Effect of the submandibular push exercise using visual feedback from pressure sensor: an electromyography study

Abstract

We developed a new exercise method called the submandibular push exercise that can strengthen the suprahyoid muscle by inducing only the motion of the hyoid bone without neck flexion. In this study, we aimed to investigate and compare the muscle activity of the suprahyoid and infrahyoid muscles in the course of performing three different swallowing exercises. Twenty healthy participants and fifteen patients with dysphagia were recruited. Each participant consecutively performed three exercises: Shaker, CTAR, and submandibular push exercises. To investigate muscle activation, surface electromyography was performed on the suprahyoid, infrahyoid, and SCM muscles, during the exercises. Root mean square (RMS) was measured. In healthy participants, the submandibular push exercise showed a significantly higher RMS value in the suprahyoid and infrahyoid muscles than the Shaker and CTAR exercises using repeated ANOVA with Tukey's post hoc test ( p < 0.05). In patients with dysphagia, the submandibular push and Shaker exercises showed significantly higher RMS value in the suprahyoid and infrahyoid muscles than the CTAR exercise. However, no significant difference was found between the submandibular push and Shaker exercises. In both healthy and patients with dysphagia, the mean RMS values of the SCM muscles during the submandibular push exercise were significantly lower than those during the Shaker exercise using repeated ANOVA with Tukey's post hoc test ( p < 0.05). In conclusion, considering the relatively superior selectiveness in suprahyoid and infrahyoid muscle contraction, the submandibular push exercise using visual feedback from pressure sensor could be an efficient supplementary exercise to the conventional swallowing muscle exercises. However, further studies may be necessary to confirm the improvement in swallowing difficulty.

Comparison of three different types of exercises for selective contractions of supra- and infrahyoid muscles

“…First, when performing the Shaker exercise, the healthy subjects and patients were instructed to perform the following exercise protocol: lie on the bed in the supine position, lift the head up and hold it for 10 s (Fig. 1 A) 18 , 21 , 23 , 24 . Second, when performing the CTAR exercise, participants were instructed to sit on a chair and press the chin as hard as possible against a CTAR device (Renodevice, Daegu, South Korea) placed under the chin (Fig.…”

“…Lastly, when performing the submandibular push exercise, the participants were instructed to sit on a chair and increase the pressure at the submandibular area against a plastic device [Renodevice, Daegu, South Korea, (Fig. 1 C,D)] without neck flexion 18 . The participants were instructed to maintain the end posture during the three exercises, and the surface EMG data were recorded.…”

“…Data were collected at a sampling rate of 50 kHz using Medelec Synergy with the following settings: high-frequency filter, 1000 Hz; low-frequency filter, 10 Hz; 1 s/div and 100 μV/div; sweep speed and gain; and common mode rejection ratio, > 110 dB 2 , 28 , 29 . The EMG activity was measured using a custom-designed disposable pre-gelled 20-mm Ag/AgCl disc electrode (CareFusion, Höchberg, Germany) 18 .…”

“…Various methods have been employed to treat dysphagia. Conventional treatment methods such as oropharyngeal (including the muscles involved in swallowing) exercises, compensated maneuvers, and electrical stimulation of the oropharyngeal area are widely applied in swallowing therapy 11 , 18 – 21 .…”

“…However, both exercises involve neck flexion movement patterns, which induce unnecessary contractions of the sternocleidomastoid (SCM) muscle and may adversely affect contractions of the selective supra- and infrahyoid muscles 25 . To overcome the limitations of the CTAR and Shaker exercises, the submandibular push exercise was introduced in a previous study 18 . However, that study used visual feedback from pressure sensors.…”