title: Lack of temporal summation but distinct aftersensations to thermal stimulation in patients with combined tension-type headache and myofascial temporomandibular disorder.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Dentistry & Oral Surgery, School of Medicine, Keio University, Tokyo, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sato
authors.forename: Hironori
authors.initials: H
authors.lastname: Saisu
authors.forename: Wataru
authors.initials: W
authors.lastname: Muraoka
authors.forename: Taneaki
authors.initials: T
authors.lastname: Nakagawa
authors.forename: Peter
authors.initials: P
authors.lastname: Svensson
authors.forename: Koichi
authors.initials: K
authors.lastname: Wajima
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D059333:Central Nervous System Sensitization / Q000502:physiology*; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D005260:Female; D006358:Hot Temperature; D006801:Humans; D059226:Nociceptive Pain / Q000503:physiopathology*; D010812:Physical Stimulation; D010865:Pilot Projects; D059227:Postsynaptic Potential Summation / Q000502:physiology*; D012680:Sensitivity and Specificity; D013127:Spinal Nerves / Q000502:physiology; D013706:Temporomandibular Joint Dysfunction Syndrome / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D018781:Tension-Type Headache / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D013997:Time Factors; D014276:Trigeminal Nerve / Q000502:physiology; D055815:Young Adult