1. From the Children's Hospital and
2. Department of Otolaryngology, Medical University, Lübeck, Germany; the
3. Vestische Kinderklinik Datteln, University Witten, Herdecke, Germany; the
4. Children's Hospital Friedrichshain, Berlin, Germany; the
5. Children's Hospital University, Bonn, Germany; the
6. Children's Hospital and the
7. Department of Phoniatrics and Pedaudiology, University Münster, Münster, Germany.