Exteroceptive suppression of masseter muscle activity in children and adolescents with primary headaches

Background: In persons voluntarily closing the mouth, electrical or mechanical stimulation of the lower part of the face on either side elicits two successive transient suppression periods (ES1 and ES2) of the electromyographic activities (EMG) of the masseter and temporalis muscles bilaterally. Some investigators found ES2 to be reduced in adults with chronic tension-type headache. Studies in patients with migraine gave normal results. In children and adolescents no studies have been published to this day.

Methods: Exteroceptive suppression of masseter muscle activity was investigated in 14 patients with migraine, in six patients with episodic tension-type headache, and in 19 controls between 6 and 18 years of age. The patients were studied in the headache-free interval. Based on the standards recommended by the European Headache Federation, we modified the registration slightly for application in children. Stimulation site was the labial commissure. EMG was recorded from the masseter muscles.

Results: Regarding ES1 no group differences were found. However, the EMG reactivation between ES1 and ES2 was shorter and ES2 was longer in the migraine group while the patients with episodic tension-type headache showed no significant modifications of ES2.

Conclusion: These findings suggest hyperexcitability of central trigeminal neurons and impairment of antinociceptive brainstem systems in children and adolescents with migraine. Reduction of ES2 in adult patients with chronic tension-type headache might be a consequence of long-lasting headache disorder.