INVESTIGATION OF EMBODIED LANGUAGE PROCESSING ON COMMAND-SWALLOW PERFORMANCE

In the command swallow condition, which is routinely employed during videofluoroscopic examination of swallowing, patients commonly are told to hold a bolus in their mouth until they are told to swallow. Both components of the command swallow, bolus hold and swallowing in response to a command, could influence the act of swallowing. The focus of the current study was to examine the linguistic influences of the verbal command on swallowing. In fact, the language induced motor facilitation theory suggests the linguistic processes associated with the verbal command should facilitate the voluntary component of swallowing. This study investigated whether language induced motor facilitation was evident under the command swallow condition as reflected in suprahyoid muscle activity measured by surface electromyography. During the experiment, 20 healthy young participants held a 5 ml liquid bolus in their mouth and swallowed the bolus after hearing 5 acoustic stimuli presented randomly: congruent action word (swallow), incongruent action word (cough), congruent pseudo-word (spallow), incongruent pseudo-word (pough), and non-verbal stimulus (1000 Hz pure-tone). Swallow latencies following the congruent action word were shorter than swallows following the non-verbal stimulus, indicating that suprahyoid muscle activity occurred earlier for following the word swallow than for the pure-tone. Longer latencies for the pseudo-words than real words also supported the language induced motor facilitation theory, but it was not clear whether the observed differences were due to reduced linguistic facilitation or longer processing-time associated with interference. Stronger support for the theory captured by lexical directionality was not evident when the words swallow and cough were compared. The facilitation effects of swallow-related action words may not have sufficient sensitivity and strength among effectors, and the incongruent word in the study may not have represented a true incongruent action against the act of swallowing. There also was no facilitation effect on peak suprahyoid muscle activity amplitude. The evidence from this study advances our understanding of the links between language and movement for behaviors that are not entirely under voluntary control. Linguistic inducement of swallowing could be useful as a swallow compensatory technique for patients with difficulty initiating oropharyngeal swallows including patients with Parkinson’s disease

Dysphagia and its effects on swallowing sounds and vibrations in adults

Abstract Background To utilize cervical auscultation as a means of screening for risk of dysphagia, we must first determine how the signal differs between healthy subjects and subjects with swallowing disorders. Methods In this experiment we gathered swallowing sound and vibration data from 53 (13 with stroke, 40 without) patients referred for imaging evaluation of swallowing function with videofluoroscopy. The analysis was limited to non-aspirating swallows of liquid with either thin (< 5 cps) or viscous ($$\approx 300\,{\text{cps}}$$ ≈300cps ) consistency. After calculating a selection of generalized time, frequency, and time frequency features for each swallow, we compared our data against our findings in a previous experiment that investigated identical features for a different group of 56 healthy subjects. Results We found that nearly all of our chosen features for both vibrations and sounds showed significant differences between the healthy and disordered swallows despite the absence of aspiration. We also found only negligible differences between dysphagia as a symptom of stroke and dysphagia as a symptom of another condition. Conclusion Non-aspirating swallows from healthy controls and patients with dysphagia have distinct feature patterns. These findings should greatly help the development of the cervical auscultation field and serve as a reference for future investigations into more specialized characterization methods

A generalized equation approach for hyoid bone displacement and penetration–aspiration scale analysis

Abstract Swallowing physiology includes numerous biomechanical events including displacement of the hyoid bone, which is a crucial component of airway protection and opening of the proximal esophagus. The objective of this study was to evaluate the potential relations between the trajectory of hyoid bone movement and the risk of airway penetration and aspiration during a videofluoroscopic swallowing study. Two hundred sixty-five patients were involved in this study, producing a total of 1433 swallows of various volumes consisting of thin liquid, nectar-thick liquid, and solids during a fluoroscopic exam. The anterior and posterior landmarks of the body of the hyoid bone were manually marked in each frame of each fluoroscopic video. Generalized estimation equations were applied to evaluate the relationship between penetration–aspiration scores and mathematical features extracted from the hyoid bone trajectories, while also considering the influence of other independent variables such as age, bolus volume, and viscosity. Our results indicated that penetration–aspiration scores showed a significant relation to age. The maximum anterior (horizontal) displacement of the anterior hyoid bone landmark was significantly associated with the penetration–aspiration scores. Differences in the displacement of the hyoid bone are useful observations in airway protection. Article highlights (1) In this work, the potential relations between the trajectory of hyoid bone movement and the risk of airway penetration and aspiration during a videofluoroscopic swallowing study were evaluated. (2) We extracted features from the hyoid bone trajectories and applied generalized estimation equations to investigate their relationship to penetration–aspiration scales. (3) The results showed that the maximum anterior (horizontal) displacement of the anterior hyoid bone landmark was significantly associated with the penetration–aspiration scales