Exteroceptive suppression of temporalis muscle activity in various types of headache

Exteroceptive suppression (ES) of temporalis muscle activity, particularly the multisynaptic ES2, has been reported to be significantly reduced in tension type headache, but not in migraine. We re-evaluated the methods of optimally analysing the single shock technique and its intra- and inter-individual variability in 26 normal subjects. These data were compared with the results in patients with migraine, post-lumbar puncture headache, headache due to meningitis, tension-type headaches in HIV infection and patients with symptomatic headache of various etiologies. ES2 was absent in about 50% of tension-type headache patients, but only in one normal subject. With the methods used here and when patients with absent ES2 were excluded, mean duration of ES2 was not significantly different between the various groups. It seems therefore necessary, in spite of increased discomfort for patients, to use complementary methods, such as averaging 16-32 responses and applying various stimulation sets, if one wants to increase the potency of temporalis ES2 as a diagnostic and pathophysiologic tool in headache.