Differences in topographical pressure pain sensitivity maps of the scalp between patients with migraine and healthy controls

OBJECTIVE: To investigate differences in topographical pressure pain sensitivity maps of the scalp between patients with migraine and healthy controls considering the chronicity (episodic/chronic) and side (strictly unilateral/bilateral) of the symptoms.

BACKGROUND: It seems that the trigeminal area is sensitized in migraine. No study has investigated topographical pressure sensitivity maps of the scalp in patients with migraine.

METHODS: Pressure pain thresholds (PPTs) were assessed from 21 points distributed over the scalp in 86 patients with episodic migraine, 76 with chronic migraine, and 42 healthy age and matched healthy controls in a blinded design. Topographical pressure pain sensitivity maps based on interpolation of the PPTs were constructed. Clinical features of migraine, anxiety, and depression (Hospital Anxiety and Depression Scale, HADS) were collected.

RESULTS: The multivariate ANCOVA revealed significant differences in PPT between points (F = 55.674; P < .001) and groups (F = 5.316; P = .006), but not sides (F = 0.880; P = .417). No significant effect of gender (F = 0.897; P = .656), depression (F = 1.109; P = .220), or anxiety (F = 0.981; F = 0.569) was found. Post hoc comparisons revealed: (1) lower PPTs in both migraine groups than in healthy controls in all points (P < .001); (2) no significant differences between chronic or episodic migraine (P > .335) except for Fp1 (P = .045) and Fp2 (P = .017) points where subjects with chronic migraine had lower PPTs than those with episodic migraine; (3) no differences between bilateral/unilateral migraine (P > .417). An anterior to posterior gradient was found, with the lowest PPTs located in frontal regions and the highest PPTs in occipital areas (all groups, P < .001).

CONCLUSIONS: We found that patients with migraine exhibited generalized pressure pain hypersensitivity in the head as compared to healthy controls and that hypersensitivity was similar between episodic/chronic and unilateral/bilateral migraine. Topographical pressure pain sensitivity maps revealed an anterior to posterior gradient of pressure pain sensitivity in both migraine and control groups.