Study Of Clinical And Neuroimaging Features In Late-life Depression

ChapterⅠStudy of clinical features and prognostic factors in late-life depressionObjective:To investigate the differences in life events,cognitive function and coping style between patients with late-life depression and healthy controls.And to explore the factors related to treatment response of late-life depression.Methods:135 late-life depression patients and 133 healthy controls were admitted,the number of which completed the baseline investigation was 131 and 130 respectively.The baseline investigation consisted of the 24-item Hamilton Depression Scale(HAMD),Geriatric Depression Scale (GDS),Life Events Scale(LES),Social Support Rating Scale(SSRS)and Mini-Mental State Examination(MMSE).The late-life depression subjects accepted open treatment with monotherapy of Selective Serotonin Reuptake Inhabitors(SSRIs)for 8 weeks.The severity of symptoms was assessed with HAMD-24 at baseline and 1,2,4,8 weekend.Multiple stepwise regression was used to determine the factors related to treatment response.Results:(1)Significant differences were found in total score of MMSE,score of immediate memory,calculation and attention, short-range memory,language comprehension between the late-life depression group and control group(p＜0.05),as well as the total score of life events,number of negative events,score of negative events,score of family events(p＜0.05).There were significant differences in total score of social support and availability of support between the two groups(p＜0.05).(2)The inefficiency of treatment was 32.8%in 122 late-life depression patients who completed more than 4 weeks follow-up.The main factors related to treatment response were poor compliance to treatment,comorbidity of psychotic symptoms,inappropriate previous treatment,bipolar affective disorder and poor social support.Conclussion.Cognitive dysfunction is common in late-life depression.Compared with healthy controls,late-life depression has more negative events and poorer social support.It is necessary to take integrated interventions to improve the treatment response and prognosis of late-life depression,which may be influenced by biologic factors and social psychic factors. ChapterⅡControl study of gray matter and white matter intensity in first-episode,medication-naive late-life depressionObjective:To examine the alterations of brain gray matter and white matter intensity in first-episode,medication-naive late-life depressive patients by using magnetic resonance imaging.Try to find some evidence of brain structural abnormalities in early stage of late-life depression.Methods:15 first-episode,medication-naive late-life depressive patients and 15 well matched healthy controls underwent 1.5-Tesla magnetic resonance imaging.13 valid datas were gained in each group respectively.Statistical parameters maps(SPM2)based on MATLAB6.5 was used for preprocessing of the MRI scans,which included normalization,segment and smoothing.For exploring gray matter/white matter intensity difference between the late-life depression and controls,a two-sample t test was performed on preprocessed maps in a voxel-based morphometry(VBM)with p＜0.01(uncorrected for multiple comparisons) and clusters of size＞200 voxels were considered as significant differences.Results:Compared with healthy controls,the gray matter areas showed hypointensity in patients with first-episode,medication-naive late-life depression were hibateral superior frontal gyrus,hibateral middle frontal gyrus,hibateral medial frontal gyrus,right parietal lobe,right precuneus,left cuneus,left precuneus,left parahippocampal gyrus;gray matter areas showed hyperintensity were right cingulate gyrus and left posterior lobe;left superior temporal gyrus showed whit matter hypointensity,and right cingulate gyrus showed white matter hyperintensity.Conclussion:Gary matter hypointensity areas are mainly localized at frontal gyrus in patients with first-episode,medication-naive late-life depression,and white matter hyperintenshity at right cingulate gyrus, which suggest that frontal-subcortical circuits may play a role in the pathomechanism of late-life depression.ChapterⅢControl study of white matter integrity of the whole brain in first-episode,medication-naive late-life depressionObjective:To explore the white matter integrity of the whole brain and possible subcortical circuits lesions in late-life depresssion by using diffusion tensor imaging on the basis of structural MRI.Methods:15 first-episode,medication-naive late-life depressive patients and 15 well matched healthy controls underwent diffusion tensor imaging using spin-echo sequence.And 13 valid datas were gained in each group respectively.The diffusion tensor matrix and fractional anisotropy were calculated.Statistical parameters maps(SPM2)based on MATLAB6.5 was used to preprocess the DTI images,then a two-sample t test was performed on preprocessed maps in a voxel-based morphometry(VBM)with p＜0.01(uncorrected for multiple comparisons) and clusters of size＞50 voxels were considered as significant differences.Results:Compared with healthy controls,patients with late-life depression showed significantly lower fractional anisotropy(FA)at the right cingulate gyrus limbic,left cingulate gyrus limbic,right anterior cingulate gyrus and left brainstem;and higher FA at claustrum and extra-nuclear left sublobe,cerebellar tonsil right posterior lobe.Conclussion:The white matter integrity at hibateral cingulate gyrus and right anterior cingulate gyrus is disrupted in patients with first-episode,medication-naive late-life depression.Together with the fingdings in ChapterⅡ,we conclude that frontal-limbic system disconnection may exist in early stage of late-life depression,which give evidence to the hypothesis of frontal-striatum-limbic circuits abnormalities in late-life depression.