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.
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.
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.
This is a preview of subscription content, log in to check access.
Buy single article
Instant access to the full article PDF.
Price includes VAT for USA
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
This is the net price. Taxes to be calculated in checkout.
Papers of particular interest, published recently, have been highlighted as: • Of importance
• Cichero JAY, Steele CM, Duivestein J, Clave P, Chen J, Kayashita J, et al. The need for international terminology and definitions for texture modified foods and thickened liquids used in dysphagia management: foundations of a global initiative. Curr Phys Med Rehabil Rep. 2013;1(4):280–91. https://doi.org/10.1007/s40141-013-0024-z. http://link.springer.com/article/10.1007%2Fs40141-013-0024-z Paper describing variation in terminology around the world used to describe categories of food texture and liquid consistency for use in dysphagia management, illustrating the need for standard terms and measurement.
Garcia JM, Chambers E, Molander M. Thickened liquids: practice patterns of speech-language pathologists. Am J Speech Lang Pathol. 2005;14(1):4–13.
• Logemann JA, Gensler G, Robbins J, Lindblad AS, Brandt D, Hind JA, et al. A randomized study of three interventions for aspiration of thin liquids in patients with dementia or Parkinson’s disease. J Speech Lang Hear Res. 2008;51(1):173–83. Largest known randomized trial of the effect of liquid consistency on aspiration rates in people with dysphagia (dementia or Parkinson’s Disease), compared directly within a videofluoroscopy exam. Efficacy of thickened liquids for eliminating aspiration in this population was determined.
• Steele CM, Alsanei WA, Ayanikalath S, Barbon CE, Chen J, Cichero JA, et al. The influence of food texture and liquid consistency modification on swallowing physiology and function: a systematic review. Dysphagia. 2015;30(1):2–26. https://doi.org/10.1007/s00455-014-9578-x. http://bit.ly/1wvZydp Systematic review of > 10,000 references from the medical and engineering scientific literature regarding the influence of liquid consistency and food texture on swallowing function and physiology. Findings include evidence that thicker liquids do help to decrease aspiration. However, evidence was also found that residue begins to accumulate when liquids are too thick.
American Dietetic Association National Dysphagia Diet Task Force. National Dysphagia Diet: standardization for optimal care. Chicago: Faulhaber, D; 2002.
Steele CM, Van Lieshout PHHM, Goff D. The rheology of liquids: a comparison of clinicians? Subjective impressions and objective measurement. Dysphagia. 2003;18(3):182–95.
Glassburn DL, Deem JF. Thickener viscosity in dysphagia management: variability among speech-language pathologists. Dysphagia. 1998;13(4):218–22.
Cichero JA, Jackson O, Halley PJ, Murdoch BE. How thick is thick? Multicenter study of the rheological and material property characteristics of mealtime fluids and videofluoroscopy fluids. Dysphagia. 2000;15(4):188–200.
• Cichero JAY, Lam P, Steele CM, Hanson B, Chen J, Dantas RO, et al. Development of international terminology and definitions for texture-modified foods and thickened fluids used in dysphagia management: the IDDSI framework. Dysphagia. 2017;32(2):293–314. https://doi.org/10.1007/s00455-016-9758-y. http://link.springer.com/article/10.1007/s00455-016-9758-y. Paper describing the process followed by the International Dysphagia Diet Standardisation Initiative to develop a new framework of terminology, definitions and measurement techniques to classify texture modified foods and thickened liquids used in dysphagia management.
• Hanson B. A review of diet standardization and bolus rheology in the management of dysphagia. Curr Opin Otolaryngol Head Neck Surg. 2016;24(3):183–90. Review paper regarding rheology and measurement of fluid characteristics relevant to dysphagia.
Cichero JAY, Jackson O, Halley PJ, Murdoch BE. How thick is thick? Multicenter study of the rheological and material property characteristics of mealtime fluids and videofluoroscopy fluids. Dysphagia. 2000;15(4):188–200.
Hiiemae KM, Palmer JB. Food transport and bolus formation during complete feeding sequences on foods of different initial consistency. Dysphagia. 1999;14(1):31–42.
Burbidge AS, Cichero JAY, Engmann J, Steele CM. “A day in the life of the fluid bolus”: an introduction to fluid mechanics of the oropharyngeal phase of swallowing with particular focus on dysphagia. Appl Rheol. 2016;26:1–10.
Nicosia MA. Theoretical estimation of shear rate during the oral phase of swallowing: effect of partial slip. J Texture Stud. 2013;44(2):132–9.
Nicosia MA, Robbins JA. The fluid mechanics of bolus ejection from the oral cavity. J Biomech. 2001;34(12):1537–44. Epub 2001/11/22
Shama F, Sherman P. Identification of stimuli controlling the sensory evaluation of viscosity II. J Texture Stud. 1973;4(1):111–8.
Stokes JR, Boehm MW, Baier SK. Oral processing, texture and mouthfeel: from rheology to tribology and beyond. Curr Opin Colloid Interface Sci. 2013;18(4):349–59.
Vickers Z, Damodhar H, Grummer C, Mendenhall H, Banaszynski K, Hartel R, et al. Relationships among rheological, sensory texture, and swallowing pressure measurements of hydrocolloid-thickened fluids. Dysphagia. 2015;30(6):702–13.
Ong J, Steele CM, Duizer LM. Sensory characteristics of liquids thickened with commercial thickeners to levels specified in the International Dysphagia Diet Standardisation Initiative (IDDSI) framework. Food Hydrocoll. 2018;79:208–17.
Nyström M, Stading M, Qazi W, Bulow M, Ekberg O. Effects of rheological factors on perceived ease of swallowing. Appl Rheol. 2015;25:63876.
Waqas MQ, Wiklund J, Altskär A, Ekberg O, Stading M. Shear and extensional rheology of commercial thickeners used for dysphagia management. J Texture Stud. 2017;48(6):507–17.
Budke J, Garcia JM, Chambers EIV. Comparisons of thickened beverages using line spread measurements. J Acad Nutr Diet. 2008;108(9):1532–5.
Lund AM, Garcia JM, Chambers IVE. Line spread as a visual clinical tool for thickened liquids. Am J Speech Lang Pathol. 2013;22(3):566–71.
Nicosia MA, Robbins J. The usefulness of the line spread test as a measure of liquid consistency. Dysphagia. 2007;22(4):306–11. Epub 2007/06/22
Watanabe E, Yamagata Y, Fujitani J, Fujishima I, Takahashi K, Uyama R, et al. The criteria of thickened liquid for dysphagia management in Japan. Dysphagia. 2018;33(1):26–32.
Association professionelle des nutritionnistes experts en dysphagie. Énoncé de position. https://opdq.org/wp-content/uploads/2013/07/APNED_EnonceDePosition_IDDSI_Francais.pdf Accessed April 18, 2018.
Allain A-FL, M. Desrosiers, T. Évaluation de la dysphagie: Après l'ajout de sulfate de baryum aux ailments, peut-on faire les recommandations appropriées quant aux textures et consistances pour les personnes dysphagiques? : Ordre professionel des diététistes du Québec; 2010. p. 19-20. https://www.opdq.org/wp-content/uploads/2013/08/NSE_Vol8no1_printemps_2010.pdf. Accessed April 18, 2018.
van Vliet T. On the relation between texture perception and fundamental mechanical parameters for liquids and time dependent solids. Food Qual Prefer. 2002;13(4):227–36.
Skriver A, Holstborg J, Qvist KB. Relation between sensory texture analysis and rheological properties of stirred yogurt. J Dairy Res. 1999;66(4):609–18.
Garcia JM, Chambers EIV, Molander M. Thickened liquids: practice patterns of speech-language pathologists. Am J Speech Lang Pathol. 2005;14(1):4–13.
Abbas KA, Abdulkarim SM, Saleh AM, Ebrahimian M. Suitability of viscosity measurement methods for liquid food variety and applicability in food industry - a review. J Food Agric Environ. 2010;8(3&4):100–7.
Kim CH, Lipták BG. Viscometer-laboratory. In Lipták BG, editor. Instrument Engineers’ Handbook, 4th edition, Vol. 1: Process Measurement and Analysis. CRC Press; 2003. pp 1708–22.
Park JW, Kim IJ, Lee HJ. Fork test: a new simple and reliable consistency measurement for the dysphagia diet. Geriatr Nurs. 2016;37(4):292–5.
Tsang C, Hori SE, Peladeau-Pigeon M, Steele CM. The fork-test: a simple table-top test of viscosity? Dysphagia. 2012;27(4):572. https://doi.org/10.1007/s00455-012-9428-7.
Dieticians Association of Australia and The Speech Pathology Association of Australia Limited. Texture-modified foods and thickened fluids as used for individuals with dysphagia: Australian standardised labels and definitions. 2007; 64: 553–576.
National Patient Safety Agency, Royal College Speech and Language Therapists, British Dietetic Association, National Nurses Nutrition Group, Hospital Caterers Association. Dysphagia diet food texture descriptions. 2011. http://www.thenacc.co.uk/assets/downloads/170/Food%20Descriptors%20for%20Industry%20Final%20-%20USE.pdf. Accessed on: April 18, 2018.
Office of the Chief Coroner, Province of Ontario. Geriatric and Long Term Care Review Committee 2016 Annual Report. http://www.mcscs.jus.gov.on.ca/sites/default/files/content/mcscs/docs/GLTRC%202016%20English.pdf. Accessed on: April 18, 2018.
• Robbins J, Gensler G, Hind J, et al. Comparison of 2 interventions for liquid aspiration on pneumonia incidence: a randomized trial. Ann Intern Med. 2008;148(7):509–18. Follow up to Logemann’s randomized trial of the effect of liquid consistency on in people with dysphagia, looking at 3 month health status outcomes including pneumonia. Extremely thick liquids resulted in poorer outcomes for adults with dementia or Parkinson’s disease who were confirmed to aspirate on thin liquids; these outcomes included a higher incidence of pneumonia as well as higher rates of dehydration and mortality.
The authors would like to thank Steve Pong for his assistance with line-spread testing.
Conflict of Interest
Carly E. A. Barbon declares no conflicts of interest.Catriona M. Steele serves as a board member for the International Dysphagia Diet Standardisation Initiative and has received speaker fees/travel expense support from International Dysphagia Diet Standardisation Initiative.
Human and Animal Rights and Informed Consent
This article does not contain any studies with human or animal subjects performed by any of the authors.
This article is part of the Topical Collection on Swallowing Disorders
About this article
Cite this article
Barbon, C.E.A., Steele, C.M. Thickened Liquids for Dysphagia Management: a Current Review of the Measurement of Liquid Flow. Curr Phys Med Rehabil Rep 6, 220–226 (2018). https://doi.org/10.1007/s40141-018-0197-6
- Deglutition disorders
- Thickened liquids
- Texture modification