This study investigated the effect of a repeated and standardized jaw protrusion training (JPT) task on corticomotor excitability as assessed by motor evoked potentials (MEPs) in masseter and tongue muscle with the use of transcranial magnetic stimulation (TMS).

Sixteen healthy participants performed three series of a standardized JPT task on three consecutive days. Each day participants performed 41-min of JPT consisting of three series. In all series, participants were instructed to target 50% and 100% of the maximum jaw protrusion positions. In the first and third series without any feedback but during the second series, participants were provided a custom-made mandibular advancement device to help achieve the correct protruded position. Single pulse TMS was applied to elicit MEPs from right masseter, right tongue and right first dorsal interosseous muscles (FDI) (as control), pre and post-task on Day-1 and -3.

Masseter MEPs and tongue MEPs were significantly dependent on stimulus intensity (P < 0.001) and on task session (P < 0.001). Amplitude of masseter and tongue MEPs at post-task Day-3 were significantly higher compared to baseline values (pre-task Day-1) (P < 0.005). FDI MEPs were dependent on stimulus intensity only (P < 0.001) but not on task session (P = 0.677).

Our novel findings suggest that participants performing an active and repeated JPT task demonstrate neuroplasticity in terms of increased corticomotor excitability not only in masseter muscles but also in tongue muscles. This finding may have implications for patients with obstructive sleep apnea treated by a mandibular advancement device where the lower jaw is passively held in a protruded position.

本研究通过使用经颅磁刺激 (TMS) 的咬肌和舌肌的运动诱发电位 (MEP) 评估了重复和标准化的下颌前伸训练 (JPT) 任务对皮质运动兴奋性的影响。

16 名健康参与者连续三天执行了三个系列的标准化 JPT 任务。参与者每天进行 41 分钟的 JPT，包括三个系列。在所有系列中，参与者都被要求瞄准最大下颌前伸位置的 50% 和 100%。在第一个和第三个系列中没有任何反馈，但在第二个系列中，为参与者提供了一个定制的下颌前移装置，以帮助实现正确的突出位置。在第 1 天和第 -3 天的任务前和任务后，应用单脉冲 TMS 从右咬肌、右舌和右第一背骨间肌 (FDI)（作为对照）引发 MEP。

咬肌 MEP 和舌头 MEP 显着依赖于刺激强度 (P < 0.001) 和任务会话 (P < 0.001)。与基线值（任务前第 1 天）相比，任务后第 3 天咬肌和舌头 MEP 的振幅显着更高（P < 0.005）。FDI 欧洲议会议员仅依赖于刺激强度（P < 0.001），而不依赖于任务会话（P = 0.677）。

我们的新发现表明，执行积极和重复的 JPT 任务的参与者不仅在咬肌中，而且在舌头肌肉中，在皮质运动兴奋性增加方面表现出神经可塑性。这一发现可能对接受下颌前移装置治疗的阻塞性睡眠呼吸暂停患者有影响，该装置下颌被动保持在突出位置。