Evaluation of an impedance-based method to monitor the insertion of the electrode array during cochlear implantation.

PURPOSE: Cochlear implantation is a prevalent remedy for severe-to-profound hearing loss. Optimising outcomes and hearing preservation, and minimising insertion trauma, require precise electrode placement. Objective monitoring during the insertion process can provide valuable insights and enhance surgical precision. This study assesses the feasibility and performance of an impedance-based method for monitoring electrode insertion, compared to the surgeon's feedback. METHODS: The study utilised the Insertion Monitoring Tool (IMT) research software, allowing for real-time measurement of impedance and evoked compound action potential (eCAP) during electrode insertion in 20 patient implantations. This enabled an impedance-based method to continuously assess the status of each electrode during the insertion process. The feasibility and performance was evaluated and compared to the surgeon's feedback approach. eCAP measurements focused merely on feasibility without searching specific responses. RESULTS: The IMT demonstrated feasibility in measuring real-time impedances and eCAP during the insertion of the electrode array. The impedance-based method exhibited potential for accurately monitoring the insertion depth with a high success rate. However, further development is needed to improve the number of usable contacts. CONCLUSIONS: Objective monitoring with the impedance-based method shows promise as a valuable tool to enhance the precision of cochlear implant electrode insertion respecting insertion distance estimation. The IMT research software proved feasible in recording real-time impedances and eCAP during electrode insertion. While this impedance-based method exhibits high success rates, further improvements are required to optimise the number of usable contacts. This study highlights the potential of objective monitoring techniques to enhance cochlear implantation outcomes.

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.

The influence of intraoperative auditory brainstem responses on vibroplasty coupling-quality and analysis of the impact of different fixation steps on the coupling.

PURPOSE: The Vibrant Soundbridge (VSB) is an established active-middle-ear-implant for patients with moderate-to-profound hearing-loss. This surgery is referred to as "Vibroplasty". Sufficient transfer of the VSB's floating-mass-transducers (FMT) energy to the inner ear is a crucial factor influencing the coupling-quality (CQ). However, assessing CQ is hamper by two issues: the method of CQ-assessment itself and the method of FMT-fixation during Vibroplasty. METHODS: This prospective study explored the influence of intraoperative auditory-brainstem-response (+ ABR) measurements and various fixation methods on postoperative CQ after Vibroplasty as compared to matched-patients after Vibroplasty without intraoperative ABR (-ABR). Propensity-score-matching was performed based on preoperative bone-conduction-pure-tone-average-3 (BC-PTA3) at 1-, 2- and 4 kHz. Primary outcome parameters were postoperative CQ-PTA3, intraoperative ABR threshold for various fixation methods and postoperative BC-PTA3. RESULTS: A total of 28 patients were included, of which 14 were + ABR. Preoperative BC-PTA3, sex, age, and number of previous surgeries did not differ significantly between groups (all p > 0.301). Mean postoperative CQ-PTA3 was significantly better for + ABR (1.8 vs. 12.3 dB-HL; p = 0.006). Mean intraoperative ABR threshold was superior for cartilage-counter-bearing and cartilage-housing compared to additional fixation with injectable-platelet-rich- fibrin (53 vs. 56 & 57 dB-HL, respectively; p = 0.04; η2 = 0.33). Mean postoperative BC-PTA3 did not significantly differ between patients (41.4 vs. 41.8 dB-HL; p = 0.77). A total of 7% of the patients required intraoperative readjustment of the FMT based on unsatisfactory intraoperative ABR threshold. CONCLUSION: Intraoperative ABR measurement resulted in significantly better postoperative CQ. Cartilage-counter-bearing and cartilage-housing were observed to have superior CQ. A total of 7% of the patients could be spared revision-Vibroplasty due to intraoperative ABR measurement.

Stapedius reflex thresholds obtained in a free sound field as an indicator for over- and understimulation in cochlear implant listeners.

OBJECTIVE: The goal of this study was to determine open field stapedius reflex thresholds (oSRTs) in CI patients with fittings based on subjective loudness ratings. A further objective was to compare these oSRTs and those of eSRT-based fittings that are similar to the oSRTs of normal hearing. DESIGN: Impedance measurements of the ear drum were taken while subjects were wearing their audio processors. The stapedius reflex was elicited by electrical stimulation transmitted through the activated CI system in response to an acoustic stimulus presented in the free sound field. STUDY SAMPLE: Subjects were 50 experienced CI users (n = 57 ears) with CI fittings based on subjective loudness scaling. RESULTS: A reference range for the oSRTs was defined that was identified in CI patients with eSRT-based fittings. Sound levels for stapedius reflex detection were inside the reference target range in 70% of the cases, below the reference range (i.e. down to 40 dB HL) in 20% of the cases, and above the reference range in 10% of the cases. CONCLUSION: Stapedius reflex detection in a free sound field may help detect fittings with too high or too low stimulation levels that might reduce audiological performance.

Improving Spatial Hearing when Wearing Ski Helmets in Order to Increase Safety on Ski Slopes.

This study investigated the effect of a new type of ear pads for ski helmets on the hearing performance of 13 young adults (mean age: 22 years). Free-field hearing thresholds and sound localization performance of the subjects were assessed in three conditions: without helmet, with a conventional helmet and with the modified helmet. Results showed that the modified helmet was superior to the conventional helmet in all respects, but did not allow for a performance level observed without a helmet. Considering the importance of precise hearing and sound localization during alpine skiing, acoustically improved ear pads of ski helmets, as demonstrated in this study, can essentially contribute to enhancing the safety on ski slopes.

Modified Power Piston Versus Simultaneous Stapedotomy With Hearing Aids in Otosclerosis: A Follow-Up Study Exploring Speech Recognition, Quality of Life and Usage of Device.

OBJECTIVE: To compare audiologic outcomes, quality-of-life (QoL) and usage-of-device (UoD) between case-matched, otosclerotic patients with mixed hearing loss (MHL) which received (a) stapedotomy and postoperative amplification with hearing aids (SDT+HA) or (b) short-incudial process coupled active middle ear implant with simultaneous stapedotomy (mPP). STUDY DESIGN, SETTING, AND PATIENTS: Prospective, matched case-control, follow-up study conducted at two tertiary otologic referral centers. Eligible were all otosclerotic patients with MHL, which received mPP at either of the two institutions. A case-matched-cohort of SDT+HA-patients was generated from the hospitals database based on preoperative audiologic findings. MAIN OUTCOME MEASURES: For sound- and speech perception, primary outcome parameters were the mean postoperative, aided air-conduction pure tone average (mpa-AC-PTA) and word recognition score at 80 dB speech level (mpa-WRS), for QoL the mean Nijmegen-Cochlear-Implant-Questionnaire (NCIQ) total-score, and for UoD the mean score rated on a 10-point Likert-scale. RESULTS: A total of 28 patients were included; 14 received mPP; mpa-AC-PTA and mpa-WRS significantly improved from 47.1 dB-HL to 34.3 dB-HL (-12.8 dB-HL; p < 0.001) and from 75.0% to 93.2% (+18.2%; p = 0.002) compared to 46.5 dB-HL to 31.9 dB-HL (-14.8 dB-HL; p < 0.008) and 75.0% to 93.2% (+18.2%; p = 0.002) for SDT+HA. No significant difference between groups was observed (all p > 0.1). NCIQ total-score between groups did not significantly differ (70.4 vs. 69.9; p = 0.93). UoD for mPP was significantly higher (6.1 vs. 3.0; p < 0.001). CONCLUSIONS: If medical/technical problems prevent usage of HA in otosclerosis with MHL, mPP can be considered as effective treatment option with similar audiological outcome and QoL. A significantly higher UoD for mPP was observed.

Cost-utility Analysis of Cochlear Implantation in Adults With Single-sided Deafness: Austrian and German Perspective.

BACKGROUND: Single-sided deafness (SSD) is associated with a loss of binaural hearing. Major limitations of such patients are poor speech understanding in noisy environments and a lack of spatial hearing. To date, cochlear implantation is the most promising approach to overcome these deficits in this group of patients. OBJECTIVE: Cost-effectiveness analyses of cochlear implantation in patients with unilateral deafness. The model targets Austrian and German SSD patients who can either opt for treatment with a cochlear implant (CI) or decide against a CI and stay without any treatment. METHODS: A Markov model analyzed as microsimulation was developed using TreeAge Pro 2019 software. Pre- and postoperative utility values generated with HUI-3 were used to populate the model. Costs covered by the national insurance were considered. Costs and utilities were discounted by 3%. A model time horizon of 20 years was set. RESULTS: According to Austrian base-case analysis, the incremental cost-utility ratio (ICUR) was €34845.2 per quality-adjusted life year gained when comparing the "CI strategy" to the "no treatment strategy." The ICUR is marginally lower when adapting a German cost perspective-it was €31601.25 per quality-adjusted life year gained. Sensitivity analyses showed that the cost-effectiveness results are stable. Analyses also showed that the longer the time horizon is set, the more favorable the cost-effectiveness result is. CONCLUSIONS: Based on currently available data, the Markov microsimulation model suggests that cochlear implantation is cost-effective in Austrian and German patients with SSD if no other treatment option is considered within the model.

Stapedius reflex evoked in free sound field in cochlear implant users compared to normal-hearing listeners.

OBJECTIVE: To determine the relation between stapedius reflex thresholds in cochlear implant users evoked once through direct electric stimulation on single channels (ESRT) and once through acoustic stimulation in free sound field. For comparison, stapedius reflex thresholds were obtained in free sound field in a normal-hearing control group. DESIGN: For each participant a new ESRT-based fitting was created. Stapedius reflex thresholds were obtained for this new fitting in free sound field for different loudness adjustments. Acoustic stimuli for eliciting the stapedius reflex were narrow band noise signals covering the audiometric frequency range. STUDY SAMPLE: N = 29 experienced CI users (34 ears) and N = 10 normal hearing listeners. RESULTS: ESRT-based fitting resulted in different stapedius reflex behaviour compared to normal-hearing listeners. A frequency dependence was observed. Stapedius reflex thresholds decreased with increasing centre frequencies of acoustic narrow band noise stimuli. A linear relation between upper stimulation levels on the implant channels and corresponding stapedius reflex thresholds evoked in free sound field was found. CONCLUSION: The found correlation may be a guideline for adjusting the electrical dynamic range during cochlear implant fitting. This allows the implant system to mimic the natural reflex behaviour in the best possible way and potentially avoid overstimulation.

Does Cochlear Implantation Affect Openness-to-Experience in Profound Postlingual Hearing Loss?

Recent studies suggest that hearing loss in postlingually deafened adults may be associated with lowered levels of the personality factor Openness to experience. This study investigated whether cochlear implantation in postlingually deafened adults raises the level of Openness to experience. Fifty-five postlingually deafened adults (mean age: 63 years) were assessed with the Neuroticism-Extraversion-Openness-Five-Factor-Inventory (NEO-FFI), a questionnaire capturing the five personality factors Extraversion, Openness to experience, Neuroticism, Agreeableness, and Conscientiousness. Personality assessment occurred before cochlear implantation and 24 months after implant activation. On factors Extraversion, Neuroticism, Agreeableness, and Conscientiousness the mean scores of the sample were equal to population norms, both before and after cochlear implantation. On factor Openness to experience, the mean score was significantly lower before cochlear implantation, and remained so thereafter. Openness to experience may be reduced in some groups of deaf or hard of hearing persons. Cochlear implantation had no effect on any personality factor, at least not after two years of implant use.

Subjective Hearing Impression and Quality of Life in Patients With Bilateral Active Middle Ear Implants.

OBJECTIVE: This study compared the quality of life in patients with bilateral active middle ear implants to their quality of life when they were unilaterally implanted. DESIGN: Twenty-one patients implanted sequentially with the Vibrant Soundbridge (VSB) active middle ear implant completed quality-of-life surveys. The patients were asked to rate whether and to what extent their quality of life has changed upon receiving a second VSB. Hearing-specific quality of life was assessed with the Speech, Spatial, and Qualities of Hearing Scale (SSQ12-B), and general quality of life was with the Glasgow Benefit Inventory (GBI). In addition, the patients completed a health-related quality-of-life questionnaire (AQoL-8D). Finally, the changes in hearing-related and general quality of life were correlated to the change in word recognition ability after implantation of the second VSB (Freiburg monosyllabic word test; unilateral VSB versus bilateral VSB at 65 dB SPL). RESULTS: On the SSQ12, subjects scored a median of + 2.73 (p < 0.001; significantly different from zero) on a scale of -5 to + 5 where 0 indicates no change. All three subscores showed significant improvement. On the GBI, patients reached a median overall score of + 23.6 (p < 0.001; significantly different from zero) on a scale of -100 to + 100 where 0 indicates no change. Here, the improvement was mainly visible in the general subscore, whereas the social support and physical health subscores did not change due to the intervention. Both subjective benefit rating scores strongly correlated with the change in word recognition scores, suggesting that both hearing and general quality of life improved with increased word recognition due to bilateral VSB use. No significant correlation was found between the subjects' general health (as measured by AQoL-8D utility scores) and SSQ12-B or GBI overall scores. CONCLUSION: Usage of a second active middle ear implant substantially improved our patients' subjective hearing and general quality of life compared with unilateral use. The increase in quality of life may be linked to improved speech understanding due to bilateral use of a middle ear implant. Furthermore, these outcomes were not influenced by our patients' general health state at the time of survey.

How the Brain Understands Spoken and Sung Sentences.

The present study investigates whether meaning is similarly extracted from spoken and sung sentences. For this purpose, subjects listened to semantically correct and incorrect sentences while performing a correctness judgement task. In order to examine underlying neural mechanisms, a multi-methodological approach was chosen combining two neuroscientific methods with behavioral data. In particular, fast dynamic changes reflected in the semantically associated N400 component of the electroencephalography (EEG) were simultaneously assessed with the topographically more fine-grained vascular signals acquired by the functional near-infrared spectroscopy (fNIRS). EEG results revealed a larger N400 for incorrect compared to correct sentences in both spoken and sung sentences. However, the N400 was delayed for sung sentences, potentially due to the longer sentence duration. fNIRS results revealed larger activations for spoken compared to sung sentences irrespective of semantic correctness at predominantly left-hemispheric areas, potentially suggesting a greater familiarity with spoken material. Furthermore, the fNIRS revealed a widespread activation for correct compared to incorrect sentences irrespective of modality, potentially indicating a successful processing of sentence meaning. The combined results indicate similar semantic processing in speech and song.

Cochlear implantation in adults with single-sided deafness: generic and disease-specific long-term quality of life.

PURPOSE: To determine the 2-year outcome of health-related quality of life (HRQoL) in adults who received a cochlear implant (CI) for single-sided deafness (SSD). METHODS: Twenty adults (mean age at implantation: 47 ± 11 years) with SSD (PTA worse ear: 113 dB HL, PTA better ear: 14 dB HL) were administered the Nijmegen Cochlear Implant Questionnaire (NCIQ), and the Health Utility Index 3 (HUI 3). Questionnaire administration occurred before cochlear implantation and 3, 6, 12, and 24 months after implant activation. RESULTS: Of the 20 patients, 2 discontinued CI use within the observation period due to poor benefit. The NCIQ total score of the sample increased significantly over time (p = 0.003). The largest increase occurred within the first 3 months of CI use. Also, the HUI 3 multi-attribute utility score increased significantly (p = 0.03). The post-treatment increase of this score (+ 0.11 points) indicated that the gain in HRQoL was clinically relevant. Patients with a duration of deafness > 10 years had in all measures an equal HRQoL improvement than had patients with a duration of deafness < 10 years. CONCLUSION: Cochlear implantation led to significant improvement of hearing-specific and generic HRQoL in our patients. The improvement was seen after 3 or 6 months but did not increase further at later intervals. Patients with long-lasting SSD may be at higher risk of discontinuing CI use. However, if they adapt to the CI, they can experience an equal increase of HRQoL as patients with a short duration of SSD.

How Therapeutic Tapping Can Alter Neural Correlates of Emotional Prosody Processing in Anxiety.

Anxiety disorders are the most common psychological disorders worldwide resulting in a great demand of adequate and cost-effective treatment. New short-term interventions can be used as an effective adjunct or alternative to pharmaco- and psychotherapy. One of these approaches is therapeutic tapping. It combines somatic stimulation of acupressure points with elements from Cognitive Behavioral Therapy (CBT). Tapping reduces anxiety symptoms after only one session. Anxiety is associated with a deficient emotion regulation for threatening stimuli. These deficits are compensated e.g., by CBT. Whether Tapping can also elicit similar modulations and which dynamic neural correlates are affected was subject to this study. Anxiety patients were assessed listening to pseudowords with a different emotional prosody (happy, angry, fearful, and neutral) prior and after one Tapping session. The emotion-related component Late Positive Potential (LPP) was investigated via electroencephalography. Progressive Muscle Relaxation (PMR) served as control intervention. Results showed LPP reductions for negative stimuli after the interventions. Interestingly, PMR influenced fearful and Tapping altered angry prosody. While PMR generally reduced arousal for fearful prosody, Tapping specifically affected fear-eliciting, angry stimuli, and might thus be able to reduce anxiety symptoms. Findings highlight the efficacy of Tapping and its impact on neural correlates of emotion regulation.

Impact of listening to music while wearing a ski helmet on sound source localization.

OBJECTIVES: In recreational skiing and snowboarding, listening to music may be associated with an increased injury risk due to impaired sound localization. Thus, we evaluated effects of listening to music at different sound levels on sound source localization while wearing a ski helmet. DESIGN: within-subjects design. METHOD: Sound source localization of 20 participants (50% females; age: 23.8±2.4years) was assessed in an anechoic chamber under six conditions: (1) head bare, (2) wearing a ski helmet, (3) wearing a ski helmet and insert ear phones, and (4-6) the latter and listening to music at 3 different sound levels of 45, 55, and 65dB sound pressure level (SPL), respectively. RESULTS: One-way repeated measures ANOVA show that the percentage of correct sound localization was significantly affected by various conditions: F (5, 95)=138.2, p<.001 (ƞ2=0.88). Compared to the situation "head bare" with a correct score of 88%, increasing music sound levels of 45, 55 and 65dB SPL significantly decreased the ability to correctly localize the sound source to 54%, 45% and 37% correct scores, respectively. Also, angular errors [F (5, 95)=31.0, p<.001, ƞ2=0.62] and front rear confusion [F (2.8, 53.4)=57.9, p<.001, ƞ2=0.75] were significantly affected by wearing a ski helmet and listening to music simultaneously. CONCLUSIONS: Listening to music while wearing a ski helmet impacts negatively on sound source localization. The extent of worsening strongly depends on the sound level.

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.

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.

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.