Study On EEG Characteristics Of Patients With Stroke And Cognitive Impairment Before And After Treatment

Stroke is an acute cerebrovascular disease.It has four characteristics in morbidity,mortality,disability,and recurrence.After stroke,cerebral blood circulation is caused by blockage or rupture of blood vessels in the brain,damaging the brain tissue in the corresponding site,and appearing various dysfunctions.Among them,cognitive dysfunction is a common complication,including memory,attention,orientation,aphasia,loss of identity,visual space disorders and so on.Rehabilitation of cognitive function depends on the patient's active learning and rehabilitation exercises.Post-stroke cognitive impairment(PSCI)patients cannot effectively cooperate with medical staff to treat,which brings difficulties to the rehabilitation process and effect evaluation.At present,clinical assessment methods for PSCI patients are mostly assessed using medical scales.The subjective and repetitive effects of rehabilitation evaluation methods increase the difficulty of clinical rehabilitation evaluation.Therefore,exploring a method that can assist in judging the degree of rehabilitation of PSCI patients will promote the rehabilitation process.Neurorehabilitation evaluation is more specific and accurate than behavioral evaluation,and it is a hotspot in the field of rehabilitation evaluation.This thesis takes resting electroencephalogram(EEG)as the research object,analyzes the changes of EEG before and after treatment of stroke cognitive impairment(PSCI)patients,and explores the possibility of EEG as an auxiliary tool for post-stroke cognitive function evaluation and prognosis judgment.At the same time,it provides support for further research on the relationship between EEG and cognitive function.The EEG analysis process is divided into two parts: signal preprocessing and feature analysis.The preprocessing includes filtering,re-reference,independent component analysis and other steps.The pre-processed EEG feature analysis is mainly performed by power spectrum analysis and brain network analysis.In the power spectrum analysis,the power of EEG in the ?,?,?,and ? frequency bands of PSCI patients with improved cognitive function after rehabilitation treatment was calculated based on the Welch algorithm.And quantify the characteristics of EEG before and after treatment by relative power,power ratio between frequency bands and cerebral hemisphere symmetry index,and through statistical paired sample t test method,screen out the power spectrum characteristics with significant changes before and after treatment.From the experimental results,it was found that after rehabilitation treatment of PSCI patients,the low-band power of EEG decreased,the high-band power increased,and the symmetry of the left and right cerebral hemispheres was improved.It indicates that the participation of cognitive activities of neurons and tissues in patients with PSCI is improved,and the degree of brain balance involved in cognitive and physiological activities is improved.In the analysis of brain networks,the Synchronization Likelihood(SL)algorithm is used to calculate brain networks in different frequency bands,and for the actual problem of comparison between patients before and after treatment,a concept of using personal thresholds to construct a binary network is proposed.The graph theory method analyzes the topological structure attributes of the brain network,and through statistical paired sample t test method,screen out the brain network features with significant changes before and after treatment.From the experimental results,it was found that after rehabilitation treatment,PSCI patients' EEG's ?-band brain function network connectivity was enhanced,and various parameters of the brain function network changed significantly,indicating that the global connectivity of the brain function network was improved,and the information exchange ability between brain regions enhanced.The above research results show that the EEG of PSCI patients changes accordingly with the cognitive function rehabilitation treatment process,confirming the possibility of EEG as an auxiliary judgment basis for improving cognitive function after stroke.At the same time,it provides support for further research on the relationship between EEG and cognitive function and the final realization of neurorehabilitation evaluation.