Researchers have suggested that in order to more effectively assess dementia risk in highly educated older adults, a different cutoff point on an existing mental function assessment should be used. The report is published in the July issue of Archives of Neurology.

A test called the mini-mental state examination (MMSE) is the most frequently used screening exam for testing cognitive function – that is, thinking, learning, and memory abilities. In their report, Sid E. O’Bryant, Ph.D. (Texas Tech University Health Sciences Center) and colleagues write: “The MMSE is used to screen patients for cognitive impairment, track changes in cognitive functioning over time and often to assess the effects of therapeutic agents on cognitive function. Performance on the MMSE is moderated by demographic variables, with scores decreasing with advanced age and less education.” Individuals can achieve a maximum MMSE score of 30, and a score of 24 or less generally indicates some type of cognitive dysfunction.

O’Bryant and colleagues used a sample of 1,141 participants from the Mayo Clinic Alzheimer Disease Research Center and Alzheimer Disease Patient Registry who had 16 years of education or more. The researchers focused on the MMSE scores of the patients – about 75.9 years old and 93% white. The sample consisted of 307 patients with dementia 176 with mild cognitive impairment, and 658 patients without dementia who were considered the control group.

The researchers found that the standard MMSE cut-off score of 24 classified 89 % of the participants in the proper dementia category. This traditional score had a 66% sensitivity and a 99% specificity for the detection of dementia. This means that 66% of the time, an individual with an MMSE score of 23 or lower would be correctly classified as having dementia; and that 99% of the time, an individual with a score of 24 or higher would be correctly classified as not having dementia. The researchers experimented with changing the cut-off score and found that raising it to 27 improved the sensitivity to 89% and lowered the specificity to 78% – resulting in an overall increase in correct diagnoses from 89% to 90%.

“The current findings are not intended to encourage the diagnosis of cognitive impairment or dementia based on total MMSE scores alone,” conclude the authors. “Instead, these results provide practitioners with revised criteria for appropriate management of highly educated older white patients. Specifically, older patients who present with memory complaints (reported by themselves or others) who have attained a college degree or higher level of education and who score below 27 on the MMSE are at increased risk of cognitive dysfunction and dementia and should be referred for a comprehensive evaluation, including formal neuropsychological studies.”

O’Bryant and colleagues propose that the new cut-off be used for earlier detection of dementia in this class of highly educated individuals. Early diagnosis may be crucial given that highly educated individuals tend to experience cognitive decline and death more quickly after an Alzheimer’s disease diagnosis.

Detecting Dementia With the Mini-Mental State Examination in Highly Educated Individuals
Sid E. O’Bryant, PhD; Joy D. Humphreys, MA; Glenn E. Smith, PhD; Robert J. Ivnik, PhD; Neill R. Graff-Radford, MD; Ronald C. Petersen, MD, PhD; John A. Lucas, PhD
Archives of Neurology (2008). 65[7]: pp. 963 – 967.
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Written by: Peter M Crosta