Thermal and mechanical quantitative sensory testing in chinese patients with burning mouth syndrome – a probable neuropathic pain condition?

Abstract

BackgroundTo explore the hypothesis that burning mouth syndrome (BMS) probably is a neuropathic pain condition, thermal and mechanical sensory and pain thresholds were tested and compared with age- and gender-matched control participants using a standardized battery of psychophysical techniques.MethodsTwenty-five BMS patients (men: 8, women: 17, age: 49.5 ± 11.4 years) and 19 age- and gender-matched healthy control participants were included. The cold detection threshold (CDT), warm detection threshold (WDT), cold pain threshold (CPT), heat pain threshold (HPT), mechanical detection threshold (MDT) and mechanical pain threshold (MPT), in accordance with the German Network of Neuropathic Pain guidelines, were measured at the following four sites: the dorsum of the left hand (hand), the skin at the mental foramen (chin), on the tip of the tongue (tongue), and the mucosa of the lower lip (lip). Statistical analysis was performed using ANOVA with repeated measures to compare the means within and between groups. Furthermore, Z-score profiles were generated, and exploratory correlation analyses between QST and clinical variables were performed. Two-tailed tests with a significance level of 5 % were used throughout.ResultsCDTs (P < 0.02) were significantly lower (less sensitivity) and HPTs (P < 0.001) were significantly higher (less sensitivity) at the tongue and lip in BMS patients compared to control participants. WDT (P = 0.007) was also significantly higher at the tongue in BMS patients compared to control subjects . There were no significant differences in MDT and MPT between the BMS patients and healthy subjects at any of the four test sites. Z-scores showed that significant loss of function can be identified for CDT (Z-scores = −0.9±1.1) and HPT (Z-scores = 1.5±0.4). There were no significant correlations between QST and clinical variables (pain intensity, duration, depressions scores).ConclusionBMS patients had a significant loss of thermal function but not mechanical function, supporting the hypothesis that BMS may be a probable neuropathic pain condition. Further studies including e.g. electrophysiological or imaging techniques are needed to clarify the underlying mechanisms of BMS.

Group II mGluRs suppress hyperexcitability in mouse and human nociceptors

“…A few recent studies have begun to investigate the physiology of viable human DRG neurons and have highlighted some similarities as well as some potentially important differences in how human DRG neurons respond to stimuli previously tested only in rodents [14; 29; 31; 52]. However, our study is the first to show that inflammation-induced sensitization of human nociceptors, a neural correlate of hyperalgesia, can be blocked by a candidate analgesic in vitro .…”

Refractory burning mouth syndrome: clinical and paraclinical evaluation, comorbidities, treatment and outcome

“…pain during the night and unilateral burning, but this was the patients’ clinical picture we observed. Patients did not undergo an intraoral quantitative sensory test that has been shown to be abnormal in recent reports indicating significant loss of thermal function but not mechanical function in BMS patients, supporting the hypothesis that BMS may be a probable neuropathic pain condition [38]. …”

Neurophysiology and genetics of burning mouth syndrome

“…In agreement with the present findings, thermal hypoesthesia at the tongue mucosa has been reported in most previous studies using appropriately sized small thermodes and age‐matched controls. Both CDTs and WDTs have rather consistently been found to be higher in BMS patients compared to control subjects (Forssell et al, ; Mo et al, ; Puhakka et al, ). These thermal QST findings of loss of function are compatible with the concept of BMS as a neuropathic pain condition due to focal small fibre neuropathy (Lauria et al, ; Puhakka et al, ; Yilmaz et al, ).…”