Neurophysiology and genetics of burning mouth syndrome

Abstract

Background and aims Neuropathic mechanisms are involved in burning mouth syndrome (BMS), and variation of the dopamine D2 receptor (DRD2) gene contributes to experimental pain perception. We investigated whether neurophysiologic findings differ in BMS patients compared to healthy controls, and whether 957C>T polymorphism of the DRD2 gene influences thermal sensitivity or pain experience in BMS. Methods Forty‐five BMS patients (43 women), mean age 62.5 years, and 32 healthy controls (30 women), mean age 64.8 years, participated. Patients estimated pain intensity, interference, suffering and sleep with Numeric Rating Scale. Blink reflex tests of the supraorbital (SON), mental (MN) and lingual (LN) nerves, and thermal quantitative sensory testing were done. The results were analysed with ANOVA. DRD2 gene 957C>T polymorphism was determined in 31 patients, and its effects on neurophysiologic and clinical variables were analysed. Results Cool (p = 0.0090) and warm detection thresholds (p = 0.0229) of the tongue were higher in BMS patients than controls. The stimulation threshold for SON BR was higher in patients than in controls (p = 0.0056). The latencies of R2 component were longer in BMS patients than in controls (p = 0.0005) at the SON distribution. Habituation of SON BR did not differ between the groups. The heat pain thresholds were highest (p = 0.0312) in homozygous patients with 957TT, who also reported most interference (p = 0.0352) and greatest suffering (p = 0.0341). Genotype 957CC associated with sleep disturbances (p = 0.0254). Conclusions Burning mouth syndrome patients showed thermal hypoesthesia within LN distribution compatible with small fibre neuropathy. The DRD2 957C>T genotype influences perception and experience of BMS pain. Significance The results confirm earlier findings of neuropathic pain in BMS. The DRD2 957 C>T genotype influences perception and experience of clinical pain in BMS.

Psychophysical characterisation of burning mouth syndrome—A systematic review and meta‐analysis

“…The search identified a total of 123 records from the six databases. Therefore, 13 articles and one conference abstract were included in the study, but the proportion of articles reporting specific outcomes was calculated based only on the 13 full articles [32][33][34][35][36][37][38][39][40][41][42][43][44] (Figure 1).…”

“…33,37,38,41,44 All the other studies (61.5%) were considered for meta-analysis. 31,[33][34][35]38,39,41,42 However, WDT, CDT, HPT, CPT and MPT were the only comparable outcome measures reported by more than one article. Regarding the article by Watanabe et al, 32 the chronic BMS subgroup was selected as representative.…”

“…42 All studies were cross-sectional. [32][33][34][35][36][37][38][39][40][41][42][43][44] Regarding the characteristics of the studied populations, two of the articles (15.4%) had only a few subjects affected by BMS. 33,36 The majority of the patients were women with ages ranging between 30 and 82 years old, and age differences between groups of 1 to 10.9 years.…”

“…33,36 The majority of the patients were women with ages ranging between 30 and 82 years old, and age differences between groups of 1 to 10.9 years. [32][33][34][35][36][37][38][39][40][41][42][43][44] In relation to primary outcomes, the individual studies reported several differences in sensory profiles between BMS and controls, with many combinations of thermal and mechanical sensory impairments in the patients. These alterations included WDT, CDT, CPT, HPT, PHS, MDT, MPT, MPS and WUR.…”

Burning mouth syndrome: epidemiology, diagnosis and modern treatment standards.

“…W jednym z badań udokumentowano synergistyczne działanie gabapentyny z kwasem alfa-liponowym [20]. W literaturze istnieją doniesienia o skuteczności loflazepinianu etylu w leczeniu BMS w monoterapii, lub w przypadku braku efektu, w połączeniu z amitryptyliną lub z milnacipranem [29]. W innych badaniach oceniano skuteczność stosowania m.in.…”