Brain alterations and neurocognitive dysfunction in patients with complex regional pain syndrome

April 2015

Highlights

•Significant cortical thinning in the prefrontal cortex was observed in CRPS patients.
•Patients with CRPS made significantly more perseverative errors on the WCST.
•Patients with CRPS showed significantly longer stop-signal response time.
•The alterations may explain executive dysfunction and disinhibited pain perception.

Abstract

Few studies have examined the involvement of specific sub-regions of the prefrontal cortex in complex regional pain syndrome (CRPS). We analyzed cortical thickness to identify morphological differences in local brain structures between patients with CRPS and healthy control subjects (HCs). Furthermore, we evaluated the correlation between cortical thickness and neurocognitive function. Cortical thickness was measured in 25 patients with CRPS and 25 HCs using the FreeSurfer method. Pain severity and psychiatric symptoms were assessed using the Short Form McGill Pain Questionnaire and the Beck Depression and Anxiety Inventories (BDI and BAI), respectively. Neurocognitive function was assessed via the Wisconsin Card Sorting Test (WCST) and the stop-signal task (SST). The right dorsolateral prefrontal cortex (DLPFC) and left ventromedial prefrontal cortex (VMPFC) were significantly thinner in CRPS patients than in HCs. CRPS patients made more perseveration errors on the WCST and had longer SST reaction times compared with HCs. Although BDI and BAI differ significantly between the groups, they were not correlated with cortical thickness. Our study suggests that the pathophysiology of CRPS may be related to reduced cortical thickness in the DLPFC and VMPFC. The structural alterations in DLPFC may explain executive dysfunction and disinhibited pain perception in CRPS.