Application of piezoelectric braided cord to dysphagia-detecting system

Abstract

We developed a system with a simple structure for sensing movement during swallowing through simple operations using piezoelectric poly(l-lactic acid) (PLLA) braided cords as a motion sensor. In the system, the analog-signal-processing part of the PLLA braided cord sensor is composed of analog-signal-adjusting parts, a multiplexer, an analog-to-digital (A/D) converter, and so forth, the data is processed on a personal computer, and finally the dependence of the signal intensity on the position and time of the motion during swallowing is plotted as a three-dimensional plot. The results of a swallowing function test using our developed system appeared to coincide with that of a diagnostic test described in a medical textbook. In addition, the subject experienced little restriction of the motion during the measurement using our system. The experimental results suggest that our system has potential use as a wearable device as a useful and portable tool for healthcare.

A Prototype Sensor System Using Fabricated Piezoelectric Braided Cord for Work-Environment Measurement during Work from Home

“…Therefore, there is no need for a circuit system or a personal computer (PC) that requires complex calculations for processing because sensing is the only required procedure. Taking these features together, piezoelectric PLLA braided cords can be used as sensors that can detect expansion, contraction, shear, and bending, depending on how they are tied or embroidered with the type of stich pattern [ 3 , 4 , 5 , 20 , 21 , 22 ].…”

“…We considered attaching a piezoelectric PLLA braided cord as a sensor to a cushion placed on a chair used at home when working from home. The idea was to embroider cushion covers with the piezoelectric PLLA braided cord, which had been studied already for a long time (an example of embroidery with the PLLA braided cord is shown in Figure 2 and used as a sensor) [ 3 , 4 , 5 , 20 , 21 ] However, with this ideas, in order to embroider the sheets, it is necessary to collect them from each home and then prepare them according to the shape of each chair before experiments on vital sign sensing during telework can be conducted. This takes too much time and effort to prepare, and clinical trials cannot be conducted.…”

“…Therefore, we attempted to develop a piezoelectric PLLA braided cord sensor on a tape that can be attached to each cushion cover as it is. The knowledge gained from our studies on piezoelectric PLLA embroidery is useful for the design of the motion sensor used here [ 3 , 4 , 5 , 20 , 21 ]. When the piezoelectric PLLA braided cord is attached to clothing and used as a sensor, the sensor does not directly bear the weight; however, in this setup, a static load such as human weight is applied to the cushion of the chair.…”

“…That is, the load is always applied vertically to the cord sensor. This makes a large difference in the design of the sensor [ 3 , 4 , 5 , 20 , 21 ]. For example, if the piezoelectric PLLA braided cord is under the weight of the person sitting on the chair, the braided cord may be displaced from its initial position on the chair for measurements, which should cause abnormal conditions that should be prevented [ 3 , 4 , 5 , 20 , 21 ].…”

“…This makes a large difference in the design of the sensor [ 3 , 4 , 5 , 20 , 21 ]. For example, if the piezoelectric PLLA braided cord is under the weight of the person sitting on the chair, the braided cord may be displaced from its initial position on the chair for measurements, which should cause abnormal conditions that should be prevented [ 3 , 4 , 5 , 20 , 21 ]. The basic condition that ensures the stability of sensing is to provide a safe, easy, and reliable means of mounting so that anyone can use it easily.…”