Noise Reduction in Swallowing Muscle Activity Measurement Based on Mixture Gaussian Distribution Model

Abstract

For the noninvasive measurement of swallowing muscle activity, surface electromyograms and swallowing sounds are used. The electromyogram electrodes can be placed appropriately only by experts with specialized knowledge about the location of the swallowing muscle group. Therefore, these sensors have not been used for measurements in food development, for which there were no experts. In order to develop a simple swallowing muscle measurement method for food development, we proposed a sensor sheet consisting of multiple electromyogram electrodes and observed that different swallowing muscle activities could be measured depending on the type of food. In this work, we study a calculation method for the elimination of noise, which is inevitable in electromyograms, from the sensor sheet measurement results and prove that the method improves the performance of the swallowing muscle activity measurements.

Detection of swallowing disorders using a multiple channel surface electromyography sheet: A preliminary study

“…Accurately measuring representative sEMG may be difficult if the subject is out of averaged size; for example, in the case of children, different sensor sheet sizes are required. 12 …”

“…Although the efficacy of the data collection method itself has been proved in past research, it may not yet be applicable in some sEMG cases, including brain disorders in this study. In particular, the threshold method was used in this study, and the determination of swallowing onset was occasionally affected by noise 12 , 21 in the sEMG waveform; therefore, we excluded measurements not reaching the threshold. These data deficiencies are also considered to be influenced by biological causes and technical factors, including the recording electrodes’ location in relation to the change of posture and variations in muscle size and activity among individuals (also between young and elderly patients).…”

“…We invented a sEMG sensor sheet comprising multiple electrodes that measure supra and infrahyoid muscle activities while swallowing. 12 , 13 The sensor sheet comprises disposable electrodes N-01IS3® (Nihon Kohden Corp., Tokyo, Japan), a foam pad 75 A® (Nihon Kohden Corp., Tokyo, Japan), and single-sided skin tape#1776® (3M Japan Limited, Tokyo, Japan). The sensor sheet was height 150 mm × maximum width 62 mm; the size was determined based on the human cervical configuration.…”

“…The thresholds for the activity onset and offset were defined as follows. 12 The threshold was set two-fold larger than the average sEMG amplitude of baseline interval in each position, which was the period when there was very less sEMG response for 0.5 s. The onset was defined as the time when the value of sEMG voltage exceeded a threshold, closest to the time of the largest swallowing sound, whereas the offset was defined as the time when the voltage fell below the threshold, closest to the time of the largest swallowing sound ( Fig. 2 ).…”

“…We recently invented a sEMG sensor sheet comprising multiple electromyogram electrodes that can be easily attached to the front of the neck. 12 The sensor sheet can measure various muscle activities (suprahyoid and infrahyoid muscles) related to swallowing; thus, it can easily and noninvasively measure muscle activity during swallowing.…”