Development of a simple evaluation instrument for liquid thickness measurement

Area of Science:

• Fluid dynamics and rheology in food science.
• Clinical engineering and medical device development.
• Swallowing disorder diagnostics and management.

Background:

• Traditional methods like the line spread test (LST) for evaluating thickened liquids are time-consuming.
• Accurate and rapid assessment of liquid viscosity is crucial for managing dysphagia.
• Existing methods may not meet the need for quick clinical evaluations.

Purpose of the Study:

• To develop a novel, simple instrument for rapid evaluation of thickened liquids.
• To improve upon existing methods by incorporating fluid engineering principles.
• To reduce the time required for classifying liquid consistencies for dysphagia diets.

Main Methods:

• Designed a new instrument with an optimized funnel and evaluation procedure.
• Prepared thickened liquids using xanthan gum at viscosities of 50, 150, 300, and 500 mPa∙s.
• Measured the time for liquid to flow 50mm, averaging eight trials for classification.

Main Results:

• The instrument classified samples in 2.22–3.29s (mildly thick), 3.29–9.16s (moderately thick), and 9.16–23.14s (extremely thick).
• Evaluation of extremely thick liquids was reduced to approximately 23 seconds, a 27-second improvement over conventional methods.
• The instrument successfully classified liquids according to the Japanese Dysphagia Diet 2013 criteria.

Conclusions:

• The developed instrument offers a rapid and effective method for evaluating thickened liquids.
• This innovation has the potential to enhance clinical efficiency in dysphagia management.
• Further design improvements are planned for broader clinical application.