Effects of viscosity and head position on the surface electromyography of the suprahyoid muscles during swallowing / 中华物理医学与康复杂志

ABSTRACT

Objective:To explore the effect of swallowing fluids of different viscosities in different head positions on the surface electromyography (sEMG) of the suprahyoid muscles.Methods:Twenty healthy adults were asked to swallow 5ml of liquids with 5 different viscosities in 3 different head positions. sEMG signals were recorded from their suprahyoid muscles in real time. The interactions between viscosity, head position and suprahyoid muscle activation were determined using simple effect analysis.Results:Significant head position and viscosity effects were observed. In the head-turning-right or the right head-flexion position, the net amplitude values of the left suprahyoid muscles were significantly higher than those from the right side when swallowing fluid of the same viscosity. Meanwhile, the net amplitude values of the left suprahyoid muscles increased gradually and significantly from the neutral position to the head-turning-right and the right head-flexion positions. When swallowing fluid with a viscosity of 0 to 3, the net amplitude values of the right suprahyoid muscles in the right head-flexion position were significantly lower than in the neutral and right head-flexion positions. With a viscosity of 4 the values of the former were significantly higher than the latter. The net amplitude of the left superhyoid muscle group when swallowing zero-viscosity food in a head-turning-right position was significantly lower than that when swallowing food of viscosity 1 to 4. In the right head-flexion position, the net amplitude of the left superhyoid muscle group when swallowing zero-viscosity food was significantly lower than that when swallowing food of viscosity 2 to 4. When swallowing fluid of viscosity 1 it was also significantly lower than that when swallowing food of viscosity 3 to 4. In the same position, the net amplitude of the right suprhyoid muscle group when swallowing fluid of viscosity 4 was significantly higher than that with a viscosity of 0 to 1. At viscosity 3 it was significantly higher than with a viscosity of 1.Conclusion:Swallowing fluids of different viscosities in different head positions can affect the contraction of the suprahyoid muscles to different degrees.