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Coordination of mastication and swallowing
J B Palmer1, N J Rudin, G Lara
1Department of Rehabilitation Medicine, Johns Hopkins University, Baltimore, Maryland.
Dysphagia
|January 1, 1992
Summary
This study investigated how chewing, moving food in the mouth, and swallowing work together. It found that preswallow food transport mechanisms closely resemble the oral phase of swallowing.
Area of Science:
- Biomechanics of swallowing
- Oral motor control
- Deglutition physiology
Background:
- Coordinated function of mastication, oral transport, and swallowing is crucial for safe and efficient food intake.
- Understanding the precise timing and muscle activity during these processes is essential for diagnosing and treating dysphagia.
Purpose of the Study:
- To examine the coordination between mastication, oral transport, and swallowing during the intake of solids and liquids.
- To analyze the timing of bolus transport and swallowing phases in relation to the masticatory gape cycle.
Main Methods:
- Simultaneous videofluorography (VFG) and electromyography (EMG) were used in four normal subjects consuming barium-impregnated foods.
- Intramuscular electrodes recorded activity in the masseter, suprahyoid, and infrahyoid muscles.
- Ninety-four swallows were analyzed frame-by-frame for bolus transport, swallowing onset, and masticatory cycle phases.
Main Results:
- Barium entered the pharynx significantly before swallow onset, with shorter intervals for liquids.
- Nearly all swallows initiated during the intercuspal (minimum gape) phase of the masticatory cycle.
- Preswallow bolus transport involved tongue and hyoid protraction, similar to the oral phase of swallowing, integrated within masticatory cycles.
Conclusions:
- The masticatory cycle provides a framework for integrating chewing, transport, and swallowing.
- Preswallow transport mechanisms are highly similar to the oral phase of swallowing.
- Jaw adductor and abductor muscle activity patterns facilitate this integration.