Effects of different levels of food on the acoustic characteristics of swallowing sounds in healthy elderly people

For half a century, cervical auscultation has been proposed as a novel method for screening aspiration in patients with dysphagia. Most of the previous studies focused on the effects of food consistency, volume, and head-neck position on swallowing sounds. However, the effects of standardized liquid viscosity and food texture on swallowing sounds are not fully understood due to the lack of uniform standardized bolus preparation. Currently, there is insufficient guidance in the literature for the appropriate liquids and foods for swallowing training, and there is also a lack of studies using acoustic signals to monitor swallowing progress continuously. Objective: Based on the IDDSI grading, using acoustic analysis technology, to study the effects of different levels of food on the swallowing characteristics of healthy elderly people, and to lay a preliminary research foundation for further early screening and rehabilitation dietary treatment of patients with dysphagia. Methods: Thirty healthy elderly people who met the criteria were selected as the research subjects. Eight kinds of food with different levels were prepared based on the IDDSI grading standard. A throat microphone (iASUS NT3-R, CA, USA) was used to collect the swallowing sounds of eating different levels of food. RavenPro1.6.0 software was used to perform sound segmentation, annotation, and swallowing acoustic index measurement. Results: There were significant differences in the duration and peak power density of the sound signals of different liquids and foods. As the food level increased, the duration of swallowing also increased. As the food level increased, the peak frequency density of the sound decreased, and there were statistical differences between men and women. Level four was more suitable to be classified as "food". It suggests that swallowing acoustic monitoring can be used for clinical screening of dysphagia, and provide a basis for long-term swallowing behavior detection and clinical management.