EXTEROCEPTIVE SUPPRESSION OF TEMPORALIS MUSCLE-ACTIVITY - A BLIND-STUDY OF TENSION-TYPE HEADACHE, MIGRAINE, AND CERVICOGENIC HEADACHE

Exteroceptive suppression of temporalis muscle activity (ES2 duration) has been reported to be reduced in chronic tension-type headache in p revious open studies (with varying stimulus and analysis methods). We studied ES2 duration and latency in 11 patients with chronic tension-t ype headache, 10 patients with cervicogenic headache, 11 migraine pati ents, and 9 headache-free control subjects. The investigator was blind ed as to the diagnostic category. Electrical stimuli of 0.5 ms duratio n and at least three times sensory threshold (median 9.6 mA) were used . ES2 was obtained in all but one (control) subject and the control ES 2 duration mean was 33.5 (SD 8.5) ms (80% EMG amplitude reduction crit erion). Mean ES2 duration differences were not found between the four groups. None of the headache patients had ES2 durations below the cont rol group range. ES2 duration tended to decrease with increasing durat ion of headache history. Consistent asymmetries of ES2 latency and dur ation were not found among patients with (unilateral) cervicogenic hea dache. Thus, the role of ES2 in headache diagnosis still seems to be u nsettled.