ABSTRACT
Objective To investigate the characteristics and neural mechanisms of visual attention dysfunction in patients with hypertension using the event related potentials(ERPs).Methods Visual Oddball pattern was adopted to analyze P3a and P3b components of 15 essential hypertensives and 15 normotensives,and all the participants were submitted to cognitive assessment by Mini-Mental State Examination (MMSE).Results ①Novelty stimulus:the mean amplitude of N2 in hypertensive patients ((1.56± 1.15) μV) was decreased than normal controls ((-2.19±1.15) μV,P＜0.05),particularly at forehead-central sites (P＜0.05).In addition,the amplitude of P3a of hypertensive patients ((6.27± 1.01) μV) was different from normal controls ((7.09± 1.01) μV),but there was no statistical significance(P＞0.05).The latency of visual P3a was significantly longer in patients with hypertension group ((432.83 ± 8.22) ms) than that in control group ((403.10 ± 8.22) ms,P＞ 0.05).②Target stimulus:compared with control group ((6.75 ±0.90)μV),visual P3b amplitude in hypertension group ((4.08 ± 0.90) μV) was significantly declined (P＜ 0.05).Besides,the latency of visual P3b of hypertensive patients ((440.70 ± 6.42) ms) was different from normal controls ((436.91±6.42) ms),but there was no statistical significance(P＞0.05).③Compared with control group (27.31± 1.22),the M MSE score of patients with hypertension (24.55±2.42) was decreased (P＜0.05).The amplitude of visual P3b was positively correlated with MMSE scores in parietal region(r=0.51,P＜0.05).Conclusions The abilities of visual involuntary attention and voluntary attention are damaged in patients with hypertension,the impact degree of hypertension on two kinds of attention and the neural mechanisms are different.Moreover,there is a significant positive correlation between the amplitude of visual P3b and MMSE,which prompts that visual P3b for clinical early assessment of attention in patients with hypertension provides more objective neurophysiological basis.