1. Voice Care Center Bad Rappenau, Bad Rappenau, Germany
2. Department of Psychology and Psychotherapy, Witten/Herdecke University, Trimberg Research Academy, University of Bamberg, Bamberg, Germany
3. Dental treatment, Korschenbroich, Germany
4. Klinik für Audiologie und Phoniatrie, Charite Universitätsmedizin Berlin, Berlin, Germany