Investigation of Embodied Language Processing on Command-Swallow Performance in Healthy Participants.

Purpose During videofluoroscopic examination of swallowing, patients commonly are instructed to hold a bolus in their mouth until they hear a verbal instruction to swallow, which usually consists of the word swallow and is commonly referred to as the command swallow condition. The language-induced motor facilitation theory suggests that linguistic processes associated with the verbal command to swallow should facilitate the voluntary component of swallowing. As such, the purpose of the study was to examine the linguistic influences of the verbal command on swallowing. Method Twenty healthy young adult participants held a 5-ml liquid bolus in their mouth and swallowed the bolus after hearing one of five acoustic stimuli presented randomly: congruent action word (swallow), incongruent action word (cough), congruent pseudoword (spallow), incongruent pseudoword (pough), and nonverbal stimulus (1000-Hz pure tone). Suprahyoid muscle activity during swallowing was measured via surface electromyography (sEMG). Results The onset and peak sEMG latencies following the congruent action word swallow were shorter than latencies following the pure tone and pseudowords but were not different from the incongruent action word. The lack of difference between swallow and cough did not negate the positive impact of real words on timing. In contrast to expectations, sEMG activity duration and rise time were longer following the word swallow than the pure tone and pseudowords but were not different from cough. No differences were observed for peak suprahyoid muscle activity amplitude and fall times. Conclusions Language facilitation was observed in swallowing. The clinical utility of the information obtained in the study may depend on the purposes for using the command swallow and the type of patient being assessed. However, linguistic processing under the command swallow condition may alter swallow behaviors and suggests that linguistic inducement could be useful as a compensatory technique for patients with difficulty initiating oropharyngeal swallows.

Detection of Swallow Kinematic Events From Acoustic High-Resolution Cervical Auscultation Signals in Patients With Stroke.

OBJECTIVE: To examine whether there were any associations between high-resolution cervical auscultation (HRCA) acoustic signals recorded by a contact microphone and swallowing kinematic events during pharyngeal swallow as assessed by a videofluoroscopic (VF) examination. DESIGN: Prospective pilot study. SETTING: University teaching hospital, university research laboratories. PARTICIPANTS: Patients (N=35) with stroke who have suspected dysphagia (26 men + 9 women; age = 65.8±11.2). METHODS: VF recordings of 100 liquid swallows from 35 stroke patients were analyzed, and a variety of HRCA signal features to characterize each swallow were calculated. MAIN OUTCOME MEASURES: Percent of signal feature maxima (peak) occurring within 0.1 seconds of swallow kinematic event identified from VF recording. RESULTS: Maxima of HRCA signal features, such as standard deviation, skewness, kurtosis, centroid frequency, bandwidth, and wave entropy, were associated with hyoid elevation, laryngeal vestibule closure, and upper esophageal sphincter opening, and the contact of the base of the tongue and posterior pharyngeal wall. CONCLUSIONS: Although the kinematic source of HRCA acoustic signals has yet to be fully elucidated, these results indicate a strong relationship between these HRCA signals and several swallow kinematic events. There is a potential for HRCA to be developed for diagnostic and rehabilitative clinical management of dysphagia.