Degree Of Difficulty In Performing Daily Activities Is Associated With Progression To Dementia

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Main Category: Alzheimer's / Dementia
Article Date: 16 Sep 2009 - 2:00 PDT

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Mild cognitive impairment is often considered a transitional state between normal cognitive function and Alzheimer's dementia. A report in the September issue of Archives of Neurology (one of the JAMA/Archives journals) shows that individuals who have more difficulties performing routine activities appear more likely to progress quickly to dementia.

According to background information in the article, mild cognitive impairment is recognized as a risk factor for dementia and an important public health issue, "Annual conversion rates [from mild cognitive impairment to dementia] often range from 10 percent to 15 percent in clinic samples. Conversion rates in community-based studies are often substantially lower (i.e., 3.8 percent to 6.3 percent per year)," the authors explain. "Clearly patients with mild cognitive impairment 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 mild cognitive impairment."

In this study, Sarah Tomaszewski Farias, Ph.D., of the University of California, Davis, and colleagues examined 111 individuals with mild cognitive impairment. Of these, 46 percent (51 patients) were recruited from patients referred to a university-based memory disorders clinic on suspicion of cognitive decline. 54 percent (60 patients) were recruited directly through community outreach. All participants underwent annual clinical evaluations, diagnostic imaging, routine laboratory tests and neuropsychological evaluations.

During monitoring of an average 2.4 years, results showed that 28 individuals progressed from mild cognitive impairment to dementia. Of these patients 23 were from the clinic and 5 were from the community. On a yearly basis, 13 percent of the clinic-based group and 3 percent of the community group converted into dementia.

The only factor linked with conversion from mild cognitive impairment to dementia was the degree of functional impairment at the beginning of the study, other than recruitment source. None of the other variables, such as demographic, cognitive or neuroimaging was correct in predicting this evolution.

The authors explain: "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 for future conversion to dementia. The greater functional impairment at baseline within the clinically recruited group appears to account for their increased risk of conversion."

The results imply that "in an educationally and ethnically diverse population, those with more functional impairment at their baseline evaluation - regardless of whether they are actively seeking an evaluation for a neurodegenerative disease - are at increased risk for conversion to dementia even within a relatively short follow-up period," they write in closing.

Arch Neurol. 2009; 66[9]:1151-1157
Archives of Neurology

Written by Stephanie Brunner (B.A.)
Copyright: Medical News Today
Not to be reproduced without permission of Medical News Today

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