Comparison of speech production in upright and supine position

Abstract

Speech is usually produced in an upright sitting or standing posture. Measurements and judgments of speech may be made in conditions requiring a supine position, however. These conditions include MRI recordings, and oral procedures, such as, adjustments to dental appliances, medical and surgical procedures. It is of interest, therefore, to see whether gravity has strong or systematic effects on tongue behavior. In the present study, 13 subjects repeated several words, which contained extreme consonant and vowel tongue positions, during upright and supine condition. Ultrasound imaging provided midsagittal tongue contours, in each condition, for comparison. A neck brace was used to stabilize transducer placement and the palate was used as a physiological reference to register the data sets. Results showed a significant subject effect. In supine position the tongue was more posterior than upright for seven subjects, more anterior for two subjects and varied by phoneme for four subjects. However, there was no significant phoneme effect. The direction of change and the amount of change were not directly related. Most subjects had small upright-supine differences. The largest differences, less than 3 mm on average, were in the posterior tongue.

Limb versus Speech Motor Control: A Conceptual Review

“…In the case of speech, intelligibility was preserved independently of the head's orientation. Stone et al (2007) observed similar differences in tongue movements during speech production in upright versus supine position. Simulations based on a realistic 3D biomechanical tongue model that employed the same motor commands for upright and supine position reproduced these differences (Buchaillard et al, 2009).…”

Effect of body position on vocal tract acoustics: Acoustic pharyngometry and vowel formants

“…No consistent differences were found in formant frequencies or bandwidths between body positions or type of speech material. Stone et al (2007) and Tiede et al (2000) concluded from their data that the physiological effects of gravity on the acoustic properties of speech are negligible. Buchaillard et al (2009) concluded similarly from a biomechanical model of the tongue and oral cavity (OC).…”

“…One of the most consistent observations is that the pharyngeal (nasopharyngeal and/or oropharyngeal) cavity is smaller in the supine as opposed to the upright position during speech, as determined from APh (Jan et al, 1994), computed tomography (CT; Sutthiprapaporn et al, 2008), MRI (Engwall, 2006;Kitamura et al, 2005;Traser et al, 2014), ultrasound (Stone et al, 2007;Wrench et al, 2011), x-ray microbeam (Tiede et al, 2000), and videofluoroscopy (Bae et al, 2014). This effect can be explained by gravity pulling the tongue root posteriorly when the subject is in the supine position, thereby reducing the size of the pharynx.…”

“…The sole significant difference between upright and supine positions was a higher F1 frequency for the vowel /i/ in the supine position. Stone et al (2007) measured the F1 and F2 frequencies of three vowels (/i/ as in "feet," /ae/ as in "hat," and /a/ as in "hot") produced by 13 speakers. They reported no significant differences for words of continuous speech but some significant differences for isolated production of sustained consonants and vowels.…”

Polish pronunciation animations developed on the basis of electromagnetic articulography

“…Despite huge technological advances enabling three-dimensional computer modeling of the structures examined, the MRI method still yields unsatisfactory results with regard to image accuracy and speed of sampling (speakers have to prolong a particular articulation, often for many seconds); it is also negatively influenced by the effect of gravity on articulation, because speakers have to lie down during testing (cf. Stone et al 2007). neither of the abovementioned methods - ultrasonography or magnetic resonance imaging - has been used in poland for articulation investigations.…”