Effects of induced stress on experimental pain sensitivity in chronic tension-type headache sufferers

Background and purpose:  It has been proposed that stress may contribute to chronic tension-type headache (CTH) through hyperalgesic effects on already sensitized pain pathways in CTH sufferers. This hypothesis could be partially tested by examining effects of stress on mechanical and thermal pain sensitivity in CTH sufferers. Such examinations have not been reported to date.
Materials and methods:  In the present study, we measured cephalic and extra-cephalic pressure [pressure-pain threshold (PPT)] and cold-pain thresholds (CPT) in CTH sufferers ( n  = 8 females, n  = 8 males) and healthy control subjects ( n  = 8 males, n  = 7 females) recruited from the general population before and after exposure to a 15-min stressful mental task.
Results:  Results indicated that PPT's at head and hand were lower in the CTH compared with control group both before and after task exposure. PPT's and CPT's decreased from pre- to post-task in both groups, with a significantly greater pre- to post-task reduction in cephalic PPT in the CTH compared with control group. Subjective stress increased from pre- to post-task in both groups and did not differ between groups. In the CTH group, stress reactivity was negatively correlated with PPT's, whilst absolute stress levels were positively correlated with pre- to post-task decrease in PPT's.
Conclusions:  The main finding is an enhanced hyperalgesic effect of stress on cephalic pressure-pain sensitivity in the CTH sufferers compared with the healthy controls. The results support the hypothesis that stress may contribute to CTH through hyperalgesic effects on already sensitized pain pathways in CTH sufferers.