Increased somatosensory amplification is associated with decreased pressure pain thresholds at both trigeminal and extra‐trigeminal locations in healthy individuals

Abstract

Background: The diagnosis of temporomandibular disorders (TMD) is based on patient history and physical examination, and may require medical imaging. Masticatory muscle palpation is essential to make a diagnosis of TMD. However, the response of masticatory muscles to mechanical pressure stimuli depends on many physical and psychological factors. Objective: This study aimed at determining the impact of somatosensory amplification (SSA)-an estimate of somatic awareness and bodily hypervigilance-on pressure pain thresholds (PPTs) measured at both trigeminal and extra-trigeminal locations in healthy individuals. Methods: PPTs were measured at the right anterior temporalis and superficial masseter, and the thenar eminence of the right hand in one hundred healhty individuals (69F, 31M), divided in three groups based on their SSA scores: low (N = 32), intermediate (N = 34) and high (N = 34). General linear models were used to test betweengroup differences in PPTs including sex as a covariate. The level of significance was set at P < .05. Results: Individuals with high SSA had lower PPTs at the anterior temporalis than individuals with low (P = .006) and intermediate (P = .001) SSA. No significant betweengroup differences were found in PPTs measured at the masseter (P = .372). PPTs measured at the thenar eminence were significantly lower in the high than the low SSA group (P = .009). Females had lower PPTs at the masseter than males (P = .021) but not at other muscle locations (all P > .05). Conclusion: Increased somatosensory amplification is associated with decreased pressure pain thresholds at both trigeminal and extra-trigeminal locations in healthy individuals. SSA could be a potential confounder while diagnosing TMD and evaluating treatment outcomes.

Temporomandibular disorders cases with high-impact pain are more likely to experience short-term pain fluctuations

“…Remarkably, we did not observe a statistically significant difference in PPT between cases and controls, despite low-impact TMD cases presenting numerically lower mean PPT in the face in visits 1 and 2. This finding is in contrast to a body of literature reporting decreased PPT over the masseter muscles in TMD cases when compared to controls 88 – 90 , however this discrepancy has also been reported previously by others 91 and it has been recently suggested that somatosensory amplification may act as confounder for decreased PPT 92 . We observed that jaw pain ratings across visits were correlated between each other in the low-impact TMD group, while in the high-impact TMD group significant positive correlations were found between PPT across visits (both face and hand sites), which could suggest that pain-related impact status differentially contributes to the longitudinal pattern for clinical and experimental pain in each of these TMD groups.…”

Smiling, Yawning, Jaw Functional Limitations and Oral Behaviors With Respect to General Health Status in Patients With Temporomandibular Disorder—Myofascial Pain With Referral

“…These researchers highlighted that somatosensory amplification tends to be greater in patients with facial pain than in pain-free cases ( 73 ). However, recent studies revealed no relationship between severity of somatosensory amplification and the frequency of oral behaviors and trait anxiety ( 75 ).…”

Influence of genetic polymorphisms on mechanical pain sensitivity and endogenous pain modulation of trigeminal and spinal areas

“…However, such influence was not observed in a spinal area. This is a curious finding, as previous case–control studies demonstrated lower PPT values in TMD patients, 71,72 both in trigeminal and spinal areas. This could indicate a generalised hypersensitivity of the central nervous system 73,74 .…”