Gloria Chi-Fishman

Effects of systematic bolus viscosity and volume changes on hyoid movement kinematics.

Using ultrasonography with head and transducer stabilization, this study examined the effects of maximally controlled, systematic changes in bolus viscosity (thin juice-like, 7 cP; nectar-like, 243–260 cP; honey-like, 724–759 cP; spoon-thick, 2760–2819 cP) and volume (5, 10, 20, 30 cc) on hyoid kinematics in 31 healthy subjects (16 male, 15 female) in three age groups (20–39, 40–59, 60–79 years). Frame-by-frame hyoid displacements were tracked from digitized images of 612 swallows. Measures of movement durations, maximal amplitudes, total distances, and peak velocities were subjected to repeated measures multivariate analyses of variance with viscosity, volume, age, and gender as factors. Results showed that (1) spoon-thick swallows had the greatest preswallow gesture and total movement durations; (2) larger-volume swallows had significantly greater maximal amplitudes, forward peak velocity, and total vertical distance; (3) older subjects had longer start-to-max duration (though shorter preswallow gesture and total movement durations), greater maximal vertical amplitude, longer total vertical distance, and greater backward peak velocity than younger subjects; (4) males had greater values for all kinematic parameters except preswallow gesture, hyoid-at-max, and max-to-end durations. The results illustrate the importance of examining the interrelations among kinematic variables to better understand task accommodation and motor control strategies. The evidence also supports the concept of suprahyoid–infrahyoid functional adaptation and compensation in the healthy elderly.

Dependence on diffusion time of apparent diffusion tensor of ex vivo calf tongue and heart.

The time dependence of the apparent diffusion tensor of ex vivo calf heart and tongue was measured for diffusion times (τd) between 32 and 810 ms. The results showed evidence of restricted diffusion in the muscle tissues of both organs. In regions where the myofibers are parallel, the largest eigenvalue (λ1) of the diffusion tensor remained the same for all diffusion times measured, while the other eigenvalues (λ2, λ3) decreased by 29–36% between τd = 32 ms and τd = 400 ms. In regions where the fibers cross, the λ1 also changed, decreasing by 17% between τd = 32 ms and τd = 400 ms. The restricting compartment size and volume fraction were effectively estimated by fitting the time courses of the eigenvalues to a model consisting of a nonrestricted compartment and a cylindrically restricted compartment. To our knowledge, this study is the first demonstrating diffusion time dependence of measured water diffusion tensor in muscular tissue. With improvement in scanning technology, future studies may permit noninvasive, in vivo detection of changes in muscle myoarchitecture due to disease, treatment, and exercise. Magn Reson Med, 2005. Published 2005 Wiley‐Liss, Inc.

Quantitative lingual, pharyngeal and laryngeal ultrasonography in swallowing research: A technical review

Because of its distinct advantage in radiation‐free soft tissue imaging, ultrasonography has been widely used to study lingual, pharyngeal, hyoid, laryngeal, and even esophageal action during swallowing in individuals of all ages. Qualitative ultrasonographic observations have made considerable contributions to our understanding of deglutition. Quantitative ultrasonographic swallowing research has also grown by leaps and bounds over the years with advances in imaging technologies and analytical methodologies. As a technical primer for new investigators, this paper reviews the modern methods for quantitative analysis in ultrasonographic swallowing research. The intended outcome is a basic understanding of the application of ultrasonography with various analysis options to the quantitative study of the deglutitive action of selected upper aerodigestive structures. Though proven useful for swallowing research, ultrasonography has inherent limitations and methodological issues. Future technological advancement and sophisticated image processing and analysis algorithms will resolve some of these issues.

Effects of Physostigmine on Swallowing and Oral Motor Functions in Patients with Progressive Supranuclear Palsy: A Pilot Study

Abstract. The purpose of this pilot study was to investigate whether cholinergic stimulation reduces swallowing and oral motor disturbances in patients with progressive supranuclear palsy (PSP). A controlled, double-blind crossover trial of physostigmine, a centrally active cholinesterase inhibitor, and placebo was conducted. Patients were randomized to a 10-day crossover placebo-controlled double-blind trial of physostigmine at their previously determined best dose administered orally every 2 hr, six times per day. Patients were evaluated with ultrasound imaging of the oropharynx and an oral motor examination at baseline and during the third or fourth days of each study phase (placebo and drug). Under the double-blind placebo-controlled conditions, patients showed no statistically significant improvement in oral motor functions or swallow durations. Because patients with PSP have increased sensitivity to cholinergic blockade compared with control subjects, studies with newer, more potent cholinergic stimulating agents need further exploration. Suggestions for future research include the evaluation of newer direct cholinergic agonists in the treatment of the less-impaired PSP patients who may have a greater number of cholinergic neurons preserved and the evaluation of combined therapies.

Ultrasound Imaging and Swallowing

Ultrasound technology has advanced substantially, providing clinicians and researchers with vastly expanded noninvasive opportunities to study the dynamics of the oral pharyngeal system and the muscles and other soft tissues of the oropharynx during swallowing. In the current climate of cost containment and efficiency, ultrasound imaging presents a viable alternative to videofluorography to examine the oropharyngeal swallow. Because ultrasound imaging is uniquely suited for investigating soft tissue structures, it is used to view the abdomen, fetus, heart, bladder, genitalia, breast, and to visualize tumors and masses throughout the body (1–3). Ultrasound can be used to identify normal and abnormal oropharyngeal tissues such as the thyroid and salivary glands, tongue, palate, and floor of the mouth in various diseases, infections, and genetic conditions (4,5). Because of its inherent advantages (Table 8.1), ultrasound has been successfully adapted for viewing the oral cavity during swallowing (6–9). Real-time ultrasound is totally noninvasive, dynamic, and has no known bioeffects and minimal risk to the patient. Studies can therefore be performed repeatedly or for extended periods of time without risk of future tissue change from effects of long-term radiation. This property is especially relevant when one is studying infants and children who are at greater risk than adults for showing the cumulative effects of ionizing radiation. The air interface at the surface of the tongue is a nearly perfect reflector of sound, thus clearly displaying the lingual musculature and vessels both at rest and during oral motion. Ultrasound imaging is ideally suited to identifying the various soft tissues that compose the upper aerodigestive tract. In addition, the transduction properties of sound waves allow these soft tissues to be distinguished from ingested fluids, semisolids, and solid materials. Since no contrast material is needed to visualize the oropharynx and the bolus during swallowing, any type of food commonly ingested by the patient can be used during a study. The ultrasound examination is conducted with the adult or child patient seated in a comfortable position, while an infant is held on the mother’s lap. All ultrasound systems are portable, have built-in video systems, online computerized image processing and measurement programs, a computer keyboard, display screen, and hard copy printout capacity. Ultrasound is easy to use and provides reliable diagnostic information. Because of these advantages, ultrasound technology is well suited to evaluate individuals of any age from infancy to senescence, and any neurological, systemic, genetic, traumatic, developmental, or progressive condition that affects oral physiology.

Volumetric tongue reconstruction by fusing bidirectional MR images

In this paper we describe a 3D reconstruction method that fuses sagittal and coronal images. In our volumetric MRI study of the human tongue, multiple contiguous slices were acquired in the sagittal and the coronal planes. A bidirectional linear interpolation method was developed that estimated target voxel value using weighted neighbor pixels in the bounding slices. A wavelet fusion method was then employed to integrate prominent subband coefficients. Experiments have shown that fusion-based image reconstruction reduced artifacts, greatly improved reconstruction accuracy, and enhanced image details. Our method casts new light on MR imaging and image processing that demand high resolution in a short acquisition time

A pseudo wavelet-based method for accurate tagline tracing on tagged MR images of the tongue

In this paper, we present a pseudo wavelet-based tagline detection method. The tagged MR image is transformed to the wavelet domain, and the prominent tagline coefficients are retained while others are eliminated. Significant stripes are extracted via segmentation, which are mixtures of tags and anatomical boundary that resembles line. A refinement step follows such that broken lines or isolated points are grouped or eliminated. Without assumption on tag models, our method extracts taglines automatically regardless their width and spacing. In addition, founded on the multi-resolution wavelet analysis, our method reconstructs taglines precisely and shows great robustness to various types of taglines.

An accurate tongue tissue strain synthesis using pseudo-wavelet reconstruction-based tagline detection

This paper describe our work on tagline detection and tissue strain synthesis. The tagline detection method extends our previous work16 using pseudo-wavelet reconstruction. The novelty in tagline detection is that we integrated an active contour model and successfully improved the detection and indexing performance. Using pseudo-wavelet reconstruction-based method, prominent wavelet coefficients were retained while others were eliminated. Taglines were then extracted from the reconstructed images using thresholding. Due to noise and artifacts, a tagline can be broken into segments. We employed an active contour model that tracks the most likely segments and bridges them. Experiments demonstrated that our method extracts taglines automatically with greater robustness. Tissue strain was also reconstructed using extracted taglines.