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Antwerpen, Belgium

De Varebeke S.P.J.,Campus Virga Jesse | Termote B.,Jessa Hospital | Van Camp G.,University of Antwerp | Govaerts P.J.,Eargroup | And 5 more authors.
Otology and Neurotology

HYPOTHESIS: Focal sclerosis of one or more semicircular canals on computed tomographic (CT) scans and a corresponding signal loss on magnetic resonance (MR) imaging are radiologic lesions that are linked to patients who are suffering from advanced otovestibular impairment caused by hereditary DFNA9 hearing loss. BACKGROUND: DFNA9 is a hereditary hearing loss that is characterized by late-onset progressive imbalance and hearing deterioration, caused by mutations in the COCH gene. To date, no radiologic lesions have been associated with this condition. STUDY DESIGN: A retrospective chart review SETTING: Tertiary referral center SUBJECTS: The radiologic data of 9 patients who presented between 2007 and 2012 with otovestibular deterioration caused by a mutation in the COCH gene were reviewed. RESULTS: All 9 subjects were carriers of the same c.151C > T, p.Pro51Ser (P51S) - missense mutation in the COCH gene. In 8 of them similar sclerotic lesions and/or narrowing were demonstrated in one or more semicircular canals on computed tomography CT scan, with a signal loss at corresponding areas on T2-weighted magnetic resonance (MR) images. In 1 patient, the posterior part of the vestibule was also affected. The posterior canals were affected in most cases (58%), compared with the superior (21%) and lateral canals (16%) or the vestibule (5%). Only 68.4% of the lesions on MR images were also visible on CT scans, suggesting a fibrotic process without calcification. Ears presenting radiologic lesions showed significantly more severe hearing loss (median PTA 104 dB HL) compared with unaffected ears (58 dB HL). CONCLUSION: Eight of 9 subjects with the same P51S mutation in the COCH gene showed similar radiologic lesions, affecting the PSCC in the majority of the cases. These radiologic abnormalities occurred in more advanced stages of the otovestibular deterioration, supporting the hypothesis that these lesions might represent the end phase of a low-grade chronic inflammation or protein deposition. A new phenotypic and characteristic radiologic feature of DFNA9 has been discovered. © 2014, Otology & Neurotology, Inc. Source

Schrauwen I.,University of Antwerp | Venken K.,transnational University of Limburg | Venken K.,Ghent University | Vanderstraeten K.,University of Antwerp | And 12 more authors.
Genes and Immunity

Otosclerosis is a common form of hearing loss, characterized by disordered bone remodeling in the otic capsule. Within the otosclerotic foci, several immunocompetent cells and immune-modulating factors can be found. Different etiological theories involving the immune system have been suggested. However, a genetic component is clearly present. In large otosclerosis families, seven autosomal-dominant loci have been found, but none of the disease-causing genes has been identified. This study focused on the exploration of the second otosclerosis locus on chromosome 7q34-36 (OTSC2), holding the T-cell receptor beta locus (TRB locus). A significantly lower T-cell receptor-Β (TCR-Β) mRNA expression and percentage of blood circulating TCR-αΒ T cells was detected in OTSC2 patients compared with controls and patients with the complex form of the disease. Further analysis illustrated more significant disturbances in specific T-cell subsets, including an increased CD28 null cell population, suggesting a disturbed T-cell development and ageing in OTSC2 patients. These disturbances could be associated with otosclerotic bone remodeling, given the known effects of immunocompetent cells on bone physiology. These data implicate the TRB locus as the causative gene in the OTSC2 region and represent an important finding in the elucidation of the disease pathology. © 2010 Macmillan Publishers Limited All rights reserved. Source

Hammer A.,VU University Amsterdam | Vaerenberg B.,Eargroup | Vaerenberg B.,University of Antwerp | Kowalczyk W.,Leiden Institute for Advanced Computer Science | And 3 more authors.
Proceedings of the Annual Conference of the International Speech Communication Association, INTERSPEECH

This paper describes a distance measure which estimates the distance between a language sample and a reference corpus with regard to graphemes, phonemes and the relation between them. The underlying assumption of this approach is that a language's phoneme distribution can be partially accessed via graphemes. The advantage of using such a measure in speech audiometry is twofold: (i) it may be applied to determine how representative existing word lists are with respect to the distribution of speech sounds in the target language of the test subject; (ii) it enables the audiologist to generate highly representative lists based on large corpora of languages for which broad phonetic transcription is lacking. In this paper the development of the de novo distance measure is described and demonstrated for Dutch. The technique itself however, is language-independent and has been applied successfully to 10 other EU-languages. As such, it paves the way to generating representative word lists as part of speech audiometric test batteries for any given language. Copyright © 2013 ISCA. Source

Coene M.,VU University Amsterdam | Hammer A.,VU University Amsterdam | Kowalczyk W.,Leiden Institute for Advanced Computer Science | Bosch L.T.,Radboud University Nijmegen | And 3 more authors.
Proceedings of the Annual Conference of the International Speech Communication Association, INTERSPEECH

In the literature, languages have been identified as having more or less transparent orthographies, depending on the degree of predictability of their spelling-to-sound correspondences. Quantitative measures based on large-scaled language corpora which are capable to objectively assess such cross-linguistic variation are rather scarce. The quantitative assessment method presented here builds on the correlation between distances of phonemic and graphemic frequency distributions of a given sample and similar distances obtained from large corpora of the same language. The metric itself may be used as a research tool to investigate the potential effect of orthographic transparency on the development and performance of reading in different populations. Copyright © 2013 ISCA. Source

Blamey P.J.,Bionics Institute | Blamey P.J.,University of Melbourne | Maat B.,University of Groningen | Baskent D.,University of Groningen | And 23 more authors.
Ear and Hearing

To compare speech perception outcomes between bilateral implantation (cochlear implants [CIs]) and bimodal rehabilitation (one CI on one side plus one hearing aid [HA] on the other side) and to explore the clinical factors that may cause asymmetric performances in speech intelligibility between the two ears in case of bilateral implantation. Design: Retrospective data from 2247 patients implanted since 2003 in 15 international centers were collected. Intelligibility scores, measured in quiet and in noise, were converted into percentile ranks to remove differences between centers. The influence of the listening mode among three independent groups, one CI alone (n = 1572), bimodal listening (CI/HA, n = 589), and bilateral CIs (CI/CI, n = 86), was compared in an analysis taking into account the influence of other factors such as duration of profound hearing loss, age, etiology, and duration of CI experience. No within-subject comparison (i.e., monitoring outcome modifications in CI/HA subjects becoming CI/CI) was possible from this dataset. Further analyses were conducted on the CI/CI subgroup to investigate a number of factors, such as implantation side, duration of hearing loss, amount of residual hearing, and use of HAs that may explain asymmetric performances of this subgroup. Results: Intelligibility ranked scores in quiet and in noise were significantly greater with both CI/CI and CI/HA than with a CI-alone group, and improvement with CI/CI (+11% and +16% in quiet and in noise, respectively) was significantly better than with CI/HA (+6% and +9% in quiet and in noise, respectively). From the CI/HA group, only subjects with ranked preoperative aided speech scores >60% performed as well as CI/CI participants. Furthermore, CI/CI subjects displayed significantly lower preoperative aided speech scores on average compared with that displayed by CI/HA subjects. Routine clinical data available from the present database did not explain the asymmetrical results of bilateral implantation. Conclusions: This retrospective study, based on basic speech audiometry (no lateralization cues), indicates that, on average, a second CI is likely to provide slightly better postoperative speech outcome than an additional HA for people with very low preoperative performance. These results may be taken into consideration to refine surgical indications for CIs © 2015 Wolters Kluwer Health, Inc. Source

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