Stomatognathic function in Duchenne muscular dystrophy: a case-control study

AimThis study aimed to analyse electromyographic activity, masticatory efficiency, muscle thickness, and bite force of individuals with Duchenne muscular dystrophy (DMD). MethodForty males aged 4-15 years, 20 with DMD and 20 healthy age-, height-, and weight-matched controls, underwent electromyography and ultrasonography of temporalis, masseter, and sternocleidomastoid muscles during postural control of the jaw, mastication, and maximal molar bite force. ResultsThe normalized electromyography signals showed higher activity in masseter and temporal muscles at rest, during protrusion, left and right laterality, and fatigue condition in the group with DMD than in the comparison group (p0.05). For masticatory efficiency of cycles, in analysis of non-habitual chewing of flavourless gum, and habitual chewing of peanuts and raisins, the group with DMD presented lower averages (p0.05). For the muscle thickness, the results showed that there was a lower muscle thickness in the group with DMD for all muscles during the rest and maximal voluntary contraction, except for masseter and sternocleidomastoid in the maximal voluntary contraction. In the maximal molar bite force, the group with DMD presented higher values for both sides than the comparison group (p0.05). InterpretationPatients with DMD show muscle changes related to the stomatognathic system, in their activity, bite force, and muscle thickness. What this paper adds Males with Duchenne muscular dystrophy presented changes in muscle activities related to jaw conditions. They consistently showed less chewing and a greater threshold of muscle fatigue. They consistently showed decreased maximal molar bite force. (AU)