Mechanism Of Behavioral And Psychological Symptoms Of Dementia In Alzheimer’s Disease Based On Quantitative EEG Analysis

Purpose: Learning the manifestation of quantitative EEG analysis in Behavioral and Psychological Symptoms of Dementia(BPSD)in patients with Alzheimer’s disease(AD)is to explore the correlation between EEG and psychobehavioral symptoms of Alzheimer’s disease,to provide objective biological basis for clinical identification of BPSD,and to determine whether EEG parameters can be used for clinical evaluation of BPSD internal grouping.Methods: From November 2021 to December 2022,AD patients who received outpatient treatment or inpatient treatment in Chengdu Fourth People’s Hospital and outpatient treatment or inpatient treatment in the Department of Neurology of Sichuan People’s Hospital were collected.According to the Neuropsychiatric Symptom Scale(NPI),the patients were divided into a psychotic symptom group with obvious delusional and/or hallucinations(51 cases),a non-psychotic symptom group with neurobehavioral abnormalities other than delusional or hallucinations(37 cases),and an asymptomatic group(14 cases).The psychotic symptom group and the non-psychotic symptom group were collectively referred to as BPSD group.We first collected the basic clinical data of the patients and performed neuropsychological scale tests.Meanwhile,the brain structure was quantitatively scored by cranial magnetic resonance imaging(MRI).In addition,scalp electroencephalogram was collected for quantitative analysis of brain network topology,brain network attributes and power spectrum energy.Results:1.The comparison between the asymptomatic group,the psychotic symptom group and the non-psychotic symptom group showed no statistical significance in gender and educational level,but significant differences in age and course of disease.The psychotic symptom group and the non-psychotic symptom group were older and had longer course of disease.2.The results of behavioral indicators showed that there were significant differences in MMSE,ADL and NPI scores among the three groups of patients with psychotic symptoms,non-psychotic symptoms and asymptomatic symptoms.The MMSE score and ADL score were the lowest in the non-psychotic symptom group and the highest in the asymptomatic group.The NPI score of the psychotic symptom group was significantly higher than that of the non-psychotic symptom group.3.Structural imaging results showed that there were significant differences in the total score of Fazekas,the paraventral score of Fazekas,the deep white matter score of Fazekas,the total score of MTA,the left score of MTA,and the right score of MTA among the three groups.All scores in both the psychotic and non-psychotic groups were significantly higher than those in the asymptomatic group.In addition,MTA scores were significantly higher in the non-psychotic symptom group than in the psychotic symptom group.4.Compared with the asymptomatic group,the brain network topology of AD patients in the psychiatric symptom group showed significant changes,mainly manifested as enhanced contralateral connectivity of the posterior brain regions and attenuation of the anterior and posterior brain regions connectivity.However,there were specific differences in brain network topology between the two groups of AD patients under different frequency bands,and patients with psychiatric symptoms had more enhanced brain interval coupling relationships under delta and beta bands.These differences were also found in the non-psychotic and asymptomatic groups,but the number of significantly enhanced brain connections was smaller than in the psychotic group.In addition,a significant decrease in functional connectivity between the right prefrontal lobe and the left temporal region in the theta band was observed in the cephalic surface brain network of patients with non-psychotic symptoms,suggesting that the decrease in the contralateral prefrontal temporal region connectivity may be a characteristic characteristic of abnormal neural activity in the brain region unique to patients with non-psychotic symptoms.5.From the perspective of network attributes,the psychotic symptom group showed the highest clustering coefficient,the shortest shortest path length,and the highest global and local efficiency(especially delta band and beta band),that is,the highest network information connection efficiency,the most efficient information transmission path and high defense capability.6.The results showed that the average relative power of the whole brain in the delta band was significantly lower in the psychotic and non-psychotic symptom groups than in the asymptomatic group,while the average relative power of the theta band was significantly higher than that in the asymptomatic group.In addition,the average relative power of the whole brain in the beta band was higher in the non-psychotic symptom group than in the asymptomatic group.There were significant differences in the distribution of the brain regions of each frequency band,mainly in the frontal,central,parietal and temporal regions.In betla band,there were significant differences among the three groups in the frontopolar and lateral frontotemporal regions.7.Correlation analysis was conducted on behavioral scale,structural imaging scale and EEG characteristics respectively,and correlation between MMSE,ADL,Fazekas,MTA scores and brain network attributes in different groups of AD patients was calculated.(1)The MMSE score of AD patients with psychotic symptoms was negatively correlated with the alpha band brain network attribute,while the MMSE score of patients with non-psychotic symptoms was negatively correlated with the theta band brain network attribute.(2)The ADL score of asymptomatic group was positively correlated with the attributes of theta band brain network.(3)The Fazekas scores of AD patients with psychotic symptoms were positively correlated with the global efficiency and local efficiency of scalp brain network in delta band.(4)The MTA score of AD patients in the non-psychotic symptom group was significantly correlated with the EEG characteristics of alpha band,while the MTA score of AD patients in the asymptomatic group was significantly correlated with the EEG characteristics of beta band.Conclusion:Our study found that there were significant changes in behavioral scale scores and neural activity characteristics of AD patients in the BPSD groups,especially in AD patients with hallucination and/or delusion,suggesting that the changes in neural activity are expected to become potential biomarkers of BPSD in AD patients.In addition,we found that the scalp-brain network connectivity of AD patients in the psychotic symptom group was significantly enhanced,and the network attributes were significantly correlated with the scores of behavioral and structural imaging scales such as MMSE and ADL,suggesting that the abnormal functional structure of the brain network may be the neural mechanism of the abnormal behavior.This also provides a theoretical basis and foundation for the clinical use of EEG parameters for the grouping and evaluation of BPSD internal subtypes.