Study Finds Way to Catch Signs of Cognitive Decline in More Women
Gender differences in verbal memory skills can lead to faulty test results
Alzheimer’s disease doesn’t happen overnight. Symptoms appear gradually, starting with a condition called mild cognitive impairment (MCI).
People with MCI may have a cluster of mild problems but can still function on their own. They might forget appointments, have trouble coming up with words, repeat questions or have difficulty learning new things or solving simple problems. About half of people diagnosed with the condition will develop Alzheimer’s disease within five years.
“The patients often think they are fine. Their families see the signs and bring them in for testing,” says Dr. Cynthia Munro, an associate professor and neuropsychologist at the Johns Hopkins University School of Medicine.
A recent study, however, is questioning the accuracy of cognitive function test results. Women tend to score higher than men on verbal memory tests at all stages of life. Researchers at the University of California San Diego (UCSD) School of Medicine speculated that this advantage might be masking early symptoms of dementia in women.
Adjusting Cognitive Test Scores for Gender
For a study published Nov. 12, 2019, in the journal Neurology, the researchers reviewed the brain scans of 985 adults ages 55 to 90 and administered cognitive assessments. They analyzed gender differences in the amount of amyloid plaque found — a hallmark of Alzheimer’s — and compared that to the subjects’ test scores.
The researchers found that women with the same level of Alzheimer's-related brain changes as men still scored better on memory tests.
The researchers found that women with the same level of Alzheimer’s-related brain changes as men still scored better on memory tests. But when verbal memory cutoff scores were tailored to the subjects’ gender, 10% more women and 10% fewer men were identified as having the memory-related form of MCI.
Dr. Erin Sundermann, an assistant psychiatry professor at UCSD and one of the study leaders, said the results suggest that women are able to compensate for early dementia through their superior verbal skills.
It also would explain why women show a more repaid decline than men after an Alzheimer’s diagnosis since they are diagnosed at a later stage of the disease. But Sundermann says these findings need to be replicated by other researchers before changes in scoring the tests are recommended.
Age-Related Memory Issues or MCI?
Gender variations aside, differentiating between normal age-related cognitive decline and MCI can be tricky. Munro says it’s common for “the worried well” to contact her for testing. These are high-functioning, successful people who notice a decline in their mental sharpness in midlife, she says.
“They have high expectations and intolerance of the normal slowness of thinking that happens to everyone,” Munro says.
That was the experience of Ruth Weltch, a retired nurse in Cardiff, UK, who grew concerned a few years ago because she was having trouble remembering conversations and recalling common words. Her physician recommended scheduling a cognitive assessment at a teaching hospital.
Her diagnosis after the test? “Age and overload,” says Weltch, 57, who was still working a demanding job during the time she was tested. The director of the memory assessment service attributed her symptoms to the normal age-related memory loss that can be exacerbated at menopause and when under stress. Her recall was slower and compromised, but it didn’t resemble MCI or dementia, the physician said.
For Weltch, the solution was “accepting where you are in life,” she says. She still has slower memory recall, but says taking the cognitive assessment put her mind at ease. “The doctor told me to slow things down, and I changed some things I had control over [that were adding stress].”
Identifying and Treating MCI
Cognitive assessments may be administered by a behavioral neurologist, geriatric psychiatrist, psychologist, geriatrician or other health care professional at a dementia clinic.
“It is a battery of tests, not just one,” says Munro about the several-hour evaluation. “Establishing the cause and scope of impairment is helpful in setting a baseline for future evaluations to determine if MCI is progressing to dementia,” she explains.
The test may begin with a one-hour interview about symptoms and family history. The clinician will explore possible underlying problems that can cause mental decline.
“It’s important to rule out something that is reversible. If the [cognitive impairment] is from sleep apnea, depression or too many medications, we can change that,” Munro says.
The patient is then presented with questions and simple tasks that test memory, language skills, thinking ability and other intellectual functions. They may be asked to recall words recited 30 minutes before, for example. Weltch was asked to name items starting with the letter ‘S.’
When MCI is diagnosed as a precursor to Alzheimer’s, treatment options are limited. “Aerobic exercise that keeps up the heart rate is one of the few things shown to be helpful [to slow progression],” says Munro. Other studies suggest that getting more sleep may have a protective effect on memory.
Stress reduction shows some promise as well, especially in women. Munro conducted a study published in March 2019 which found that midlife women who had a higher number of stressful life experiences in the previous year showed a greater decline in memory performance than men who had stressful life events.
Munro stresses there is no scientific evidence that cognitive training, diet, medications or supplements can improve memory or thinking.
“It’s a misunderstanding that if you go full-out in cognitive training that you can stop the disease,” she says. Instead, she recommends strategies that can improve the quality of a person’s life and annual testing to monitor symptoms. For some people, MCI never worsens.
Study Implications for Research and Care
The UCSD study has implications for research and patient care if the results are confirmed. Scientists have only been looking at gender differences outside of reproductive medicine for the past decade, Sundermann notes.
“If we are leaving women [with MCI] out of clinical drug trials and putting in men [misdiagnosed with MCI], this dilutes important research,” she says.
Readjusting the cutoff scores for MCI assessments along sex-specific lines could eliminate a 20% diagnostic error rate, too.
More women will benefit from getting help earlier. When a MCI diagnosis is delayed, women lose out on opportunities for clinical trials, advance planning for care, or therapies at the early disease stage when treatments are more likely to be effective, Sundermann says.
For men, fewer will be subjected to worry from a false diagnosis, she adds.