Frederike Hassepass

Unilateral deafness in children: audiologic and subjective assessment of hearing ability after cochlear implantation.

Objectives Recently, several studies have shown that a cochlear implant is a suitable treatment for hearing rehabilitation of adults with unilateral sensorineural hearing loss (UHL), and benefits for speech comprehension in noise and localization have been demonstrated. The aim of this clinical study was to evaluate the benefit of cochlear implantation in children with UHL in comparison to their unaided listening situation. Study design Prospective repeated measures single subject design. Setting Tertiary referral center; cochlear implant (CI) program Patients Three children (4, 10, and 11 yr) with noncongenital UHL resulting from different causes were enrolled in the study. Intervention After extensive consultation with each family and confirming CI-candidacy, each child received a cochlear implant. Main Outcome Measures Open set speech recognition measures in competing background noise and tests of sound localization were performed for unaided preoperative and CI-aided postimplant intervals after 6 and 12 months. The parent and child versions of the Speech, Spatial and Qualities scale (SSQ) were used for subjective evaluation of hearing at preimplant and 12-month postimplant intervals. Conclusion All children consistently use their CI 1 year postimplant. Our preliminary results suggest binaural hearing benefits for speech understanding in noise, localization ability and subjectively perceived hearing ability for school-aged children with UHL. Trends for CI-benefits in younger preschoolaged children are confirmed through subjective assessment reported by the parents. The benefits in hearing performance suggest binaural integration and processing of electric and acoustic stimulation arriving at 2 different ears is possible for children with UHL.

Cochlear Implantation in Children with Single-Sided Deafness: Does Aetiology and Duration of Deafness Matter?

For adult patients with single-sided deafness (SSD), treatment with a cochlear implant (CI) is well established as an acceptable and beneficial hearing rehabilitation method administered routinely in clinical practice. In contrast, for children with SSD, CI has been applied less often to date, with the rationale to decide either on a case-by-case basis or under the realm of clinical research. The aim of our clinical study was to evaluate the longitudinal benefits of CI for a group of children diagnosed with SSD and to compare their outcomes with respect to patient characteristics. Evaluating a pool of paediatric SSD patients presenting for possible CI surgery revealed that the primary aetiology of deafness was congenital cochlear nerve deficiency. A subgroup of children meeting the CI candidacy criteria for the affected ear (the majority with acquired hearing loss) were enrolled in the study. Preliminary group results suggest substantial improvements in speech comprehension in noise and in the ability to localise sound, which was demonstrated through objective and subjective assessments after CI treatment for the group, with results varying from patient to patient. Our study shows a trend towards superior outcomes for children with acquired hearing loss and a shorter duration of hearing loss compared to congenitally deafened children who had a longer duration of SSD. This indicates an interactive influence of the age at onset, aetiology and duration of deafness upon the restoration of binaural integration and the overall benefits of sound stimulation to two ears after CI treatment. Continued longitudinal investigation of these children and further studies in larger groups may provide more guidance on the optimal timing of treatment for paediatric patients with acquired and congenital SSD.

The new mid-scala electrode array: a radiologic and histologic study in human temporal bones.

Hypothesis To analyze the quality of insertion of the newly developed midscala (MS) electrode, which targets a midscalar electrode position to reduce the risk of trauma to the lateral wall and the modiolus. Background Modern cochlear implant surgery aims for a safe intracochlear placement of electrode arrays with an ongoing debate regarding cochleostomy or round window (RW) insertion and the use of lateral wall or perimodiolar electrode placement. Intracochlear trauma after insertion of different electrodes depends on insertion mode and electrode design and may result in trauma to the delicate structures of the cochlear. Methods We performed a temporal bone (TB) trial with insertion of the MS electrode in n = 20 TB‘s after a mastoidectomy and posterior tympanotomy. Insertion was performed either via the RW or a cochleostomy. Electrode positioning, length of insertion, and angle of insertion were analyzed with rotational tomography (RT). TBs were histologically analyzed. Results of RT and histology were compared. Results Scala tympani (ST) insertion could be accomplished reliably by both RW and via a cochleostomy approach. In 20 TBs, 1 scala vestibuli insertion, 1 incomplete (ST), and 1 elevation of basilar membrane were depicted. No trauma was found in 94.7% of all ST insertions. RT allowed determination of the intracochlear electrode position, which was specified by histologic sectioning. Conclusion The new MS electrode seems to fulfill reliable atraumatic intracochlear placement via RW and cochleostomy approaches. RT is available for evaluation of intracochlear electrode position, serving as a potential quality control instrument in human implantation.

Revision surgery due to magnet dislocation in cochlear implant patients: an emerging complication.

Objectives To analyze the cause and effect of magnet dislocation in cochlear implant (CI) recipients requiring magnet revision surgery for treatment. Study Design Retrospective study. Setting Tertiary referral center. Interventions Case reports from 1,706 CI recipients consecutively implanted from January 2000 to December 2011 were reviewed. The number of cases requiring magnet revision surgery was assessed. Results Revision surgery involving magnet removal or replacement was indicated in 1.23% (21/1,706), of all CI recipients. Magnet dislocation occurring during magnetic resonance tomography (MRI), at 1.5 Tesla (T), with the magnet in place and with the application of compression bandaging around the head, was the main cause for revision surgery in 47.62% (10/21) of the affected cases. All 10 cases were implanted with Cochlear Nucleus cochlear implants. These events occurred, despite adherence to current recommendations of the manufacturer. Conclusion The present study underlines that MRI examination is the main cause of magnet dislocation. The use of compressive bandaging when using 1.5-T MRI does not eliminate the risk of magnet dislocation. Additional cautionary measures are for required for conditional MRI. We recommend X-ray examination after MRI to determine magnet dislocation and avoid major complications in all cases reporting pain during or after MRI. Additional research regarding silicon magnet pocket design for added retention is needed. Effective communication of guidelines for precautionary measures during MRI examination in CI patients is mandatory for all clinicians involved. MRI in CI recipients should be indicated with caution.

Magnet Dislocation: An Increasing and Serious Complication Following MRI in Patients with Cochlear Implants

PURPOSE Cochlear implantation (CI) represents the gold standard in the treatment of children born deaf and postlingually deafened adults. Initial magnetic resonance imaging (MRI) was contraindicated in CI users. Meanwhile, there are specific recommendations concerning MRI compatibility depending on the type of CI system and the device manufacturer. Some CI systems are even approved for MRI with the internal magnet left in place. The aim of this study was to analyze all magnet revision surgeries in CI patients at one CI center and the relationship to MRI scans over time. MATERIALS AND METHODS Between 2000 and 2013, a total of 2027 CIs were implanted. The number of magnet dislocation (MD) surgeries and their causes was assessed retrospectively. RESULTS In total 12 cases of MD resulting from an MRI scan (0.59 %) were observed, accounting for 52.2 % of all magnetic revision surgeries. As per the labeling, it was considered safe to leave the internal magnet in place during MRI while following specific manufacturer recommendations: MRI intensity of 1.5 Tesla (T) and compression head bandage during examination. CONCLUSION A compression head bandage in a 1.5 T MRI unit does not safely prevent MD and the related serious complications in CI recipients. We recommend a Stenvers view radiograph after MRI with the internal magnet in place for early identification of MD, at least in the case of pain during or after MRI examination. MRI in CI patients should be indicated with restraint and patients should be explicitly informed about the possible risks. Recommendations regarding MRI compatibility and the handling of CI patients issued with MRI for the most common CI systems are summarized.

Clinical outcome after cochlear implantation in patients with unilateral hearing loss due to labyrinthitis ossificans.

Objectives Cochlear implantation (CI) is the treatment of choice in bilateral labyrinthitis ossificans (LO). The aim of this clinical case study was to evaluate audiologic and subjective outcomes after CI treatment for unilateral hearing loss (UHL) because of LO and to identify optimal timing for treatment. Patients Three subjects (age 40, 54, and 68 yr) with UHL because of LO were enrolled. Duration of deafness was 1.5, 12, and 120 months. Intervention After extensive consultation, testing with conventional contralateral routing of signal hearing aid and bone-anchored hearing instrument, CI candidacy was confirmed and CI surgery performed. Main Outcome Measures Test of open-set speech recognition in background noise and sound localization were performed preoperatively, in unaided and aided conditions, and in the CI-aided condition, at 6 and 12 months postoperatively. Subjective assessment via the Speech, Spatial and Qualities scale (SSQ) and the Tinnitus Visual Analogue Scale was performed at preimplant and 12 months postimplant. Conclusion The data show moderate-to-high hearing benefit after CI in 2 cases and no benefit for the third. SSQ and tinnitus scales show benefit from CI use in both cases. CI treatment should be performed as early as possible, ideally before signs of obliteration are evident. Counseling on all rehabilitation options is important.

Radiologic Results and Hearing Preservation With a Straight Narrow Electrode via Round Window Versus Cochleostomy Approach at Initial Activation.

Objective To evaluate the potential influence of two different cochlear implant (CI) electrode carrier approaches to the scala tympani in terms of insertion depth and angle as well as hearing preservation. Study Design Retrospective follow-up study. Setting Tertiary care academic center. Patients Forty-one adult subjects underwent cochlear implantation using the Cochlear Nucleus CI 422 slim straight electrode (Cochlear Limited, New South Wales, Australia) with the intent of achieving atraumatic electrode insertion and hearing preservation. Interventions Fourteen subjects were implanted using a cochleostomy approach and 27 via a round window approach. Main Outcome Measures Radiologic assessment of insertion depth and angle was performed on postoperative rotational tomography. Postoperative low-frequency hearing preservation, complete loss of residual low-frequency hearing, and speech perception in quiet measures were obtained in defined intervals for both groups. Results Mean insertion depth reached 21.5 mm (standard deviation, 1.1), whereas mean insertion angle of 388 degrees (standard deviation, 34.7) was revealed for all CI recipients, with no significant difference between the cochleostomy cohort and the round window cohort. The CI-aided speech perception in quiet showed significantly higher scores 3 to 4 months after activation compared with the preoperative speech perception results. The audiologic data demonstrated no statistically significant difference in probability of complete loss of residual low-frequency hearing at initial activation between the cochleostomy group and the round window group. Conclusion The present results suggest that similar insertion depth and angle as well as similar low-frequency hearing preservation can be achieved in cochlear implantation with this straight narrow electrode via either cochleostomy approach or round window approach at least at initial activation. This fact gives the surgeon the opportunity to adapt access to the scala tympani as needed.

Comparison of speech discrimination in noise and directional hearing with 2 different sound processors of a bone-anchored hearing system in adults with unilateral severe or profound sensorineural hearing loss.

Objective To evaluate and compare the benefit of a bone-anchored hearing implant with 2 different sound processors in adult patients with unilateral severe to profound sensorineural hearing loss (UHL). Study Design Prospective crossover design. Setting Tertiary referral center. Patients Eleven adults with UHL and normal hearing in the contralateral ear were assigned to 2 groups. Intervention All subjects were unilaterally implanted with a bone-anchored hearing implant and were initially fitted with 2 different sound processors (SP-1 and SP-2). SP-1 is a multichannel device equipped with an omnidirectional microphone and relatively simple digital signal-processing technology and provides a user-adjustable overall gain and tone control with compression limiting. SP-2 is a fully channel-by-channel programmable device, which can be set with nonlinear dynamic range compression or linear amplification. In addition, SP-2 features automatic noise management, an automatic multichannel directional microphone, microphone position compensation, and an implementation of prescription rules for different types of hearing losses, one of them unilateral deafness. After at least 1-month use of the initial processor, both groups were fitted with the alternative processor. Main Outcome Measures Speech discrimination in noise and localization tests were performed at baseline visit before surgery, after at least 1-month use of the initial processor, and after at least 2-week use of the alternative processor. Results Relative to unaided baseline, SP-2 enabled significantly better overall speech discrimination results, whereas there was no overall improvement with SP-1. There was no difference in speech discrimination between SP-1 and SP-2 in all spatial settings. Sound localization was comparably poor at baseline and with both processors but significantly better than chance level for all 3 conditions. Conclusion Patients with UHL have an overall objective benefit for speech discrimination in noise using a bone-anchored hearing implant with SP-2. In contrast, there is no overall objective benefit from SP-1. Depending on the speech-in-noise presentation setting, the difference between objective benefit from SP-2 and SP-1 might be mainly attributed to the new technological features in SP-2 unavailable in SP-1 such as 1) automatic noise management reducing the noise in the speech signal and thus improving the signal-to-noise ratio of the resulting signal on the better ear, 2) programmable multichannel sound-processing and nonlinear dynamic range compression offering considerably greater control over signal amplification compared to SP-1, and 3) implementation of a prescription rule for unilateral deafness addressing the specific amplification needs of patients with UHL by reducing amplification in the low frequencies and applying additional gain in the high frequencies. Sound localization is poor but better than chance level in the unaided condition as well as in both bone-anchored hearing system–aided conditions.

Electrophysiological Detection of Intracochlear Scalar Changing Perimodiolar Cochlear Implant Electrodes: A Blinded Study.

Objective To investigate whether a previous established neural response telemetry (NRT) ratio corresponds with the scalar position of the CI electrode. Study Design Retrospective blinded controlled study. Setting Tertiary referral center. Patients The electrophysiological data sets of 85 patients with measured intraoperative NRTs were evaluated. All patients were implanted with the same CI system. Using a flat panel tomography system, the position of the electrode array was confirmed radiologically. Interventions The radiological results were blindly compared with the intraoperatively obtained electrophysiological data (NRT ratio) and statistically evaluated. In a second step, irregularities between the NRT ratios and the radiologically confirmed electrode positions were determined and the entire study material was investigated deeper. Main Outcome Measures Correlation of the NRT ratio with the intracochlear position of the CI electrode. Results By electrophysiological evaluation only, 69 patients were detected without a scalar change at first. In 16 patients, a scalar change was probable. A significant correlation between the radiological results and the NRT ratios was found. Secondly, additional patient characteristics were identified which influences the electrode’s position. Excluding those patients, the selectivity and specificity of the NRT ratio could be increased to a higher level. Conclusion Evidenced by a blinded group of patients, we are able to show that the electrode array position within the cochlea could be predicted using the NRT ratio.

Binaural integration of periodically alternating speech following cochlear implantation in subjects with profound sensorineural unilateral hearing loss.

In cochlear implant (CI) recipients with unilateral hearing loss (UHL) and normal hearing (NH) in the contralateral ear, the central auditory system receives signals of different auditory modalities, i.e. electrically via the CI ear as well as acoustically via the NH ear. The present study investigates binaural integration of bimodal stimulation in the central auditory system of 10 CI subjects with UHL by applying a modified version of the Rapidly Alternating Speech Perception (RASP) test to characterise speech recognition ability under monotic and dichotic listening arrangements. Subsequently, the results for each monotic and dichotic test condition were compared to quantify the binaural benefit from CI usage. The study results demonstrate significantly improved speech recognition under dichotic compared to monotic listening conditions, providing evidence that there is binaural integration of acoustically and electrically transmitted speech segments in the central nervous system at brainstem and cortical levels. In contrast to more commonly used tests of binaural integration, such as localisation, the RASP test provides the clinical option to investigate binaural integration involving structures at the cortical level.