轻度认知障碍患者记忆力的功能磁共振研究

目的为探索早期诊断阿尔茨海默病 (AD)的方法 ,将神经心理测定和功能磁共振 (fMRI)检查相结合 ,了解轻度认知障碍 (MCI)患者在记忆方面的脑功能情况。方法 9例MCI患者和 9名正常对照在进行无意义图形记忆和再认时行fMRI检查 ,对反应时间、正确率和fMRI的脑激活图进行比较。结果患者的反应时间比正常对照明显延长 (P <0 0 1) ,正确率显著降低 (P <0 0 0 1)。脑激活图显示 ,与对照相比 ,在记忆编码时 ,患者主要在左侧前额叶背外侧和海马旁回、以及以右侧为主的后部脑区激活减弱 ,记忆提取时 ,在双侧前额叶背外侧 ,左侧海马旁回和前扣带回 ,以及后部脑区激活减弱。结论MCI患者的记忆功能已有损害。记忆功能的fMRI检查与认知神经心理学的联合研究能为早期诊断AD提供有力的参考依据。

Memory deficit for the patients with mild cognitive impairment:A functional magnetic resonance imaging study

ObjectiveTo provide the early diagnosis of Alzheimer's disease(AD), the memory in the patients with mild cognitive impairment(MCI) was detected under the functional magnetic resonance imaging(fMRI), combined with the behavioral experiment.Methods9 patients with MCI and 9 controls matched for the age, gender, level of education and handedness performed encoding and retrieval of nonsense line drawings, presented visually while the MR machine was scanning. ResultsCompared with the controls, the patients manifested longer reaction time and lower correct ratio. The patients' brain activation showed: the first episode of encoding of nonsense line drawings elicited distributed activation in bilateral dorsal lateral frontal lobes, left parahippocampus, bilateral temporal-occipital conjunction, parietal lobes and visual cortex in the control subjects. While these activations decreased in the second episode of encoding of the same stimuli, much stronger activation was found in most same areas during the retrieval phase except for the right parietal lobe, in which the patients showed stronger activation. Moreover, activation in the anterior cingulate cortex was observed only in the retrieval phase. The patients showed weaker and smaller activation in almost all activation areas during all tasks in the normal subjects. ConclusionThe patients with MCI have the deficit in memory. The examination of encoding and retrieval of nonsense line drawings by means of the behavioral experiment and fMRI test can offer a powerful reference for the early diagnosis of AD.