Lack of temporal summation but distinct aftersensations to thermal stimulation in patients with combined tension-type headache and myofascial temporomandibular disorder.

Aims: To compare patients with combined tension-type headache and myofascial temporomandibular disorder (TMD) with control subjects on two measures of central processing-ie, temporal summation and aftersensations to heat stimulation in the trigeminal nerve and spinal nerve territories.

Methods: A novel heat stimulation protocol was used in which 13 females with tension-type headache/TMD and 20 female controls were exposed to 11 painful heat stimuli at a rate of 0.33 Hz. Two temperature ranges (low, 44°C to 46°C; high, 45°C to 47°C) were tested on the cheek and arm in separate trials. Perceived pain was rated on a 100-mm visual analog scale after the second, sixth, and eleventh stimulus presentation and every 15 seconds after the final stimulus presentation (aftersensations) for up to 3 minutes. The duration of aftersensations was compared using the student unpaired t test with Welch correction.

Results: Temporal summation was not observed in any of the groups, but aftersensations were consistently reported. The aftersensations lasted longer in tension-type headache/TMD patients (right cheek, 100.4 ± 62.0 seconds; right arm, 115.4 ± 64.0 seconds) than in controls (right cheek, 19.5 ± 2.5 seconds; right arm, 20.3 ± 2.7 seconds) (P < .05). A cutoff value (right cheek, 44.6 seconds; right arm, 41.5 seconds) provided a sensitivity and specificity of 0.77 and 0.95, respectively, with the high stimulus protocol.

Conclusion: The results from this pilot study suggest that aftersensations to painful heat stimulation can appear without temporal summation. Furthermore, the developed test protocol has a good predictive value and may have the potential to discriminate between tension-type headache/TMD patients and control subjects.