Trigeminal Neuropathy and Brain Plasticity

Objectives: The Trigeminal Neuralgia (TN) mechanism remains an ambiguous and contentious process. Our study aims to investigate the central nervous system plasticity, specifically the Grey Matter Volume (GMV) alteration in TN patients using the Voxel-Based Morphometry (VBM) method.
Methods: Fifty-four patients with TN consisting of 30 classical trigeminal neuralgia(TN1) patients and 24 painful post-traumatic trigeminal neuropathy (TN2) patients were compared to 30 healthy control (HC), matched for age and sex. All subjects were right-handed. Pain intensity, pain duration and psychological conditions were evaluated. High-resolution 3D T1-weighted images were obtained with a MRI 3Tesla scanner. Image pre-processing and the GMV calculations were implemented using SPM12 with Matlab R2015b. We designed one-way ANOVA between-subjects integrated in SPM12 included three groups (TN1, TN2 and HC) and compared GMV between groups using the VBM method ( p<0.001_uncorrected). We performed a regression analysis to test whether GMV is related to pain duration, pain intensity as well as to psychological status. The region of interest (ROI) analysis was performed at p< 0.05 in order to correct for multiple comparisons.
Results: A significant increased GMV was found in the inferior parietal lobule in TN2 compared to either HC or TN1. The GMV increased significantly in TN1 in the superior temporal gyrus compared to HC and in compared to TN2. In the TN1 group, there was a significant reduction of GMV in the right inferior temporal gyrus while no significant GMV reduction was found in TN2 in compare to HC. Additionally, we found a significant increase of GMV in the middle frontal gyrus and the inferior parietal lobule in TN1 compared to HC. Regression analysis showed little significant results.
Conclusions: We found some evidence that each kind of pain is associated with particular brain regions. However, further studies are needed to obtain more data for statistical analysis.