Comparative Study On Cognitive Function And Neuroimage Between Amnestic And Vascular Mild Cognitive Impairment

Objective To assess if the cognitive presentation and grey and white matter change differ between amnestic and vascular MCI, two populations of MCI underwent the Neuropsychological Test Battery and optimized voxel-based morphometry.Methods All participants were from database of 1068 shanghai community-dewelling subjects in China?s national study on the evaluation, early recognition, and treatment of psychological problems in the elderly, supported by the Ministry of Science and Technology, National Pillar Program, between January 2010 and December 2013. In Part one, 44 patients with a MCI, 44 patients with v MCI and 44 NC subjects were selected and assessed by the Neuropsychological Test Battery. The Neuropsychological Test Battery comprises the following cognitive tests of various cognitive domains: the Digit Span(forward and backward span length), Auditory Verbal Learning Test, Associative Learning Test, Visual Recognition Function Test, Verbal Fluency Test, Wechsler?s Mapping, and Wechsler?s Block Diagram. In Part two, 35 patients with a MCI, 10 patients with v MCI and 35 NC subjects underwent 3D magnetic resonance imaging. GM atrophy and WM damage and correlations between cognitive measures and brain volume loss were performed by using optimized voxel-based morphometry.Results In Part one, all cognitive tests of various cognitive domains in the Neuropsychological Test Battery showed significant difference between patients and normal control subjects(P<0.05). However, there was not any significantly different between patients with a MCI and v MCI assessed by the Neuropsychological Test Battery(P>0.05). Wilks' Lambda discriminant analysis showed that cognitive measures of MMSE, Mo CA, NTB, CDR, HIS and ADL achieved a classification accuracy of 87.7% for distinguishing a MCI(81.1%), v MCI(90.0%) and NC(92.3%)(Wilks? Lambda=0.549, c2=51.643, P=0.027). In Part two,compared with normal control subjects, patients with a MCI exhibited significant gray matter volume reductions mainly in bilateral temporal lobe and limibic system(left > right). In addition, white matter volume loss was found predominately in left temporal lobe and hippocampus. Conversely, patients with v MCI had gray matter volume reductions in right frontal lobe, right basal ganglia, and bilateral limbic system(left > right). White matter damaged in bilateral frontal, temporal, occipital, limbic and right parietal lobe and right corpus callosum(P<0.001,voxel size>100mm3, uncorrected). Patients with a MCI had a larger grey matter volume loss significantly in bilateral limbic lobe, left frontal and temporal lobe, right parietal and occipital lobe compared with patients with v MCI. Patients with v MCI had worse white matter volume loss significantly in the left frontal, limbic lobe and basal ganglia compared with patients with a MCI(P<0.01, voxel size>100mm3, uncorrected). Both the MMSE and the Mo CA showed a similar relationship with gray and white matter degeneration in patients with a MCI, reflecting greater cognitive impairment with decreased gray matter in the left temporal lobe and hippocampus and with white matter degradation in frontal, temporal, occipital, limbic lobe and cerebellum. Both the MMSE and the Mo CA showed a similar relationship with gray matter degeneration in patients with v MCI, showing greater cognitive impairment with decreased gray matter in the left thalamus and hippocampus. For patients with v MCI, white matter deterioration of the right thalamus, sub-lobar and left corpus callosum was correlated with the MMSE, and the bilateral limbic lobe, cerebellum, and the right thalamus and the right temporal lobe was correlated with the Mo CA(P<0.001,voxel size >1000mm3, uncorrected).Conclusions Our findings suggest different patterns of cognitive change in healthy older adults and MCI patients. Thus, decline in multiple domains may be an important feature for distinguishing healthy older adults and patients with MCI. However, we can not find any significant difference between a MCI and v MCI. In addition, consistent with previous studies, patients with a MCI were more specific to grey matter atrophy in limbic lobe, and patients with v MCI were worse in white matter damage in the left frontal, limbic lobe and basal ganglia. The Mo CA and MMSE was more specific to gray matter integrity whereas both of them reflected a more global reduction in both gray and white matter. The MMSE and Mo CA was more correlative with the left brain grey matter loss than the right part, although significant asymmetry of brain damage was not found in patients. Cognitive impairment of a MCI was associated with temporal lobe and hippocampus, however, v MCI was with thalamus. More white matter lesions were correlated with cognitive impairment in a MCI and v MCI.