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NEWS FROM THE ALZHEIMER'S ASSOCIATION INTERNATIONAL CONFERENCE: Does the Evidence Support the Benefits of Population Screenings for Dementia? Not So Much, New Analysis Reveals

Fallik, Dawn

doi: 10.1097/01.NT.0000433499.41929.62
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A new analysis of population screenings for dementia found that overall the results did not have an impact on clinical outcomes. But neurologists say screenings for certain age groups, those over 65, for example, may be helpful.

There is a dearth of evidence to show that population screenings for cognitive impairment have a significant benefit on clinical or psychosocial outcomes, according to a new analysis of research presented in July at the Alzheimer's Association International Conference. But neurologists not involved with the review said they would recommend continuing screening for certain age groups in an attempt to detect those with dementia who were missed by the system.

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Diagnosing the disease could help provide patients and caretakers with support, local programs, and medication where necessary, they said.

The analysis, led by Carol Brayne, MD, an epidemiologist, professor of public health, and director of the University of Cambridge Institute of Public Health in Cambridge, UK, reviewed population screening studies published by May 2012. The research team found “no evidence of the effect of screening on patient outcomes such as cognitive, mental or emotional health, social function or planning.”

There has been an increased push for screening and early diagnosis for a variety of reasons, said both the study authors and the neurologists interviewed for this story.

“We want to feel like we're doing something,” said David S. Knopman, MD, a professor of neurology at the Mayo Clinic in Rochester, MN. “The idea that screening for disease is a good thing is widely held in medicine.” Dr. Knopman is also a member of the Alzheimer's Association Medical and Scientific Advisory Council.

He said there are several issues with screening tests for Alzheimer's and other cognitive impairment diseases. Mostly they are insensitive and influenced by many extraneous factors such as low education, sleep deprivation, recent exposure to drugs and alcohol, and chronic illness.

There's also a major concern about who undergoes the screening, and to what end result.

“There is a general confusion about screening. Is the goal to detect people who might become demented in the future but are not now? Or is the goal to recognize “people who have dementia now? That's never been clear.”

The review found that three primary studies reported on the direct cost per patient diagnosed, two compared a population screen scenario to other models of dementia care, and one looked at screening in older drivers.

“These suggest that substantial resources are required to screen for dementia, which are determined by the age of the screened population, the properties of the screening instrument and the extent to which general practitioners are involved in follow-up assessments,” the study authors wrote in the abstract.

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Sudha Seshadri, MD, a professor of neurology at the Boston University School of Medicine, said that as part of the Framingham Heart Study, for which she is an investigator, researchers perform a detailed cognitive battery and MRI testing. Sometimes cognitive testing can miss brain pathology, she noted, which brings up legal concerns Incidental findings on MRIs are also a problem, causing anxiety for patients.

Dr. Seshadri said she is “strongly supportive” of screening for cognitive decline in older patients, in the same way doctors screen for blood pressure, lipids and bone density. However, it should be completed in a physician or nurse-lead geriatric practice setting because the inherent variability in assessment makes the screening a complex assessment and should not be attempted using a computerized or technician-based test aimed at the general population.

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“Careful population stratification to identify persons at a higher a priori risk of developing dementia is important to ensure higher pre-test probabilities and thus fewer false positives,” said Dr. Seshadri. “I have been working with an National Institute on Aging-led group to help with such population stratification. We recommend cognitive screening tests at the Medicare Annual Wellness visit for persons over age 85 at the time of the visit. For persons aged 65-85 we suggest assessing a simple score based on a few easily ascertainable symptoms and signs.

“We do not recommend screening for men or women below age 65. These recommendations are based on six-year dementia risks within four large population-based US samples, the Framingham Study, the Cardiovascular Health Study, The Sacramento Area Latino Study on Aging, and the [University of Michigan] Health and Retirement Study.”

The review was particularly timely, neurologists said, because Medicare now pays for a visit solely dedicated to cognitive impairment screening.

Jason Karlawish, MD, director of the Alzheimer's Disease Center's Education at Information Transfer Core at the University of Pennsylvania, said the goal of the screening should highlight those who need assistance.

Many think that screening is futile because there is no pharmacological cure, he said. The medical field should consider treatment to include reducing the burden on caregivers and on the patient.

“What we should be doing is identifying those who are disabled and whose needs are not being adequately addressed — they have poorly managed finances, rotting food at home, messed up medications, driving that threatens their safety or the safety of other people,” said Dr. Karlawish, an associate professor and senior fellow of the University of Pennsylvania Center for Bioethics.

“We need to think about how we could structure things to support those suffering from these disabilities. In all likelihood, it's not a general medical clinic that should be offering screening, it should be practices that focus on older adults and part of a geriatric assessment should be asking about cognitive problems.”

Dr. Knopman said the hope is that the Medicare screening might give primary care physicians the time to do more than a routine screening.

“It's said that about 50 percent of those with diagnosable dementia do not have a diagnosis on their medical record,” he said. “And just picking up those patients will take effort on the part of primary care physicians and often they just don't have the time. We'd like to be able to just find the people who are obviously demented and need help.”

Dr. Seshadri agreed, saying that patient concerns should not be dismissed and there should be an exploration of the real risk, based on assessment of health status, family history, lifestyle, cognitive testing and — if indicated — referral to a neurologist, psychiatrist or geriatrician.

Dr. Karlawish said that earlier screening looking at those “at risk of decline” raises ethical issues because there's no clear screening determination indicating those who have the potential to develop dementia.

“Screening is a work in progress,” he said. “There's the Medicare mandate for screening which starts at 65 and that puts us between diagnosing those with dementia and asking us to identify those at risk for cognitive impairment and that's a questionable mandate.”

Even the variety of screening tests makes it difficult to point to one assessment that would be appropriate across the board.

“The brain is a hard organ to measure and cognitive tests are a fickle instrument,” said Dr. Karlawish.

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•. The Framingham Heart Study:
    •. The Cardiovascular Health Study:
      •. Sacramento Area Latino Study on Aging:
        •. The University of Michigan Health & Retirement Study:
          © 2013 American Academy of Neurology