Readiness potential as a neurophysiological marker of functional movement disorders

Functional movement disorders (FMD) are widespread and have a significant negative impact on the quality of life of patients. The pathogenesis is not completely clear, but currently there is ongoing research on searching for biological markers using methods such as functional magnetic resonance imaging and electroencephalography (EEG). Objective: detection of the features of the amplitude-frequency characteristics of the readiness potential (RP) formed during FMD. Material and methods. We examined 22 patients with a clinically diagnosed FMD and 22 healthy volunteers (all participants were right-handed). Both patients and the control group underwent an EEG in Erickson's Flanker paradigm with registration of the RP. RP was recorded in the projection area of the precentral gyrus (electrodes C3/C4/C5/C6 in the standard 10–20 overlay scheme). Results. Comparative analysis of RP parameters showed the presence of significant frequency-amplitude differences between the main group and the control group in the right hemisphere in the absence of significant differences in the left hemisphere. At the same time, significant differences were demonstrated between the FMR group and the control group both in terms of the latent period (time to the onset of RP): 33.66±23.69 ms versus 276.28±176.1 ms (p<0.05), and its amplitude: -0.85±0.294 μV versus -0.35±0.26 μV (p<0.05). Conclusion. The results of the present study suggest that neurophysiological parameters such as RP can be considered as a potential diagnostic marker to improve the diagnosis of FMR.