Mechanomyographic activity in the human lateral pterygoid muscle during mandibular movement

Shigehisa Kawakami, Naoki Kodama, Naoto Maeda, Shunichi Sakamoto, Kazuhiro Oki, Yoshinobu Yanagi, Jun Ichi Asaumi, Teruta Maeda, Shogo Minagi

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

The activity of the lateral pterygoid muscle has been regarded to be related to the pathological condition of the temporomandibular joint (TMJ) in the craniomandibular disorders. Because the lateral pterygoid muscle is a deep muscle, a needle electrode is necessary for EMG recordings. The purpose of this study was to establish a non-invasive method for the evaluation of muscle activity of the lateral pterygoid muscle using mechanomyogram (MMG). In three male subjects, surface electromyogram (EMG) in the left masseter muscle, left anterior and posterior belly of the temporal muscle, left anterior belly of the digastric muscle and needle EMG of the inferior head of the lateral pterygoid were recorded during mandibular movement tasks simultaneously with the MMG derived from a condenser microphone in the external ear canal. There were significant positive correlations between the needle EMG signal of the lateral pterygoid muscle and the MMG signal for the tasks of static jaw opened position of 30mm of interincisal distance (p=0.000, R 2=0.725), static jaw opened position of 40mm of interincisal distance (p=0.000, R 2=0.753), 5mm protruded mandibular position (p=0.000, R 2=0.653), the most protruded mandibular position (p=0.000, R 2=0803). On the contrary, for the task of maximal clenching, there was no significant correlation between the EMG signal of the lateral pterygoid muscle and the MMG signal. These results suggest that the activity of the lateral pterygoid muscle could be evaluated by the MMG signals recorded in the external ear canal, unless jaw closing major muscles show active contraction.

Original languageEnglish
Pages (from-to)157-162
Number of pages6
JournalJournal of Neuroscience Methods
Volume203
Issue number1
DOIs
Publication statusPublished - Jan 15 2012

Keywords

  • Electromyogram
  • Jaw movement
  • Lateral pterygoid muscle
  • Mechanomyogram

ASJC Scopus subject areas

  • Neuroscience(all)

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