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Updated: Feb 2, 2026

Stimulating the Lip Motor Cortex with Transcranial Magnetic Stimulation
Published on: June 14, 2014
Assessment of hypoxic lip training for lip incompetence by electromyographic analysis of the orbicularis oris muscle
Saori Yoshizawa1, Mai Ohtsuka1, Tomoo Kaneko1
1Department of Oral Functional Science, Faculty of Dental Medicine and Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan.
Introduction:
The aims of this study were to determine the difference in electromyography (EMG) of the orbicularis oris muscles between subjects with lip incompetence and lip competence and to elucidate the effectiveness of hypoxic lip training with EMG.
Methods:
Twenty-five subjects (14 men, 11 women; mean age, 24.5 ± 2.6 years) were divided into 2 groups by sealed lip ratio: 13 subjects with lip incompetence (LI) and 12 subjects with lip competence (LC). Integral values of EMG for the orbicularis oris muscle during lip closing were estimated (baseline, T1). Then the subjects in the LI group performed the hypoxic lip training every day for 4 weeks. The EMG recordings were repeated during the training (T2), immediately after the training (T3), 4 weeks after the training (T4), and 8 weeks after the training (T5).
Results:
In the LI group, the EMG values during lip closing were significantly higher than those of the LC group, and the values of EMG during lip closing at T3 were significantly lower than those at T1. In the posttraining period, the values of EMG at T4 and T5 were significantly lower than those at T1. The results suggested that subjects with lip incompetence need greater orbicularis oris muscle activity to keep their lips closed.
Conclusions:
The suggested standardized lip training could be used as a training method for patients with lip incompetence.
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