Neuromotor Control Differences in the Upper Extremity Between Those With and Without Rheumatoid Arthritis

Abstract

Rheumatoid Arthritis (RA) causes inflamed synovial membranes that can affect functional ADL’s, motor performance, and neuromotor control. The constraints of RA limit the range of motion and functionality of the upper extremity, which will influence movement patterns and potentially modify neural processing. The purpose of this study was to assess neuromotor control differences in the upper extremity between those with and without RA. Using brain activity measurement and motion capture, we expected to find that RA patients perform less accurate movements and adopt different movement patterns than healthy controls. Further, we hypothesized RA participants would have increased neural processing within the frontal cortex. Ten healthy controls and one RA patient completed eight trial blocks manipulating fifteen marbles of varying size. All participants had their brain activity assessed through EEG and fine motor performance measured via Vicon Nexus motion capture system. Results were expected to demonstrate changes in theta and alpha power and to correlate with restricted movements in RA patients. Results showed a significantly reduced elbow joint angle among the RA participant and higher levels of brain activation for both the small and large marble manipulation. Qualitative compensatory actions were observed in the RA participant’s movements. The young and middle-aged healthy controls explored a greater degree of change at the elbow for both marble sizes. Additionally, the young healthy control experienced the lowest brain activation throughout the trials and the middle-aged control had a brain activation between that of the young control and RA patient. Overall, the results demonstrate the use of EEG as an effective tool to measure cognitive workload in RA patients while performing fine motor tasks.