Exteroceptive suppression of temporal muscle activity is normal in chronic tension-type headache and not related to actual headache state.

The aim of the present study was to compare the late exteroceptive suppression period (ES2) of temporalis muscle activity between patients with chronic tension-type headache and healthy controls, and to investigate the influence, if any, of actual headache on ES2. ES2 was recorded in 55 patients and in 55 controls with a previously evaluated methodology and analysed by a blinded observer. The first 20 patients were randomly studied on 2 additional days, 1 day with and 1 day without headache. The duration of ES2 did not differ between patients and controls and did not differ on days with headache compared with days without headache. ES2 duration was not related to the frequency of headache, headache intensity, age, pericranial muscle tenderness or electrical pain threshold. Our results strongly indicate that ES2 is normal in chronic tension-type headache and therefore may not be related to the pathophysiology of this disorder.