIONS: High-resolution spiral computed tomography is used to identify malformations. Magnetic resonance imaging is used to detect the presence of an acoustic nerve and determine the integrity of the auditory pathway and central nervous system structures. Both imaging techniques may be used intraoperatively, as well as facial nerve monitoring and electrical auditory brainstem response monitoring. Three-dimensional reconstructions are helpful in preoperative planning. Large vestibular aqueducts and vestibular malformations can be successfully managed. RESULTS: Postoperative results have been encouraging, although children with malformations tend to occupy the lower third of rehabilitation results of all children with implants.

Child↗