Application of amplitude of low‑frequency fluctuation to altered spontaneous neuronal activity in classical trigeminal neuralgia patients: A resting‑state functional MRI study

: Recent studies have reported structural and functional abnormalities in multiple brain regions of classical trigeminal neuralgia (CTN) patients. Differences in spontaneous neuronal activity between CTN patients and healthy subjects, however, remain unknown. The aim of the present study was to investigate alterations in brain activity by application of amplitude of low frequency fluctuation (ALFF), thus analyzing the correlation between durations of spontaneous pain intensity and ALFF values in CTN patients. A total of 28 CTN patients (male, n=12; female, n=16) and 28 healthy controls (HCs; male, n=12; female, n=16) matched for age and sex were enrolled. All subjects underwent resting‑state functional magnetic resonance imaging and changes in spontaneous brain activity were investigated using an ALFF method. Receiver operating characteristic (ROC) curve analysis was applied to differentiate ALFF values of CTN patients from HCs. Altered ALFF values and clinical manifestations were evaluated using Pearson's correlation analysis. ALFF values of the bilateral inferior cerebellum, bilateral fusiform gyrus, right precentral gyrus, left inferior temporal gyrus, right superior cerebellum, left inferior occipital gyrus and right superior occipital gyrus were significantly higher in CTN patients when compared to HCs. ROC curve analysis of each brain revealed a near‑perfect AUC accuracy. Pearson's correlation analysis revealed the visual analog scale of the right eye to be positively correlated with both left inferior temporal and occipital gyral findings, while episode duration likewise was positively associated with left inferior temporal gyral findings. CTN patients exhibited abnormal spontaneous activity in multiple brain regions closely related to pain regulation and perception, while VAS and CTN episode duration were positively correlated with ALFF signal values in some brain regions. The present findings provide further insight into the pathological mechanisms underlying CTN.