Masseter and Temporalis Muscle EMG Levels and Bite Force in Migraineurs

Abstract

The purpose of this study was to compare absolute and proportional electromyography (EMG) levels in the masseter and temporalis muscles during performance of a variety of oral functions for migraineurs and age-and sex-matched controls. Both groups consisted of nine women and one man, with a mean age of 43 years (range, 29 to 51 years). Absolute resting EMG levels and those levels during swallowing and speech were not significantly different between the groups, but the levels of the group with migraine were significantly higher during maximum voluntary effort contractions on the anterior teeth and on the posterior teeth for both muscles. When expressed as a percentage of those levels obtained at maximal posterior contraction (ie, proportional levels), no difference in functional activity was demonstrated between groups. It was concluded that the two groups studied had similar levels of EMG activity in the masseter and temporalis muscles during the normal oral functions investigated, but that the group with migraine had higher levels of absolute EMG activity during anterior and posterior maximum voluntary contractions. Furthermore, the group with migraine demonstrated higher levels of anterior and posterior bite force, although not correlated with EMG levels.

Bite Force and Influential Factors on Bite Force Measurements: A Literature Review

“…The most widely accepted recording device is the strain-gage bite force transducer. 46,[50][51][52][53][54][55][56] The strain-gage bite force transducer is available in different heights and widths. Ferrario et al 22 and Kogawa et al 30 have measured bite force with 4 mm height and 5x7 mm wide strain-gaged transducer.…”

Can Masticatory Electromyography be Normalised to Submaximal Bite Force?

“…The present study used a low bite force (20 N) reference value for normalisation, which allowed for successful normalisation from 25% to 100% bite force. Other researchers have used MVCs performed on transducers or dynamometers to normalise an array of submaximal tasks on different biting (or non-biting) surfaces (4,6). Although biting different surfaces may create greater variation in EMG or bite force results (1), normalisation is necessary for comparison of individual versus group results but also enables researchers to compare their results with prior studies (5,18).…”

“…Bite force and masticatory muscle activity can be used to assess the functional performance of the jaw within research studies and may be useful within clinical applications. Previous investigations have combined bite force with electromyography (EMG) measurements to explore differences in masticatory muscle symmetry (1), masticatory function of participants with different facial types (2, 3) and masticatory func-tion of healthy individuals versus those with a limiting condition such as temporomandibular disorder or migraines (4).…”

“…Some previous studies have presented jaw muscle EMG data as absolute values rather than normalising them to a common EMG signal (4,7,15). However, the amount of variation due to differences in sex, skin thickness and electrode placement can be reduced if the results are normalised.…”

Mean power frequency during speech in myalgia patients

“…However, as clenching is likely to cause pain in myalgia patients and as the occlusal condition can affect electromyographic activities during clenching, it might not be suitable for the purpose of measuring masticatory muscle pain. Myalgia patients rarely complain pain during daily speech movements because both electromyographic activities of masseter muscle and the range of mouth opening during speech are small (10–13). As we would like to decrease the influence of pain induced by test movement, we used speech as a test movement.…”