Chronic temporomandibular disorders are associated with higher propensity to develop central sensitization: a case–control study

Abstract

Temporomandibular disorders (TMD) include a group of musculoskeletal disorders that may involve increased responsiveness of nociceptive neurons in the central nervous system (ie, central sensitization). To test this hypothesis further, this study examined whether, as compared with healthy subjects, patients with chronic TMD have a greater propensity to develop secondary mechanical hyperalgesia-a phenomenon that can be confidently attributed to central sensitization. In this case-control study, we assessed the area of secondary mechanical hyperalgesia induced experimentally by delivering high-frequency electrical stimulation (HFS) to the volar forearm skin in 20 participants with chronic TMD and 20 matched healthy controls. High-frequency electrical stimulation consisted in 12 trains of constant-current electrical pulses (5 mA) delivered at 42 Hz. The area of secondary mechanical hyperalgesia was evaluated 30 minutes after applying HFS. The area of secondary mechanical hyperalgesia induced by HFS was on average 76% larger in the chronic TMD group (M 5 67.7 cm 2 , SD 5 28.2) than in the healthy control group (M 5 38.4 cm 2 , SD 5 14.9; P 5 0.0003). Regarding secondary outcomes, there was no group difference in the intensity of secondary mechanical hyperalgesia, but allodynia to cotton after HFS was more frequent in the chronic TMD group. To the best of our knowledge, this is the first study to show that individuals with chronic TMD have an increased propensity to develop secondary hyperalgesia in a site innervated extratrigeminally. Our results contribute to a better understanding of the pathophysiology of chronic TMD.

Verbal support from a stranger reduces the development of mechanical hypersensitivity: behavioural, electrophysiological evidence and the moderating role of attachment styles

“…However, in contrast with our previous findings [28] we found no effect of social support on the spread of hypersensitivity. This is another instance of a dissociation between the spread and the subjective ratings of hypersensitivity as has been found in previous studies [12,28,40,59]. While some of these studies have succeeded in modulating only the spread of hypersensitivity [12,28,40], others have only been able to modulate the subjective ratings of hypersensitivity [59].…”

“…This is another instance of a dissociation between the spread and the subjective ratings of hypersensitivity as has been found in previous studies [12,28,40,59]. While some of these studies have succeeded in modulating only the spread of hypersensitivity [12,28,40], others have only been able to modulate the subjective ratings of hypersensitivity [59]. Although both the spread and the subjective ratings are typically used as markers of hypersensitivity, it remains unclear at present, as to why the two measures are sometimes differentially modulated.…”

The impact of the social context on the development of secondary hyperalgesia: an experimental study

“…Such a dissociation between the area of SH and subjective ratings was also found by Matre et al (2006) where a placebo intervention reduced the area of SH, but not the intensity ratings [45]. A more recent study using MFS also showed that patients (vs healthy controls) with Temporomandibular Disorders developed a 76% larger area of SH, but showed no difference in the intensity of SH [15]. On the other hand, Torta et al (2022) found that an observational learning intervention attenuated subjective ratings but not the area [65].…”

“…45 A more recent study using MFS also showed that patients (vs healthy controls) with temporomandibular disorders developed a 76% larger area of SH but showed no difference in the intensity of SH. 15 On the other hand, Torta et al (2022) found that an observational learning intervention attenuated subjective ratings but not the area. 66 Such dissociations indicate that the 2 measures may be indices of slightly different phenomena or perhaps different aspects of the same phenomenon that are influenced by different variables.…”

Healthy women show more experimentally induced central sensitization compared with men

“…It is typically recorded as secondary mechanical hyperalgesia (SMH) or dynamic mechanical allodynia (DMA). 20 , 73 , 83 , 102 Such measurements rely on cooperation and feedback from the tested person. 42 Therefore, the measures are potentially subject to factors influencing response behaviour in the tested person, such as disposition, motivation, expectation, or interaction, with the experimenter that can vary between men and women.…”