Abnormal Brain Responses to Action Observation in Complex Regional Pain Syndrome

Abstract

Patients with complex regional pain syndrome (CRPS) display various abnormalities in central motor function, and their pain is intensified when they perform or just observe motor actions. In this study, we examined the abnormalities of brain responses to action observation in CRPS. We analyzed 3-T functional magnetic resonance images from 13 upper limb CRPS patients (all female, ages 31-58 years) and 13 healthy, age-and sex-matched control subjects. The functional magnetic resonance imaging data were acquired while the subjects viewed brief videos of hand actions shown in the first-person perspective. A pattern-classification analysis was applied to characterize brain areas where the activation pattern differed between CRPS patients and healthy subjects. Brain areas with statistically significant group differences (q < .05, false discovery rate-corrected) included the hand representation area in the sensorimotor cortex, inferior frontal gyrus, secondary somatosensory cortex, inferior parietal lobule, orbitofrontal cortex, and thalamus. Our findings indicate that CRPS impairs action observation by affecting brain areas related to pain processing and motor control. Perspective: This article shows that in CRPS, the observation of others' motor actions induces abnormal neural activity in brain areas essential for sensorimotor functions and pain. These results build the cerebral basis for action-observation impairments in CRPS.

Neuropsychological Changes in Complex Regional Pain Syndrome (CRPS)

“…For instance, tactile stimulation of the fingers of both hands resulted in weaker superior [77] and inferior parietal lobe evoked responses [140] in people with CRPS compared to healthy controls. Furthermore, relative to healthy people, individuals with CRPS showed greater activation of the inferior parietal lobe during movement (relative to rest) of the affected compared to unaffected hand [178] and when they were observing hand movements (relative static hands) [179]. Finally, another study reported reduced grey matter volume in the inferior parietal lobe in early-stage (less than 10 months) CRPS, compared to healthy controls [30].…”

Complex Regional Pain Syndrome: An update

“…Abnormalities in central motor function and changes in cortical paths could be used in the future as possible biomarkers. [22][23] In conclusion, the diagnosis of CRPS is purely clinical, based on the history, symptoms and signs. Classical radiographs should always be performed to assess bone integrity, given the strong association with trauma.…”

Psychological, social and biological correlates of body perception disturbance in complex regional pain syndrome

“…Indeed, studies employing structural and functional magnetic resonance imaging (Barad et al 2014;Hotta et al 2017;Maihöfner et al 2004;Pleger et al 2014;Shokouhi et al 2017) and magnetoencephalographic recordings (Buntjen et al 2017) have shown cortical reorganization of the primary somatosensory cortex, altered grey matter structure, abnormal brain system morphology, and changed neural activities in brain areas dealing with sensorimotor functions, pain perception, and emotional experiencing. The prefrontal cortex is thinner in patients suffering from CRPS than in healthy controls (Lee et al 2015), resulting in impairment of executive functions (Libon et al 2010) as well as disinhibited pain perception.…”