Figure 2: The swallowing waveform with the magnetic swallowing monitoring device. The upper waveform represents the distance waveform, and the lower waveform represents the sound waveform. The vertical line indicates the start of the swallowing. The solid lines above the temporal axis indicate the duration of swallowing. (A) Normal swallowing in a 48-year-old healthy man, (B) piecemeal deglutition in a 65-year-old woman with Parkinson’s disease (PD), and (C) double swallowing in an 80-year-old woman with PD.