1. Phoniatrics Unit Faculty of Medicine, Sohag University Sohag Egypt
2. Otolaryngology Department Faculty of Medicine, Sohag University Sohag Egypt
3. Physiology Department Faculty of Medicine, Sohag University Sohag Egypt
4. Pediatric Department Faculty of Medicine, Sohag University Sohag Egypt
5. Otolaryngology Department Faculty of Medicine, Aswan University Aswan Egypt