Introduction Various factors, including an aging population and expanding eligibility criteria, may increase the demand for cochlear implants (CIs), potentially resulting in longer waiting times.... Show moreIntroduction Various factors, including an aging population and expanding eligibility criteria, may increase the demand for cochlear implants (CIs), potentially resulting in longer waiting times. In most Dutch CI centers, the time between referral and surgery exceeds 6 months. Clinical experience suggests that during the waiting period for cochlear implantation, hearing and communication difficulties increase. Simultaneously, there is an interest in outcomes more closely aligned with patient values and needs, which resulted in the SMILE (Societal Merit of Interventions on hearing Loss Evaluation) study. This paper presents results on observed changes in societal and participatory outcomes during waiting time in participants with a time to CI surgery exceeding 6 months. Methods SMILE is a prospective multi-center study including 232 individuals who were referred for unilateral CI. Continuous and nominal data from multiple questionnaires, sent immediately after referral and shortly before surgery, were analyzed by computing differences, Cohen’s D, and odds ratios. Results Of the total 232 participants, 102 had a time between inclusion and surgery exceeding 6 months. Of these, 89 had (partially) filled out surveys at both time points. Of all the domain scores 55% did not show differences between timepoints. All Cohen’s D estimates were relatively small, ranging from −0.298 to 0.388 for those outcomes that showed noteworthy changes. Conclusion Waiting time from referral to surgery, even though exceeding 6 months, was observed to not seriously affect non-clinically-prioritized patients in an adverse way. Future investigations should identify subgroups on tolerable waiting times regarding short- and long-term outcomes. Show less
Background The spiral ganglion hypothesis suggests that pathogenic variants in genes preferentially expressed in the spiral ganglion nerves (SGN), may lead to poor cochlear implant (CI) performance... Show moreBackground The spiral ganglion hypothesis suggests that pathogenic variants in genes preferentially expressed in the spiral ganglion nerves (SGN), may lead to poor cochlear implant (CI) performance. It was long thought that TMPRSS3 was particularly expressed in the SGNs. However, this is not in line with recent reviews evaluating CI performance in subjects with TMPRSS3-associated sensorineural hearing loss (SNHL) reporting overall beneficial outcomes. These outcomes are, however, based on variable follow-up times of, in general, 1 year or less. Therefore, we aimed to 1. evaluate long-term outcomes after CI implantation of speech recognition in quiet in subjects with TMPRSS3-associated SNHL, and 2. test the spiral ganglion hypothesis using the TMPRSS3-group. Methods This retrospective, multicentre study evaluated long-term CI performance in a Dutch population with TMPRSS3-associated SNHL. The phoneme scores at 70 dB with CI in the TMPRSS3-group were compared to a control group of fully genotyped cochlear implant users with post-lingual SNHL without genes affecting the SGN, or severe anatomical inner ear malformations. CI-recipients with a phoneme score <= 70% at least 1-year post-implantation were considered poor performers and were evaluated in more detail. Results The TMPRSS3 group consisted of 29 subjects (N = 33 ears), and the control group of 62 subjects (N = 67 ears). For the TMPRSS3-group, we found an average phoneme score of 89% after 5 years, which remained stable up to 10 years post-implantation. At both 5 and 10-year follow-up, no difference was found in speech recognition in quiet between both groups (p = 0.830 and p = 0.987, respectively). Despite these overall adequate CI outcomes, six CI recipients had a phoneme score of <= 70% and were considered poor performers. The latter was observed in subjects with residual hearing post-implantation or older age at implantation. Conclusion Subjects with TMPRSS3-associated SNHL have adequate and stable long-term outcomes after cochlear implantation, equal to the performance of genotyped patient with affected genes not expressed in the SGN. These findings are not in line with the spiral ganglion hypothesis. However, more recent studies showed that TMPRSS3 is mainly expressed in the hair cells with only limited SGN expression. Therefore, we cannot confirm nor refute the spiral ganglion hypothesis. Show less
Hypothesis: Insertion speed during cochlear implantation determines the risk of cochlear trauma. By slowing down insertion speed tactile feedback is improved. This is highly conducive to control... Show moreHypothesis: Insertion speed during cochlear implantation determines the risk of cochlear trauma. By slowing down insertion speed tactile feedback is improved. This is highly conducive to control the course of the electrode array along the cochlear contour and prevent translocation from the scala tympani to the scala vestibuli. Background: Limiting insertion trauma is a dedicated goal in cochlear implantation to maintain the most favorable situation for electrical stimulation of the remaining stimulable neural components of the cochlea. Surgical technique is one of the potential influencers on translocation behavior of the electrode array. Methods: The intrascalar position of 226 patients, all implanted with a precurved electrode array, aiming a mid-scalar position, was evaluated. One group (n = 113) represented implantation with an insertion time less than 25 seconds (fast insertion) and the other group (n = 113) was implanted in 25 or more seconds (slow insertion). A logistic regression analysis studied the effect of insertion speed on insertion trauma, controlled for surgical approach, cochlear size, and angular insertion depth. Furthermore, the effect of translocation on speech performance was evaluated using a linear mixed model. Results: The translocation rate within the fast and slow insertion groups were respectively 27 and 10%. A logistic regression analysis showed that the odds of dislocation increases by 2.527 times with a fast insertion, controlled for surgical approach, cochlear size, and angular insertion depth (95% CI = 1.135, 5.625). We failed to find a difference in speech recognition between patients with and without translocated electrode arrays. Conclusion: Slowing down insertion speed till 25 seconds or longer reduces the incidence of translocation. Show less
Purpose The aim of this study was to evaluate the intracochlear position of the Slim Modiolar Electrode (SME) after insertion via the extended Round Window (eRW) approach, and to correlate this... Show morePurpose The aim of this study was to evaluate the intracochlear position of the Slim Modiolar Electrode (SME) after insertion via the extended Round Window (eRW) approach, and to correlate this with residual hearing preservation and speech perception outcomes. Methods Twenty-three adult participants, consecutively implanted with the SME via the eRW approach, were included in this prospective, single-center, observational study. Electrode position was evaluated intra-operatively using X-ray fluoroscopy and TIM measurement, and post-operatively using ultra-high resolution CT. Residual hearing [threshold shift in PTA between pre- and post-operative measurement, relative hearing preservation (RHP%)] and speech perception were evaluated at 2 and 12 months after surgery. Results In each of the 23 participants, complete scala tympani positioning of the electrode array could be achieved. In one participant, an initial tip fold-over was corrected during surgery. Average age at implantation was 63.3 years (SD 13.3, range 28-76) and mean preoperative residual hearing was 81.5 dB. The average post-operative PTA threshold shift was 16.2 dB (SD 10.8) at 2 months post-operatively, corresponding with a RHP% score of 44% (SD 34.9). At 12 months, the average RHP% score decreased to 37%. Postoperative phoneme scores improved from 27.1% preoperatively, to 72.1% and 82.1% at 2 and 12 months after surgery, respectively. Conclusion Use of the eRW approach results in an increased likelihood of complete scala tympani insertion when inserting the SME, with subsequent excellent levels of speech perception. However, residual hearing preservation was found to be moderate, possibly as a result of the extended round window approach, emphasizing that it is not an all-purpose approach for inserting this particular electrode array. Show less
In this thesis cochlear morphology and the intra-cochlear position of cochlear implant electrode arrays is being studied. Gaining insight in the variance of cochlear morphology allows to study the... Show moreIn this thesis cochlear morphology and the intra-cochlear position of cochlear implant electrode arrays is being studied. Gaining insight in the variance of cochlear morphology allows to study the effect of morphological characteristics on surgical and speech perception outcomes following cochlear implantation. Furthermore, evaluating the intra-cochlear position of cochlear implant electrode arrays contributes to the search for the optimal position of the array in terms of speech perception outcomes. Show less
Today, many deaf children can be given access to oral language thanks to a cochlear implant, a surgically implanted electronic device that provides a sense of sound thanks to electric stimulation... Show moreToday, many deaf children can be given access to oral language thanks to a cochlear implant, a surgically implanted electronic device that provides a sense of sound thanks to electric stimulation of the auditory nerve. In this study, the acquisition of personal pronouns is considered to be a measure for the effectiveness of cochlear implantation in congenitally deaf children. Pronouns are morphemes with low perceptual prominence. They are semantically complex and lack morphophonological regularity. Building on these insights, the acquisition of pronouns is quite a challenge for hearing-impaired children. The goal of this study is to examine whether a cochlear implant provides deaf children with sufficient auditory input to acquire low salient and complex functional items like personal pronouns and to compare the results to those obtained in hearing peers. Different developmental steps in pronoun acquisition have been examined including the building of the pronominal paradigm and its morphological attributes and the acquisition of co-referring and binding relations between pronouns and their antecedents. The results show that although cochlear-implanted children start out with a delay in the acquisition of pronouns, they are able to partially catch up with their hearing peers during the later stages. By the age of seven, most cochlear-implanted children have attained a target production and comprehension of pronouns. Based on these results, cochlear implantation below 24 months may be considered to be an effective way to provide pre-lingual deaf children with the necessary sensory input to acquire pronouns despite their initial deprivation of spoken language input. Show less
Cochlear implants (CIs) are a well accepted treatment for hearing impaired people. In pre- and postoperative assessment of CI-candidates imaging plays an important role to analyze anatomy, rule out... Show moreCochlear implants (CIs) are a well accepted treatment for hearing impaired people. In pre- and postoperative assessment of CI-candidates imaging plays an important role to analyze anatomy, rule out pathology and determine intracochlear positioning and integrity of the implant. Developments in CI-design, differences in surgical approach and broadening of treatment indications have raised new questions to radiologists, which were the subject of several studies described in this thesis. For optimal, a-traumatic positioning of a CI precise information about the inner ear anatomy is mandatory. We describe the development, validation and application of a method for 3-dimensional medical image exploration of the inner ear. This renders a tool to obtain cochlear dimensions on clinical computer tomography (CT) images. This will be useful for patientspecific implantplanning. It also shows an anatomical substrate for cochlear trauma during insertion. For postoperative imaging we studied the value of multislice-CT for optimal visualization of the implant within the cochlea. Its role to evaluate operation technique and electrode design, to study frequency mapping and to assess cochlear trauma is discussed. Moreover an international consensus for an objective cochlear framework is presented, forming a common ground for clear and easy exchange of findings in scientific and clinical studies. Show less
