The number of residents in care facilities has increased with the increase in the number of elderly people in Japan. In the previous study, we developed a device equipped an apron with an accelerometer, and the iAcc value of the device during swallowing was significantly larger than that during rest in both young and elderly people. However, there is still left a problem of the motion artifact of the subjects. In this study, we proposed a signal processing method which is robust to the motion artifact of the subjects. The iAcc value of X axis during chewing was larger than that of Z axis in the all young and four fifths in the elderly people. The iAcc value of Z axis during swallowing was larger than that of X axis in the all young and four fifths in the elderly people. The iAcc values obtained from the proposed method were robust to the motion artifact of the subjects.
