Swallowing appears more accessible than chewing since it involves the neck (pharyngeal) region, rather than the head. Our early investigations were focused on EMG and strain sensing collars. EMG sensors at submental and hyoid positions showed sufficient signal quality for detection of swallows due to the muscle contractions at the neck. However, the relevant muscles are in deep layers of the neck and signals are filtered by head movement muscles (Sternocleidomastoid). Strain at the neck could be detected due to hyoid movement during swallowing. However, the signal quality highly depends on the prominence of the hyoid.
Later investigations concentrated on a combination of EMG and vibration signals to compensate for errors in the swallowing detection. Besides the swallowing event, the swallowed material (bolus) influences the signals. We investigated viscosity and volume.
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