Altered regional brain morphology in patients with chronic facial pain.

ABSTRACT

BACKGROUND: Persistent idiopathic facial pain (PIFP) is defined as a persistent, unilateral facial pain, not associated with sensory loss or other physical signs and with no obvious structural abnormalities that would sufficiently explain pain experience. OBJECTIVE: We were interested whether there is evidence of altered brain morphology in patients with PIFP as it has been described in other chronic pain conditions. METHODS: Using voxel-based morphometry we investigated regional gray matter volume in 11 PIFP patients and 11 age- and sex-matched healthy controls. Furthermore we calculated lateralization indices (LI) to investigate differences in interhemispheric gray matter asymmetries. RESULTS: We report a decrease in gray matter volume in the left anterior cingulate gyrus and left temporo-insular region, as well as in the left and right sensory-motor area, projecting to the representational area of the face. Analyses of LI values demonstrated an increased rightward asymmetry in the middle-anterior insular cortex in patients in comparison with healthy controls. CONCLUSION: Our data support previous findings showing that chronic pain states are display-altered brain morphology in brain regions know to be part of the pain system.