Simple Test Quickly Detects Alzheimer's Disease in Older Adults
A simple test of the ability to tell time and count change may provide a new approach to screening for Alzheimer’s disease and other forms of dementia in older adults, according to a study in this week’s Journal of the American Geriatrics Society and an earlier report in the Journal of Gerontology.
If widely adopted, the test could fill a void in doctors’ offices, hospitals, clinics and nursing homes where no form of screening for dementia is currently being used, thus leaving thousands of individuals at risk.
“While screening has been recommended for all older persons, tests now available are complex and time consuming to perform and, therefore, not widely used. The result is that dementia often goes unrecognized in its early stages,” said Sharon Inouye, M.D., associate professor at the Yale School of Medicine, who led a Yale team of researchers in developing the test.
She said the Time & Change (T & C) test – in which patients are asked to tell time on a clock with hands set to 11:10 and to count out one dollar in change – is highly accurate in identifying patients who need further evaluation for possible dementia. Those who fail to complete the tasks within a reasonable time limit can be referred for more thorough testing.
In the study in the Journal of Gerontology, 776 hospitalized patients between the ages of 70 and 98 (average age, 83 years) received standard tests for dementia, with 14 percent testing positive. The T & C test successfully identified 86 percent of patients who tested positive and 71 percent of patients who tested negative on the standard tests.
In a second study of 100 outpatients, which was published in the Journal of the American Geriatrics Society, 16 percent were found to have dementia on standard tests. The T & C test successfully identified 63 percent of patients who tested positive and 96 percent of patients who tested negative on standard tests. Based on these results, Inouye estimates that the T & C test could reduce the percentage of patients with dementia unrecognized by doctors from 44 percent to 19 percent.
Unlike some tests now being used, the T & C test proved reliable in patients of various educational levels and ethnic and cultural backgrounds. It was also quick and easy for doctors to perform, requiring an average of only 21 seconds to administer, said Inouye, who collaborated on the research with Julie T. Robison, research affiliate in epidemiology and public health; and Tanya E. Froehlich and Emily D. Richardson in internal medicine (geriatrics).
Dementia is a very frequent problem in older adults, with 4 to 6 percent of Americans aged 65 and older (1.5 to 2.2 million people) suffering from severe dementia, and another 13 percent (5 million people) suffering from milder forms. The problem is expected to become even more common as the population ages.
“By the year 2040, dementia rates are expected to increase fivefold. At least 7 to 10 million Americans will be affected by severe dementia, if effective preventive or treatment measures are not developed,” Inouye said. She added that the total national cost for dementia has been estimated at more than $67 billion per year, measured in 1991 dollars, including costs of diagnosis, medical treatment, nursing home care and informal long-term care.
In an editorial accompanying the outpatient study, Dr. Eric B. Larson of the University of Washington Medical Center in Seattle noted that dementia is “a growing public health burden…that can truly be characterized as a silent epidemic” because it so frequently goes unrecognized.
In urging adoption of simple screening methods by clinicians, Larson noted that patients with dementia cannot be relied upon to report symptoms of illness or to follow even simple medication regimens, thus complicating their medical care. They are twice as likely to have automobile accidents and can fall prey to unscrupulous persons who take advantage of their vulnerability for financial gain, he added.
“Continued neglect of a progressive dementia in an isolated older person will often lead to a crisis situation characterized by devastation of a person’s health and living situation,” said Larson, who noted that family members may be very helpful when questioned specifically about cognitive dysfunction, but often consider the symptoms normal and fail to report them.
In the T & C test, a large clock-face with hands set at 11:10 is held 14 inches from the participant’s eyes. He or she is given two tries to tell the time within a 60-second period. Response time and any difficulties – vision problems, tremors, weakness or pain – are recorded. In the second part of the test, a typical assortment of change (three quarters, seven dimes and seven nickels) is placed on a well-lighted tabletop, and the participant is given two chances within a three-minute period to select one dollar in change. Response time and difficulties are recorded again.
“The test is not designed to replace standard tests, but to be used as an initial screening to identify people who should be evaluated more thoroughly with more sensitive tests,” Inouye said.