Electrically Evoked Stapedius Reflex Measurements in Cochlear Implantation and its Application in the Postoperative Fitting Process.

Measuring the electrically evoked stapedius reflex during the fitting of cochlear implants (CIs) provides a reliable estimation of maximum comfort levels, resulting in the programming of the CI with high hearing comfort and good speech understanding. Detection of the stapedius reflex and the required stimulation level on each implant channel is already being performed during surgery, whereby intraoperative stapedius reflexes are observed through the surgical microscope. Intraoperative stapedius reflex detection is both an indicator that the auditory nerve is responding to electrical stimulation up to the brainstem and a test for the ability to perform postoperative stapedius reflex measurements. Postoperative stapedius reflex thresholds can be used to estimate upper stimulation levels in the CI fitting process. In particular, in children or patients unable to provide feedback on loudness perception, this method avoids inadequate stimulation with the CI, which can result in poor hearing performance. In addition, overstimulation can be avoided, which could even lead to refusal to use the device.

Localization of Low- and High-Frequency Sounds in Cochlear Implant Recipients Using a Contralateral Hearing Aid.

BACKGROUND AND OBJECTIVES: The ability to localize sounds is partly recovered in patients using a cochlear implant (CI) in one ear and a hearing aid (HA) on the contralateral side. Binaural processing seems effective at least to some extent, despite the difference between electric and acoustic stimulation in each ear. To obtain further insights into the mechanisms of binaural hearing in these listeners, localization of low- and high-frequency sounds was tested. STUDY DESIGN: The study used a within-subject design, where participants were tasked with localizing sound sources in the horizontal plane. The experiment was conducted in an anechoic chamber, where an array of seven loudspeakers was mounted along the 24 azimuthal angle span from -90° to +90°. Stimuli were applied with different frequencies: broadband noise and high- and low-frequency noise. SUBJECTS: Ten CI recipients participated in the study. All had an asymmetric hearing loss with a CI in the poorer ear and an HA on the contralateral side. MAIN OUTCOME MEASURES: Accuracy of sound localization in terms of angular error and percentage of correct localization scores. RESULTS: The median angular error was 40° in bimodal conditions for both broadband noise and high-frequency noise stimuli. The angular error increased to 47° for low-frequency noise stimuli. In the unilaterally aided condition with an HA, only a median angular error of 78° was observed. CONCLUSIONS: Irrespective of the frequency composition of the stimuli, this group of bimodal listeners showed some ability to localize sounds. Angular errors were larger than those reported in the literature for bilateral CI users or single-sided deaf listeners with a CI. In the unilateral listening condition with HA, only localization of sounds was not possible for most subjects.

Successful Cochlear Implantation of a Split Electrode Array in a Patient With Far-advanced Otosclerosis Assisted by Electromagnetic Navigation: A Case Report.

BACKGROUND: Incomplete electrode insertion is frequent when implanting ossified cochleae with conventional linear electrodes. If split electrode arrays (SEA) are used, this complication occurs less frequently resulting in improved audiological performance (AP). Additional implementation of electromagnetic navigation systems (EMNS) may add additional safety to this procedure and may further improve AP. However, previously performed SEA cochlea implantations rarely implemented EMNS. The few cases reported a laborious approach with customized, three-dimensional-printed microstereotactic headframes, which limited clinical feasibility. Moreover, no postoperative AP was reported. In this case report a more feasible approach, using a commercially available EMNS, is described and postoperative AP is reported. PATIENT: A 70-year-old man with far-advanced otosclerosis was referred because of unsatisfactory speech intelligibility (monosyllabic word score of 0% at 75 dB sound pressure level) after cochlear implantation of a conventional linear electrode. Preoperative computed tomography revealed subtotal cochlear ossification and incomplete electrode insertion. INTERVENTION: Four titanium screws were inserted into the petrous bone for computed tomography-based registration using an EMNS. The previous mastoidectomy was expanded, the misplaced conventional linear electrode extracted and a manual, free-handed superior cochleostomy at the level of the tendon of the tensor tympani muscle was performed. The location and course of the drill-out procedure for the SEA was planned and verified with EMNS. RESULTS: Full electrode insertion for both electrode arrays of the SEA was achieved without any nerve dysfunction. Monosyllabic word score, determined 207 days after surgery, improved to 50 and 60% at 65 and 75 dB sound pressure level respectively. CONCLUSION: The implementation of EMNS in SEA cochlear implantation added additional safety to the procedure, which resulted in full electrode insertion and superior AP. Yet, outcome in cochlear implantation may vary. Larger case series to confirm this observation are required. The approach proposed for EMNS-guided SEA in this case report, using commercially available EMNS, may lead to a more frequent implementation in clinical routine due to its good clinical feasibility. Thus, larger case series may be generated.

Hearing preservation cochlear implantation in children: The HEARRING Group consensus and practice guide.

OBJECTIVES: To provide multidisciplinary cochlear implant teams with a current consensus statement to support hearing preservation cochlear implantation (HPCI) in children, including those children with symptomatic partial deafness (PD) where the intention is to use electric-acoustic stimulation (EAS). The main objectives are to provide guidelines on who is a candidate, how to assess these children and when to implant if Med-El Flex electrode arrays are chosen for implantation. METHODS: The HEARRING group reviewed the current evidence and practice regarding the management of children to be considered for HPCI surgery emphasizing the assessment needed prior to implantation in order to demonstrate the benefits in these children over time. The consensus statement addresses following three key questions: (1) Should these children be treated? (2) How to identify these children? (3) How to manage these children? SUMMARY: The HEARRING group concludes that irrespective of the degree of residual hearing present, the concepts of hearing and structure preservation should be applied in every child undergoing cochlear implantation and that HPCI is a safe and reliable treatment option. Early detection and multidisciplinary assessment are key to the identification of children with symptomatic PD, these children should undergo HPCI as early as possible.

Auditory and cognitive development in a partially deaf child with bilateral electro-acoustic stimulation: a case study.

OBJECTIVE: To study the long-term evolution of speech and intelligence in a child with partial deafness and normal hearing in the low frequencies after sequentially receiving cochlear implants in both ears. DESIGN: Retrospective chart review. STUDY SAMPLE: Male child aged 6 years was followed over a time period of four years. RESULTS: The paediatric patient had normal hearing up to 1 kHz and profound hearing loss at all higher frequencies symmetrical in both ears. Deprivation of high-frequency sounds resulted in retarded development of speech, language and cognitive skills. The choice for rehabilitation was cochlear implantation with the aim of preserving a considerable amount of low-frequency hearing. With natural hearing at low frequencies and electrical stimulation at high frequencies, the child was able to compensate most of his developmental deficits. Moreover, spatial hearing was almost normal. CONCLUSIONS: Electro-natural stimulation without amplification of the low frequencies (electro-natural hearing) provides access to the whole audible frequency range for children, who suffer from partial deafness in the high frequencies and are normal hearing at low frequencies. Such provision allows for regular speech development and favours the development of spatial hearing. The case report also demonstrates a strong impact on intellectual performance.

Electrically evoked compound action potentials are different depending on the site of cochlear stimulation.

One of the many parameters that can affect cochlear implant (CI) users' performance is the site of presentation of electrical stimulation, from the CI, to the auditory nerve. Evoked compound action potential (ECAP) measurements are commonly used to verify nerve function by stimulating one electrode contact in the cochlea and recording the resulting action potentials on the other contacts of the electrode array. The present study aimed to determine if the ECAP amplitude differs between the apical, middle, and basal region of the cochlea, if double peak potentials were more likely in the apex than the basal region of the cochlea, and if there were differences in the ECAP threshold and recovery function across the cochlea. ECAP measurements were performed in the apical, middle, and basal region of the cochlea at fixed sites of stimulation with varying recording electrodes. One hundred and forty one adult subjects with severe to profound sensorineural hearing loss fitted with a Standard or FLEXSOFT electrode were included in this study. ECAP responses were captured using MAESTRO System Software (MED-EL). The ECAP amplitude, threshold, and slope were determined using amplitude growth sequences. The 50% recovery rate was assessed using independent single sequences that have two stimulation pulses (a masker and a probe pulse) separated by a variable inter-pulse interval. For all recordings, ECAP peaks were annotated semi-automatically. ECAP amplitudes were greater upon stimulation of the apical region compared to the basal region of the cochlea. ECAP slopes were steeper in the apical region compared to the basal region of the cochlea and ECAP thresholds were lower in the middle region compared to the basal region of the cochlea. The incidence of double peaks was greater upon stimulation of the apical region compared to the basal region of the cochlea. This data indicates that the site and intensity of cochlear stimulation affect ECAP properties.

Improvement of sound source localization abilities in patients bilaterally supplied with active middle ear implants.

CONCLUSIONS: Patients, who are bilaterally supplied with active middle ear implants, perform slightly better in sound localization tasks than when unilaterally aided or unaided. OBJECTIVES: To investigate the impact of bilateral use of active middle ear implants on sound source localization in the horizontal plane in patients with a sloping moderate-to-severe hearing loss. METHODS: Ten adults supplied with Med-EL Vibrant Soundbridge systems (VSB) in both ears participated in the study. Four listening conditions were tested: unaided, aided with VSB on left or right ear and on both sides. In each condition the subjects had to judge the direction of broadband noises delivered randomly across a semicircular array of 11 loudspeakers arranged in an anechoic chamber. RESULTS: When unaided or bilaterally aided, the subjects localized on average 40% of the stimuli correct; when unilaterally aided (left or right), this rate dropped to 20-30% in either condition. Precision of sound localization was highest when bilaterally aided, i.e. the mean RMS angular error was 10°, and lowest when unilaterally aided, i.e. 15°. This is in line with bilateral hearing aid users, who show similar performance in sound localization tasks.

Quality standards for bone conduction implants.

CONCLUSION: Bone conduction implants are useful in patients with conductive and mixed hearing loss for whom conventional surgery or hearing aids are no longer an option. They may also be used in patients affected by single-sided deafness. OBJECTIVES: To establish a consensus on the quality standards required for centers willing to create a bone conduction implant program. METHOD: To ensure a consistently high level of service and to provide patients with the best possible solution the members of the HEARRING network have established a set of quality standards for bone conduction implants. These standards constitute a realistic minimum attainable by all implant clinics and should be employed alongside current best practice guidelines. RESULTS: Fifteen items are thoroughly analyzed. They include team structure, accommodation and clinical facilities, selection criteria, evaluation process, complete preoperative and surgical information, postoperative fitting and assessment, follow-up, device failure, clinical management, transfer of care and patient complaints.

Results from high-frequency hearing screening in 14- to 15-year old adolescents and their relation to self-reported exposure to loud music.

OBJECTIVE: Data from high-frequency hearing screening in adolescent students were analysed to investigate whether practices of listening to loud music are reflected in the hearing status of young people. DESIGN: Students were screened for their hearing at frequencies 2, 4, and 6 kHz and at a level of 20 dB HL. Failure of the screening was defined by missing at least one frequency in one ear. In addition to hearing screening, the students filled out a questionnaire asking for practices related to exposure to loud music. STUDY SAMPLE: 1296 adolescents aged 14 to 15 years. RESULTS: The overall rate of failing the hearing screening was 14.9% (95% CI: 13.0%-16.8%). The rate was similar in adolescents with no, little, or moderate exposure to loud music (10% to 15%), but significantly increased (22% to 25%) in adolescents with high exposure. CONCLUSIONS: The observed failing rate compares well to findings on the prevalence of hearing deficits in adolescents reported in other studies. In addition, our study suggests that the risk for hearing damage from loud music is not steadily increasing with increase of exposure, but exists only under conditions of extreme listening.

18F-FET PET/CT in advanced head and neck squamous cell carcinoma: an intra-individual comparison with 18F-FDG PET/CT.

PURPOSE: To assess the diagnostic value of O-2-fluoro-18(F)-ethyl-L-tyrosine ((18)F-FET) positron emission tomography/computed tomography (PET/CT) for patients with advanced head and neck squamous cell carcinoma compared with 18F-fluoro-2-deoxy-D-glucose ((18)F-FDG) PET/CT at initial staging and following radiochemotherapy. PROCEDURES: Thirteen patients were prospectively enrolled; each of them underwent an (18)F-FDG PET/CT and (18)F-FET PET/CT before treatment. Ten of those were scanned 10 weeks after treatment. RESULTS: Sensitivity, specificity, and accuracy for (18)F-FDG PET/CT (primary and lymph node metastases) at initial staging were 89%, 50%, and 81%. For (18)F-FET PET/CT the numbers were 70%, 90%, and 74%. Sensitivity, specificity, and accuracy for (18)F-FDG PET/CT at follow-up were 71%, 65%, and 67%. For (18)F-FET PET/CT the numbers were 29%, 100%, and 83%. Additionally, (18)F-FDG PET/CT detected a higher number of second malignancies or distant metastases. CONCLUSIONS: (18)F-FET is no substitute for (18)F-FDG. Although it is more specific, too many malignant lesions are missed due to its lower sensitivity.

Murine malaria is associated with significant hearing impairment.

BACKGROUND: Plasmodium falciparum malaria has been suspected to cause hearing loss. Developmental, cognitive and language disorders have been observed in children, surviving cerebral malaria. This prospective study aims to evaluate whether malaria influences hearing in mice. METHODS: Twenty mice were included in a standardized murine cerebral malaria model. Auditory evoked brainstem responses were assessed before infection and at the peak of the illness. RESULTS: A significant hearing impairment could be demonstrated in mice with malaria, especially the cerebral form. The control group did not show any alterations. No therapy was used. CONCLUSION: This suggests that malaria itself leads to a hearing impairment in mice.

Acute otitis externa: efficacy and tolerability of N-chlorotaurine, a novel endogenous antiseptic agent.

OBJECTIVE: The study's objective was to test the tolerability and efficacy of the endogenous antiseptic N-chlorotaurine (NCT) in comparison with a standard clinical treatment according to a phase IIb clinical trial protocol. STUDY DESIGN: The antimicrobial agent NCT was compared with the antibiotic component drops Otosporin (containing neomycin, polymyxin B, and hydrocortisone) for topical treatment of acute otitis externa in a randomized and rater-blinded clinical study. METHODS: Fifty patients suffering from acute otitis externa were divided into two groups according to a randomized list. The test group was treated with 1 mL of 1% aqueous NCT solution, the reference group with 1 mL of Otosporin. The substances were applied to the external ear canal at one daily session until the signs of infection disappeared. Efficacy and tolerability were evaluated daily by visual analogue scale and a six-step infection score. In addition, smears were analyzed to identify the causative pathogens. RESULTS: Both medications were equally well tolerated by the patients. The treatment was successful for all patients of the NCT group, whereas in one patient from the reference group, the infection did not disappear. The inflammation score improved more rapidly in the NCT group, which resulted in an earlier termination of the therapy. This difference became highly significant on days 4 to 7 (P <.01 each). Time needed for disappearance of inflammation (score 0) was 5.6 +/- 1.6 (mean +/- SD, range 3-9) days in the NCT group and 7.4 +/- 1.6 (range 4-10) days in the Otosporin group (P <.001). As expected, microbiologic cultures from ear swabs revealed Pseudomonas aeruginosa (58%) followed by Staphylococcus aureus (18%) as the main causative pathogens. CONCLUSIONS: NCT appears to be well tolerated and more effective than the therapy using antibiotic component drops. Because of its endogenous nature and its higher efficacy, NCT appears to be a good choice for topical treatment of acute otitis externa.