Isolating Brain Regions Implicated in the Affective Components of Neuropathic Pain

Abstract

Introduction/Aim: The psychosocial factors implicated in neuropathic pain are profound. Pain symptoms can lead to prolonged manifestations of affective and other psychological disorders (e.g., negative mood; avoidance behaviors). In this investigation, we sought to (1) evaluate the extent to which psychological factors are elevated in an acute neuropathic pain cohort, and (2) evaluate brain changes implicated in the affective components of acute neuropathic pain. Methods: Participants included ankle sprain patients with acute neuropathic pain (n = 24, Age = 16.1 years, SD = 4.1), and age- and gender-matched healthy controls (n = 12, Age = 16.1, SD = 2.95). Participants were evaluated using self-report questionnaires of psychological and pain-related symptoms: Multidimensional Anxiety Scale for Children-MASC; Children’s Depression Inventory-CDI; Fear of Pain Questionnaire-FOPQ, Functional Disability Inventory-FDI, Pediatric Pain Screening Tool-PPST, and Pain Catastrophizing Scale-PCS. Cortical thickness and sub-cortical volumes were extracted from Freesurfer. Results: The neuropathic pain cohort exhibited elevated scores on the CDI, FOPQ, FDI, PPST, and PCS relative to controls (p < 0.05). K-means clustering was used to create groups within the patient cohort with lower vs. higher psychological questionnaire scores. In patients with elevated questionnaires scores, greater cortical thickness was found in regions implicated in pain processing, including the orbitofrontal gyrus and caudal anterior cingulate cortex compared to patients with lower scores (p < 0.01). Discussion/Conclusions: Neuropathic pain implicates many brain regions. Here, we demonstrated that persons with acute injury-induced neuropathic pain and greater levels of psychological manifestations display increased cortical thickness in regions involved in processing pain and its psychological components. Findings inform the diversity of changes observed in neuropathic pain patients.