Waking and sleeping temporalis EMG levels in tension-type headache patients.

Temporalis muscle activity in tension-type headache subjects (n = 36) and in matched nonheadache controls (n = 36) was evaluated in this study. Subjects' cumulative temporalis muscle activity was recorded every 30 minutes for 3 days and night using an electromyographic recorder. Analysis of variance showed that neither the waking nor the sleeping overall muscle activity levels for these two groups were statistically different. When the waking EMG data were dichotomized into function and nonfunction activities, a significant difference was found between groups during jaw function (i.e., chewing and talking). These data suggest that headache subjects are using their temporalis muscles with less efficiency than nonheadache subjects during function. This elevated EMG is more likely a consequence of pain (via protective splinting or guarding) rather than a cause in tension-type headache sufferers.