Eeva Sala, MD, PhD, is a specialist in ENT and Laryngology, and is Associate Professor in Phoniatrics in the Medical Faculty at the University of Turku, Finland. She has 62 publications in peer-reviewed scientific journals, in the fields of voice, speech hearing, voice disorders and acoustics, and noise conditions in preschools and school classrooms, to her credit. Her publications also include 144 other scientific and professional articles, eight chapters in professional medical books, and two books. Leena Rantala, PhD, is Associate Professor in Logopaedics, at the University of Oulu, Finland, and a Senior Lecturer in the Department of Logopaedics at the University of Tampere, Finland. Her publications include 28 articles in peer-reviewed scientific journals, two books and one book chapter.