Measurement of the metabolites in the cortical masticatory area of patients with sleep bruxism: a magnetic resonance spectroscopy study

Abstract

To determine whether there are in vivo differences of metabolites levels in bilateral cortical masticatory area(CMA) of patients with sleep bruxism, compared with healthy controls using proton magnetic resonance spectroscopy(1H-MRS). Accordingly to explore if cortical control of the central jaw motor system is abnormal in sleep bruxism patients. Fifteen sleep bruxism patients and fifteen age- and gender-matched healthy controls underwent 1H-MRS of bilateral CMA using J-difference edited point-resolved spectroscopy sequence(MEGA-PRESS) technique. Levels of metabolites were quantified from the ratio of the metabolite integral to the unsuppressed water signal. Differences of levels of γ-aminobutyric acid(GABA), glutmate(Glu) and N-acetyl aspartate(NAA) in bilateral CMA between sleep bruxism patients and healthy controls were tested using two-way ANOVA. Edited spectra were successfully obtained from the bilateral CMA in all of the participants. Levels of GABA+, glutmate and NAA in right and left CMA in sleep bruxism patients were (2.45±0.48)×10(-3), (2.35±0.62)×10(-3), (10.65±1.84)×10(-3), (10.49±2.37)×10(-3), (10.70±3.61)×10(-3), and (11.26±4.01)×10(-3) respectively. In contrast, levels of GABA+, glutmate and NAA in right and left CMA in healthy controls were (2.63±0.68)×10(-3), (2.65±0.97)×10(-3), (11.19± 1.34)×10(-3), (10.58±3.14)×10(-3), (11.82±1.80)×10(-3), and (11.95±3.23)×10(-3). There were no differences in levels of GABA+(P=0.196), Glu(P=0.590), and NAA(P=0.292) between sleep bruxism patients and healthy controls, nor in inbilateral CMA(GABA+: P=0.837; Glu: P=0.510; NAA: P=0.628). The results indicate the absence of any alteration of the cortical control of the central jaw motor system in the levels of GABA, Glu and NAA in patients with sleep bruxism.