Task: Question Answering
Input (English): Context: Myofascial pain syndromes due to trigger points (TrPs) are clinical entities, but more evidence is needed to evaluate TrP palpation. Chronic tension-type headache (CTTH) is the most prevalent chronic headache with high socioeconomic costs. The primary aim was to study whether TrP palpation can distinguish patients with headache patients from healthy controls.', 'Double-blinded, controlled design.', 'Twenty patients with the diagnosis of CTTH, and 20 healthy age-matched and sex-matched control participants.', 'TrP palpation revealed more TrPs in patients (N=17) versus controls (N=6) (P=0.0005). Referred pain was also more frequent in patients (N=17) versus controls (N=9) (P=0.04). Further, TrP palpation also identified a higher pain intensity than at a control point (CtP) in both groups (P=0.0001). Pain intensity at TrPs in patients was higher than in controls (P=0.0010), and CtPs were also more tender in patients than in controls (P=0.0167). For spontaneous electromyographic activity no difference between TrPs versus CtPs within or between groups could be detected.\Question: Are myofascial trigger points very prevalent in patients with chronic tension-type headache : a double-blinded controlled study?
Output (English): These findings suggest that active TrPs are much more frequent in CTTH than in controls and the number and pain intensity of TrPs may be used to distinguish between the 2 groups. Spontaneous electromyographic activity could not be demonstrated, and the underlying biology of TrPs is still unclear.