Stable long-term outcomes after cochlear implantation in subjects with TMPRSS3 associated hearing loss: a retrospective multicentre study.

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. 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.

Contralateral hearing loss in children with a unilateral enlarged vestibular aqueduct.

OBJECTIVE: To evaluate the long-term ipsi- and contralateral hearing of patients with a unilateral enlarged vestibular aqueduct (EVA). STUDY DESIGN: Multicenter retrospective cohort study. SETTING: Three tertiary otology and audiology referral centers. PATIENTS AND DIAGNOSTIC INTERVENTIONS: A total of 34 children with a unilateral enlarged vestibular aqueduct as identified on CT and/or MR imaging were evaluated with pure tone and speech perception audiometry. MEAN OUTCOME MEASURES: Radiologic measurements of the vestibular aqueduct, ipsi- and contralateral hearing loss, ipsi- and contralateral hearing loss progression over time and DNA test results. RESULTS: All patients in this cohort with unilateral EVA presented with hearing loss. Hearing loss was progressive in 38% of the ipsilateral ears. In 29% of the children, hearing loss was also found in the contralateral ear without EVA. In 90%, the contralateral hearing was stable, with a mean follow up of 4.2 years. We found a significant correlation between the severity of the hearing loss and the size of the EVA. A genetic diagnosis associated with EVA and/or SNHL was found in only 7%. CONCLUSION: About a third of the children with unilateral EVA are at risk of developing hearing loss in the contralateral ear. This indicates that at least in some patients with a unilateral EVA, a bilateral pathogenic process underlies the hearing loss, in contrary to what the imaging results suggest. These findings are important for counseling of EVA patients and their parents and have implications for follow up.

Speech perception in congenitally, pre-lingually and post-lingually deaf children expressed in an equivalent hearing loss value.

OBJECTIVES: To investigate the speech perception performance of children with a cochlear implant (CI) after 3 and 4 years of follow-up and to study the influence of age at implantation, duration of deafness and communication mode on the variability in speech perception performance. STUDY DESIGN: A broad battery of speech perception tests was administered to 67 children with a CI. The results were reduced into one measure: the 'equivalent hearing loss (EHL)'. This outcome measure refers to the performance of a reference group of severely and profoundly hearing impaired children with conventional hearing aids. PARTICIPANTS: The population comprised 35 congenitally, 17 pre-lingually and 15 post-lingually deaf children implanted between 1989 and 1999. The population was homogeneous with respect to cognition, residual hearing and support at home as a result of conservative inclusion criteria. RESULTS: During the first 2 years after implantation, post-lingually deaf children showed the fastest rate of improvement in speech perception. After 3 years of implant use, the early implanted pre-lingually deaf children and congenitally deaf children implanted under the age of 6 years caught up with the post-lingually deaf children. Pre-lingually deaf children implanted after a relatively long-duration of deafness tended to show poorer performance than those with a shorter duration. Performance of congenitally deaf children implanted after the age of 6 years was poorer and progress was slower. In the congenitally deaf children, 36% of the variability in performance was explained by duration of deafness, whereas in the children with pre- and post-lingually acquired deafness, communication mode explained 69% of the variance. CONCLUSIONS: All children derived benefit from their CI for speech perception tasks, but performance varied greatly. Several children reached EHL levels around 70 dB; their speech perception was equal to that of a child with conventional hearing aids who has 70 dB HL. After early implantation, the levels of performance that were eventually achieved differed no more than 10 dB, irrespective of whether the onset of deafness was pre-lingual or postlingual. In congenitally deaf children, duration of deafness played a major role in speech perception performance, whereas in the children with pre-lingually and post-lingually acquired deafness together, mode of communication was a major factor.

Three-year follow-up of children with postmeningitic deafness and partial cochlear implant insertion.

OBJECTIVES: To evaluate the long-term outcome of children with postmeningitic deafness and partial insertion of the Nucleus electrode array, and to compare their speech perception performance with that of children with full insertion of the electrode array. DESIGN: A battery of seven speech perception tests was administered to 25 children with a cochlear implant (CI). Results were reduced into one score: equivalent hearing loss (EHL). SETTING: Tertiary referral centre. PARTICIPANTS: The partial insertion group comprised seven children, mean age at implantation 5.5 years, mean duration of deafness 3.6 years. The full-insertion control group comprised 18 children. Mean age at implantation: 4.4 years; mean duration of deafness: 2.9 years. All the children became deaf between 0 and 3 years of age. MAIN OUTCOME MEASURES: Over a 3-year follow-up period, the children with partial insertion showed continuing progress, although there was wide variation in performance and the rate of progression. Some open-set comprehension could even be achieved with the insertion of only eight electrodes of a nucleus device. RESULTS: Three years after implantation, speech perception in the partial insertion children was poorer than that in the control groups with long (P < 0.01; 95% confidence interval 7-43 dB EHL) and short duration of deafness (P < 0.0001; 95% confidence interval 28-53 dB EHL). They showed slower progress and reached a poorer EHL plateau. Four of the seven children acquired open-set word recognition. CONCLUSIONS: Patients with partial insertion of the electrode array benefit from a CI, although less than patients with complete insertion.