A Self-Sensing Instrument for Investigation of Rheology in Dysphagia

Dysphagia is the term used to describe disorders that affect our ability to swallow. This problem affects most stroke patients, people suffering cancers of the head or neck, and is also often found in the general elderly population. The potential problems of choking, pneumonia, malnutrition and dehydration can be potentially fatal for these vulnerable patients. Fortunately, these risks can be minimised by controlling a patient's diet: some patients have particular difficulties with thin, watery, liquids, and often semi-solid foods can be problematic. Specialist Speech and Language Therapists (SLTs) examine individual patients to identify a range of consistencies that can be swallowed safely. So, the dysphagic patient's safety depends on the consistency of their diet. However, it is difficult to mix drinks to the right thickness when judging the consistency by eye, even with specialist training. The issue is further confused because the SLTs have to rely on descriptive terms to convey this consistency information. Phrases like honey thick , can be drunk through a straw are inexact and subject to varying personal interpretation. Away from specialist care, there is no means of controlling consistency.This project will use engineering research to create an accurate and reliable device (a rheometer ) which can be used to measure the flow properties of drinks and fluid foods . The aim of this is to ensure that the patients only receive consistencies that they can swallow safely. The device will enable SLTs to be precise in their analysis and treatment of patients; SLTs in different locations will be able to communicate and make meaningful comparisons, which will enable the start of scientific research into the relationship between dysphagia and fluid consistency. The fluids used (e.g. thickened drinks, smoothies) have complex behaviours, for example their viscosity strongly depends on the rate at which they are flowing. Some also show elastic, jelly-like, behaviour. The rheometer will be able to quantify these effects for greater understanding, promoting new collaborative research between engineers and SLTs, and establishing the UK as a leader of this brand new research area. This research will also provide the potential to specifically design food products that are particularly easy and safe to swallow / of enormous benefit to an industrial partner in dysphagia products: Fresenius-Kabi Ltd.The engineering research that is required to create this rheometer involves using new design techniques to create a unique electromagnetic actuator. This actuator will be optimised for use in a self-sensing mode / where the actuator both provides torque and motion, while at the same time measuring that torque and motion. This emerging technique removes the need for separate sensors and means the device can be small, simply constructed, robust and reliable. These characteristics are perfectly suited to creating a device for mass production, and portable use around dysphagic patients in hospitals, care homes or at home. A patent will be pursued for this device.The novel design techniques used will include finite element modelling of the interrelations between non-linear electromagnetic, mechanical and thermal behaviour of the actuator. This research will dramatically improve the capabilities of electromagnetic devices, which will be of great interest to scientists and industrialists. As well as enabling new types of miniature devices, the work will produce improvements that are applicable to existing devices. This will specifically support and enhance current research being carried out for the materials testing machine company, Instron Ltd.There is enormous potential for improving health and quality of life if the problems associated with dysphagia can be avoided by controlling diet consistency; this device will allow that work to start.