Getting the consistency right in thickened liquids using Viscgo Sticks: A validation study

Abstract

Background: Dysphagia is a condition whereby a person's ability to swallow, eat and drink is impacted. One strategy to manage dysphagia and aid safe swallowing is the modification of food and drink, including using thickening agents to thicken drinks. Drinks are thickened to levels appropriate to a person's swallowing abilities and the underutilised ‘syringe flow test’ is currently the recommended method for checking thickness levels. Viscgo Sticks were developed as a practical alternative to the flow test. Methods: This is a real-world validation study designed to determine validity and reliability of Viscgo Sticks. Independent researchers and healthcare professionals tested Viscgo Sticks (Viscgo Limited) against the flow test in three levels of thickened drinks. Researchers also conducted tests with different thickening agents and different drink types: water, milk, orange juice and hot tea. Results: The intra- and inter-rater reliability of Viscgo Sticks was moderate to almost perfect (κ = 0.45–0.98) within and between researchers and substantial (κ = 0.66–0.67) within and between healthcare professionals. When tested by researchers and healthcare professionals against the flow test, Viscgo Sticks correctly classified 83.33%–100% of thickened drinks with high accuracy (area under curve = 0.70–1.00). Conclusions: A simple and reliable tool like Viscgo Sticks, which can verify a prescribed thickness level of liquid, is invaluable in healthcare settings where day-to-day drink preparation occurs. Overall, Viscgo Sticks provide a reliable and valid means to test thickened drinks in clinical practice with a few exceptions identified.