He became assistant professor in Cologne in 1990, and was guest professor at Berlin's Humboldt University in 1999 . Since 2001 he has been professor and senior researcher at the Department of Phoniatrics, Pedaudiology and Communication Disorders, Medical School, RWTH Aachen University.
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While advanced research at the University is carried out in virtually every field of modern medicine, its contribution is most widely recognized in such disciplines as immunology, endocrinology, oncology, nuclear medicine, anaesthesiology, surgery, nephrology, gynaecology and obstetrics ( especially perinatology ), ecology, parasitic and tropical diseases, AIDS, viral hepatitis, hematology, child oncology, cytophysiology and cytopathology, development of the central nervous system, immunology of skin diseases, clinical pharmacology, genetics, audiology, phoniatrics and optometry.
