Comparison of glottic areas measured by acoustic reflections vs. computerized tomography

Abstract

We compared measurements of glottic area obtained by acoustic reflection technique with anatomically equivalent area measured from computerized tomographic (CT) scans of the neck in 11 subjects with glottic pathology. Both measurements were performed in the supine position during tidal breathing at functional residual capacity. We found excellent agreement in glottic areas obtained by both methods: the mean (+/- SD) values were 1.8 +/- 0.8 cm2 for the acoustic method and 1.7 +/- 0.9 cm2 for the CT method. Linear regression analysis revealed the following relationship between the area measured by acoustic technique (AAC) and that measured by CT (ACT): AAC = 0.81.ACT + 0.36. There was a significant correlation between the two measurements of glottic area (r = 0.95, P less than 0.0001). We conclude that the acoustic reflection technique may be used reliably in clinical and physiological studies concerned with glottic geometry.

Realistic glottal motion and airflow rate during human breathing

“…However, our results are in agreement with previous studies based on the acoustic reflection [40][41][42] or MRI technique [43]. In particular, D'Urzo et al [40] used both acoustic reflection and CT methods to measure glottal area of 11 subjects.…”

“…In particular, D'Urzo et al [40] used both acoustic reflection and CT methods to measure glottal area of 11 subjects. The results derived from both methods were similar.…”

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

“…The APh, also known as an acoustic reflectometer, is a noninvasive Food and Drug Administration approved unit that uses sound echoes to measure the geometry of the oral and pharyngeal cavities/upper airway. It has been in use for several decades as an accurate, non-invasive method of examining the upper airway (Hoffstein and Zamel, 1984;D'Urzo et al, 1987;D'Urzo et al, 1988;Hoffstein and Fredberg 1991;Marshall et al, 1993) both clinically to investigate adults and children with sleep related disorders (Brown et al, 1987;Gelardi et al, 2007;Jung et al, 2004;Marshall et al, 1993;Monahan et al, 2005), and more recently in speech research to study changes or differences in VT dimensions related to aging (Xue et al, 1999), race (Xue and Hao, 2006;), as well as in atypically developing speakers with Down Syndrome (Xue et al, 2010). The APh technique is similar to that of an active sonar and entails emitting pulses of sounds of known frequency and amplitude into the VT, then using the amplitude and arrival times of the reflected acoustic waves to construct the areadistance function of the upper airway, specifically the cross-sectional area of the upper airway as a function of the distance from the glottis to the teeth.…”

Normative Standards for Vocal Tract Dimensions by Race as Measured by Acoustic Pharyngometry

“…Modern imaging techniques now serve to acquire three-dimensional (3-D) shape information for the vocal tract. This process can be performed with MRI 19,20,8,12 or CT. [3][4][5][6] With these techniques, a variety of vocal tract shapes are obtained and 3-D structure reconstructions of the airway shapes can then be made by the mathematical postprocessing of these images. AR technology has been proven effective in characterizing upper airway properties in human speakers, 14,2 and it has been well validated against upper airway models 21 and with MRI and CT techniques.…”