Metabolic abnormality of pontine tegmentum in patients with REM sleep behavior disorder analyzed using magnetic...

We aimed to evaluate the metabolism differences in pontine tegmentum among patients with idiopathic RBD (iRBD), secondary RBD (sRBD) and healthy control groups using magnetic resonance spectroscopy ((1)H-MRS) and whether metabolic changes are correlated with age in patients with RBD.

The iRBD, sRBD, and control groups were composed of 18, 26, and 29 patients, respectively. All participants underwent magnetic resonance imaging (MRI) and (1)H-MRS detection at 17:00 for approximately 15min. All NAA/Cr, Cho/Cr and NAA/Cho ratios were automatically generated using FuncTool and the correlation between metabolism and age was analyzed by Pearson's correlation analysis.

Significant difference in NAA/Cr ratio was found between the sRBD group and the other groups (p<0.05). Significant difference in NAA/Cho ratio was found among all groups (p<0.05). Cho/Cr ratio remarkably increased in the control group (p<0.05) compared with the other groups. NAA/Cr ratio had an adverse correlation with age in the control, iRBD, and sRBD groups (r=-0.822, p=0.000 vs r=-0.663, p=0.003 vs r=-0.583, p=0.002). However, there was no correlation between participants age and Cho/Cr (r=-0.054, p=0.651) or NAA/Cho (r=0.029, p=0.805).

Neurons in the sRBD group were lost or damaged; however, this damage was not obvious in the iRBD group. Nevertheless, NAA and Cho levels were reduced in the local nerve cells of both RBD groups; these changes might indicate the sensitive pathogenic areas among patients with RBD.