Episodic and chronic migraineurs are hypersensitive to thermal stimuli between migraine attacks

Abstract

Objective: To determine if migraineurs have evidence of interictal cutaneous sensitisation.

Subjects and methods: Thermal and mechanical pain thresholds in 20 episodic migraineurs, 20 chronic migraineurs, and 20 non-migraine control subjects were compared. Quantitative sensory testing was conducted when subjects had been migraine-free for at least 48 h. Heat, cold and mechanical pain thresholds, and heat and cold pain tolerance thresholds were measured.

Results: Thermal pain thresholds and thermal pain tolerance thresholds differed significantly by headache group (P = 0.001). During the interictal period, episodic and chronic migraineurs were more sensitive to thermal stimulation than non-migraine controls.

Conclusions: Interictal sensitisation may predispose the migraineur to development of headaches, may be a marker of migraine activity, and a target for treatment.

Figure 1

(A) Mean heat pain thresholds and (B) mean heat tolerance thresholds (with 95% confidence interval) by headache group and body region. The main effect of headache group was significant for heat pain (F(2,57)=11.4; P<0.001) and heat tolerance (F(2,57)=11.7; P<0.001). For heat pain, significant headache group pair-wise comparisons include EM (42.7°C) vs CTL (46.4°C; P<0.001) and CM (43.4°C) vs CTL (P=0.002). For heat tolerance, significant differences were seen for EM (44.3°) vs. CTL (47.4°C; P<0.001) and CM (44.8°C) vs CTL (P=0.001). The main effect of body region (head vs arm) was not significant for heat pain (F(1,57)=3.8; P=0.057) or heat tolerance (F(1,57)=0.4; P=0.525). The interaction of body region was not significant for heat pain (F(2,57)=0.6; P=0.561) or heat tolerance (F(2,57)=0.1; P=0.945).

Figure 2

(A) Mean cold pain thresholds and (B) mean cold tolerance thresholds (with 95% confidence interval) by headache group and body region. The main effect of headache group was significant for cold pain (F(2,57)=7.40; P=0.001) and cold tolerance (F(2,57)=10.4; P<0.001). For cold pain, significant headache group pair-wise comparisons include EM (14.9°C) vs CTL (6.6°C; P=0.001); CM (11.7°C) vs CTL did not quite reach statistical significance (P=0.053). For cold tolerance, CM (10.5°C) vs CTL (4.0°C) was only significant in the head region (P=0.007). EM (head 12.2°C, arm 3.7°C) differed from CTL (head 4.0°C, arm 0.2°C) in both the head (P<0.001) and arm (P=0.023). The main effect of body region (head vs arm) was significant for cold pain (F(1,57)=105.7; P<0.001; mean difference 7.7°C) and cold tolerance (F(1,57)=177.3; P<0.001; mean difference 7.1°C). The interaction of headache group and region was not significant for cold pain (F(2,57)=0.34; P=0.711) but was significant for cold tolerance (F(2,57)=9.4; P<0.001).