正常老年人与轻度认知功能障碍患者计算任务的功能磁共振研究

目的利用fMRI探讨正常老年人与轻度认知障碍（MCI）患者计算能力的差异。方法对20例正常老年人与8名MCI患者进行简单与复杂计算时的功能MR扫描，用SPM2处理得出脑激活图，同时比较两组反应时间以及正确率。结果MCI患者的反应时间比对照组延长（P〈0．0025），正确率明显降低（P〈0．001）。脑激活图显示正常老年人存在额叶、顶叶激活，提示这些功能区与计算密切相关。而MCI患者未体现出顶叶、额叶在计算中的优势，激活区域较正常对照组广泛。结论MCI患者的计算功能已有不同程度的损害，存在广泛的代偿。计算功能的fMRI研究能为早期诊断MCI提供参考依据。

Functional MRI study of calculation task of the heathy olders and the patients with MCI

Objective To explore the difference of arithmetic calculation between the heathy olders and the patients with mild cognitive impairment(MCI)with functional magnetic resonance imaging(fMRI). Methods 20 healthy olders and 8 patients with MCI were scanned by MRI when they performed simple and complex calculation. The raw data of the fMRI were processed with the software SPM2. The reaction time and correct ratio were analyzed between them. Results Compared with the control group, the patients manifested longer reaction time and lower correct ratio. Prefrontal cortex and parietal lobe were activated during calculation task in the heathy olders,which show these regions were correlated closely with the calculation. Compared to the control group, no significant activation were found in prefrontal cortex and parietal lobe and extensive activated regions were seen. Conclusion The patients with MCI has the deficit in calculation ability and extensive compensation is present. The study of the calculation fMRI can offer a powerful reference for the early diagnosis of MCI.