Effects of sitting posture and bolus volume on activation of swallowing‐related muscles

Abstract

Swallowing is a complex physiological movement that involves the oral cavity, pharynx, larynx and oesophagus. 1 The pharyngeal phase is a particularly important clinical factor related to swallowing dysfunctions, such as dysphagia and dysfunctions in elderly individuals. 2 During normal swallowing, precise muscular movements protect the airway from bolus aspiration by moving the hyolaryngeal complex anterior and superior. 3,4 Precise muscular movement is controlled by the supra-hyoid (SH) and infra-hyoid (IH) muscle groups, and these influence the pharyngeal phase. 2,5 Head and neck posture, as well as bolus volume, are important factors affecting the pharyngeal stages of normal swallowing. 6,7 It is well known that head, neck posture and the hyoid bone are closely related to speech, swallowing, breathing, clenching and chewing. 6,8 Previous studies have demonstrated that the hyoid bone position is significantly influenced by an altered head and Abstract Background: The pharyngeal phase is a particularly important clinical factor related to swallowing dysfunctions. Head and neck posture, as well as bolus volume, are important factors affecting the pharyngeal stages of normal swallowing.Objective: The aim of our study was to identify the effects of sitting posture and bolus volume on the activation of swallowing-related muscles. Materials and Methods:Twenty-four subjects participated in the study. The subjects were positioned in three sitting postures-slump sitting (SS), lumbo-pelvic upright sitting (LUS), and thoracic upright sitting (TUS). While sitting in the chair, the subject was instructed to swallow 10 and 20 mL of water. Surface electromyography (EMG) was used to measure the muscle activity of the supra-hyoid (SH) and infra-hyoid (IH) muscles. Also, sitting posture alignment (head, cervical and shoulder angle) was also performed. Data were analysed with a repeated measures analysis of variance (RMANOVA) using a generalised linear model. Results:There was no significant difference in terms of the head angle (P = .395).However, significant differences were found in relation to the cervical angle (P < .001) and shoulder angle (P < .001). The TUS produced the lowest SH EMG activity (P = .001), in comparison to SS and LUS. The bolus volume for 20 mL showed greater SH and IH EMG activity (P < .001) than did the bolus volume for 10 mL. Conclusions:Correcting sitting posture from SS to TUS may better assist swallowingrelated muscles with less effort, irrespective of the bolus volume. K E Y W O R D Sbolus volume, infra-hyoid, sitting posture, supra-hyoid, surface electromyography, swallowing

Strategies of Screening and Treating Post-Extubation Dysphagia: An Overview of the Situation in Greek-Cypriot ICUs

“…Aspiration/Aspiration Pneumonia Resulting from Liquids/Solid Food Postural adjustment has been proven to promote swallowing in patients with confirmed or suspected dysphagia by affecting bolus flow and speed, especially when the patient has been placed in a sitting position [50]. Importantly, irrespective of the bolus volume, manipulating the cervical and shoulder angle has been shown to activate more effectively swallowing-related muscles during thoracic upright sitting [51].…”

Noninvasive Evaluation of the Biomechanical Accommodations to Bolus Volume during Human Swallowing

“…While patients with neurologically impaired dysphagia may be at the risk of penetration and aspiration with large bolus volumes, small bolus volumes beyond a certain threshold may not trigger the automatic swallowing reflex [3]. Researchers have reported the effects of bolus volume on the tongue [4], hyoid [5], and swallowing-related muscles [6]. However, few studies have simultaneously monitored the effects of bolus volume on oropharyngeal structures with noninvasive methods.…”