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作者：Caroline Cassels  
出處：WebMD醫學新聞

　　September 16, 2009 — 新研究顯示，輕微認知缺損(mild cognitive impairment，MCI)的人，若日常生活有所困難，會比日常活動沒有困難的人更可能惡化成失智。
　　
　　不論MCI病患是臨床對象或來自社區，此發現都成立。
　　
　　加州大學戴維斯分校的研究者發現，除了病患來源之外，與MCI變成失智有關的唯一因素是研究對象的功能缺損程度。作者們報告指出，人口統計學、認知、神經影像等變項都無法預測此一病程。
　　
　　由Sarah Tomazewski Farias博士所領導的此一研究發表於9月的神經學誌(Archives of Neurology)。
　　
　　每年從MCI變成失智的比率，在臨床樣本高達10%至15%，社區型研究樣本則是明顯較低，為3.8%至6.3%。
　　
　　作者們寫道，顯然地，MCI病患之間有異質性，其中有人不會迅速變成失智。因此，重點在於釐清MCI診斷患者中，迅速惡化的風險因素。
　　
　　在這個前瞻縱向研究中，研究者試圖確認，不同研究對象從MCI惡化成失智的比率是否不同，若真如此，則探究可以解釋此差異的因素。
　　
　　研究對象共111名，其中，51人(46%)來自一個大學的記憶異常門診、懷疑認知衰退者，60人(54%)直接來自社區。
　　
　　所有研究對象接受年度的臨床評估、診斷影像、例行性實驗室檢查以及神經心理評估。
　　
　　在平均2.4年的追蹤期間，28人從MCI惡化成失智，其中23人來自前述的門診，5人來自社區。每年，門診病患組有13%、社區組有3%變成失智。
　　
　　作者們寫道，因此，不論病患來自門診或社區，開始時的功能缺損情形嚴重，是後來變成失智的重要風險因素。
　　
　　作者們宣告沒有相關財務關係。

Difficulties With Activities of Daily Living Strong Predictor of Progression to Dementia

By Caroline Cassels
Medscape Medical News

September 16, 2009 — Individuals with mild cognitive impairment (MCI) who have difficulties with activities of daily living are more likely to progress to dementia than their counterparts who do not have difficulty performing routine activities, new research suggests.

This finding held true regardless of whether MCI patients were recruited from a clinic-based population or from the community.

Investigators from the University of California–Davis found that other than recruitment source, the only factor associated with conversion from MCI to dementia was the degree of functional impairment at study outset. No demographic, cognitive, or neuroimaging variables predicted this progress, the authors report.

Led by Sarah Tomazewski Farias, PhD, the study is published in the September issue of the Archives of Neurology.

Annual conversion rates from MCI to dementia range from a high of 10% to 15% in clinic samples to substantially lower rates of 3.8% to 6.3% in community-based studies.

"Clearly patients with MCI compose a heterogeneous group, of whom not all rapidly convert to dementia. As such it is important to identify risk factors for progressing rapidly among individuals diagnosed with MCI," the authors write.

In the prospective longitudinal study, researchers sought to establish whether the rates of conversion from MCI to dementia differ according to recruitment source and, if so, to investigate factors that might explain this discrepancy.

A total of 111 participants were included in the study. Of these, 51 patients (46%) were recruited from a university-based memory disorders clinic on suspicion of cognitive decline and 60 patients (54%) were recruited directly through community outreach.

All participants underwent annual clinical evaluations, diagnostic imaging, routine laboratory tests, and neuropsychological evaluations.

During an average of 2.4 years of follow-up, 28 individuals progressed from MCI to dementia, including 23 patients from the clinic and 5 from the community. Annually, 13% of the clinic-based group and 3% of the community group converted to dementia.

"Thus, regardless of whether an individual was a clinic patient or recruited directly from the community, more functional impairment at baseline was an important risk factor for future conversion to dementia," the authors write.

The authors have disclosed no relevant financial relationships.

Arch Neurol. 2009;66:1151–1157.