Feb. 20, 2001 University Park, Pa. – As if having recognizable "senior moments" isn't bad enough, now Penn State researchers say that we may lose some basic mental skills and not even realize it.
In a study of 15 normal, healthy aged men and women that is the first of its kind, the researchers found that the subjects were unable to accurately estimate their prowess at reading maps, remaining attentive and pantomiming tool use. The subjects were accurate in estimating their memory, or their ability to recall, and several others functions such as mood and vision. Dr. Anna Barrett, assistant professor of medicine and neurology in Penn State's College of Medicine and the study's principal investigator, says "The research shows that there were some areas where these normal, healthy people were unaware that their perception of their performance on some very basic mental skills didn't match their actual competence. In other words, they were unaware that they weren't performing at the level they thought they were.
"If people are unaware of their level of performance, they can't take countermeasures or seek assistance when these skills decline. Caregivers and partners need to be alert to the signs of mental loss or decline in completely normal individuals and be sensitive to the fact that the person suffering the loss may be completely unaware of it," she adds. Kerri A. Hansell, an undergraduate at Lebanon Valley College who served as a research assistant on the project, and Barrett detailed the study Wednesday, Feb. 14, at the annual meeting of the International Neuropsychology Society in Chicago, Ill. Their paper, "Unawareness of Cognitive Deficit (Cognitive Anosognosia) in Aged Subjects," was co-authored by Dr. Paul J. Eslinger, professor of medicine and neurology, Penn State; Dr. J. Kenneth Brubaker, neurologist at the Masonic Home, Elizabethtown, Pa.; and Dr. Kenneth M. Heilman, professor of neurology, University of Florida, College of Medicine. In the study, nine women and six men, who were all about 75 years old and living independently, were asked first to estimate how they would perform on four series of tests and then actually took the tests. The tests included visuospatial skills such as reading a map, copying a design and matching up lines of different angular orientation. In an attention test the subjects were asked to find all of the As in a sheet of random letters, avoid being distracted as they visually fixated on a target and inhibit inappropriate movement responses, to hold up one finger when the experimenter held up two. A tool use test asked them to move their hands, for example, as if they were using a screwdriver, a knife, or a hammer.
Barrett points out that the tool use pantomime is an especially revealing mental skills test. "Pantomime of movement is a familiar test for dementia. The inability to perform these motions is a pathological sign, " she says.
All of the study subjects were neurologically normal individuals whose performance on all of the tests fell within the normal range. However, their estimates of their performance did not match their competence.
Subjects overestimated their prowess at pantomiming tool use by 10 percent; overestimated map reading and other visiospatial skills by four percent and underestimated their ability to maintain attention by 13 percent. Estimations of memory, mood, vision and naming ability matched actual performance.
After the subjects were tested, they became better estimators -– except in tool use pantomime. Barrett notes, "Most people worry about memory decline but our subjects were accurate in estimating memory. Far more relevant to life skills is the unawareness of one's level of visiospatial skills. These skills are essential to having an accurate mental picture of where you are going when you drive a car, for example."
Although the test sample was small, Barrett says that the results are statistically significant. She also thinks the findings will prove generalizable in a larger sample.
In fact, the Penn State researcher adds, "I wouldn't be shocked if further studies showed that young people aren't any better at these estimations than their elders."
The results may reflect a normal tendency of the brain to perform "mental triage," to focus mental output more sharply on some things while leaving others more fuzzy, she explains.
Barrett and the research team are now conducting the same tests with subjects who are victims of Alzheimer's disease. The team will compare the outcomes of the Alzheimer's patients with the performance of the normal subjects. She expects the results to help diagnose deficits that are specifically related to Alzheimer's disease.
The study was supported by a grant from the Alzheimer's Disease and Related Disorder Association and by the General Clinical Research Center at the Penn State College of Medicine.
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