1. Division of Phoniatrics and Pediatric Audiology at the Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Erlangen, Medical School at Friedrich-Alexander University Erlangen-Nürnberg, Waldstrasse 1, 91054 Erlangen, Germany
2. Department of Process Machinery and Systems Engineering, Friedrich-Alexander University Erlangen-Nürnberg, Cauerstrasse 7, 91058 Erlangen, Germany