Objective.— This study aimed to establish whether increased sensitivity to mechanical stimuli is present in neural tissues in chronic tension-type headache (CTTH).
Background.— Muscle hyperalgesia is a common finding in CTTH. No previous studies have investigated the sensitivity of peripheral nerves in patients with CTTH.
Design.— A blinded controlled study.
Methods.— Pressure pain thresholds (PPT) and pain intensity following palpation of the supra-orbital nerve (V1) were compared between 20 patients with CTTH and 20 healthy matched subjects. A pressure algometer and numerical pain rate scale were used to quantify PPT and pain to palpation. A headache diary was kept for 4 weeks to substantiate the diagnosis and record the pain history.
Results.— The analysis of variance demonstrated significantly lower PPT for patients (0.86 ± 0.13 kg/cm2) than controls (1.50 ± 0.19 kg/cm2) (P < .001). Pain to palpation was also higher for patients (2.73 ± 1.58) than controls (0.15 ± 0.28) (P < .001).Within the CTTH group, intensity, frequency, and duration of the headaches were negatively correlated with PPT (rs ≤ −0.75; P < .001), and positively correlated with pain to palpation (rs ≥ 0.72; P < .001).
Conclusions.— These findings reveal that mechanical hypersensitivity is not limited to muscles but also occurs in cranial nerves, and that the level of sensitization, either due to peripheral or central processes, is related to the severity of the primary headache.