Microstructural abnormalities of the trigeminal nerve correlate with pain severity and concomitant emotional dysfunctions in idiopathic trigeminal neuralgia: A randomized, prospective, double-blind study.

OBJECTIVE: To compare cross-sectional area (CSA) and volume (V) between the trigeminal nerves (TGNs) of the affected side and the unaffected side in patients with idiopathic trigeminal neuralgia (ITN), and both nerves in normal controls, and to correlate these morphological data with degree of facial pain and emotional disorder severity in ITN patients. METHODS: Forty ITN patients and 40 matched healthy volunteers underwent three-dimensional fast imaging employing steady state acquisition (3D-FIESTA) and time-of-flight magnetic resonance angiography (TOF-MRA) focusing on CSA and V of the TGN cisternal segment. Correlations between the morphological results and scores of visual analogue scale (VAS), Hamilton Depression Rating Scale (HAMD), and Hamilton Anxiety Rating Scale (HAMA) were analyzed in two groups. RESULTS: CSA and V of the affected TGN were significantly smaller than in the unaffected TGN and both sides in controls. No statistical differences were observed between morphological data of the unaffected TGN and control TGNs. CSA and V of the affected TGN were significantly associated with VAS scores in ITN patients, and intermediate correlations were detected with HAMD and HAMA scores. CONCLUSION: Degree of atrophy in the affected TGN can be effective for evaluating facial pain and assessing emotional deficits in ITN patients.

Thalamic metabolic alterations with cognitive dysfunction in idiopathic trigeminal neuralgia: a multivoxel spectroscopy study.

INTRODUCTION: Although abnormalities in metabolite compositions in the thalamus are well described in patients with idiopathic trigeminal neuralgia (ITN), differences in distinct thalamic subregions have not been measured with proton magnetic resonance spectroscopy ((1)H-MRS), and whether there are correlations between thalamic metabolites and cognitive function still remain unknown. METHODS: Multivoxel MRS was recorded to investigate the metabolic alterations in the thalamic subregions of patients with ITN. The regions of interest were localized in the anterior thalamus (A-Th), intralaminar portion of the thalamus (IL-Th), posterior lateral thalamus (PL-Th), posterior medial thalamus (PM-Th), and medial and lateral pulvinar of the thalamus (PuM-Th and PuL-Th). The N-acetylaspartate to creatine (NAA/Cr) and choline to creatine (Cho/Cr) ratios were measured in the ITN and control groups. Scores of the visual analogue scale (VAS) and the Montreal Cognitive Assessment (MoCA) were analyzed to correlate with the neuroradiological findings. RESULTS: The NAA/Cr ratio in the affected side of PM-Th and PL-Th in ITN patients was statistically lower than that in the corresponding regions of the thalamus in controls. The NAA/Cr ratio in the affected PM-Th was negatively associated with VAS and disease duration. Furthermore, decreases of NAA/Cr and Cho/Cr were detected in the affected side of IL-Th, and lower Cho/Cr was positively correlated with MoCA values in the ITN group. CONCLUSIONS: Our result of low level of NAA/Cr in the affected PM-Th probably serves as a marker of the pain-rating index, and decreased Cho/Cr in IL-Th may be an indicator of cognitive disorder in patients with ITN.