老年抑郁症患者面孔知觉早期加工的事件相关电位研究

Early stage of face perception in patients with late-life depression： an event-related potentials study

目的采用事件相关电位技术，探讨老年抑郁症患者面孔识别（区分面孔还是非面孔）和面孔结构信息早期加工的脑电生理机制。方法被试者包括19例老年抑郁症患者（患者组）及17名健康老年人（对照组）。要求被试者观看图片并计数蝴蝶（靶刺激）呈现次数，其他图片（包括面孔、非面孔）为非靶刺激。记录32导脑电波。结果（1）患者组非靶刺激诱发的P1[（3．9±0．8）μV]和N170波幅[（-10．1±1．1）μV]均低于对照组[P1：（6．8±0．8）μV；N170：（-14．4±1．1）μV；P〈0．05—0．01]；（2）患者组和对照组均产生显著的N170效应（Nd170）以及N170翻转效应（倒立面孔图像时的N170变化），但患者组右侧颞枕区的N170效应[（～5．8±0．9）μV]弱于对照组[（-8．8±0．9）μV，P〈0．05]，翻转效应的组间差异则无统计学意义（P〉0．05）；（3）患者组靶刺激的P3潜伏期[（400±10）ms]长于对照组[（368±10）ms；P〈0．05]。结论老年抑郁症患者可能存在面孔基本水平（区分面孔还是非面孔）早期识别的损害，而对面孔结构信息的早期加工则保持相对完整。

Objective The present study was to investigate early stage of face detection and confignral analysis in patients with late-life depression by using ERP method. Methods Nineteen depressive patients aged 60 years or over （mean age： 70 ±6 years; 7 male, 12 female） and 17 non-depressed, ageand gender-matched （mean age： 67 ± 5 years; 5 male, 12 female） controls were recruited. Stimuli were randomly presented in the centre of screen consisted of faces and furniture with upright and inverted equal probability as well as butterflies as targets, and the subjects were instructed to count butterflies （targets） and ignore the non-targets. Thirty two channel electroencephalogram （EEG） was recorded by Neuroscan Nuamps System. Results （1） The occipital-temporal PI and N170 elicited by non-target stimuli were significant decreased in patients than that in controls （P 〈 0. 05-0. 01 ）. （2） Across both groups, N170 elicited by faces was stronger than furniture did （N170 effect） and delayed by inversion （N170 inversion effect）. Over the right occipito-temporal area there was an impairment of the N170 effect （P 〈 0. 05） not N170 inversion effect （ P 〉 0. 05 ） in patients than controls. （3） P3 was significantly delayed in the patients than the controls （P 〈 0. 05 ）. Conclusion The early stage of face detection not the confignral analysis of faces is impaired for patients with late-life depression.