Use of suction electrodes for measurement of intrinsic tongue muscular endurance during lingual pressure generation

Abstract

AbstractBackgroundLingual pressure (LP) generation is cooperatively controlled not only by the intrinsic tongue (I‐ton) muscles but also by hyoid muscle activation. However, the measurement of endurance and fatigue properties of I‐ton muscles is difficult due to the instability of electrodes.ObjectiveThe purpose of this study was to apply suction electrodes to measure electromyograms (EMGs) of I‐ton muscle and to evaluate integrated EMG amplitude (iEMG) and mean power frequency (MPF) of EMG in the I‐ton and hyoid muscles performing continuous LP.MethodsTwenty healthy adult volunteers (10 males, 10 females, mean age 28.8 years) were instructed to perform 10‐s LP generation tasks at 25%, 50%, 75% and 100% of maximum LP in randomised order with visual feedback. During each task, EMGs of the I‐ton, suprahyoid (S‐hyo), infrahyoid (I‐hyo) and masseter (Mass) muscles were simultaneously recorded. The iEMG and MPF of EMG burst during 10‐s LP tasks were compared. The recording period was divided into three substages to analyse temporal changes with the Friedman test.ResultsDuring the 10‐s task, the iEMG significantly increased as the LP strength increased (p < .001). There was no time‐dependent change in the I‐ton iEMG; however, the MPF of the I‐ton EMG burst decreased in all tasks (p < .05). The S‐hyo and I‐hyo iEMGs gradually increased, especially with strong LP (p < .01).ConclusionWhile I‐ton muscles may easily fatigue during 10‐s LP generation, S‐hyo and I‐hyo muscles may help compensate for the weakened I‐ton muscle activity by increasing their activity to maintain LP.