Doctors may be not be diagnosing women as early as men with brain problems associated with early signs of dementia because of how well women typically perform on simple memory tests, a study published Wednesday suggests.
Women generally perform better on verbal memory tests, according to the study published in the peer-reviewed journal Neurology. So when these common tests are used to diagnose mild cognitive impairment, women may be under-diagnosed or diagnosed too late while men may be over-diagnosed or diagnosed too early, the study found.
“If women are inaccurately identified as having no problems with memory and thinking skills when they actually have mild cognitive impairment, then treatments are not being started and they and their families are not planning ahead for their care or their financial or legal situations,” study author Erin E. Sundermann of the University of California, San Diego, said in a statement.
“For men who are inaccurately diagnosed with mild cognitive impairment, they can be exposed to unneeded medications along with undue stress for them and their families,” she added.
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Mild cognitive impairment is “the stage between the expected cognitive decline of normal aging and the more serious decline of dementia,” according to the Mayo Clinic. It is often associated with problems with memory, language, thinking and judgment.
The study found that when adjusting for differences in sex, 10% more women were diagnosed with mild cognitive impairment compared to when averages for both men and women were used. Additionally, 10% fewer men were diagnosed with the adjusted averages, the study says.
“We have often heard that men are more likely to have mild cognitive impairment than women, yet women are at least as likely to have Alzheimer’s,” said Mary Sano, director of the Alzheimer’s Disease Research at Mount Sinai School of Medicine and who was not involved in the study. “Using one score for both groups will under-diagnose women and over-diagnose men.”
“It makes sense in a lot of ways,” Dr. Steve Arnold, a professor of neurology at Harvard Medical School and the Translational Neurology Head at Massachusetts General Hospital Interdisciplinary Brain Center, said of the study. “It’s long recognized that women have a verbal advantage over men.”
Arnold, who was also not involved in the study, said men generally perform better on visual-spatial tests, and if the test were to ask participants to remember a set of images, rather than a set of words, the opposite results by sex may have occurred.
He also noted, as the study authors do in the paper, that population in the study was largely white and well-educated, a potential limitation of the research.
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To conduct the study, researchers looked at data on verbal memory tests from 985 people in the Alzheimer’s Disease Neuroimaging Initiative.
They then compared those results with the average scores between the sexes and within the sexes from a separate group of people in the Mayo Clinic Study of Aging.
The participants in the Alzheimer’s Disease Neuroimaging Initiative took tests that required them to study a list of 15 unrelated words and remember them at various time intervals. Patients were diagnosed with mild cognitive impairment if they did not reach a certain cut-off score.
Researchers confirmed the differences in diagnoses by looking at actual brain changes linked to Alzheimer’s disease, like amyloid plaque deposits, in the people studied.
Women who would not have been diagnosed with mild cognitive impairment with the un-adjusted scores but were diagnosed with the adjusted scores did show more advanced brain changes linked to dementia.
However, men who would have been diagnosed with mild cognitive impairment with the un-adjusted scores but were not diagnosed with the adjusted scores had brain changes closer to healthy adults, the study said.
Pauline Maki, one of the study’s authors, said, though, that these differences between men and women in verbal memory tests hadn’t been known for long enough for the cut-off score for diagnosis to be adjusted.
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Maki, a professor of psychiatry, psychology and OB/GYN at the University of Illinois at Chicago, said to confirm the results, researchers are looking to analyze rates of conversion to Alzheimer’s disease.
“If we are correct, then misclassified women should show higher conversion rates to Alzheimer’s disease while misclassified men should show lower conversion rates to Alzheimer’s disease,” she wrote in an email to USA TODAY.
Arnold said he wasn’t surprised by the findings and that it show the need for healthcare professionals to consider individual patients’ strengths and weaknesses as it relates to these tests.
Differences may also be present across ethnicity and races and educational background that could lead to a misdiagnosis, he said.
“The biology (of Alzheimer’s disease) may be similar but the way it shows itself and the way dementia may manifest itself can be tied to sex differences and other hereditary differences,” he said.
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This article originally appeared on USA TODAY: Dementia diagnoses may be late in women because sex difference: study