RESUMEN
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.
Asunto(s)
Implantación Coclear , Implantes Cocleares , Sordera , Pérdida Auditiva Sensorineural , Pérdida Auditiva , Humanos , Estudios Retrospectivos , Pérdida Auditiva Sensorineural/genética , Pérdida Auditiva Sensorineural/cirugía , Resultado del Tratamiento , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Proteínas de Neoplasias/genética , Serina Endopeptidasas/genéticaRESUMEN
The common methods for patient dose estimations in computed tomography (CT) are thermoluminescence dosemeter (TLD) measurements or the usage of software packages based on Monte Carlo simulations like CT-Expo or the newer CTVoxDos, which uses the ICRP Reference Adult Male (ICRP 110). Organ (OD) and effective doses of a CT protocol of the upper abdomen are compared. Compared to CTVoxDos, ODs inferred by TLD measurement using an anthropomorphic phantom differ by $\mathbf{(19\pm 16)\,\%}$ inside the primary radiation field, $\mathbf{(14\pm 2)\,\%}$ for partially primary irradiated organs and $\mathbf{(34\pm 38)\,\%}$ in the scattered radiation field. ODs estimated by CT-Expo show a mean deviation of $\mathbf{(16\pm 9)\,\%}$ (primary irradiated) and $\mathbf{(28\pm 31)\,\%}$ (scatter irradiated) from ODs estimated by CTVoxDos.
