Maezawa Hitoshi, Koganemaru Satoko, Matsuhashi Masao, Hirata Masayuki, Funahashi Makoto, Mima Tatsuya
Department of Oral Physiology, Graduate School of Dental Medicine, Hokkaido University, Kita-ku, Sapporo, 060-8586, Japan; Department of Neurological Diagnosis and Restoration, Graduate School of Medicine, Osaka University, Suita, Osaka, 565-0871, Japan.
Human Brain Research Center, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, 606-8507, Japan; Department of Rehabilitation, Graduate School of Medicine, Hokkaido University, Kita-ku, Sapporo, 060-8586, Japan; Department of Physiology and Biological Information, Dokkyo Medical University School of Medicine, Shimotsuga-Gun, Tochigi, 321-0293, Japan.
Neurosci Res. 2020 Jul;156:88-94. doi: 10.1016/j.neures.2020.02.008. Epub 2020 Feb 22.
It remains unclear whether the rhythmic processes of chewing and gait synchronize during concurrent execution in humans. To evaluate the entrainment of chewing rhythm by gait speed, we measured electromyography from the masseter and tibialis anterior muscles during chewing at a habitual rhythm while walking on a linear treadmill in 12 healthy volunteers. Vertical movement of the head was also measured using an accelerometer. Each 5-min session included gait tasks using a treadmill at three speeds: Auto: the participant's self-selected gait speed, High: Auto × 1.3, and Low: Auto ÷ 1.3. Electromyography from the masseter muscles were also measured during chewing while stationary (Chew-Only). Chewing rhythm during walking was the same as that for head movement, occurring at twice the speed of the walking rhythm, in nine participants (Low), eight participants (Auto), and eight participants (High). For these participants, chewing rhythm in the Auto and High conditions differed significantly from that in the Chew-Only condition. Significant differences in chewing rhythm were also observed among gait speeds (Low vs. Auto vs. High). Our findings demonstrate that entrainment of habitual chewing rhythm to gait speed is a significant phenomenon, and that the dominant ratio of chewing-walking-head movement rhythms is 2:1:2.
在人类同时进行咀嚼和步态这两种节律性活动时，它们是否会同步仍不清楚。为了评估步态速度对咀嚼节奏的夹带作用，我们在12名健康志愿者在直线跑步机上行走时，以习惯节奏咀嚼的过程中，测量了咬肌和胫前肌的肌电图。还使用加速度计测量了头部的垂直运动。每5分钟的时间段包括使用跑步机以三种速度进行的步态任务：自动：参与者自行选择的步态速度；高：自动速度×1.3；低：自动速度÷1.3。在静止咀嚼（仅咀嚼）时也测量了咬肌的肌电图。在行走过程中，九名参与者（低速）、八名参与者（自动速度）和八名参与者（高速）的咀嚼节奏与头部运动节奏相同，是行走节奏速度的两倍。对于这些参与者，自动速度和高速条件下的咀嚼节奏与仅咀嚼条件下的咀嚼节奏有显著差异。在不同步态速度（低速与自动速度与高速）之间也观察到咀嚼节奏的显著差异。我们的研究结果表明，习惯咀嚼节奏被步态速度夹带是一个显著现象，并且咀嚼 - 行走 - 头部运动节奏的主导比例为2:1:2。
