Megan Brooks

July 27, 2015

WASHINGTON ― Older adults who perform poorly on the Memory Binding Test (MBT) are at increased risk of developing amnestic mild cognitive impairment (aMCI) and dementia, new research suggests.

"Memory binding refers to the process of simply linking memories, and there is an idea that people with Alzheimer's disease have a deficit in memory binding," neurologist Richard B. Lipton, MD, told Medscape Medical News.

"Our belief is that the Memory Binding Test may be a cognitive marker of preclinical AD, and it's cheap, noninvasive, easy to do, takes only 10 minutes, and can be done in a doctor's office by any trained person," said Dr Lipton, director of the Division of Cognitive Aging and Dementia at Albert Einstein College of Medicine, in New York City.

Dr Lipton presented the research here at the Alzheimer's Association International Conference (AAIC) 2015.

Highly Predictive

The MBT was developed by Herman Buschke, MD, of Albert Einstein. Basically, the test measures "associative binding" through two category word lists that people are asked to remember. "It turns out that people in the preclinical stage of Alzheimer's have relative deficits in memory binding on the test," Dr Lipton said.

In a prior cross-sectional study, the MBT demonstrated "high discriminative validity" for identifying aMCI and dementia, the researchers note.

In a longitudinal study, the Einstein team administered the MBT to a group of cognitively normal older adults and followed them for up to a decade to see whether performance on the test would predict the new onset of aMCI during a decade.

Among 281 individuals free of dementia and aMCI at baseline, 54 developed aMCI during follow-up. Baseline poor performance on the MBT was associated with a more than twofold increased risk of developing aMCI (hazard ratio [HR], 2.43; P = .003).

Among 312 participants free of dementia at baseline, 34 developed incident dementia. In this group, baseline poor memory was associated with a fourfold increased risk of developing dementia (HR, 4.19; P = .0001).

"What we found that absolutely surprised and delighted us was that not only was the test highly predictive of the development of MCI or dementia over a period of a few years, but it continued to predict the onset of dementia or MCI over a decade. The exciting part of the test is that it gives us a very early cognitive marker of MCI and dementia," said Dr Lipton.

"We developed the test based on the theory that patients with AD have a memory binding deficit, so the fact that this test predicts new-onset aMCI and dementia over a decade supports this theory," he added.

The test may be a "behavioral method for flagging people well before MCI or dementia develops so we can figure out in whom we should do amyloid PET scanning or lumbar puncture and the people who that may not be necessary," he said. Going forward, the Einstein team would like to see whether the memory binding test predicts biomarkers of AD and volumetric changes on MRI, he said.

Warrants Further Study

Commenting on the results for Medscape Medical News, James A. Hendrix, PhD, director of global science initiatives, Alzheimer's Association, noted that this is "interesting preliminary research from a small study and certainly warrants more study."

"These sorts of test are cheap, noninvasive, and can be done in a doctor's office. Right now, there are some simple memory tests available that are done and that are part of the wellness plan covered by Medicare and are supposed to be part of the annual physical, but I'm not sure how many people actually get one," Dr Hendrix noted. "We need sensitive cognitive tests and people trained in giving those tests. We'd love to have a combination of good cognitive tests with good, accessible, and cheaper biomarker tests."

The study had no commercial funding. The authors report no relevant financial relationships.

Alzheimer's Association International Conference (AAIC) 2015. Abstract O3-10-04. Presented July 21, 2015.


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