The motor system shows adaptive changes in complex regional pain syndrome

Abstract

The complex regional pain syndrome (CRPS) is a disabling neuropathic pain condition that may develop following injuries of the extremities. In the present study we sought to characterize motor dysfunction in CRPS patients using kinematic analysis and functional imaging investigations on the cerebral representation of finger movements. Firstly, 10 patients and 12 healthy control subjects were investigated in a kinematic analysis assessing possible changes of movement patterns during target reaching and grasping. Compared to controls, CRPS patients particularly showed a significant prolongation of the target phase in this paradigm. The pattern of motor impairment was consistent with a disturbed integration of visual and proprioceptive inputs in the posterior parietal cortex. Secondly, we used functional MRI (fMRI) and investigated cortical activations during tapping movements of the CRPS-affected hand in 12 patients compared to healthy controls (n = 12). During finger tapping of the affected extremity, CRPS patients showed a significant reorganization of central motor circuits, with an increased activation of primary motor and supplementary motor cortices (SMA). Furthermore, the ipsilateral motor cortex showed a markedly increased activation. When the individual amount of motor impairment was introduced as regressor in the fMRI analysis, we were able to demonstrate that activations of the posterior parietal cortices (i.e. areas within the intraparietal sulcus), SMA and primary motor cortex were correlated with the extent of motor dysfunction. In summary, the results of this study suggest that substantial adaptive changes within the central nervous system may contribute to motor symptoms in CRPS.

Wherever is my arm? Impaired upper limb position accuracy in Complex Regional Pain Syndrome

“…Cortical reorganisation in regions associated with the body schema (i.e. primary somatosensory cortex, posterior parietal lobe) have been revealed by brain imaging, providing further evidence of body schema disruption [27,28,29,34].…”

“…Importantly, post-parietal lesions typically result in spatial deficits and clinical disturbances in body representation [39]. Although lesions are not known in CRPS, evidence of abnormal increased neural activation within both parietal lobes has been shown [29]. Furthermore, the degree of motor impairment correlated with activations of the parietal and motor cortices [29].…”

“…Although lesions are not known in CRPS, evidence of abnormal increased neural activation within both parietal lobes has been shown [29]. Furthermore, the degree of motor impairment correlated with activations of the parietal and motor cortices [29]. An alternative causative mechanism may therefore be that integration of multisensory and motor information about limb position within the parietal lobe is disrupted.…”

Imaging and Clinical Evidence of Sensorimotor Problems in CRPS: Utilizing Novel Treatment Approaches

“…Magnetoencephalography (MEG) studies have identified increased activity in the primary motor cortex contralateral to the CRPS affected limb in patients with upper limb CRPS (Maihöfner et al 2007). This has been shown to correlate with poor function in motor planning tasks, particularly those that require integration with visual and proprioceptive cues such as gripping an object.…”

Complex regional pain syndrome: The matter of white matter?

“…For example, the CRPS patients can have altered hand representation as a sign of cortical reorganization (Di Pietro, Stanton, Moseley, Lotze, & McAuley, 2015; Juottonen et al., 2002), and some of the observed brain alterations are associated with clinical characteristics of CRPS, such as motor dysfunction (Maihöfner et al., 2007). …”