Deafness after bacterial meningitis: an emergency for early imaging and cochlear implant surgery.
Explore the source record for details and available documents.
Cochlear Implantation↗
Biomedical subjects
Roland Laszig
Publications and source records attributed to Roland Laszig.
Preservation of residual hearing with cochlear implantation: how and why.
CONCLUSIONS: Hearing may be conserved in adults after implantation with the Nucleus Contour Advance perimodiolar electrode array. The degree of hearing preservation and the maximum insertion depth of the electrode array can vary considerably despite a defined surgical protocol. Residual hearing combined with electrical stimulation in the same ear can provide additional benefits even for conventional candidates for cochlear implantation. OBJECTIVES: We present preliminary results from a prospective multicentre study investigating the conservation of residual hearing after implantation with a standard-length Nucleus Contour Advance perimodiolar electrode array and the benefits of combined electrical and acoustic stimulation. MATERIAL AND METHODS: The subjects were 12 adult candidates for cochlear implantation recruited according to national selection criteria. A "soft" surgery protocol was defined, as follows: 1-1.2-mm cochleostomy hole anterior and inferior to the round window; Nucleus Contour Advance electrode array inserted using the "Advance-off-stylet" technique; and insertion depth controlled by means of three square marker ribs left outside the cochleostomy hole. These procedures had been shown to reduce insertion forces in temporal bone preparations. Variations in surgical techniques were monitored using a questionnaire. Pure-tone thresholds were measured pre- and postoperatively. Patients who still retained thresholds <90 dB HL for frequencies up to 500 Hz were re-fitted with an in-the-ear (ITE) hearing aid. Word recognition was tested in quiet and sentence perception in noise for the cochlear implant alone and in combination with an ipsilateral hearing aid. RESULTS: Hearing threshold level data were available for 12 patients recruited from 6 of the centres. Median increases in hearing threshold levels were 23, 27 and 33 dB for the frequencies 125, 250 and 500 Hz, respectively. These median increases include the data for two patients who had total loss of residual hearing due to difficulties encountered during surgery. "Cochlear view" X-ray images indicated that the depth of insertion varied between 300 and 430 degrees, despite modest variations in the length of the electrode inserted (17-19 mm). The insertion angle had some influence on the preservation of residual hearing at frequencies of 250-500 Hz. Six of the 12 patients retained sufficient hearing for effective use of an ipsilateral ITE hearing aid (< or = 80 dB HL at 125 and 250 Hz; < or = 90 dB HL at 500 Hz). Word recognition scores in quiet were improved from 10% to 30% with the cochlear implant plus ipsilateral hearing aid in 3 patients who had at least 3 months postoperative experience. Signal:noise ratio thresholds for sentence recognition were improved by up to 3 dB. Patients reported that they experienced greatly improved sound quality and preferred to use the two devices together.
Adult↗
Quality control after cochlear implant surgery by means of rotational tomography.
OBJECTIVE: To investigate the intracochlear electrode position in using rotational tomography in adult cochlear implant patients. STUDY DESIGN: Retrospective. SETTING: Tertiary referral center. PATIENTS: Eighteen adult patients being implanted either with a Nucleus straight electrode array or a Contour electrode with a total of 22 implanted ears. Preoperative computed tomography had been without evidence for obliteration, ossification, or malformation of the cochlea. INTERVENTION: Rotational tomography. MAIN OUTCOME MEASURES: The intracochlear electrode position was evaluated with regard to scala tympani, scala vestibuli, and a dislocation from one scala to the other. The intraoperative procedure was compared with the electrode position by analyzing the operating reports. RESULTS: Preliminary results indicate, respectively, that there is a higher incidence of intracochlear trauma in using the Contour electrode array than expected with a more frequent dislocation of electrode arrays from scala tympani to scala vestibuli and that there is a higher rate of scala vestibuli insertions. CONCLUSIONS: The impact of these findings may influence further developments of electrode arrays as well as surgical techniques for implantation.
Adult↗
Benefits of bilateral electrical stimulation with the nucleus cochlear implant in adults: 6-month postoperative results.
OBJECTIVE: To evaluate the benefits of bilateral electrical stimulation for hearing-impaired adult subjects using the Nucleus 24 cochlear implant in a multicenter study, and to compare and quantify performance on speech perception measures in quiet and in noise and localization ability for unilateral and bilateral cochlear implant use. DESIGN: : Repeated single subject measures were carried out for each subject, with each subject serving as their own control. Assessment of unilateral and bilateral listening conditions for performance on tests of speech comprehension and sound localization were performed. Speech comprehension measures were performed in quiet at 0 degree azimuth and in the presence of background noise simultaneously presented from the same speaker and spatially separated by 90 degrees, at S+45 degrees N45 degrees and at S-45 degrees N+45 degrees . Test materials included Freiburger monosyllabic words, Oldenburger sentences, and the Hochmair-Schulz-Moser sentences. Tests of localization were performed in the horizontal plane with 12 speaker locations 30 degrees apart using a shortened sentence stimulus from the Hochmair-Schulz-Moser sentences at two possible presentation levels of 55 and 70 dB sound pressure level for assessment of directionality. The binaural advantage provided by bilateral stimulation was calculated with respect to each ear separately, classified as either the better or poorer performing ear for each speech material in quiet and in noise test conditions. For localization of sound, the binaural advantage was compared with left and right ears separately. Paired comparisons for performance data in all conditions were carried out by considering measurements for each subject in different conditions as paired observations and applying the Student's t test to determine the statistical difference between the data sets. SETTING: Tertiary referral centers with a cochlear implant program. PATIENTS: Thirty-seven profoundly hearing-impaired adults were enrolled in the study, 22 simultaneously and 15 sequentially bilaterally implanted. All patients received the Nucleus 24 cochlear implant and used the Nucleus SPrint or ESPrit 3G speech processor, with the vast majority using the ACE speech coding strategy. RESULTS: For spatially separated speech in noise conditions, an interaural performance advantage for the ear closest to the speech source (i.e., with a superior signal to noise ratio) compared with that for the ear closest to the noise source (i.e., with an inferior signal to noise ratio) is consistently demonstrated regardless of whether it is the better or poorer performing ear closest to the speech signal. This is referred to as a significant binaural head-shadow benefit, resulting in a mean improvement between -10 dB and -11.4 dB in the critical signal to noise ratio required for 50% speech comprehension for the Olden-burger sentences and a mean improvement in the maximum score of 42% to 55% for the ear closest to the speech signal over the ear farthest away for the Hochmair-Schulz-Moser sentences. Bilateral stimulation is always observed to provide a performance advantage over the unilateral listening condition for either ear when ipsilateral to the noise source. In addition, as demonstrated by approximately half the subjects tested in noise with the Hochmair-Schulz-Moser sentences, a performance advantage of bilateral stimulation may be observed over the better ear alone when positioned ipsilateral to the speech signal, which is referred to as a binaural squelch effect. On average, for the group, this resulted in a statistically significant improvement in speech comprehension scores of 8% in the bilateral listening condition compared with the scores for the better ear alone. Through assessment of comprehension of coincidental speech in noise and speech in quiet, a significant benefit of binaural redundancy was noted for the group for Oldenburger sentence scores in noise and in quiet compared with unilateral scores for either ear and for the Freiburger monosyllabic words in quiet in comparison with the better ear alone scores. Binaural stimulation also led to a significant improvement in localization ability over either monaural condition, with the root mean square degrees of error reduced by 38 degrees compared with that observed for unilateral stimulation. CONCLUSION: Similar to what has been observed for bilateral acoustic stimulation in the past, bilateral electrical stimulation provides the foundation for the potential advantages of the head-shadow effect, providing a binaural head-shadow benefit and binaural auditory processing such as binaural redundancy and binaural squelch effects, all of which combine to lead to improved speech comprehension over unilateral listening conditions. The combination of improved speech comprehension and improved localization ability made available through bilateral electrical stimulation provides the necessary foundation to further assist the hearing-impaired listener to better cope with communication in the everyday listening situation both in noise and in quiet.
Adolescent↗
Navigation as a quality management tool in cochlear implant surgery.
This cadaver study assessed the value of navigation in cochlear implant surgery. Cochlear implantation was simulated on a cadaver using a Stryker-Leibinger navigation system and a Nucleus 24 Contour implant. A conventional surgical strategy consisting of mastoidectomy, posterior tympanotomy, and cochleostomy was performed. The navigated surgical procedure was evaluated for accuracy, reliability, reproducibility, and practicability. The technology of computer-assisted surgery is applicable in cochlear implantation and beneficial in as much as the navigation-controlled implantation constitutes a non-invasive instrument of quality management. Nevertheless, in order to keep the point accuracy below one millimeter, a referencing method using concealed bordering anatomical structures may be further needed to perform the cochleostomy reliably under the guidance of a navigation system. More reproducible reference systems are needed if navigated lateral skull base surgery is to be fully relied upon.
Cadaver↗
Erythropoietin to treat head and neck cancer patients with anaemia undergoing radiotherapy: randomised, double-blind, placebo-controlled trial.
BACKGROUND: Anaemia is associated with poor cancer control, particularly in patients undergoing radiotherapy. We investigated whether anaemia correction with epoetin beta could improve outcome of curative radiotherapy among patients with head and neck cancer. METHODS: We did a multicentre, double-blind, randomised, placebo-controlled trial in 351 patients (haemoglobin <120 g/L in women or <130 g/L in men) with carcinoma of the oral cavity, oropharynx, hypopharynx, or larynx. Patients received curative radiotherapy at 60 Gy for completely (R0) and histologically incomplete (R1) resected disease, or 70 Gy for macroscopically incompletely resected (R2) advanced disease (T3, T4, or nodal involvement) or for primary definitive treatment. All patients were assigned to subcutaneous placebo (n=171) or epoetin beta 300 IU/kg (n=180) three times weekly, from 10-14 days before and continuing throughout radiotherapy. The primary endpoint was locoregional progression-free survival. We assessed also time to locoregional progression and survival. Analysis was by intention to treat. FINDINGS: 148 (82%) patients given epoetin beta achieved haemoglobin concentrations higher than 140 g/L (women) or 150 g/L (men) compared with 26 (15%) given placebo. However, locoregional progression-free survival was poorer with epoetin beta than with placebo (adjusted relative risk 1.62 [95% CI 1.22-2.14]; p=0.0008). For locoregional progression the relative risk was 1.69 (1.16-2.47, p=0.007) and for survival was 1.39 (1.05-1.84, p=0.02). INTERPRETATION: Epoetin beta corrects anaemia but does not improve cancer control or survival. Disease control might even be impaired. Patients receiving curative cancer treatment and given erythropoietin should be studied in carefully controlled trials.
Anemia↗
The effect of large single radiation doses on cochlear implant function: implications for radiosurgery.
The purpose of this study was to investigate the effect of large single doses of radiation on the function of a cochlear implant. A cochlear implant (Nucleus 24 k, Cochlear Ltd., Sydney, Australia) was implanted into a cadaver head and tested for functional changes following irradiation. Within 2 h, the device was given single fractions of 16.3 Gy, 6.2 Gy and 20 Gy with 6 MV photons. The size of the fractions was derived from maximum doses registered in linear accelerator-based radiosurgery of more than 300 patients treated for benign or malignant tumors at the Department of Radiation Therapy of the University Hospital of Freiburg. After each treatment an integrity test was performed testing the impedance and current output of the CI system. The total dose of 42.5 Gy caused no changes with regard to the tested parameters. The risk of implant failure seems to be low for Nucleus 24 k cochlear implants exposed to large single doses of radiation as used in radiosurgery.
Cadaver↗
Retroauricular skin flap and primary Z-plasty for donor site closure in partial ear reconstruction.
Helical rim defects are noticeable and may well need reconstruction, especially in men. A method for reconstructing this type of defect together with primary donor site closure by Z-plasty is described. To close partial helical rim defects, a retroauricular caudally based rotational skin flap is performed to cover a conchal cartilage graft from the same ear that is harvested first and sutured into place to remodel the helical rim. To primarily close the donor site defect a retroauricular Z-plasty was developed which easily allowed primary closure of the donor site. The technique described here is straightforward, safe and reproducible. The Z-plasty approach for closing the donor site is useful, since the slight disturbance of the hairline is well hidden retroauricularly. This technique can be considered as a single-stage repair modality for the reconstruction of helical rim defects within primary donor site closure.
Ear Deformities, Acquired↗
Evaluation of the HiFocus electrode array with positioner in human temporal bones.
The aim of the study presented was to assess the insertion mode and possible intracochlear trauma after implantation of the HiFocus electrode with positioner in human temporal bones. The study was performed in five freshly frozen temporal bones. The position of electrodes was evaluated using conventional X-ray analysis, rotational tomography and histomorphological analysis. Insertion of the HiFocus electrode with positioner resulted in considerable trauma to fine cochlear structures including fracture of the osseous spiral lamina, dislocation of the electrode array from the scala tympani into the scala vestibuli and fracture of the modiolus close to the cochleostomy. The implication of the results regarding clinical outcome will be discussed.
Cochlear Implantation↗
Receptive and expressive language skills of 106 children with a minimum of 2 years' experience in hearing with a cochlear implant.
OBJECTIVE: The aim of the study was to assess the speech development of children with at least 2 years' hearing experience with a cochlear implant (CI). METHODS: One hundred and six children were tested, all of whom had used the CI for at least 2 years. Receptive and expressive language development were tested using the scales of early communication skills for hearing-impaired children after Geers and Moog and the Reynell developmental language scales III. In addition, free-field audiometry was performed. Pre-postoperative measurements were compared statistically, and a linear regression analysis was carried out. RESULTS: Clear improvements in the gain in functional hearing 2 years after receiving the CI as well as clear improvements in both speech perception and speech production were ascertained. All deviations were statistically highly significant (P<0.000). The receptive and expressive speech test results correlate positively to a great extent. The results of logistic regressive analysis indicate that the speech production measured depends decisively on age at implantation, age at time of test, speech production before implantation, and additional handicaps. CONCLUSION: Based on the conception of the WHO, a statistically significant improvement of both impairment and disability can be confirmed. In the present study, the regression analysis established the age at implantation as the most important prognostic factor. While the percentage of children with good speech development is larger with early implanted children than with late implanted children, some of the children among the early implanted group show unsatisfactory speech development of unknown origin. Improvements in speech development are likely to be achieved when more children are diagnosed and implanted early. This finding urgently requires the introduction of a general newborn screening program. Thorough anamnesis and assessment during parent counseling of the manifold factors described are a prerequisite for the precise estimation of the difficulties to be met and the expected effectiveness of the implant in each individual case.
Audiometry↗
Transcription factor modulation and expression in the rat auditory brainstem following electrical intracochlear stimulation.
Neuronal activity in sensory organs elicited by adequate or electrical stimulation not only invokes fast electrical responses but may also trigger complex molecular changes inside central neurons. Following electrical intracochlear stimulation with a cochlear implant under urethane anesthesia, we observed changes in the phosphorylation state of the cAMP response element binding protein (CREB) and the expression of the immediate-early genes c-fos and egr-1, molecules known to act as transcription factors, in a tonotopically precise pattern in central auditory neurons. These neurons resided in the posteroventral and anteroventral cochlear nucleus, the dorsal cochlear nucleus, the lateral superior olive, the medial nucleus of the trapezoid body, the dorsal and ventral nucleus of the lateral lemniscus, and the central nucleus of the inferior colliculus. Moreover, effects of electrical stimulation were identified in the medial vestibular nucleus and the lateral parabrachial nucleus. Regionally, CREB was dephosphorylated wherever immediate-early gene expression went up. These massive stimulation-dependent modulations of transcription factors in the ascending auditory system are indicative of ongoing changes that modify the chemistry and structure of the affected cells and, consequently, their response characteristics to subsequent stimulation of the inner ear.
Animals↗
Threshold, comfortable level and impedance changes as a function of electrode-modiolar distance.
OBJECTIVE: The study investigated the hypothesis that threshold and comfortable levels recorded from cochlear implant patients would reduce, and dynamic range increase, as distance of the electrode from the modiolar wall (radial distance) decreases. Two groups of cochlear implant patients participated; one group using the Nucleus' 24 Contour electrode array, and one group using the Nucleus standard straight (banded) array. The Nucleus 24 Contour array has been shown in temporal bone studies to lie closer to the modiolus than the banded array. The relationship of electrode impedance and radial distance is also investigated. DESIGN: The study, conducted at three centers, evaluated 21 patients using the Contour array, and 36 patients using the banded array. For each patient, threshold, comfortable levels and dynamic range were measured at four time points. Common ground electrode impedance was recorded clinically from each patient, at time intervals up to 12 wk. An estimate of the radial distance of the electrode from the modiolus was made by analysis of Cochlear view x-rays. RESULTS: Threshold and comfortable levels were significantly lower for the Nucleus 24 Contour array than for the banded array. However, dynamic range measurements did not show the predicted increase. In a majority of subjects, a significant correlation was found between the estimated radial distance of the electrode from the modiolus and the measured threshold and comfortable levels. This trend was not observed for dynamic range. The analysis indicates that other factors than radial distance are involved in the resultant psychophysical levels. Clinical impedance measures (common ground) were found to be significantly higher for the Contour array. However, the electrodes on the Contour array are half-rings, which are approximately only half the geometric size of the full rings as electrodes of the standard array. When the geometric electrode area in the two array designs are normalized, the trends in the electrode impedance behavior are similar. CONCLUSIONS: The results support the hypothesis that the relationship between the radial distance of the electrode and the psychophysical measures are influenced by patterns of fibrous tissue growth and individual patient differences, such as etiology and neural survival. Impedance measures for the Nucleus 24 Contour electrode array were higher than the banded electrode array, but this is primarily due to the reduction in electrode surface area. The different outcomes in impedance over time suggest differences in the relative contributions of the components of impedance with the two arrays.
Acoustic Impedance Tests↗
Results from a European clinical investigation of the Nucleus multichannel auditory brainstem implant.
OBJECTIVE: This study was designed to investigate the perceptual benefits and potential risks of implanting the Nucleus(R) multichannel auditory brainstem implant. DESIGN: Between September 1992 and October 1997 a total of 27 subjects received a Nucleus 20- or 21-channel Auditory Brainstem Implant (ABI). All subjects involved in the trial had bilateral acoustic tumour as a result of neurofibromatosis type 2 (NF2) resulting in complete dysfunction of the VIIIth nerve. The study used each subject as their own control without a preoperative baseline because residual hearing, if existing, was destroyed at surgery by tumour removal. A battery of speech tests was conducted to evaluate each patient's performance and communication abilities. Tests were conducted, where possible, in the auditory-only, visual-only, and auditory-visual conditions at 3 days postoperatively (baseline), at 3-mo intervals for the first year and every 12 mo thereafter. A subjective performance questionnaire was administered together with an extensive neurological examination at each test interval. RESULTS: 27 subjects involved in this trial were successfully implanted with a Nucleus ABI. One subject died 2 days postoperatively due to a lung embolism unrelated to the device. Twenty-six subjects underwent device activation and all but one patient received auditory sensation at initial stimulation (96.2%). On average 8.6 (+/-4.2) of the available 21 electrodes were used in the patients' MAPs. Performance evaluation measures showed that the majority of users had access to auditory information such as environmental sound awareness together with stress and rhythm cues in speech that assist with lipreading. Although most subjects did not achieve any functional auditory-alone, open-set speech understanding, two subjects from this series (7.4%) did receive sufficient benefit to be able to use the ABI in conversation without lipreading. CONCLUSIONS: Although the medical risks and surgical complexity associated with ABI device implantation are far greater than those for a cochlear implant, the clinical results from this trial show that the Nucleus multichannel ABI is capable of providing a significant patient benefit over risk ratio for subjects suffering loss of hearing due to bilateral retrocochlear lesions.
Acoustic Stimulation↗
Ultracision: an alternative to electrocautery in revision cochlear implant surgery.
Explore the source record for details and available documents.
Cochlear Implantation↗
Nondestructive three-dimensional analysis of electrode to modiolus proximity.
PURPOSE: To propose a nondestructive method for three-dimensional analysis of inner ear morphology after cochlear implantation for isolated petrous bones. MATERIALS AND METHODS: After implantation of cochlear implant electrode arrays, fresh temporal bones were investigated on a new C-arm-based radiographic device permitting the generation of cross-sectional images and of three-dimensional models from multiple two-dimensional radiographic images taken under different projections (cone-beam computed tomography). Cross-sectional images and multiplanar reformations with a slice thickness of 0.15 mm were acquired. The relationship of the electrode to the modiolus was analyzed (distance between electrode and the modiolus; position of the electrode inside the tympanic or vestibular scale). Histologic preparation was used as a gold standard. RESULTS: In all cases, cone-beam computed tomography gave similar information concerning the position of the electrode compared with histologic analysis (tympanic scale versus vestibular scale, proximity versus distance to the modiolus). Perforation of the electrode from the tympanic to the vestibular scale could be assessed three-dimensionally in the cross-sectional images. In contrast to histology, cross-sectional imaging based on radiography is performed in less than 10 minutes and needs no preparation of the object. Because it is nondestructive, it can be repeated and used as a control after position-correcting maneuvers. CONCLUSION: Cross-sectional imaging based on radiography is a valuable tool for the analysis of the electrode-modiolus relationship after cochlear implantation in isolated temporal bones, which may confirm histologic analysis.
Cochlear Implantation↗
Intracochlear insertion of electrodes using hyaluronic acid in cochlear implant surgery.
Hyaluronic acid has been proposed as a lubricant for improving the outcome of cochlear implant surgery. We describe a method which includes coating the electrodes with a thin layer of hyaluronic acid as well as using a droplet of the lubricant on the cochleostomy to provide additional magnification, like a lens, that facilitates the insertion of the electrode array. The use of hyaluronic acid reduces trauma to the cochlea and avoids contaminating perilymph by blood or by saline used during the operation. It is an efficacious and reliable method for cochlear implant surgery.
Cochlear Implantation↗
Clarion 1.2 standard electrode array with partial space-filling positioner: radiological and histological evaluation in human temporal bones.
The purpose of this study was to evaluate whether use of a positioner for situating the Clarion 1.29 standard electrode array in close proximity to the modiolus, causes damage to fine intra-cochlear structures, and to provide a comparison with results obtained for insertions of the array performed without a positioner. The study was performed in seven freshly frozen human temporal bones. Electrode location and intra-cochlear trauma was analysed using cross-sectional imaging and histological analysis. Insertion of the Clarion array did not reveal major trauma. The devices inserted with the positioner showed a consistently closer location of the electron array towards the modiolus, however, insertion resulted in significant displacement of both the electrode array and the positioner resulting in severe destruction of the basilar membrane and osseous spiral lamina along the length of the basal and middle turns. The devices inserted with the positioner resulted in major trauma to the basilar membrane and osseous spiral lamina. Therefore, systematic safety studies in larger samples of human temporal bones should be performed and the results carefully evaluated before implantation can be recommended unreservedly.
Basilar Membrane↗