Generalized neck-shoulder hyperalgesia in chronic tension-type headache and unilateral migraine assessed by pressure pain sensitivity topographical maps of the trapezius muscle

Spatial changes in pressure pain hypersensitivity are present throughout the cephalic region (temporalis muscle) in both chronic tension-type headache (CTTH) and unilateral migraine. The aim of this study was to assess pressure pain sensitivity topographical maps on the trapezius muscle in 20 patients with CTTH and 20 with unilateral migraine in comparison with 20 healthy controls in a blind design. For this purpose, a pressure algometer was used to assess pressure pain thresholds (PPT) over 11 points of the trapezius muscle: four points in the upper part of the muscle, two over the levator scapulae muscle, two in the middle part, and the remaining three points in the lower part of the muscle. Pressure pain sensitivity maps of both sides (dominant/non-dominant; symptomatic/non-symptomatic) were depicted for patients and controls. CTTH patients showed generalized lower PPT levels compared with both migraine patients (P = 0.03) and controls (P < 0.001). The migraine group had also lower PPT than healthy controls (P < 0.001). The most sensitive location for the assessment of PPT was the neck portion of the upper trapezius muscle in both patient groups and healthy controls (P < 0.001). PPT was negatively related to some clinical pain features in both CTTH and unilateral migraine patients (all P < 0.05). Side-to-side differences were found in strictly unilateral migraine, but not in those subjects with bilateral pain, i.e. CTTH. These data support the influence of muscle hyperalgesia in both CTTH and unilateral migraine patients and point towards a general pressure pain hyperalgesia of neck-shoulder muscles in headache patients, particularly in CTTH.