A Novel Exercise to Improve Suprahyoid Muscle Area and Intensity as Evaluated by Ultrasonography

Insufficient suprahyoid muscle strength with poor opening of the upper esophageal sphincter can cause dysphagia. This study investigated whether an exercise of the suprahyoid muscle, named forehead exercise for suprahyoid muscles (FESM, "Enge-Odeko-Taiso" in Japanese), improves the geniohyoid muscle area and intensity using ultrasonography. Sixty-four participants (15 men and 49 women, 82.8 ± 6.0 years) living independently with no symptoms of swallowing difficulties were enrolled. The participants were divided into the FESM and the control group. The FESM is an isometric exercise involving repetitions of looking into the navel as if the chin is pulled back with little neck motion using a hand pushed against the forehead for resistance. This exercise is performed five times in 10 courses a day (total 50 times) for 8 weeks. Participants in the control group did not conduct any exercises. Body mass index, hand grip strength, gait speed, calf circumference, Mini Nutritional Assessment short-form, eating assessment tool, repetitive saliva swallowing test (RSST), and Food Intake LEVEL Scale scores were examined. The ultrasonographic geniohyoid muscle area, intensity, and RSST were investigated before and after the program. In the FESM group, the geniohyoid muscle area increased from 2.24 to 2.52 cm² (P < 0.05), intensity decreased from 34.6 to 32.0 (P < 0.05), and the median RSST increased from 5 to 6 (P < 0.05) significantly. Conversely, no significant differences were observed in the control group. The FESM was effective to increase the area and decrease the intensity of the geniohyoid muscle and may improve swallowing function.