The durations and temporal relationships of electromyographic activity from the submental complex, superior pharyngeal constrictor, cricopharyngeus, thyroarytenoid, and interarytenoid muscles were examined during swallowing of saliva and of 5- and 10-ml water boluses. Bipolar, hooked-wire electrodes were inserted into all muscles except for the submental complex, which was studied with bipolar surface electrodes. Eight healthy, normal, subjects produced five swallows of each of three bolus volumes for a total of 120 swallows. The total duration of electromyographic activity during the pharyngeal stage of the swallow did not alter with bolus condition; however, specific muscles did show a volume-dependent change in electromyograph duration and time of firing. Submental muscle activity was longest for saliva swallows. The interarytenoid muscle showed a significant difference in duration between the saliva and 10-ml water bolus. Finally, the interval between the onset of laryngeal muscle activity (thyroarytenoid, interarytenoid) and of pharyngeal muscle firing patterns (superior pharyngeal constrictor onset, cricopharyngeus offset) decreased as bolus volume increased. The pattern of muscle activity associated with the swallow showed a high level of intrasubject agreement; the presence of somewhat different patterns among subjects indicated a degree of population variance.

No abstract

Increasing tongue-to-palate pressure coincides with increased muscle activity. Activation of the floor-of-mouth, tongue, and jaw closing muscles increased tongue-to-palate pressure. These findings support the use of a tongue-press exercise to strengthen floor-of-mouth muscles, tongue, and jaw-closing muscles.

Submental surface electromyographic recordings are commonly used in the investigation of swallowing disorders. The measured electromyography is thought to reflect the actions of floor-of-mouth muscles. Although this is a reasonable assumption, to date there have been no investigations to delineate which muscles contribute to this surface recording. The primary goal of this experiment was to determine which muscles contribute most to the submental surface. Electromyography was recorded simultaneously from the submental surface as well as from five individual muscles: mylohyoid, anterior belly of the digastric, geniohyoid, genioglossus and platysma. Three analysis methods were performed to estimate individual muscle contributions: correlation, numeric, and analytic. For the numeric and analytic analyses, a linear model was defined and used to represent the relationship between the surface and intramuscular recordings. Muscles that received a high correlation, numeric and/or analytic value were considered to be primary contributors to the submental recording. Regardless of analysis approach, the primary contributions to the submental surface recording were the mylohyoid, anterior belly of the digastric, and the geniohyoid muscles. Contributions from the genioglossus and the platysma muscles were minimal. Contributions as a function of bolus volume and viscosity are also discussed.

A sour bolus has been used as a modality in the treatment of oropharyngeal dysphagia based on the hypothesis that this stimulus provides an effective preswallow sensory input that lowers the threshold required to trigger a pharyngeal swallow. The result is a more immediate swallow onset time. Additionally, the sour bolus may invigorate the oral muscles resulting in stronger contractions during the swallow. The purpose of this investigation was to compare the intramuscular electromyographic activity of the mylohyoid, geniohyoid, and anterior belly of the digastric muscles during sour and water boluses with regard to duration, strength, and timing of muscle activation. Muscle duration, swallow onset time, and pattern of muscle activation did not differ for the two bolus types. Muscle activation time was more tightly approximated across the onsets of the three muscles when a sour bolus was used. A sour bolus also resulted in a stronger muscle contraction as evidenced by greater electromyographic activity. These data support the use of a sour bolus as part of a treatment paradigm.