The characteristics of cognitive impairment in depression: a combined functional magnetic resonance and event-related potential study

Abstract

Objective To investigate the characteristics and relative pathogenesis of cognitive impairment in people with depression. Methods 24 people with depression and 24 healthy controls were evaluated respectively with HAMD scale, the WCST test, N-BACK task P300 and fMRI. Results (1) The WCST scores, N-back reaction (MRT), the P300 incubation period in depression group were significantly different from those in control group(P300 wave amplitude(4.12±1.51)μV vs (6.42±1.73)μV; P300 latency(392.02±23.60)ms vs (309.43±21.39)ms, t=4.922, P<0.01; t=12.726, P<0.01). (2) The illness course had positive correlation with Rep(r=0.596, P<0.01) and mRT(r=0.518, P<0.01). The P300 latency had positive correcation with Rpe(r=0.929, P<0.01) and mRT(r=0.939, P<0.01). (3)Compared with control group, the decreased activation area in patients with depression were as follows: bilateral frontal gyrus, left middle frontal gyrus, inferior frontal gyrus and superior parietal lobule. Conclusion The depressive patients exist cognitive impairment mainly in frontal lobe. The longer with the illness, the wose with the impairment.P300 incubation period is a sensitive indicator of the frontal executive function. Key words: Depression; Cognitive function; Event related potential; Fuctional magnetic resonance image