July 22, 2008
Providing a different cutoff point on the Mini-Mental State Exam, or MMSE, a 30-question questionnaire commonly used to suggest a diagnosis of Alzheimer's, may identify more college-educated adults with early disease, a new study suggest. The findings could be important, since disease-modifying treatments, which are now under development, may be most effective early in the course of Alzheimer's.
Doctors commonly use the MMSE to assess thinking, learning and memory problems. The test takes only 5 to 10 minutes to perform and asks a series of 30 questions requiring math, memory and orientation skills.
Questions are fairly simple, such as what year is it? What season is this? What is the month? What state are we in? What hospital or office are we in? What floor are we on? The test can be administered over time to track the progress of mental deteriorations.
"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," the authors write. "Performance on the MMSE is moderated by demographic variables, with scores decreasing with advanced age and less education."
Currently, a score below 24 out of 30 correct typically suggest serious memory problems that may suggest a diagnosis of Alzheimer's. But people with little formal education typically perform worse on the MMSE than those who are college educated.
In highly educated men and women with more than 16 years of formal education, the study found, a score below 27 may be a better marker of serious memory problems. The findings appeared in the July issue of The Archives of Neurology, a medical journal of the American Medical Association.
Sid E. O'Bryant, Ph.D., of the Texas Tech University Health Sciences Center, and colleagues reviewed the MMSE scores of 1,141 highly educated participants (93 percent white, average age 75.9 years) in the Mayo Clinic Alzheimer Disease Research Center and Alzheimer Disease Patient Registry. These included 307 patients with Alzheimer's or other forms of dementia; 176 patients with mild cognitive impairment, a less serious form of memory loss that may develop into Alzheimer's disease; and 658 control patients who were mentally normal.
With the traditional cut-off score of 24 on the MMSE, 89 percent of the participants were accurately classified in terms of dementia status. This score had a sensitivity of 66 percent, meaning that a person with a score of 23 or lower would be correctly identified as having dementia 66 percent of the time. The 24-cutoff had a specificity of 99 percent, meaning those with a score of 24 or higher would be correctly diagnosed as not having dementia 99 percent of the time.
By raising the cut-off score to 27 for college-educated seniors, the sensitivity increased to 89 percent, and the specificity rose to 78 percent, correctly classifying 90 percent of the participants overall.
"The current findings are not intended to encourage the diagnosis of cognitive impairment or dementia based on total MMSE scores alone," the authors write. "Instead, these results provide practitioners with revised criteria for appropriate management of highly educated older white patients."
Specifically, the researchers note, older patients who present with memory complaints -- reported themselves or by family members --- should be asked about their formal education. "Those 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," the researchers write, "and should be referred for a comprehensive evaluation, including formal neuropsychological studies."
The authors suggest that use of this new cut-off point may help facilitate early detection of dementia in highly educated individuals. Timely support may be particularly important in this population. When treatments that stem the course of Alzheimer's become available they may be most beneficial early in the course of the disease. Individuals with more education tend to decline and die more quickly after they are diagnosed with Alzheimer's disease, the authors note.
Sid E.O'Bryant, Ph.D.; Joy D. Humphreys, M.A.; Glenn E. Smith, Ph.D., et al: "Detecting Dementia With the Mini-Mental State Examination in Highly Educated Individuals." Archives of Neurology, Volume 65, Number 7, July 15, 2008, pages 963-967.