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Artificial throat solves swallowing problems

Problems with swallowing food and drink are more common than one might suppose, and they increase with advancing years. In the project The Gothenburg Throat, RISE has participated in developing a model of a throat that allows the detailed study of food flow. Food companies will now be using the model to develop foods that are easy and safe to swallow.

Approximately one in five of Sweden’s 50+ age group have some form of problem with swallowing food or fluids, a condition known as dysphagia. In the 70+ age group, approximately 40% of Swede’s suffer from the condition.

"As a result, many over-80s eat poorly, leading to a lack of calories, lost muscle mass and a negative health spiral. Many of them are undernourished and are prone to pneumonia or suffer falls as a result of frailness. In certain cases, this leads to death,” says Mats Stading at RISE.

One solution to this problem is food and drink that is easier to swallow. When it comes to food, this may be a matter of producing it in pieces with an easily chewed consistency that do not risk ending up in the lungs. The largest cause of swallowing problems, however, is actually water, which can easily end up in the windpipe and, from there, the lungs.

“To address this, one can mix the water with the thickening agent xanthan gum, or E415 as it is also known. One example of easily swallowed food is timbale, which can be made using fish, meat or vegetables and is finely sieved and texture modified to give a consistency much like a slightly harder but smooth omelette,” says Mats Stading.

Enables study of swallowing difficulties

The Gothenburg Throat is the name of the model constructed by RISE of the swallowing tract (pharynx) through which air, food and liquid pass. The model throat, which has the same geometry as the human trachea and esophagus, can be used by researchers and food developers to, with the aid of ultrasound and manometry, study in detail the problems that can arise when a dysphagic individual swallows something such as a glass of water.

“The model can be adjusted to the desired speed and volume of swallowing and has an epiglottis that folds down when drinking or swallowing is taking place. The air flow is also cut off, as we swallow on exhalation, while at the same time the nasal passage opens to allow air and aroma to escape. All physiological events during the swallowing process are included,” explains Mats Stading.

There is a valve that opens in the lower part of the throat to allow food into the stomach. Mats Stading describes the entire thing as a physical model with valves. By measuring the flow profile and pressure, researchers obtain data on the importance of consistency and can then make the necessary adjustments.

"We discover how a swallow of something makes its way down into the stomach and how it is affected on the way down,” concludes Mats Stading.

Unnecessary risks to patients are avoided

For medical researchers, the model provides the opportunity to study dysphagia without the need for patients to participate in experiments and be exposed to unnecessary risks. Another problem inherent in patient participation is that many elderly dysphagics also suffer from dementia.

In future, anyone suffering from dysphagia can expect to have a wider range of suitable foods to choose from.

"Indeed, we will be developing a simplified model that food companies can buy in order to test which products are suitable for dysphagia sufferers,” says Mats Stading.

Waqas Muhammad is one of those working on the project. His work resulted in the doctoral thesis Exploring the role of rheology in bolus flow using an in-vitro approach. Rheology is the study of the change in form and the flow of matter. Waqas defended his thesis on 25 January at Chalmers University of Technology.

Gothenburg throat

RISE's role: Project coordinator, design and construction
Partner: Skåne University Hospital
Budget: SEK 7.2 million
Financier: Formas
Duration: 2014-2018

Published: 2019-02-12