Artikel
Electrophysiological evidence for central neuroplasticity of the contralesional ear in patients with unilateral vestibular schwannoma
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Autoren
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Georgios Naros
- Klinik für Neurochirurgie, Universitätsklinikum Tübingen, Tübingen
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Giulia Del Moro
- Klinik für Neurochirurgie, Universitätsklinikum Tübingen, Tübingen
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Teresa Leao
- Klinik für Neurochirurgie, Universitätsklinikum Tübingen, Tübingen
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Birat Niraula
- Klinik für Neurochirurgie, Universitätsklinikum Tübingen, Tübingen
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Marina Liebsch
- Klinik für Neurochirurgie, Universitätsklinikum Tübingen, Tübingen
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Florian H. Ebner
- Klinik für Neurochirurgie, Universitätsklinikum Tübingen, Tübingen
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Marcos Tatagiba
- Klinik für Neurochirurgie, Universitätsklinikum Tübingen, Tübingen
| Veröffentlicht: | 2. Juni 2015 |
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Gliederung
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Objective: Vestibular schwannomas (VS) are often associated with tinnitus of the affected ear. The current pathophysiological concept of tinnitus involves neuroplasticity in auditory structures due to sensory deafferentation resulting in an increase of central gain. While idiopathic tinnitus usually occurs suddenly, a VS is a slow growing process enabling neuroplastic adaptation and compensation of the ipsi- and contralesional auditory system. In the present study, we describe electrophysiological findings in patients with unilateral VS indicating an adaptation of central auditory gain of the contralesional ear.
Method: The presented retrospective study enrolls 250 patients scheduled for microsurgical resection of an unilateral VS. Electrophysiological and clinical pre- and postoperative evaluation included auditory brainstem responses (ABR), speech discrimination score (SDS) and pure tone audiometry (PTA) of both the ipsilesional (IL) and contralesional (CL) ears. Patients were classified by the presence of tinnitus (TN+ and TN-) and hearing loss according the Gardner-Robertson (GR) score.
Results: TN+ had significant stronger hearing impairment of the affected IL ear in comparison to TN- patients (p=0.016, Wilcoxon). There was no difference in hearing of the healthy CL ear (p>0.05, Wilcoxon). There was no difference between TN+ and TN- in any IL ABR parameters except for wave V latency (p=0.041, Kruskalwallis). In contrast, for the healthy CL ear there was a significant increase of wave V and I-III, I-V latencies as well as a decrease of wave V amplitudes in TN+ compared to TN- patients (p<0.05, Kruskalwallis).
Conclusions: Our electrophysiological results indicate that in patients with unilateral VS the presence of ipsilesional tinnitus leads to an increase of contralesional ABR latencies and the reduction of wave V amplitudes. We interpret these findings as an adaptation of the healthy auditory system to the increased central auditory gain of the affected side. The present study provides further insights in the pathophysiology of VS-associated tinnitus and might help to implement new therapeutic approaches.
