Significance Of Event-related Potentials For Early Diagnosis Of Mild Cognitive Impairment

Objective: To explore the early change feature of event-related potential(ERP)in patients with mild cognitive impairment(MCI)when they engaged in face perception, number-object control judging tasks and single-unit additive mental calculation,and to investigate the significance of event-related potentials for early diagnosis of mild cognitive impairment.Methods: 16 patients with MCI(patient group),16 healthy matching aging controls(NC group)were served as subjects in experiment.The continuous electroencephalographic were recorded during the courses of face perception, number-object control judging and single-unit additive mental calculation tasks with the 32 sites brain electricity recording system produced by NeuroScan of USA. Compared correct-rate and reaction-time,analyzed the amplitudes,latencies of the early components(P1,P2,N1,N170),P300,and slow potential,with independent- samples T test and the analysis of variance of repeated measurement,with using off-line analysis to the continuous electroencephalographic.Results: 1. In face perception tasks,the response-time had no significant difference between the two groups(P>0.05),though slightly later in the MCI group;in the MCI group,the average correct-rate was worse than in the NC group(P<0.05).In number- object control judging and single-unit additive mental calculation tasks,in the MCI group,the response-time was significantly later(P<0.01),the average correct-rate was worse than in the NC group(P<0.05).2. In face perception tasks,compared with N170 in NC group,N170 was significantly lower at temporal-occipital region and delayed in MCI group.3. In Number-object control judging tasks,Compared with early components of event-related potentials in NC group,N1 and P1 was significantly lower at central-prefrontal and occipital region,N170 was significantly higher at temporal- occipital region in MCI group;N170 and P2 was delayed at temporal-occipital and central-prefrontal region in MCI group.4. In single-unit additive mental calculation tasks,Compared with early components of event-related potentials in NC group,N170 and P2 was significantly higher at temporal-occipital and central-prefrontal region and delayed in MCI group.Compared with P300 in NC group,P300 was significantly lower at middle and right encephalic region during the course of 250-350ms(P<0.05),significantly higher at left encephalic region(P<0.05)and lower at right encephalic region during the course of 250-350ms(P<0.01)in MCI group.Compared with slow potentials in NC group,the mean amplitudes was higher at left encephalic region(P<0.05)and significantly lower at right encephalic region(P<0.01)during the course of 250- 750ms in MCI group.It was significantly lower at left encephalic region(P <0.01)and higher at right encephalic region(P<0.01)during the course of 750-1150ms and 1550-1950ms in MCI group. It was higher at middle and right encephalic region during the course of 1150-1550ms(P<0.05)in MCI group.Conclusion: 1. The cognitive function in patients with MCI was damaged,such as face perception,number-object control judging and single-unit additive mental calculation.2. The nervous activity and cognitive processing in patients with MCI with abnormal was abnormal in the early stages of cognitive function,such as face perception,number-object control judging and single-unit additive mental calculation.3. It was declined that the ability of face perception,number-object control judging and single-unit additive mental calculation.The activation of the related brain areas in MCI group was slower,and the use of brainresources was slower and more than in NC group.4. N170 in face perception,early components of event-related potentials,P300 and slow potentials in single-unit additive mental calculation can be methods for evaluating cognitive impairment of patients,they will probably be the components to detecting mild cognitive impairment.