Stretch reflex and pressure pain thresholds in chronic tension-type headache patients and healthy controls.

To compare the jaw-stretch reflex and pressure pain thresholds (PPT) in chronic tension-type headache (CTTH) patients and healthy controls, 30 patients (15 male and 15 female) and 30 age- and sex-matched healthy subjects were investigated. Stretch reflexes were recorded in the temporalis and masseter muscles and PPT was determined in the anterior temporalis, splenius capitis and masseter muscles. The results showed that the amplitude of the stretch reflex in CTTH patients was higher compared with control subjects (P < 0.045), and higher in women compared with men in the right and left anterior temporalis muscles (P < 0.009). There were no differences in the PPT value between CTTH and control subjects (P > 0.509), whereas women showed significantly lower PPT measurements (P < 0.046). The results demonstrated a facilitation of the stretch reflex pathways in CTTH patients that is unrelated to measures of pericranial sensitivity.