Altered resting-state functional brain activity in patients with chronic post-burn pruritus

Pruritus, a common symptom of burn wounds, arises from skin tissue damage and abnormal tissue healing. Chronic post-burn pruritus (CPBP) is defined as itching that persists for six weeks or more. The brain mechanisms underlying CPBP are not understood adequately. This study aims to explore abnormal brain function in CPBP patients and identify potential pathogenesis of pruritus.

Twenty patients with CPBP and twenty healthy controls (HCs) participated in the study and underwent resting-state functional magnetic resonance imaging (fMRI) scans. Brain activity was evaluated using regional homogeneity (ReHo), amplitude of low-frequency fluctuations (ALFF), and fractional ALFF (fALFF) measures. Preprocessing of fMRI data involved steps such as slice timing correction, motion correction, and nuisance regression to account for physiological noise and head motion. Statistical analyses included two-sample t-tests to compare ReHo, ALFF, and fALFF values between CPBP patients and HCs, with age as a covariate, and Spearman correlation analysis to explore relationships between brain activity measures and clinical characteristics.

The study revealed significant differences in brain activity between CPBP patients and HCs. CPBP patients exhibited altered higher ReHo in regions including the bilateral middle frontal gyrus, medial superior frontal gyrus, precuneus, left insula, right caudate, and bilateral cerebellar tonsils, with decreased ReHo in the right precentral gyrus. ALFF analysis showed increased activity in the bilateral middle frontal gyrus, medial superior frontal gyrus, right precuneus, and right inferior frontal gyrus, and decreased ALFF in the left precentral gyrus and right postcentral gyrus. fALFF values were notably higher in the bilateral medial superior frontal gyrus and precuneus. Several brain regions with significant differences in ReHo, ALFF, and fALFF were extensively correlated with the burned area and pruritus scale scores.

Our data suggest that patients with CPBP show alterations in ReHo, ALFF, and fALFF values primarily in brain regions associated with the default mode network and sensorimotor areas. These results may provide valuable insights relevant to the neuropathology of CPBP.