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Cognitive functions in aMCI: An ERP studyBackground: Alzheimer's disease(AD)is a neurodegenerative disorder characterized by a gradual decline in cognitive functions.Complaint of memory impairment is usually the initial symptom of AD patients.Symptoms gradually spread to deficits of multiple cognitive domains.Event-related potentials(ERP)could instantly reflect neuronal activity and is very useful for quantifying order of appearance of different stages of cognitive processing.Objective: To explore deficits of multi-dimensional cognitive functions in aMCI using ERP.Methods: We compared the behavioral results and amplitude and latency of ERP components between amnestic mild cognitive impairment(aMCI)and healthy controls(HC).Standardized low-resolution brain electromagnetic tomography analysis(s LORETA)was applied for source analysis.In addition,subgroup analyses were performed to explore the effect of influencing factors on ERP components.Results:(1)In the mental rotation paradigm,the present study detected reduced accuracy(ACC)and delayed reaction time(RT)in aMCI patients,compared to HC(p < 0.05).In addition,aMCI showed decreased P300 amplitude at the CPz electrode elicited by left and right stimuli,compared to HC(p < 0.05).(2)Additionally,aMCI showed reduced ACC,delayed RT and decreased P300 amplitude at the central-parietal(CP1,CPz and CP2)and parietal(P1,Pz and P2)electrodes in 0-and 1-back task compared to HC in the visuospatial working memory N-back paradigm(p < 0.05).In addition,s LORETA showed enhanced brain activation in the right superior parietal lobule during P300 time range in aMCI compared to HC(p < 0.05).(3)In Stroop paradigm,the study showed significant interaction effect of group and stimuli type on N450 amplitude(F(1,66)= 412.0,p < 0.001).(4)In Go/Nogo paradigm,the study showed increased false alarm rate,delayed RT and decreased N200 amplitudes at the Fz,Cz and Pz electrodes in aMCI,compared to HC(p < 0.05).In addition,in the Nogo condition,s LORETA showed enhanced brain activation in the right medial frontal cortex during N200 time range in aMCI,compared to HC(p < 0.05).(5)However,it indicated no significant difference in perceptual feature related P50,N170 components and nonvoluntary attention related MMN,P300 a components between aMCI and HC.Conclusions: aMCI showed deficits in idea,working memory and executive function.However,they showed no deficits in perceptual feature and nonvoluntary attention.Moreover,the study showed the diagnositic value of ERP for aMCI.Part? Exploring influencing factors of cognition related ERP componentsBackground: Previous studies have shown that age,gender,apolipoprotein E(APOE)epsilon 4 status and cognitive reserve(CR)are important influcing factors for Alzheimer's disease(AD).Objective: To investigate the effects of age,gender,APOE ?4 status and CR on ERP components associated with idea and working memory,executive function,perceptual feature and nonvoluntary attention.Methods: APOE genotyping and CR index questionnaire were performed for aMCI and HC.Peak amplitude and latency of the ERP components were extracted.In both aMCI and HC,regression analysis was performed to identify the influcing factors for each cognition related ERP component.Results: Regression analysis indicated that APOE ?4 status was associated with P300 amplitude at Pz electrode elicited by mental rotation paradigm and that at CPz electrode elicited by visuospatial working memory 1-back paradigm in HC(left hand stimuli in mental rotation task: r =-0.373,p = 0.014;right hand stimuli in mental rotation task: r =-0.391,p = 0.009;visuospatial working memory: r =-0.351,p = 0.014).In addition,gender was associated with N170 amplitude at Fz electrode elicited by face perception paradigm and P50 amplitude at FCz electrode elicited by paired-click paradigm and MMN,P300 amplitude at Fz electrode elicited by novel stimuli during auditory oddball paradigm(facial stimuli in perceptual feature: r =-0.533,p = 0.002;non-facial stimuli in perceptual feature: r =-0.505,p = 0.003;the first stimuli in paired-click paradigm: r = 0.530,p < 0.001;the second stimuli in paired-click paradigm: r = 0.395,p = 0.009;MMN in auditory Oddball task: r =-0.403,p = 0.007;P300 in auditory Oddball task: r = 0.393,p = 0.009).Subgroup study indicated:(1)In the mental rotation paradigm,APOE ?4 carriers showed reduced P300 amplitude with respect to noncarriers(p < 0.05),whereas no significant differences in ACC or RT were detected between APOE ?4 carriers and noncarriers in both HC and aMCI patients.Additionally,s LORETA showed enhanced brain activation in the right parahippocampal gyrus during P300 time range in APOE ?4 carriers with respect to noncarriers in aMCI patients(p < 0.05).(2)In face perception paradigm,male showed decreased N170 amplitude and delayed P300 latency at Fz electrode compared to female in both aMCI and HC(p < 0.05).Additionally,s LORETA indicated enhanced brain activation in the right cuneus during N170 time range and in the right middle occipital gyrus during P300 time range in male, compared to female in HC(p < 0.05).(3)In paired-click paradigm,male showed decreased P50 and P300 amplitudes at FCz electrode compared to female in both aMCI and HC(p < 0.05).But the ratio waveform of the two clicks showed no significant difference between male and female.In addition,s LORETA showed enhanced brain activation in the right insula during P50 time range in male compared to female in aMCI(p < 0.05).(4)In auditory oddball paradigm,male showed decreased P300 amplitude at Fz ecletrode compared to female(p < 0.05).Additionally,s LORETA indicated decreased brain activation in the right postcentral gyrus during MMN time range in male,compared to female in HC(p < 0.05).Conclusions: APOE ?4 is the influencing factor of the working memory.Additionally,gender is the influencing factor of sensory gating and nonvoluntary attention. |
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