成年年轻和年老复发性抑郁症的静息态脑功能低频振幅比较研究

Comparative study on low frequency amplitude of resting brain function between younger and older adults with recurrent depression

目的探索成年年轻和年老复发性抑郁症脑功能活动改变特征。方法选取复发性抑郁症患者和同期健康对照者各32例,根据年龄分为年轻复发性抑郁组、年轻健康组、年老复发性抑郁组和年老健康组各16例。四组患者经过静息态脑功能磁共振(rs-fMRI)扫描后,进行全脑范围内低频振幅(ALFF)比较,完成汉密尔顿抑郁量表(HAMD-17)评定,并进一步分析差异脑区与HAMD-17评分的相关性。结果四组间ALFF差异脑区在左侧额上回、左侧角回、右侧角回、右侧颞中回/右侧颞上回、左侧顶缘下角回及左侧丘脑/左侧苍白球具有统计学意义(P<0.005)。事后分析显示,较年老健康组,年老复发性抑郁组在左侧额上回、左侧角回、右侧角回、右侧颞中回/右侧颞上回、左侧顶缘下角回及左侧丘脑/左侧苍白球的ALFF值更高。较年轻健康组,年轻复发性抑郁组在左侧角回、右侧颞中回/右侧颞上回及左侧顶缘下角回的ALFF值更低。较年轻复发性抑郁组,年老复发性抑郁组在左侧额上回、左侧角回、右侧颞中回/右侧颞上回、左侧顶缘下角回及左侧丘脑/左侧苍白球的ALFF值更高。相关性分析显示,年轻复发性抑郁组左侧额上回ALFF值与HAMD-17评分呈正相关(P<0.05)。结论成年年轻和年老复发性抑郁患者虽有相似的临床症状,但在部分相同的大脑区域存在异常的神经功能活动,其差异与默认网络及皮层-纹状体-苍白球-丘脑环路功能障碍密切相关。

Objective Major Depressive Disorder(MDD) is a common clinical psychiatric disorder with significant and persistent depressed mood, slow thinking, reduced interest and cognitive function as its main clinical manifestations. Epidemiological surveys show that MDD has become the second most prevalent mental illness in China, and there are more than 300 million patients with MDD worldwide. It is expected that MDD will rank the first in the global burden of disease by 2030, with a high risk of disability and suicide. Some studies have even shown that about 25% of MDD patients experience relapse within the first 6 months after discharge, and 30%~50% of patients relapse within 2 years after discharge, the severity of MDD increasing with the times of recurrence. Therefore, the neurobiological pathogenesis of recurrent depression warrants further study. Resting-state functional Magnetic Resonance Imaging(rs-fMRI) has been gradually applied in scientific research fields such as psychiatric disorders because of its advantages of non-invasiveness, ease of implementation and reproducibility. Amplitude of Low Frequency-Fluctuation(ALFF) is one of the commonly used observation indexes of rs-fMRI, which can directly reflect the intensity of neuronal spontaneous activity in the brain and provide the characteristics of local neuronal spontaneous activity. Previous studies have shown that there are significant differences in ALFF in the prefrontal-limbic system and the emergent network among patients with recurrent depression, patients with first-episode depression and healthy individuals, but there is a lack of neuroimaging studies on patients with recurrent depression of different onset ages at home and abroad. Therefore, in this study, based on rs-fMRI technique, the ALFF method was used to compare the abnormal spontaneous activity of whole-brain neurons in recurrent depression patients of different ages and to tap into the neuroimaging signatures of recurrent depression in different ages, in order to facilitate the improvement of clinical understanding of the neurobiological mechanisms of recurrent depression. Methods 32 patients with recurrent depression and 32 healthy controls were selected, and 16 patients each were divided into younger recurrent depression group, younger control group, older recurrent depression group and older control group according to their ages. All subjects in the four groups underwent rs-fMRI scans for whole-brain range ALFF comparisons, and were assessed with Hamilton Depression Scale-17 items(HAMD-17). The correlation between differential brain regions and HAMD-17 scores was further analyzed. Results The ALFF values in left superior frontal gyrus, left angular gyrus, right angular gyrus, right middle temporal gyrus/right superior temporal gyrus, left inferior parietal marginal gyrus and left thalamus/left pallidum among four groups were significantly different(P<0.005). Post hoc analysis showed that older recurrent depression group had higher ALFF values in left superior frontal gyrus, left angular gyrus, right angular gyrus, right middle temporal gyrus/right superior temporal gyrus, left inferior parietal marginal gyrus and left thalamus/left pallidum than older control group. Compared to younger control group, younger recurrent depression group showed lower ALFF values in left angular gyrus, right middle temporal gyrus/right superior temporal gyrus and left inferior parietal marginal gyrus. Compared to younger recurrent depression group, older recurrent depression group showed higher ALFF values in left superior frontal gyrus, left angular gyrus, right middle temporal gyrus/right superior temporal gyrus, left inferior parietal marginal gyrus and left thalamus/left pallidum. Correlation analysis showed a positive correlation between ALFF value in left superior frontal gyrus and HAMD-17 score in young recurrent depression group(P<0.05). Conclusions Although younger and older adult patients with recurrent depression have similar clinical symptoms, there exist abnormal neurofunctional activities in some of the same brain regions, which are closely related to the default mode network and cortico-striato-pallidum-thalamic loop dysfunction. This study provides some implications for differentiating the differences in neuropathological mechanisms between younger recurrent depressed patients and older recurrent depressed patients.