1. Speech-Language Pathology, SRH University of Applied Health Sciences, 40210 Düsseldorf, Germany
2. Harris College of Nursing & Health Sciences, Texas Christian University, Fort Worth, TX 76109, USA
3. Department for Medical Statistics and Biomathematics, Medical Faculty Mannheim, University of Heidelberg, 68165 Mannheim, Germany
4. Department of Phoniatrics and Pediatric Audiology, University Hospital Münster, University of Münster, 48149 Münster, Germany