Detecting Dementia in Highly Educated People
A great deal of literature exists as to the association between low levels of education and an increased risk of dementia. Much less information is available regarding highly educated people and dementia. Available data points to a steeper rate of decline and earlier mortality rates once dementia is diagnosed. Because of this, early identification of cognitive dysfunction is highly desirable in order for treatment to begin as soon as possible.
The most commonly administered screening test for cognitive dysfunction is the Mini-Mental State Examination (MMSE). The test itself lasts between five to ten minutes and consists of a series of questions that assess orientation, registration (i.e. name these three objects), attention, recall and language. Despite its simplicity the MMSE offers a relatively sensitive marker of overt dementia. However, it is known that people from certain cultural groups or low intelligence or low education may score poorly. However, people who are well educated may score well and this effectively masks the fact they have cognitive impairment.
Recently, Sid E.O'Bryant, Ph.D., of the University of Texas Tech University Health Sciences Center, reviewed MMSE scores from patients who reported having 16 or more years of education. This included 307 people with dementia, 176 with mild cognitive impairment and 658 people who acted as controls and who did not have dementia.
The maximum score on an MMSE is 30. Traditionally, a score of 24 results in an 89 percent accurate classification of dementia. When using this score against the high education sample a 0.66 estimate of sensitivity and a 0.99 estimate of specificity was achieved. In other words, an individual with a score of 23 or less would be correctly identified as having a dementia 66 percent of the time and someone with a score of 24 or above would be correctly diagnosed as having dementia 99 percent of the time. What O'Bryant and his colleagues noted was that by raising the cut off point to 27, it identified 70 of the 104 patients with dementia who were missed using the traditional cutoff. Therefore, graduates with an MMSE score of 26, coupled with complaints of cognitive decline, are almost 10 times more likely to have dementia than those who obtain a score of 27 or higher.
According to O'Bryant, "these results provide practitioners with revised criteria for appropriate management of highly educated older white patients. Specifically, older patients who present 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 should be referred for a comprehensive evaluation, including formal neuropsychological studies".
O'Bryant, S.E., Humphreys, J.D., Smith, G.E., Ivnik, R.J., Graff-Radford, N.R., Petersen, R.C., Lucas, J.A (2008) Detecting Dementia With the Mini Mental State Examination in Highly Educated Individuals. Arch. Neurol. 65 (7) 963-967.