Cochlear-facial dehiscence - the most common cause of facial nerve stimulation from a cochlear implant? A case-control study.

OBJECTIVES: To investigate the prevalence of cochlear-facial dehiscence (CFD) and other radiographical pathologies in ears with facial nerve stimulation (FNS) from a cochlear implant (CI). METHODS: Retrospective case-control study of 27 patients with CI and FNS on either ear (study group) and 27 patients without FNS, matched for age, sex and type of electrode array (control group). Preoperative CT scans of all 108 ears were re-evaluated. Subanalyses included comparisons between the study and control groups and associations between FNS and radiographic pathologies. RESULTS: CFDs were detected in 20 of 54 ears (37%) in the study group and in 3 of 54 ears (6%) in the control group (P < 0.001). The corresponding numbers of otosclerosis were 10 (18%) and 0 (P = 0.011) and of developmental anomalies 16 (30%) and 8 (15%) (not significant). FNS was present in 33 ears in the study group, of which 14 (42%) had a CFD. FNS was absent in six ears with CFD and CI, four of which contralateral to an ear with FNS. Eight of 14 ears with FNS and CFD had a lateral electrode array and six had a perimodiolar electrode array. We found no association between the presence of CFD and stimulation thresholds for FNS. The adjusted odds ratio for developing FNS in the presence of a CFD was 9.9 (95% CI 2.7-36.0). CONCLUSIONS: CFD was the most common radiographic pathology in ears with FNS, with a 10-fold increased risk of FNS. To avoid CI-related FNS, preoperative CT scan and awareness of typical dehiscence symptoms are strongly recommended.

Validation of the Norwegian Version of the Speech, Spatial and Qualities of Hearing Scale (SSQ).

INTRODUCTION: The main objective of the study was to validate the Norwegian translation of the Speech, Spatial and Qualities of Hearing Scale (SSQ) and investigate the SSQ disability profiles in a cochlear implant (CI) user population. METHODS: The study involved 152 adult CI users. The mean age at implantation was 55 (standard deviation [SD] = 16), and the mean CI experience was 5 years (SD = 4.8). The cohort was split into three groups depending on the hearing modality: bilateral CIs (BCIs), a unilateral CI (UCI), and bimodal (CI plus contralateral hearing aid; HCI). The SSQ disability profiles of each group were compared with those observed in similar studies using the English version and other translations of the SSQ. Standard values, internal consistency, sensitivity, and floor and ceiling effects were investigated, and the missing-response rates to specific questions were calculated. Relationships to speech perception were measured using monosyllabic word scores and the Norwegian Hearing in Noise Test scores. RESULTS: In the BCI group, the average scores were around 5.0 for the speech and spatial sections and 7.0 for the qualities section (SD ∼2). The average scores of the UCI and HCI groups were about one point lower than those of the BCI group. The SSQ disability profiles were comparable to the profiles in similar studies. The slopes of the linear regression lines measuring the relationships between the SSQ speech and monosyllabic word scores were 0.8 per 10% increase in the monosyllabic word score for the BCI group (explaining 35% of the variation) and 0.4 for the UCI and HCI groups (explaining 22-23% of the variation). CONCLUSION: The Norwegian version of the SSQ measures hearing disability similar to the original English version, and the internal consistency is good. Differences in the recipients' pre-implantation variables could explain some variations we observed in the SSQ responses, and such predictors should be investigated. Data aggregation will be possible using the SSQ as a routine clinical assessment in global CI populations. Moreover, pre-implantation variables should be systematically registered so that they can be used in mixed-effects models.

Long-Term Outcomes of Round Window Reinforcement for Superior Semicircular Canal Dehiscence Syndrome.

OBJECTIVE: To report long-term patient reported outcome measures (PROMs) after standardized round window rein-forcement (RWR) with thin cartilage and perichondrium for superior semicircular canal dehiscence syndrome (SSCDS). METHODS: Cross-sectional survey in 2020 and retrospective longitudinal study of outcomes at 3 months, 1 year, and last follow-up after 28 consecutive RWRs. Endpoints were the last follow-up for PROMs and 1 year postoperatively for audiometry and cVEMP. RESULTS: At the last follow-up (mean 2.4 years postoperatively), improvement was reported for 19/28 ears (68%) in symptoms overall; for 17/27 ears (63%) in auditory symptoms, and for 12/24 (50%) in vestibular symptoms. Nine ears (32%) required further surgery. No major complications occurred. On the group level, postoperative improvement at 3 months declined significantly for auditory and vestibular symptoms over time, and stayed stable beyond 1 year. Improved ears had on average 2.9 years follow-up. Improvement correlated significantly with SSCD length, and was associated with contralateral dehiscence. Thirteen ears (46%) had another potential cause of vestibular symptoms. This group showed significantly less improvement. Audiometric test results did not predict PROMs. CONCLUSIONS: Since long-term outcomes do not compare with those reported for plugging and repair, RWR is not suggested as a first line intervention for SSCDS. Considering the stable rates of improvement on average 2.9 years postoperatively and the absence of major complications, RWR may be an alternative to plugging or repair in fragile patients who do not accept the risk of complications with more invasive surgery, and who accept that results may deteriorate over time.

Effect of Proximity to the Modiolus for the Cochlear CI532 Slim Modiolar Electrode Array on Evoked Compound Action Potentials and Programming Levels.

BACKGROUND: The first surgeries with CI532 showed an effect of the proximity of the electrode to the modiolus on the Evoked Compound Action Potentials (ECAPs). OBJECTIVES: Objectives of the study were to investigate the effect of the "pullback" procedure on intraoperative ECAP responses in three different electrode array positions and additionally to compare behavioral thresholds with the thresholds obtained in a group of patients using the standard insertion. The hypothesis of this study is that pullback will cause lower ECAPs and behavioral thresholds. PATIENTS: The study included 40 patients, 20 in the pullback insertion group and 20 in the standard insertion group (without pullback). METHOD: During insertion of the CI532 electrode array, ECAP was performed in three different positions for the pullback group: at initial insertion, at over-insertion, and after pullback. Insertion was monitored by fluoroscopy. In the standard group, ECAP was performed at the initial position, which is also the final position. ECAP thresholds (T-ECAPs) were compared within subjects at the initial and the final position in the pullback group and between groups in the final positions of the pullback and standard groups. Programming levels (C- and T-levels) were compared between the two groups 1 year after switch-on. RESULTS: Intraoperative measurements pullback shows lower average T-ECAPs after pullback compared to thresholds in initial position. Comparison of intraoperative T-ECAPs at the final positions showed no statistically significant difference between the pullback group and the standard insertion group. Furthermore, 1 year after switch-on there was no statistically significant difference in C- and T-levels between the two groups. CONCLUSION: The pullback maneuver of the CI532 electrode array after an over-insertion gave significantly lower T-ECAPs compared to the thresholds at the initial position. However, the between-groups analysis of pullback and standard insertion showed neither significantly different T-ECAPs nor different programming levels. Because T-ECAPs and programming levels vary considerably between subjects, large groups are required to detect differences between groups. Additionally, the effect pullback technique to preserving the residual hearing is not known yet.

Sustained reduction of tinnitus several years after sequential cochlear implantation.

OBJECTIVE: This study aimed to explore the short- and long-term effects of a second cochlear implant (CI-2) on the reduction of tinnitus annoyance and tinnitus handicap. DESIGN: In a combined retrospective and prospective cohort study, tinnitus annoyance was measured before receiving the CI-2 (Pre), more than two years after (Post1) and more than seven years after (Post2), using the Tinnitus Handicap Inventory (THI), the Visual Analog Scale for the assessment of perceived tinnitus loudness (VAS-L) and annoyance (VAS-A), and a self-report questionnaire. STUDY SAMPLE: Twenty sequentially bilaterally implanted adults with bothersome tinnitus. RESULTS: CI-2 implantation resulted in a statistically significant reduction of tinnitus handicap from severe at Pre to mild at Post1 (THI mean score reduced from 61.3 [SD = 19.4] to 29.3 [SD = 23.5]). The reduction in tinnitus annoyance was statistically significant from Pre to Post 2 (VAS-A reduced from 7.1 [SD = 1.5] to 3.4 [SD = 2.2]). The reduction in tinnitus loudness was not statistically significant. CONCLUSIONS: The provision of a CI-2 for severely and profoundly hearing-impaired individuals with bothersome tinnitus is an effective method of providing long-term tinnitus relief.

Fusion of Technology in Cochlear Implantation Surgery: Investigation of Fluoroscopically Assisted Robotic Electrode Insertion.

The HEARO cochlear implantation surgery aims to replace the conventional wide mastoidectomy approach with a minimally invasive direct cochlear access. The main advantage of the HEARO access would be that the trajectory accommodates the optimal and individualized insertion parameters such as type of cochlear access and trajectory angles into the cochlea. To investigate the quality of electrode insertion with the HEARO procedure, the insertion process was inspected under fluoroscopy in 16 human cadaver temporal bones. Prior to the insertion, the robotic middle and inner ear access were performed through the HEARO procedures. The status of the insertion was analyzed on the post-operative image with Siemens Artis Pheno (Siemens AG, Munich, Germany). The completion of the full HEARO procedure, including the robotic inner ear access and fluoroscopy electrode insertion, was possible in all 16 cases. It was possible to insert the electrode in all 16 cases through the drilled tunnel. However, one case in which the full cochlea was not visible on the post-operative image for analysis was excluded. The post-operative analysis of the electrode insertion showed an average insertion angle of 507°, which is equivalent to 1.4 turns of the cochlea, and minimal and maximal insertion angles were recorded as 373° (1 cochlear turn) and 645° (1.8 cochlear turn), respectively. The fluoroscopy inspection indicated no sign of complications during the insertion.

Speech-in-Noise Perception in Children With Cochlear Implants, Hearing Aids, Developmental Language Disorder and Typical Development: The Effects of Linguistic and Cognitive Abilities.

Children with hearing loss, and those with language disorders, can have excellent speech recognition in quiet, but still experience unique challenges when listening to speech in noisy environments. However, little is known about how speech-in-noise (SiN) perception relates to individual differences in cognitive and linguistic abilities in these children. The present study used the Norwegian version of the Hearing in Noise Test (HINT) to investigate SiN perception in 175 children aged 5.5-12.9 years, including children with cochlear implants (CI, n = 64), hearing aids (HA, n = 37), developmental language disorder (DLD, n = 16) and typical development (TD, n = 58). Further, the study examined whether general language ability, verbal memory span, non-verbal IQ and speech perception of monosyllables and sentences in quiet were predictors of performance on the HINT. To allow comparisons across ages, scores derived from age-based norms were used for the HINT and the tests of language and cognition. There were significant differences in SiN perception between all the groups except between the HA and DLD groups, with the CI group requiring the highest signal-to-noise ratios (i.e., poorest performance) and the TD group requiring the lowest signal-to-noise ratios. For the full sample, language ability explained significant variance in HINT performance beyond speech perception in quiet. Follow-up analyses for the separate groups revealed that language ability was a significant predictor of HINT performance for children with CI, HA, and DLD, but not for children with TD. Memory span and IQ did not predict variance in SiN perception when language ability and speech perception in quiet were taken into account. The finding of a robust relation between SiN perception and general language skills in all three clinical groups call for further investigation into the mechanisms that underlie this association.

The impact of ethnicity on cochlear implantation in Norwegian children.

OBJECTIVES: To explore the impact of parental ethnicity on cochlear implantation in children in Norway with regard to incidence rates of cochlear implants (CIs), comorbidies, age at onset of profound deafness (AOD), age at first implantation, uni- or bilateral CI, and speech recognition. METHOD: This retrospective cohort study included all children (N = 278) aged <18 years in Norway who received their first CI during the years 2004-2010. RESULTS: 86 children (30.9%) in our study sample had parents of non-Nordic ethnicity, of whom 46 were born in Nordic countries with two non-Nordic parents. Compared with the background population, children with non-Nordic parents were 1.9 times more likely to have received CI than Nordic children (i.e., born in Nordic countries with Nordic parents). When looking at AOD, uni-vs. bilateral CIs, and comorbidities, no significant differences were found between Nordic children and children with a non-Nordic ethnicity. Among children with AOD <1 year (n = 153), those born in non-Nordic countries with two non-Nordic parents (n = 6) and adopted non-Nordic children (n = 6) received their first CI on average 14.9 and 21.1 months later than Nordic children (n = 104), respectively (p = 0.006 and 0.005). Among children with AOD <1 year, those born in Nordic countries with two non-Nordic parents (n = 31) received their CI at an older age than Nordic children, but this difference was not significant after adjusting for calendar year of implantation and excluding comorbidity as a potential cause of delayed implantation. The mean age at implantation for children with AOD <1 year dropped 2.3 months/year over the study period. The mean monosyllable speech recognition score was 84.7% for Nordic children and 76.3% for children born in Norway with two non-Nordic parents (p = 0.002). CONCLUSIONS: The incidence of CI was significantly higher in children with a non-Nordic vs. a Nordic ethnicity, reflecting a higher incidence of profound deafness. Children born in Norway have equal access to CIs regardless of their ethnicity, but despite being born and receiving care in Norway, prelingually deaf children with non-Nordic parents are at risk of receiving CI later than Nordic children. Moreover, prelingually deaf children who arrive in Norway at an older age may be at risk for a worse prognosis after receiving a CI due to lack of auditory stimulation in early childhood, which is critical for language development and late implantation; this is a serious issue with regard to deafness among refugees.

Sequential Bilateral Cochlear Implantation in Children: Outcome of the Second Implant and Long-Term Use.

OBJECTIVES: The aim of this retrospective cohort study was to assess speech perception outcomes of second-side cochlear implants (CI2) relative to first-side implants (CI1) in 160 participants who received their CI1 as a child. The predictive factors of CI2 speech perception outcomes were investigated. In addition, CI2 device use predictive models were assessed using the categorical variable of participant's decision to use CI2 for a minimum of 5 years after surgery. Findings from a prospective study that evaluated the bilateral benefit for speech recognition in noise in a participant subgroup (n = 29) are also presented. DESIGN: Participants received CI2 between 2003 and 2009 (and CI1 between 1988 and 2008), and were observed from surgery to a minimum of 5 years after sequential surgery. Group A (n = 110) comprised prelingually deaf children (severe to profound) with no or little acquired oral language before implantation, while group B (n = 50) comprised prelingually deaf children with acquired language before implantation, in addition to perilingually and postlingually deaf children. Speech perception outcomes included the monosyllable test score or the closed-set Early Speech Perception test score if the monosyllable test was too difficult. To evaluate bilateral benefit for speech recognition in noise, participants were tested with the Hearing in Noise test in bilateral and "best CI" test conditions with noise from the front and noise from either side. Bilateral advantage was calculated by subtracting the Hearing in Noise test speech reception thresholds in noise obtained in the bilateral listening mode from those obtained in the unilateral "best CI" mode. RESULTS: On average, CI1 speech perception was 28% better than CI2 performance in group A, the same difference was 20% in group B. A small bilateral speech perception benefit of using CI2 was measured, 3% in group A and 7% in group B. Longer interimplant interval predicted poorer CI2 speech perception in group A, but only for those who did not use a hearing aid in the interimplant interval in group B. At least 5 years after surgery, 25% of group A and 10% of group B did not use CI2. In group A, prediction factors for nonuse of CI2 were longer interimplant intervals or CI2 age. Large difference in speech perception between the two sides was a predictor for CI2 nonuse in both groups. Bilateral advantage for speech recognition in noise was mainly obtained for the condition with noise near the "best CI"; the addition of a second CI offered a new head shadow benefit. A small mean disadvantage was measured when the noise was located opposite to the "best CI." However, the latter was not significant. CONCLUSIONS: Generally, in both groups, if CI2 did not become comparable with CI1, participants were more likely to choose not to use CI2 after some time. In group A, increased interimplant intervals predicted poorer CI2 speech perception results and increased the risk of not using CI2 at a later date. Bilateral benefit was mainly obtained when noise was opposite to CI2, introducing a new head shadow benefit.

The Norwegian Hearing in Noise Test for Children.

OBJECTIVES: The aims of this study were to create 12 ten-sentence lists for the Norwegian Hearing in Noise Test for children, and to use these lists to collect speech reception thresholds (SRTs) in quiet and in noise to assess speech perception in normal hearing children 5 to 13 years of age, to establish developmental trends, and to compare the results with those of adults. Data were collected in an anechoic chamber and in an audiometric test room, and the effect of slight room reverberation was estimated. DESIGN: The Norwegian Hearing in Noise Test for children was formed from a subset of the adult sentences. Selected sentences were repeatable by 5- and 6-year-old children in quiet listening conditions. Twelve sentence lists were created based on the sentences' phoneme distributions. Six-year-olds were tested with these lists to determine list equivalence. Slopes of performance intensity (PI) functions relating mean word scores and signal to noise ratios (SNRs) were estimated for a group of 7-year-olds and adults. HINT normative data were collected for 219 adults and children 5 to 13 years of age in anechoic and audiometric test rooms, using noise levels 55, 60, or 65 dBA. Target sentences always originated from the front; whereas, the noise was presented either from the front, noise front (NF), from the right, noise right (NR) or from the left, noise left (NL). The NR and NL scores were averaged to yield a noise side (NS) score. All 219 subjects were tested in the NF condition, and 95 in the NR and NL conditions. Retest of the NF at the end of the test session was done for 53 subjects. Longitudinal data were collected by testing 9 children as 6, 8, and 13 years old. RESULTS: NF and NS group means for adults were -3.7 and -11.8 dB SNR, respectively. Group means for 13-year-olds were -3.3 and -9.7, and for the 6-year-olds group means were -0.3 and -5.7 dB SNR, as measured in an anechoic chamber. NF SRTs measured in an audiometric test room were 0.7 to 1.5 higher (poorer) than in the anechoic chamber. Developmental trends were comparable in both rooms. PI slopes were 8.0% dB SNR for the 7-year-olds and 10.1% for the adults. NF SRTs in the anechoic chamber improved by 0.7 dB per year over an age range of 5 to 10 years. Using a PI slope 8 to 10% per dB, the estimated increase in percent intelligibility was 4 to 7% per year. Adult SRTs were about 3 dB lower than those for 6-year-olds, corresponding to 25 to 30% better intelligibility for adults. CONCLUSIONS: Developmental trends in HINT performance for Norwegian children with normal hearing are similar to those seen in other languages, including American English and Canadian French. SRTs approach adult normative values by the age of 13; however, the benefits of spatial separation of the speech and noise sources are less than those seen for adults.