Phase Synchronization of EEG in Bilateral, Cyclical Ankle Alternating Movements of Stroke

Electroencephalogram (EEG) is a basic physiological signal of human body, which can effectively record the nervous system activities of the brain and contains rich information. The synchronization of EEG signals is not only the key to the exchange of information between different brain regions, but also reflects the neural activity of the brain, which in turn can infer people's cognitive activities. Therefore, studying the phase synchronization of EEG signals after stroke is of great significance for understanding the communication and neuroplasticity of neurons after brain injury. In this paper, the changes of EEG phase synchronization in bilateral, cyclical ankle movements alternately after stroke were studied by Hilbert transform. Ten stroke patients and six healthy adults participated in the test. The results showed that the inter-hemisphere phase synchronization index (inter-PSI) and the global PSI of patients were significantly lower than that of the healthy subjects during the task. The PSI between Cz and the affected sensory cortex associated with lower limb movements was also significantly lower than that in the control group. There was a significant negative correlation between National Institutes of Health Stroke Scale (NIHSS) and cortical synchronization. The above results indicated that PSI under ankle alternating movements may be used as a new biomarker to evaluate the recovery of patients' brain neurons.