Arquivo da categoria: Normal Swallowing

The Influence of Food Texture and Liquid Consistency Modification on Swallowing Physiology and Function: A Systematic Review

Catriona M. Steele, Woroud Abdulrahman Alsanei, Sona Ayanikalath, Carly E. A. Barbon, Jianshe Chen, Julie A. Y. Cichero, Kim Coutts, Roberto O. Dantas, Janice Duivestein, Lidia Giosa, Ben Hanson, Peter Lam, Caroline Lecko, Chelsea Leigh, Ahmed Nagy, Ashwini M. Namasivayam,Weslania V. Nascimento, Inge Odendaal, Christina H. Smith, Helen Wang

Dysphagia, October 2014.


Texture modification has become one of the most common forms of intervention for dysphagia, and is widely considered important for promoting safe and efficient swallowing. However, to date, there is no single convention with respect to the terminology used to describe levels of liquid thickening or food texture modification for clinical use. As a first step toward building a common taxonomy, a systematic review was undertaken to identify empirical evidence describing the impact of liquid consistency and food texture on swallowing behavior. A multi-engine search yielded 10,147 non-duplicate articles, which were screened for relevance. A team of ten international researchers collaborated to conduct full-text reviews for 488 of these articles, which met the study inclusion criteria. Of these, 36 articles were found to contain specific information comparing oral processing or swallowing behaviors for at least two liquid consistencies or food textures. Qualitative synthesis revealed two key trends with respect to the impact of thickening liquids on swallowing: thicker liquids reduce the risk of penetration–aspiration, but also increase the risk of post-swallow residue in the pharynx. The literature was insufficient to support the delineation of specific viscosity boundaries or other quantifiable material properties related to these clinical outcomes. With respect to food texture, the literature pointed to properties of hardness, cohesiveness, and slipperiness as being relevant both for physiological behaviors and bolus flow patterns. The literature suggests a need to classify food and fluid behavior in the context of the physiological processes involved in oral transport and flow initiation.


The effects of removable denture on swallowing

Son DS, Seong JW, Kim Y, Chee Y, Hwang CH.

Ann Rehabil Med. 2013 Apr;37(2):247-53. doi: 10.5535/arm.2013.37.2.247. Epub 2013 Apr 30.



To investigate the relationship between removable dentures and swallowing and describe risks.


Twenty-four patients with removable dentures who were referred for videofluoroscopic swallowing study (VFSS) were enrolled. We evaluated the change of swallowing function using VFSS before and after the removal of the removable denture. The masticatory performance by Kazunori’s method, sensation of oral cavity by Christian’s method, underlying disease, and National Institutes of Health Stroke Scale for level of consciousness were collected. Functional dysphagia scales, including the oral transit time (OTT), pharyngeal transit time (PTT), percentage of oral residue, percentage of pharyngeal residue, oropharyngeal swallow efficiency (OPSE), and presence of aspiration were measured.


Four patients dropped out and 20 patients were analyzed (stroke, 13 patients; pneumonia, 3 patients; and others, 4 patients). The mean age was 73.3±11.4 years. There were significant differences before and after the removal of the denture for the OTT. OTT was significantly less after the removal of the denture (8.87 vs. 4.38 seconds, p=0.01). OPSE increased remarkably after the removal of the denture, but without significance (18.24%/sec vs. 25.26%/sec, p=0.05). The OTT and OPSE, while donning a removable denture, were correlated with the masticatory performance (OTT, p=0.04; OPSE, p=0.003) and sensation of oral cavity (OTT, p=0.006; OPSE, p=0.007).


A removable denture may have negative effects on swallowing, especially OTT and OPSE. These affects may be caused by impaired sensation of the oral cavity or masticatory performance induced by the removable denture.


Age-related Differences in Tongue-Palate Pressures for Strength and Swallowing Tasks

Fei T, Polacco RC, Hori SE, Molfenter SM, Peladeau-Pigeon M, Tsang C, Steele CM.

Dysphagia. 2013 May 16.


The tongue plays a key role in the generation of pressures for transporting liquids and foods through the mouth in swallowing. Recent studies suggest that there is an age-related decline in tongue strength in healthy adults. However, whether age-related changes occur in tongue pressures generated for the purpose of swallowing remains unclear. Prior literature in this regard does not clearly explore the influence of task on apparent age-related differences in tongue pressure amplitudes. Furthermore, differences attributable to variations across individuals in strength, independent of age, have not clearly been elucidated. In this study, our goal was to clarify whether older adults have reduced tonguepalate pressures during maximum isometric, saliva swallowing, and water swallowing tasks, while controlling for individual variations in strength. Data were collected from 40 healthy younger adults (under age 40) and 38 healthy mature adults (over age 60). As a group, the mature participants had significantly lower maximum isometric pressures (MIPs). Swallowing pressures differed significantly by task, with higher pressures seen in saliva swallows than in water swallows. Age-group differences were not seen in swallowing pressures. Consideration of MIP as a covariate in the analysis of swallowing pressures revealed significant correlations between strength and swallowing pressures in the older participant group. Age-group differences were evident only when strength was considered in the model, suggesting that apparent age-related differences are, in fact, explained by differences in strength, which tends to be lower in healthy older adults. Our results show no evidence of independent differences in swallowing pressures attributable to age.


Timing Differences Between Cued and Noncued Swallows in Healthy Young Adults.

Nagy A, Leigh C, Hori SF, Molfenter SM, Shariff T, Steele CM.

Dysphagia. 2013 Mar 1


Temporal parameters such as stage transition duration, bolus location at swallow onset, and pharyngeal transit time are often measured during videofluoroscopy, but these parameters may vary depending on assessment instructions. Specifically, “command” (cued) swallows have been observed to alter timing compared to spontaneous (noncued) situations in healthy older adults. The aim of our study was to confirm whether healthy young people show timing differences for thin liquid swallows between cued and noncued conditions. Twenty healthy young adults swallowed 10-cc boluses of ultrathin barium in videofluoroscopy. The cued condition was to hold the bolus in the mouth for 5 s before swallowing. Three noncued swallows were also recorded. In the cued condition, bolus advancement to the pyriform sinuses prior to swallow initiation was seen significantly less frequently. Stage transition durations showed a nonsignificant trend toward being shorter. Pharyngeal transit times and pharyngeal response time (a measure capturing the interval between hyoid movement onset and bolus clearance through the upper esophageal sphincter) were both significantly longer in the cued condition. Our study in healthy young adults confirms findings previously observed in older adults, namely, that swallow onset patterns and timing differ between cued and noncued conditions. In particular, bolus advancement to more distal locations in the pharynx at the time of swallow onset is seen more frequently in noncued conditions. This pattern should not be mistaken for impairment in swallow onset timing during swallowing assessment.


Temporal variability in the deglutition literature

Dysphagia. 2012 Jun;27(2):162-77. doi: 10.1007/s00455-012-9397-x. Epub 2012 Feb 26.

Molfenter SMSteele CM.


A literature review was conducted on temporal measures of swallowing in healthy individuals with the purpose of determining the degree of variability present in such measures within the literature. A total of 46 studies that met inclusion criteria were reviewed. The definitions and descriptive statistics for all reported temporal parameters were compiled for meta-analysis. In total, 119 different temporal parameters were found in the literature. The three most-frequently occurring durational measures were upper esophageal sphincter opening, laryngeal closure, and hyoid movement. The three most-frequently occurring interval measures were stage transition duration, pharyngeal transit time, and duration from laryngeal closure-to-UES opening. Subtle variations in operational definitions across studies were noted, making the comparison of data challenging. Analysis of forest plots compiling descriptive statistical data (means and 95% confidence intervals) across studies revealed differing degrees of variability across durations and intervals. Two parameters (UES opening duration and the laryngeal closure-to-UES opening interval) demonstrated the least variability, reflected by small ranges for mean values and tight confidence intervals. Trends emerged for factors of bolus size and participant age for some variables. Other potential sources of variability are discussed.

Physiological variability in the deglutition literature: hyoid and laryngeal kinematics.

Dysphagia. 2011 Mar;26(1):67-74. doi: 10.1007/s00455-010-9309-x. Epub 2010 Oct 7.

Molfenter SMSteele CM.


A literature review was conducted on hyoid and/or laryngeal displacement during swallowing in healthy populations according to several inclusion criteria. Anterior and superior displacement measures of both structures from previously published studies were compiled for meta-analysis. Results showed a large degree of variability across studies for each structure and plane of movement. Potential sources of variation were identified, including statistical, methodological, stimulus-related, and participant-related sources.


Hyoid motion during swallowing: factors affecting forward and upward displacement.

Dysphagia. 2002 Fall;17(4):262-72.

Ishida RPalmer JBHiiemae KM.


During swallowing, the hyoid bone is described as moving first upward, then forward, then returning to the starting position. This study examined hyoid motion during swallowing of chewed solids and liquids. Barium videofluorography (VFG) was performed on 12 healthy volunteers eating 8-cc portions of various solid foods and drinking liquid. Hyoid position was measured frame-by-frame for 88 swallows relative to the occlusal plane of the upper teeth. The hyoid bone moved both upward and forward during swallowing, but upward displacement was sometimes very small. There was no correlation between the amplitudes of hyoid upward and forward displacements. The amplitude of upward displacement was highly variable, smaller for liquids than for solid foods (p <0.001), and, for solid foods, larger for the first swallow than for the second swallow (p = 0.02). The amplitude of forward displacement did not differ significantly between liquids and solids or between first and second swallows. We conclude that upward displacement of the hyoid bone in swallowing is related primarily to events in the oral cavity, while its forward displacement is related to pharyngeal processes, especially the opening of the upper esophageal sphincter.

Analysis of Hyoid Bone Using 3D Geometric Morphometrics: An Anatomical Study and Discussion of Potential Clinical Implications

Fakhry N, Puymerail L, Michel J, Santini L, Lebreton-Chakour C, Robert D, Giovanni A, Adalian P, Dessi P.

Dysphagia. 2013 Feb 28.


The aim of this study was to obtain a quantitative anatomical description of the hyoid bone using modern 3D reconstruction tools and to discuss potential applications of the knowledge in clinical practice. The study was conducted on 88 intact hyoid bones taken from cadavers during forensic autopsies (group 1) and on 92 bones from CT scan images of living adult subjects (group 2). Three-dimensional reconstructions were created from CT scan images using Amira 5.3.3® software. An anatomical and anthropological study of hyoid bones was carried out using metric and morphological analyses. Groups 1 and 2 were compared to evaluate the influence of muscle traction on hyoid bone shape. Characteristics of the hyoid bone were highly heterogeneous and were closely linked with the sex, height, and weight of the individuals. Length and width were significantly greater in men than in women (39.08 vs. 32.50 mm, p = 0.033 and 42.29 vs. 38.61 mm, p = 0.003), whereas the angle between the greater horns was larger in females (44.09 vs. 38.78, p = 0.007). There was a significant positive correlation between the height (Pearson coefficient correlation r = 0.533, p = 0.01) and weight (r = 0.497, p = 0.01) of subjects and the length of the hyoid bone. Significant metric differences were shown between group 1 and group 2. This very reproducible methodology is important because it may lead to clinical studies in, e.g., head and neck cancer or sleep apnea. Such studies are ongoing in our research program.


New Directions for Understanding Neural Control in Swallowing: The Potential and Promise of Motor Learning

Ianessa A. Humbert, Rebecca Z. German

Dysphagia, March 2013, Volume 28, Issue 1, pp 1-10


Oropharyngeal swallowing is a complex sensorimotor phenomenon that has had decades of research dedicated to understanding it more thoroughly. However, the underlying neural mechanisms responsible for normal and disordered swallowing remain very vague. We consider this gap in knowledge the result of swallowing research that has been broad (identifying phenomena) but not deep (identifying what controls the phenomena). The goals of this review are to address the complexity of motor control of oropharyngeal swallowing and to review the principles of motor learning based on limb movements as a model system. We compare this literature on limb motor learning to what is known about oropharyngeal function as a first step toward suggesting the use of motor learning principles in swallowing research.


Influence of chin-down posture on tongue pressure during dry swallow and bolus swallows in healthy subjects.

Dysphagia. 2011 Sep;26(3):238-45. doi: 10.1007/s00455-010-9292-2. Epub 2010 Jul 27.

Hori KTamine KBarbezat CMaeda YYamori MMüller FOno T.

The purpose of this study was to investigate the influence of chin-down posture and bolus size on tongue pressure during swallowing. Eleven healthy volunteers (7 men, 4 women; age range = 26-59 years) participated in the experiments. Tonguepressure during dry and 5- and 15-ml water swallows in neutral and chin-down postures was measured using a sensor sheet system with five measuring points on the hard palate. Sequential order, maximal magnitude, duration, and integrated value oftongue pressure at each measuring point were compared between postures and bolus sizes. Onset of tongue pressure at posterior-circumferential parts occurred earlier in dry swallow than in 5- and 15-ml water swallows in each posture. Chin-down posture was most effective for increasing tongue pressure in the 5-ml water swallow compared with dry swallow and the 15-ml water swallow, but it had almost no influence on tongue pressure with the 15-ml water swallow. These results suggest that chin-down posture increases the tongue driving force for small boluses in healthy subjects, which can be interpreted to mean that oropharyngeal swallowing in a chin-down posture requires more effort.