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.