The usefulness of the line spread test as a measure of liquid consistency

Sliced Jelly Whole Swallowing Reduces Deglutition Risk: A Novel Feeding Method for Patients with Dysphagia

Texture modification in the form of gels or jellies is used for patients with dysphagia. For over 20 years, our group has been using gelatin jellies, a type of gel, as a starting diet for patients with dysphagia. Gelatin jellies are served in a small-sliced form and swallowed whole. In sliced jelly whole swallowing (SJWS), sliced gelatin jelly (SGJ) passes through the pharynx in one lump without collapsing. This study aimed to examine the usefulness of SJWS. We analyzed the images of videofluoroscopic swallowing studies performed using the normalized residue ratio scale (NRRSv: vallecula, NRRSp: pyriform sinus), the penetration-aspiration scale (PAS), and pharyngeal transit time (PTT) in 50 patients with dysphagia and compared the results in a prospective study. SJWS had significantly less residue in both NRRSv and NRRSp than in moderately thickened liquid swallowing. No significant differences in PAS scores were found between SGJ and moderately thickened liquid. Additionally, no significant differences in PTT scores were noted between the two. This study demonstrated the usefulness of SJWS in improving swallowing safety in patients with dysphagia. Further studies are needed to evaluate the reproducibility of the test, the comparison of SGJ with other thickened liquids, and the safety of SJWS for different diseases.

Effect of Setting Time on Viscosity Stability of Xanthan Gum- and Starch-Based Thickened Beverages for Patients with Dysphagia: Comparison of IDDSI Syringe Flow Test and Line-Spread Test

Because the viscosity of thickened beverages prepared with thickeners gradually changes before consumption, achieving their desired viscosity is important for managing dysphagia. This study aimed to investigate the viscosity changes of thickened beverages (water, orange juice, and milk) prepared with xanthan gum (XG)- and starch-based commercial thickeners over time using the syringe flow test (SFT) and line-spread test (LST). The LST values of beverages stabilized more quickly (≤1.5 h) than the SFT values (2.0∼3.5 h) at level 2 (mildly thick), whereas the opposite finding was observed at level 3 (moderately thick). After stabilization in a water system, SFT and LST yielded similar results. However, the SFT values of orange juice and milk thickened with XG-based thickener exceeded the reference values at level 2 and gradually increased at level 3. These results may be attributed to particulates interrupting fluid flow from the small tip of the syringe and the high friction force caused by the contact between the thickened sample and the syringe surface. The results suggest that the LST method is more reliable than the SFT method in clearly distinguishing between levels 2 and 3 of thickened beverages and demonstrate that the viscosity measurements of thickened beverages over time after preparation were strongly influenced by the measurement tools used for predicting the thickness level.

Visual assessment and rheological characterization of shape retention of products on a surface

A device to measure the height loss of a sample extruded from a syringe on a surface is described thus emulating toothpaste extrusion from a tube with the goal to predict shape retention of the extruded ribbon. Correlations with rheological tests are considered with a special focus on experiments more likely to be implementable in an industrial environment. In agreement with previous studies, the instantaneous viscosity maximum measured in a stress ramp test is a good predictor of ribbon height loss. Up- and down-shear flow curves of the thixotropic loop were fitted with a generalized Casson equation and the correlations of the fitting parameters with the height loss were also considered. Yield stress extracted from the up-shear flow curve as well as the shape of the curve is found to define the ribbon height loss as well as the degree of thixotropy which may be quantified by the width of the loop or simply as the ratio of viscosities at low shear rate.

Improved system for measuring rheological properties of thickened liquid using an inclined parallel plate and optical sensor

The purpose of this study was to improve the method of using an inclined parallel plate (IPP) in directly estimating the yield stressτ iy and evaluating the properties of a thickened liquid. The flow curve of the relationship between the shear rate and shear stress of a liquid thickened with a xanthan gum agent was predicted using the Herschel-Bulkley fluid model ( τ = τ y + k γ ˙ n - 1 ). We supposed that the yield stressτ y and the result of a line spread test (LST) indicate the deformation state and the flow state of shear stress ( k γ ˙ n - 1 ), respectively.τ iy , the yield stressτ ry estimated adopting a rotational viscometer and LST, was investigated for three liquids thickened with xanthan gum at four concentrations (C) at intervals of 0.5 wt% within the range 0.5-2.0 wt%. Linear plots of the relations of C versusτ iy andτ ry and the LST show that with an increase in C , the resistance force (τ ry andτ iy ) increases until flow starts, after which viscosity increases. We suggest that yield stressτ iy estimated with the IPP method effectively indicates the rheological properties of thickened liquids.

Instrumental and sensory techniques to characterize the texture of foods suitable for dysphagic people: A systematic review

The interest to characterize texture-modified foods (TMFs) intended for people with oropharyngeal dysphagia (OD) has grown significantly since 2011. Several instrumental and sensory techniques have been applied in the analysis of these foods. The objective of the present systematic review was to identify the most appropriate techniques, especially for the food industry and clinical setting. The search was carried out in three online databases according to the "Preferred Reporting Items for Systematic Reviews and Meta-Analyses" (PRISMA). Across the multiple trials reviewed, Texture Profile Analysis and the Uniaxial Compression Test were most used as the instrumental technique for solid foods, and the Back Extrusion Test for fluid and semisolid foods. All trials used descriptive analysis as the sensory technique. However, the experimental conditions of the trials lacked standardization. Consequently, the results of the trials were not comparable. To properly characterize the texture of TMFs intended for OD by each technique, an international consensus is needed to establish standardized experimental conditions. Methods based on these techniques should also be validated by collaborative studies to verify repeatability, replicability, and reproducibility.

Development of a simple evaluation instrument for liquid thickness measurement

Simple methods, such as the line spread test (LST), are often used to evaluate thickened liquids in clinical settings. Although it is desirable for these simple methods to be rapid, even the LST requires approximately 1 min to complete the evaluation. Herein, we aimed to shorten this time by developing a new simple instrument for evaluating thickened liquids considering the fluid engineering perspective with improved funnel design and evaluation methods. A thickened liquid was prepared with a xanthan gum-based thickening agent and water. Samples with viscosities of approximately 50, 150, 300, and 500 mPa∙s were prepared. For evaluation, 30 ml of the sample was injected manually with the outlet closed. The outlet was then opened to allow the liquid to fall as soon as the evaluation began. The time taken for the water surface of the liquid to move 50 mm from the starting point to the target point was measured eight times using a stopwatch, and the average was taken as the evaluation time. The instrument took 2.22-3.29 s, 3.29-9.16 s, and 9.16-23.14 s to classify mildly thick, moderately thick, and extremely thick samples, respectively. This method enabled extremely thick samples to be evaluated in 23 s, which is 27 s less than the time taken by the conventional funnel method. Verification results showed that this developed evaluation instrument for thickened liquids could perform classification according to the criteria of the Japanese Dysphagia Diet 2013. We aim to improve its design for clinical use in the future.

Improvement of simplified inclined plane test for evaluation of thickened liquids by using optical sensor

The thickening management index for food for dysphagia is important in enabling recognition of the rheological properties of thickened liquids, including their static and dynamic properties. One of the static properties of these liquids is the yield stress. An improvement to the simplified inclined plane test is proposed here that involves use of an automatic system for measurement of the displacements of thickened liquids on an inclined plate. The aim of this study is to investigate the relationship between the displacements of the thickened liquids and the variable thickener concentrations using an optical sensor. To measure the displacement of each thickened liquid on a clear inclined plate, an optical sensor that has a 12-mm-long light receiving surface is selected to form a one-dimensional position-sensitive detector (1D-PSD) under the clear inclined plate. The relationship between the angle of inclination of the plate θ at which the maximum voltage occurred in the 1D-PSD and five thickener (xanthan gum) concentrations c, ranging from 1.0 to 3.0 wt% in steps of 0.5 wt%, was investigated. It was confirmed that an approximately linear plot was obtained under the condition that θ = 8.24 c + 0.18, with the correlation R = .99 (for n = 7). This result indicated that the optical sensor composed of the 1D-PSD can measure the displacements of thickened liquids with various thickener concentrations on the clear inclined plate automatically.

Relationship between Syringe Flow Measurements and Viscosity of Nectar-Thick Beverages for Dysphagia Management

Commercial cold beverages thickened with a xanthan gum (XG)-based food thickener were examined at different thickness levels by using the simple, cost-effective syringe flow test (SFT) developed by the International Dysphagia Diet Standardization Initiative (IDDSI). We prepared cold thickened beverage (CTB) samples with different thickener concentrations and measured them by extrapolating the viscosity range (51–350 mPa·s) for nectar-like consistency. CTBs were also measured via the line-spread test (LST), and the flow distance value (cm) by LST and the volume remaining (mL) in the syringe by SFT was correlated with the apparent viscosity (η_a,50). Plots comparing η_a,50 with SFT or LST values showed good exponential relationships between the measurements. The SFT showed a better relationship (R² = 0.928) than LST (R² = 0.825), indicating that the former can predict the viscosity better in the range for nectar-like consistency. In particular, the SFT showed a significant difference (R² = 0.964) compared to the LST (R² = 0.709) for thickened protein-based beverages. These results suggest that the SFT using the IDDSI methodology is a more suitable instrument than the LST for accurately evaluating the viscosity of XG-based CTBs with nectar-like consistency.

The influence of pharyngeal width on post-stroke laryngeal aspiration

BACKGROUND

Laryngeal penetration, which is a less serious form of aspiration, should be considered in patients with stroke to ensure early detection of risk of laryngeal aspiration and prevention of pneumonia.

OBJECTIVE

As a follow-up to a previous study that demonstrated the association of pharyngeal width to laryngeal aspiration, the present study sought to determine whether the pharyngeal width was related to not only laryngeal aspiration but also laryngeal penetration in patients with deglutition disorder following stroke.

METHODS

The pharyngeal width on the roentgenogram was measured and compared based on the severity of aspiration. Moreover, the optimal cut-off points were determined for predicting the penetration and aspiration so that the difference between the penetration and the aspiration could be elucidated.

RESULTS

The pharyngeal width of the patients was wider than the controls. The increase of the pharyngeal width by aspiration severity was more evident in the patients with chronic and right cerebral stroke. The optimal cut-off point of the pharyngeal width was approximately 1 mm lesser for the prediction of penetration than for aspiration.

CONCLUSIONS

The pharyngeal width could be an ancillary method for detecting penetration and aspiration in stroke patients.

Development of a ball back extrusion technique for texture analysis of fluid food

Textural properties of a food not only influence consumers' sensory preference of the product but also more importantly influence the strategy of food oral manipulation. Availability of reliable instrumental techniques has always been sought by food industry for proper assessment of food texture both in lab and online quality control. In this work a set of ball back extrusion (BBE) geometries with various ball/cup diameters (38/40, 35/40, 31.5/40, 24.5/28, all in mm) have been assessed as a fixture of a standard texture analyzer for flowability and consistency test of fluid foods. The feasibility of the new design has been tested against plate back extrusion (PBE), a current standard, for a set of fluid food materials (3 near Newtonians and 2 non-Newtonians). Pressing force and apparent maximum stress were used to quantify the flowability of fluid materials. It was observed that both techniques were able to reflect the rheological nature of the samples and were able to distinguish flowability for both Newtonian and Non-Newtonian fluids. However, the new design shows advantages against the plate back extrusion with much improved stability. Results show that BBE could replace the conventional plate-back extrusion to evaluate the flow properties of fluid foods in an industrial environment. The geometries of 35/40 or 24.5/28 ball/cup diameters (aspect ratio 0.875) were shown to give most satisfactory performance. The device is specifically suitable for texture classification of fluid foods for dysphagia management.

Texture-Modified Food for Dysphagic Patients: A Comprehensive Review

Food texture is a major food quality parameter. The physicochemical properties of food changes when processed in households or industries, resulting in modified textures. A better understanding of these properties is important for the sensory and textural characteristics of foods that target consumers of all ages, from children to the elderly, especially when food product development is considered for dysphagia. Texture modifications in foods suitable for dysphagic patients will grow as the numbers of elderly citizens increase. Dysphagia management should ensure that texture-modified (TM) food is nutritious and easy to swallow. This review addresses how texture and rheology can be assessed in the food industry by placing particular emphasis on dysphagia. It also discusses how the structure of TM food depends not only on food ingredients, such as hydrocolloids, emulsifiers, and thickening and gelling agents, but also on the applied processing methods, including microencapsulation, microgels as delivery systems, and 3D printing. In addition, we address how to modify texture for individuals with dysphagia in all age groups, and highlight different strategies to develop appropriate food products for dysphagic patients.

Effect of commercially available thickening agents on ready-to-feed infant formulas

Because of the importance of providing the appropriate fluid consistency for effective management of swallowing problems (dysphagia) in infants, this project sought to determine the effect of three commercially available thickening agents on the resulting thickened consistencies of commonly prescribed, ready-to-feed infant formulas. Nine ready-to-feed infant formulas were thickened with three different thickening agents to nectar and honey consistencies following manufacturer's instructions and their resulting thickness was measured via line spread test (LST). The nine formulas with nothing added to them (thin liquids) and the 27 target-nectar and 27 target-honey samples together created 63 unique samples for comparison. A series of one-way analysis of variance analyses were conducted to determine if the resulting thickness (as measured by LST values) for target categories of nectar and honey consistencies was significantly influenced by the type of thickening agent used. The achieved thickness of the formula samples as measured by LST values was statistically significantly different for the three different types of thickening agents used to achieve a target nectar consistency, F (2, 24) = 15.55, p < .001, η p 2 = .709. Additionally, the achieved thickness of the formula samples was statistically significantly different for the three different types of thickening agents used to achieve a target honey consistency, F (2, 24) = 16.18, p < .001, η p 2 = .709. The results of this study reveal that the choice of thickening agent impacts the resulting thickness of ready-to-feed infant formula.

Rheological and Nutritional Assessment of Dysphagia-Oriented New Food Preparations

Dysphagia that involves difficulty swallowing food and liquids is a symptom of different diseases. In some cases, patients who experience this symptom should be fed with modified consistency foods. Dysphagia is often accompanied by malnutrition and dehydration and an interesting approach to dealing with these conditions is to provide patients with nutrient-rich foods. In this study, two new food formulations for dysphagia patients are proposed: a cereal-based protein meal and a vegetable cream. The nutritional and rheological characteristics of the two innovative preparations were assessed and compared with those of commercial products. The proposed protein meal formulations meet the criteria for the “high protein” claim and the vegetable cream meets those of the “source of fiber” claim. The rheological investigation revealed that the flow properties of the innovative formulations were comparable to those of the commercial ones. Based on these preliminary outcomes, this investigation represents an interesting perspective potentially valuable to enlarge the offer of possibilities for people suffering from swallowing disorders.

A proposed method of evaluating the yield stress of a thickened liquid using a simplified inclined plane test

Managing the thickening index of food is important for dysphagia and helps in recognizing the static and dynamic rheological properties of the thickening agent. One dynamic property is the viscosity under a shear rate of 50 s^-1 , and one static property is the yield stress at a shear rate of 0 s^-1 . The purpose of this study is to design a simplified inclined plane test to identify the yield stress of a thickened liquid by observing flow behavior on an inclined plate. The yield angle (stress) is defined as the inclination angle of the plate just before the thickened liquid flows. The concentrations (yield stresses, yield angles) of a thickening agent containing xanthan gum are 1.0 (1.2, 3°), 1.5 (5.6, 13°), 2.0 (7.5, 26°), 2.5 (12.5, 26°), and 3.0 (19.1, 42°) wt% (Pa, degrees). We measured the time course of the displacement of the downstream edge (DDE) of the thickened liquid on the inclined plate. The discrete inclination angles were in the range of 0° to 42°. The DDE after 10 s was more than 4.5 mm for all concentrations of the thickening agent at an inclination greater than the yield angle of the plate. We confirmed that the yield angle identifies the yield stress for the thickened liquid via the DDE using the simplified inclined plane test with discrete inclination angles.

Changes in Pharyngeal Width Over Time as an Indicator of Dysphagia in Stroke Patients

Objective

To verify the pharyngeal width at rest as a measurement that could be used to assess changes in the degree of dysphagia over time in stroke patients.

Methods

In a cohort of stroke patients, we performed serial measurements of the pharyngeal width at the midpoints of the second (C2) and third (C3) cervical vertebral bodies using lateral neck X-rays while the patients were at rest. The JOSCYL width, a parameter named after the first initial of each developers’ surname and defined as the average value of the upper and lower pharyngeal widths, was used to formulate the JOSCYL scale, which was calculated as the JOSCYL width × 100/neck circumference. All patients also underwent serial videofluoroscopic swallowing studies (VFSSs). The Spearman correlation analysis was used to detect correlations between the serial VFSS results, JOSCYL widths, and JOSCYL scale values.

Results

Over time, we observed significant positive and negative correlations of change in the JOSCYL width and scale with changes in the Penetration-Aspiration Scale and the Dysphagia Outcome and Severity Scale scores, respectively.

Conclusion

The JOSCYL width and JOSCYL scale clearly reflected changes in dysphagia in stroke patients over time. These parameters may provide an easier method for evaluating whether post-stroke dysphagia has been alleviated.

Predictive Value of Pharyngeal Width at Rest (JOSCYL Width) for Aspiration in Elderly People

Objective

To develop a new tool for aspiration risk prediction based on pharyngeal width at rest in older adults with symptoms of aspiration.

Methods

Lateral cervical spine roentgenograms were obtained from 33 older adult patients who complained of dysphagia and from 33 healthy, age-matched controls. Pharyngeal width at rest was measured at two points. We named the average of these two pharyngeal widths ‘JOSCYL Width’, calculated ‘JOSCYL Scale’, and compared these parameters between dysphagia and control groups. Correlations of individual JOSCYL Width and JOSCYL Scale, with Penetration Aspiration Scale (PAS) and Dysphagia Outcome and Severity Scale (DOSS) scores were analyzed for the dysphagia group. To determine optimal cutoff points for predicting aspiration, a receiver operating characteristic curve analysis was performed on JOSCYL Width and JOSCYL Scale.

Results

Both JOSCYL Width and JOSCYL Scale of the dysphagia group were larger than those of the control group (p<0.001). The correlation between JOSCYL Width and severity of dysphagia was significant for the dysphagia group (PAS p=0.007; DOSS p=0.012). The correlation between JOSCYL Scale and the severity of dysphagia was also significant for the dysphagia group (PAS p=0.009; DOSS p=0.011). Optimal cutoffs for JOSCYL Width and JOSCYL Scale for predicting aspiration were 20.0 mm and 5.9, respectively.

Conclusion

JOSCYL Width and JOSCYL Scale can be new indicators for predicting aspiration in older adults. They are both precise and easy to use.

Thickened Liquids for Dysphagia Management: a Current Review of the Measurement of Liquid Flow

PURPOSE OF REVIEW

The use of thickened liquids has become one of the most common management strategies for individuals with dysphagia. The purpose of this paper is to review methods that can be used to measure the flow characteristics of liquids used in dysphagia management. We describe the measurement of apparent viscosity, measures of extensional flow, slump tests (specifically the line-spread test and Bostwick consistometry), gravity flow tests, and subjective methods.

RECENT FINDINGS

We discuss the relationship between different approaches to measuring flow, the 2002 American National Dysphagia Diet and the 2017 International Dysphagia Diet Standardisation Initiative (IDDSI) framework. A comparison of test results across four methods is provided.

SUMMARY

A consistent approach is needed for the measurement of flow for thickened liquids used in dysphagia management. This review highlights differences that can be expected across different flow testing methodologies. Adherence to a common method and measurement definitions will promote patient safety and facilitate future research regarding the effectiveness of texture modification as an intervention for dysphagia.

Comparison of two methods to categorize thickened liquids for dysphagia management in a clinical care setting context: The Bostwick consistometer and the IDDSI Flow Test. Are we talking about the same concept?

The Bostwick consistometer and the International Dysphagia Diet Standardization Initiative (IDDSI) Flow Test are both proposed methods to measure and categorize thickened liquids for dysphagia management. The objectives were to: (a) compare the Bostwick consistometer reference values used in clinical settings and the IDDSI reference values of thickened liquids suggested for nutrition care plans in the management of dysphagia when measuring commercially available preprepared thickened liquids; (b) explore the relationship between the two methods; (c) assess the interchangeability; (d) document the intra-rater reliability. Preprepared thickened liquids (n = 32) were measured twice with the Bostwick consistometer and 3 times with the IDDSI Flow Test, using a rigorous methodology. A registered dietitian nutritionist and a registered nutrition and dietetic technician performed the measurements. The Pearson's correlation coefficient was calculated to explore the relationship between the two methods. Using a linear regression equation, back-calculations of the IDDSI Flow Test values were done, based on the experimental Bostwick results. Interchangeability was assessed by documenting the level of agreement between the results with a Bland and Altman graphical analysis. Intraclass correlation coefficients calculation and a Bland and Altman graphical analysis were performed to assess reliability. The strong correlation (r = -.93, p < .001) between the IDDSI Flow Test and the Bostwick consistometer measurements suggests that they measure flow rate in a similar manner, but not exactly the same, as confirmed with the Bland and Altman graphical analysis. Thus, they produced results that are not interchangeable. However, both tests show excellent intra-rater reliability (ICC ≥ 0.99) when using a rigorous methodology. PRACTICAL APPLICATIONS: Thickened liquids are used to manage oropharyngeal dysphagia. Clinicians need to provide quality assurance/quality control (QA/QC) support in the selection or production of thickened liquids as well as staff training or patient education regarding these products. Methods and classification have been proposed to measure and categorize thickened liquids for dysphagia management, such as the line spread test, the Bostwick consistometer method, and the IDDSI Flow Test. Although empirical, these methods are more accessible to clinicians than viscometer or rheometer assessments. Clinicians need to understand the limitations of these techniques as neither appear to capture the full extent of consistency for potential beverages available on the market or produced in-house. In this article, we compare the Bostwick consistometer and the IDDSI Flow Test methods and classifications and propose a standard operating procedure in order to maximize the quality of results. We point out the large variations in consistency levels of commercial preprepared thickened liquids in light of the absence of evidence of clinical outcomes associated with either proposed methods or consistency classifications.

Comparative study of IDDSI flow test and line-spread test of thickened water prepared with different dysphagia thickeners

The flow behaviors of thickened water samples prepared with six commercial instant thickeners (A-F) were investigated at different thickness levels using the inexpensive, simple, and visual clinical tools, such as a line-spread test (LST) and a syringe flow test developed by the International Dysphagia Diet Standardization Initiative (IDDSI). Both the flow distance value measured by the LST and the volume remaining in syringe by IDDSI flow test were compared with the apparent viscosity (η_a,50 ) values measured with a sophisticated computer-controlled rheometer. The η_a,50 values of thickened water samples increased as thickener concentration increased, whereas the flow distance (cm; LST) or remaining volume (ml; IDDSI flow test) were decreased. Plots comparing η_a,50 values to LST flow distances and IDDSI volumes revealed exponential relationships (R²  = 0.926 for the LST and R²  = 0.898 for IDDSI test) between the two measurements. Such lower determination coefficient (R² ) values (0.898) by IDDSI flow test seems to be due to the stickiness characteristics of starch component in starch-based thickeners (E and F), indicating that the syringe flow test is not suitable for starch-based thickeners. However, the thickened water samples prepared only with xanthan gum (XG)-based thickeners (A-D) showed strong relationships (R²  = 0.972 for the LST and R²  = 0.939 for IDDSI test). These results suggest that the LST is a more reliable method than the IDDSI test for evaluating the correct and desirable viscosity for the dysphagia diet, and that the IDDSI test provides a means to predict the rheometer-measured viscosity of water thickened with only XG-based thickeners. PRACTICAL APPLICATIONS: The effective management of dysphagia requires the thickened fluids prepared with the correct and desirable viscosity. In terms of clinical practice, it is very important to observe the comparison of LST with IDDSI flow test to determine a suitable method for estimating the correct viscosity of thickened fluids. Our results showed good relationships between the rheometer-measured viscosity and flow values measured by the LST and IDDSI test methods for the thickened water samples prepared with different foods thickeners. The IDDSI flow test may be useful as a clinical training tool for preparing thickened fluids with only XG-based thickeners to a target level of viscosity. These results presented in this study will provide clinicians, caregivers, and patients with valuable information for IDDSI flow test as an inexpensive and simple method for measuring the correct viscosity.

Use of Textured Thin Liquids in Patients With Dysphagia

PURPOSE

The goals of this article are to explore the use of textured thin liquids for dysphagic patients who require thickened liquids and to illustrate their impact on hydration and patient satisfaction.

METHOD

A retrospective evaluation of textured thin liquids was completed using patient data looking at laboratory values relevant to the detection of dehydration (blood urea nitrogen, creatinine, sodium) and patient satisfaction (using a clinician-generated questionnaire) on different modified liquid textures. In addition, the viscosity for all liquids was tested using a rheometer.

RESULTS

Measurements show that the viscosity of the textured thin liquids examined in this pilot study are significantly lower than the viscosity of nectar-thick liquids and fall within the "thin" category as defined by the National Dysphagia Diet guidelines. Patients on honey- and nectar-thick liquids had laboratory values signifying dehydration, whereas those receiving the textured thin liquid consistency were within the normal range for all laboratory values. Importantly, when consuming textured thin liquids, patients reported significant improvement in their satisfaction related to their thirst.

CONCLUSION

The results of this pilot study highlight the consequences of common thickened liquid dietary recommendations and of the potentially beneficial clinical application of textured thin liquids for patients with dysphagia as well as the need for future prospective research.

Visualizing the Consistency of Thickened Liquids With Simple Tools: Implications for Clinical Practice

PURPOSE

Accurate texture modifications to thin liquids are a critical aspect of patients' nutritional health and well-being. This study explored the use of 3 tools (2 distance- and 1 time-measuring devices) to characterize texture-modified liquids. The objectives were to use the tools to measure modified liquids, to determine if measurements differentiated nectar and honey levels of modification, and to compare measurements with other published reports.

METHOD

We measured the flow distance of 33 prethickened water samples in centimeters (cm) using a line spread apparatus and a Bostwick Consistometer (Christison Particle Technologies). We selected a Zahn viscosity cup to measure the stream time of each prethickened liquid in seconds.

RESULTS

The 2 distance-measuring devices (line spread and Bostwick Consistometer) showed that thinner (nectar-thick) modifications spread or flowed a farther distance in comparison to thicker (honey-like) modifications. Testing with the line spread indicated that an average spread distance of 4.5 cm differentiated nectar-thick and honey-like consistencies. A flow distance of greater than 15 cm differentiated nectar from honey consistency measured with a Bostwick Consistometer. We were not successful in using the Zahn viscosity cup to determine the stream time of modified liquids.

CONCLUSIONS

Two of the tools provided objective information about levels of liquid modification, which has implications for day-to-day preparation. Measurement tools that are accurate and easy to use have the potential to provide quick and dependable feedback to verify a prescribed level of liquid modification. Further efforts are needed to standardize the application of simple measurement tools in the management of patients who consume thickened liquids.

The Criteria of Thickened Liquid for Dysphagia Management in Japan

In Japan, the viscosity of thickened liquids is different among hospitals and nursing homes. In order to standardize viscosity of thickened liquids, the dysphagia diet committee of the Japanese Society of Dysphagia Rehabilitation developed the Japanese Dysphagia Diet 2013 (JDD2013). To decide on a definition of thickened liquids, the committee reviewed categories from other countries. Especially, the criteria of the USA and Australia were used as references. The definition had three levels: mildly thick, moderately thick, and extremely thick. Then a sensory evaluation by health care workers was carried out to decide the viscosity range of each level, and a draft document was made. After collecting public comments, follow-up experiments using thickened water with thickeners using xanthan gum were performed, and the JDD2013 (Thickened Liquid) was determined. The JDD2013 (Thickened Liquid) evaluated the drinking properties, visual properties, and viscosity values of each level. The shear rate of 50 s^-1 was adopted to measure the viscosity with a cone and plate type viscometer to duplicate the measurement criteria used by the USA. We also set the values of the JDD2013 with the Line Spread Test to promote the use of guidelines in clinical practice. We believe the JDD2013 standards help hospitals and other settings that care for people with dysphagia to use the same thickness level and the same labels. In the future, the JDD2013 levels will be compared with new international guidelines to help with international understanding of the JDD2013 levels.

Development of a simple and objective evaluation method for thickened liquids using funnels

Some patients with dysphagia are prone to aspiration of low-viscosity liquids. Thickened liquids are often used in attempts to prevent aspiration. The patients should be given thickened liquids with suitable thickness, and the thickness should be constant at all time. While rotational and cone-and-plate viscometers are used for the evaluation of thickened liquids, they are high-precision and expensive equipment. To control the thickness of liquids, a simple and objective evaluation method is thus necessary. We developed a method to evaluate thickened liquids using funnels, and verified the appropriateness of this method. We measured the outflow times of five thickened liquids through funnels. One of the thickened liquids was a commercially available nutritional supplement, another was made with a thickening agent that contained guar gum, and all others were made with a thickening agent that contained xanthan gum. Four funnels with different stem sizes were tested. We found that the outflow time of thickened liquids through a funnel depended on their viscosities at a shear rate between 10 and 50 s^-1 , when the average inner diameter of the stem was in the range of 5.3-9.0 mm, and the volume of the liquid poured into the funnel was 30 mL. The correlation coefficient between the value of the sensory evaluation and the outflow time of the funnel with an average stem ID of 5.3 mm was 0.946. Therefore, this method may be useful in hospital and nursing home kitchens for evaluating thickened liquids.

PRACTICAL APPLICATIONS

The findings of this study will help develop a new method for the evaluation of thickened liquids. Funnels made from polypropylene, which are inexpensive and light, were used in this method. The process for measuring the outflow time of thickened liquids through a funnel is simple, and we can obtain quantitative data that are objective. Even though line spread test (LST) is well known as a simple measurement method, nutritional supplements and liquids thickened using a thickening agent containing guar gum have not been evaluated accurately. The funnel method was found to have a stronger correlation with sensory evaluation compared to LST. This method is useful in hospital and nursing home kitchens for evaluating thickened liquids.

Effect of Time and Temperature on Thickened Infant Formula

BACKGROUND

Unlike adult populations, who primarily depend on liquids for hydration alone, infants rely on liquids to provide them with hydration and nutrition. Speech-language pathologists working within pediatric medical settings often identify dysphagia in patients and subsequently recommend thickened liquids to reduce aspiration risk. Caregivers frequently report difficulty attempting to prepare infant formula to the prescribed thickness.

MATERIALS AND METHODS

This study was designed to determine (1) the relationship between consistencies in modified barium swallow studies and thickened infant formulas and (2) the effects of time and temperature on the resulting thickness of infant formula. Prepackaged barium consistencies and 1 standard infant formula that was thickened with rice cereal and with 2 commercially available thickening agents were studied. Thickness was determined via a line spread test after various time and temperature conditions were met.

RESULTS

There were significant differences between the thickened formula and barium test consistencies. Formula thickened with rice cereal separated over time into thin liquid and solid residue. Formula thickened with a starch-based thickening agent was thicker than the desired consistency immediately after mixing, and it continued to thicken over time. The data from this project suggest that nectar-thick and honey-thick infant formulas undergo significant changes in flow rates within 30 minutes of preparation or if refrigerated and then reheated after 3 hours.

CONCLUSIONS

Additional empirical evidence is warranted to determine the most reliable methods and safest products for thickening infant formula when necessary for effective dysphagia management.

Relationship between Apparent Viscosity and Line-Spread Test Measurement of Thickened Fruit Juices Prepared with a Xanthan Gum-based Thickener

The flow behaviors of three thickened fruit juices (orange, apple, and grape juice) prepared with a commercial instant xanthan gum (XG)-based thickener that is marketed in Korea were investigated at different thickener concentrations (1.0%, 1.5%, 2.0%, 2.5%, 3.0%, and 3.5%) and setting times (5 and 30 min) using a rheometer and a line-spread measurement method. The flow distance values measured by the line-spread test (LST) were compared with the apparent viscosity (η_a,50) values measured with a sophisticated computer-controlled rheometer. The η_a,50 values of the juices increased as thickener concentration increased, whereas their flow distances decreased. The η_a,50 values at the 30-min setting time were much higher than those at the 5-min setting time, indicating that the setting time before serving or consuming thickened juices can affect viscosity values. Plots comparing η_a,50 values to LST flow distances revealed strong exponential relationships between the two measures (R²=0.989 and R²=0.987 for the 5- and 30-min setting times, respectively). These results indicate that the LST can be a suitable instrument for evaluating the viscosity of thickened fruit juices prepared with different XG-based thickener concentrations and setting times for the dysphagia diet.

Comparison of different gum-based thickeners using a viscometer and line spread test: a preliminary study

Objective

To compare fluid thickeners composed of starch polysaccharide (STA), guar gum-based polysaccharide (GUA), and xanthan gum-based polysaccharide (XAN) with the use of a viscometer and a line spread test (LST) under various measurement conditions.

Methods

The viscosity of thickened fluid with various concentrations (range, GUA 1%-4%, XAN 1%-6%, STA 1%-7%, at intervals of 1%) was measured with a rotational viscometer with various shear rates (1.29 s^-1, 5.16 s^-1, 51.6 s^-1, and 103 s^-1) at a temperature of 35℃, representing body temperature. The viscosity of STA showed time dependent alteration. So STA was excluded. Viscosities of GUA and XAN (range of concentration, GUA 1%-3%, XAN 1%-6%, at intervals of 1%) were measured at a room temperature of 20℃. LST was conducted to compare GUA and XAN (concentration, 1.5%, 2.0%, and 3.0%) at temperatures of 20℃ and 35℃.

Results

The viscosities of 1% GUA and XAN were similar. However, viscosity differences between GUA and XAN were gradually larger as concentration increased. The shear thinning effect, the inverse relationship between the viscosity and the shear rate, was more predominant in XAN than in GUA. The results of LST were not substantially different from GUA and XAN, in spite of the difference in viscosity. However manufacturers' instructions do not demonstrate the rheological properties of thickeners.

Conclusion

The viscosities of thickened fluid were different when the measurement conditions changed. Any single measurement might not be sufficient to determine comparable viscosity with different thickeners. Clinical decision for the use of a specific thickener seems to necessitate cautious consideration of results from a viscometer, LST, and an expert's opinion.

Line spread as a visual clinical tool for thickened liquids

PURPOSE

Preparing modified liquids to a target level of consistency is critical to patients' nutritional care. This study examined the relationship of line spread (i.e., the distance a liquid flows) to viscometer measurements for a variety of product/liquid combinations and determined if flow distance visually differentiated nectar-thick versus honey-like consistency.

METHOD

Combinations of 4 thickening products (3 starch-based and 1 gum-based thickener) prepared with 6 serving-temperature liquids that had various levels of fat, fiber, and added nutrients were tested. A total of 32 product/liquid combinations tested within the target range of 80-800 centipoise (cP). Measurements were recorded using line spread and a Brookfield RVDV-II+ viscometer.

RESULTS

Nectar-thick and honey-like consistencies significantly differed in their degree of line spread. Using our line spread apparatus, a value of 4.5 cm differentiated between nectar-thick and honey-like consistencies. There was an inverse correlation (-.75) between viscometer data and line spread results. That is, high viscosity values represented samples with less flow distance (line spread), and low viscosity values represented samples with more flow distance.

CONCLUSION

Line spread appears to be a quick, objective, and visual method that might be used to help patients and their caregivers achieve more accurate and consistent thickened liquid preparation.

Pharyngeal dysphagia in inflammatory muscle diseases resulting from impaired suprahyoid musculature

Dysphagia has previously been reported in the inflammatory myopathies (IMs): inclusion body myositis (IBM), dermatomyositis (DM), and polymyositis (PM). Patients report coughing, choking, and bolus sticking in the pharynx. Myotomy has been the treatment of choice, with variable success reported. We sought to determine underlying causes of dysphagia in IM patients using instrumental evaluation. Eighteen subjects participated in the study: four with DM, six with PM, and eight with IBM. They underwent simultaneous videofluoroscopy and manometry, yielding 214 swallows for analysis regarding function of the upper esophageal sphincter (UES), swallow initiation, hyolaryngeal excursion, and pharyngeal residue. Penetration and aspiration were also recorded. UES failed to relax in two participants. High incidence of pharyngeal dysphagia was noted; 72% of participants demonstrated abnormalities, including delayed swallow initiation (24%), decreased hyolaryngeal excursion (22%), pyriform residue (17%), and penetration (22%). Dysphagia in IM patients appears to be more due to impaired muscle contraction and reduced hyolaryngeal excursion than the often held belief of failed UES relaxation. The distinction between mechanisms causing patients' dysphagia should be examined, particularly if CP myotomy is being considered as it may be contraindicated for patients with normal UES relaxation. More studies investigating IM patients pre- and post-myotomy are needed.

Objective and quantitative definitions of modified food textures based on sensory and rheological methodology

INTRODUCTION

Patients who suffer from chewing and swallowing disorders, i.e. dysphagia, may have difficulties ingesting normal food and liquids. In these patients a texture modified diet may enable that the patient maintain adequate nutrition. However, there is no generally accepted definition of 'texture' that includes measurements describing different food textures.

OBJECTIVE

Objectively define and quantify categories of texture-modified food by conducting rheological measurements and sensory analyses. A further objective was to facilitate the communication and recommendations of appropriate food textures for patients with dysphagia.

DESIGN

About 15 food samples varying in texture qualities were characterized by descriptive sensory and rheological measurements.

RESULTS

Soups were perceived as homogenous; thickened soups were perceived as being easier to swallow, more melting and creamy compared with soups without thickener. Viscosity differed between the two types of soups. Texture descriptors for pâtés were characterized by high chewing resistance, firmness, and having larger particles compared with timbales and jellied products. Jellied products were perceived as wobbly, creamy, and easier to swallow. Concerning the rheological measurements, all solid products were more elastic than viscous (G'>G''), belonging to different G' intervals: jellied products (low G') and timbales together with pâtés (higher G').

CONCLUSION

By combining sensory and rheological measurements, a system of objective, quantitative, and well-defined food textures was developed that characterizes the different texture categories.

Viscosity in infant dysphagia management: comparison of viscosity of thickened liquids used in assessment and thickened liquids used in treatment

The purpose of this study was to investigate comparability of viscosity of liquids used in assessment and treatment of infants with dysphagia. Goals of this study were as follows: (1) Establish baseline viscosity values for (a) the commercial barium assessment liquids of varying thicknesses and (b) clinically typical infant formula thickened with varied thickeners. (2) Compare the baseline viscosities of the various liquids for correlation of values. We attempted to mimic real-world situations and recreate clinical assessment and treatment conditions. We also identified and made every effort to control typical clinical variables, e.g., mixer and mixing procedure, brand of product, and temperature of liquid. The method of measurement was based on rheologic principles and used a Brookfield Engineering LVDV II + Pro Cone/Plate Viscometer at spindle and speed combinations to maximize shear rates consistent with swallowing. Statistically, there was no comparability between barium and formula mixtures, regardless of thickener utilized. The implications of these findings and the need to develop a standardized means of thickening formula to a viscosity comparable to the assessment materials are discussed.