Real-time estimation of tongue movement based on suprahyoid muscle activity

Toward a robust swallowing detection for an implantable active artificial larynx: a survey

Total laryngectomy consists in the removal of the larynx and is intended as a curative treatment for laryngeal cancer, but it leaves the patient with no possibility to breathe, talk, and swallow normally anymore. A tracheostomy is created to restore breathing through the throat, but the aero-digestive tracts are permanently separated and the air no longer passes through the nasal tracts, which allowed filtration, warming, humidification, olfaction, and acceleration of the air for better tissue oxygenation. As for phonation restoration, various techniques allow the patient to talk again. The main one consists of a tracheo-esophageal valve prosthesis that makes the air passes from the esophagus to the pharynx, and makes the air vibrate to allow speech through articulation. Finally, swallowing is possible through the original tract as it is now isolated from the trachea. Yet, many methods exist to detect and assess a swallowing, but none is intended as a definitive restoration technique of the natural airway, which would permanently close the tracheostomy and avoid its adverse effects. In addition, these methods are non-invasive and lack detection accuracy. The feasibility of an effective early detection of swallowing would allow to further develop an implantable active artificial larynx and therefore restore the aero-digestive tracts. A previous attempt has been made on an artificial larynx implanted in 2012, but no active detection was included and the system was completely mechanic. This led to residues in the airway because of the imperfect sealing of the mechanism. An active swallowing detection coupled with indwelling measurements would thus likely add a significant reliability on such a system as it would allow to actively close an artificial larynx. So, after a brief explanation of the swallowing mechanism, this survey intends to first provide a detailed consideration of the anatomical region involved in swallowing, with a detection perspective. Second, the swallowing mechanism following total laryngectomy surgery is detailed. Third, the current non-invasive swallowing detection technique and their limitations are discussed. Finally, the previous points are explored with regard to the inherent requirements for the feasibility of an effective swallowing detection for an artificial larynx. Graphical Abstract.

Effects of Resistive Jaw-Opening Exercise with Elastic Bands on Suprahyoid Muscle Activation in Normal Subjects

OBJECTIVE

The effect of a resistive jaw-opening exercise using an elastic band on suprahyoid muscle activity and tongue strength was examined in healthy volunteers.

METHODS

Twenty-one adults wore an elastic loop around their head and mandible. To prescribe the appropriate elastic band resistance, the 10-repetition maximum (10 RM) was measured among 4 bands at baseline. Band loops, starting with the highest resistance value band, were sequentially applied to determine the suitability for 10 RM. During the exercise, the participants were required to open their jaw maximally and maintain the position for 10 s; then, they rested for 10 s. This procedure was repeated for 20 min, 3 days per week for 8 weeks to test suprahyoid muscle activation during effortful swallowing; isometric tongue pressures of the tongue tip and base at baseline, after 4, and after 8 weeks of training were measured.

RESULTS

Peak suprahyoid muscle activation amplitudes during effortful swallow and isometric pressures at the tongue tip significantly increased after 8 weeks.

CONCLUSION

The 8-week resistive jaw-opening exercise significantly improved strength of the suprahyoid muscle and tongue pressures in healthy subjects. These positive results warrant further investigation of the therapeutic effects and feasibility of this resistive exercise.

Noninvasive tongue-motion controlled computer mouse for the disabled

BACKGROUND

A patient whose spinal cord was damaged due to accident may result in Tetraplegia or lose the ability to control his/her daily living environment. Currently, patients must use an invasive tool tongue movement, to help the patient communicate with the external environment.

OBJECTIVE

This study designed a non-invasive tongue movement computer mouse system that allows the patient to use tongue movement to control a computer to communicate with the external environment.

METHODS

Via a pressure sensor and assistive holder designed in this study, the pressure sensor can be moved using the assistive holder close to the mylohyoid muscle of the patient's lower jaw. The changes in pressure from the mylohyoid muscle are converted into computer mouse control signals to control a computer to communicate with the external environment.

RESULTS

This study is based on ISO9241-Part 9 to design four kinds of training modes with varying difficulties. The data were collected from five able persons participating in the test over 7 days. The data includes throughput, path efficiency, test completion time and reaction time. The data verifies that the proposed system is stable and practical for persons with disabilities.

CONCLUSION

The non-invasive computer mouse system for sensing tongue movement can completely breakthrough the limitations of the invasive tongue movement sensing system. This study uses non-invasive, simple tongue movements that correspond to the stretching and shrinking of the lower jaw mylohyoid muscle to control the computer mouse.