Correspondence: Svante Granqvist, Division of Speech and Language Pathology, Department of Clinical Science, Intervention and Technology (CLINTEC) Karolinska Institutet (KI), Stockholm, Sweden. E-mail: svante.granqvist@ki.se (Received 18 December 2013; accepted 5 April 2014) ORIGINAL ARTICLE Resonance tube phonation in water: High-speed imaging, electroglottographic and oral pressure observations of vocal fold vibrations - a pilot study SVANTE GRANQVIST 1,2 , SUSANNA SIMBERG 3 , STELLAN HERTEGÅRD 4,5 , SOFIA HOLMQVIST 3 , HANS LARSSON 1 , PER-ÅKE LINDESTAD 4,5 , MARIA SÖDERSTEN 1,6 & BRITTA HAMMARBERG 1 1 Division of Speech and Language Pathology, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet (KI), Stockholm, Sweden, 2 Basic Science and Biomedicine, School of Technology and Health (STH), Royal Institute of Technology (KTH), Stockholm, Sweden, 3 Department of Psychology and Logopedics, Abo Akademi University, Turku, Finland, 4 Division of Otolaryngology, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet (KI), Stockholm, Sweden, 5 Department of Otolaryngology, Phoniatric Section, Karolinska University Hospital Huddinge, Stockholm, Sweden, and 6 Department of Speech Language Pathology, Karolinska University Hospital, Stockholm, Sweden Abstract Phonation into glass tubes (‘resonance tubes’), keeping the free end of the tube in water, has been a frequently used voice therapy method in Finland and more recently also in other countries. The purpose of this exploratory study was to inves- tigate what effects tube phonation with and without water has on the larynx. Two participants were included in the study. The methods used were high-speed imaging, electroglottographic observations of vocal fold vibrations, and measurements of oral pressure during tube phonation. Results showed that the fluctuation in the back pressure during tube phonation in water altered the vocal fold vibrations. In the high-speed imaging, effects were found in the open quotient and amplitude variation of the glottal opening. The open quotient increased with increasing water depth (from 2 cm to 6 cm). A modula- tion effect by the water bubbles on the vocal fold vibrations was seen both in the high-speed glottal area tracings and in the electroglottography signal. A second experiment revealed that the increased average oral pressure was largely determined by the water depth. The increased open quotient can possibly be explained by an increased abduction of the vocal folds and/or a reduced transglottal pressure. The back pressure of the bubbles also modulates glottal vibrations with a possible ‘massage’ effect on the vocal folds. This effect and the well-defined average pressure increase due to the known water depth are different from those of other methods using a semi-occluded vocal tract. Key words: Back pressure, bubbles in water, electroglottography, high-speed imaging, oral pressure, resonance tube phonation in water, semi-occluded vocal tract Introduction During the last decades, there have been a great number of studies describing different voice training techniques using a so-called semi-occluded vocal tract (1–3). These methods often include phonating in narrow glass tubes or different kinds of straws. Phonation into glass tubes, so-called ‘resonance tubes’, keeping the free end of the tube in the air or submerged in water, has been a frequently used voice therapy method in Finland from the 1960s (4–6). The resonance tubes used in clinical practice still generally follow the dimensions suggested by Sovi- järvi and are 26–28 cm long with an inner diameter of 9 mm for adults (5–7). The method, and how it is used in voice therapy today, has been described by Simberg and Laine (8). Logopedics Phoniatrics Vocology, 2014; Early Online: 1–9 ISSN 1401-5439 print/ISSN 1651-2022 online © 2014 Informa UK, Ltd. DOI: 10.3109/14015439.2014.913682 Logoped Phoniatr Vocol Downloaded from informahealthcare.com by Karolinska Universitetssjukhus on 05/28/14 For personal use only.