The Roles of Cognitive Indicators and Quantitative MRI Measurement in Early Diagnosis of Alzheimer Disease / 中国心理卫生杂志

ABSTRACT

Objective: To determine the cognitive function and MRI-based measurement of MTL structures in patients with Alzheimer disease (AD) and to find a sensitive cognitive marker or specific MRI-based measurements for early diagnosis of AD. Method:Fifty-two AD patients, 27 VD (vascular dementia) patients and 35 aged matched normal control were recruited. The cognitive functions were evaluated with Alzheimer disease assessment scale-Cognitive portion (ADAS-Cog), Wechsler memory scale-revised and Mini-Mental Status Examination (MMSE). MTL structures, including hippocampal formation, amygdala and parahippocampal gyrus, were measured by MRI volumetric measurements. Result: Compared with VD patients and healthy controls, there was more pronounced reduction of performance on the main cognitive domains in AD patients, which indicated the diffused deficits of AD, including learning and memory, comprehension, language, orientation and concentration. The atrophy of MTL structures was more prominent in AD patients. A moderate diagnostic accuracy of 83.3% was achieved by Fisher's linear discriminant model, which comprised the scores of word recall, recall of test instructions, commands, constructional praxis and orientation in ADAS-Cog, and the performance on picture recall, visual recognition visual reproduction, logic memory and touch test in Wechsler memory test and part of memory in MMSE. In diagnose of AD, MRI based volumetry of left temporal horn of lateral ventricle and amygdalohippocampal complex had the sensitivity of 78.4% and accuracy of 77.1%. When cognitive indicators were combined with MRI based measurement, the diagnostic accuracy increased to 90.5%. Conclusion: AD produces more diffused cognitive deficit and severer atrophy of MTL structure. Combination of cognitive indicator with MRI based measurement can improve accuracy in diagnosis of AD.