Researchers at University Hospitals Case Medical Center are beginning a study of functional magnetic resonance imaging (fMRI) to detect how brain activation in patients in early and middle stages of Alzheimer's disease compares to people without it.
When part of the brain is activated by doing a task, blood flows to that part of the brain. "fMRI allows for analysis of brain activation patterns, revealed through blood flow patterns that arise after administering a stimulus, such as showing someone a photograph," said Curtis Tatsuoka, PhD, principal investigator of a new study which hopes to develop a faster, more precise and more efficient real-time method for fMRI experimentation. This is an important tool for studying how Alzheimer's disease impacts brain functioning.
With support from Philips Healthcare, Dr. Tatsuoka and Alan Lerner, MD, Director of the Center for Brain Health and Memory at UH Case Medical Center, will study brain activation by using fMRI while research participants perform tasks such as solving math problems or remembering names associated with people's faces.
"We would expect that people with Alzheimer's disease would have less brain activation, and less blood flowing to certain parts of their brains, when performing tasks when compared to people without Alzheimer's doing the same tasks," said Dr. Lerner, who is co-principal investigator of the study and a Professor of Neurology at Case Western Reserve University School of Medicine. "We can use images of blood flow as a way of measuring brain health or severity of disease."
Dr. Tatsuoka, a biostatistician in the Department of Neurology at UH Case Medical Center and Case Western Reserve University School of Medicine, said detecting blood flow changes in fMRIs can be difficult because they can be hidden by a lot of extraneous information, or "noise," in the images. To compensate for this noise, researchers have patients repeat tasks over and over again for a pre-determined number of times while undergoing imaging.
"It can take a lot of experimentation to detect that signal," said Dr. Tatsuoka. "You ask patients to repeat a task again and again, and you might get the same results each time, but after awhile, they also could become tired or simply move their heads too often, making blood flow patterns difficult to ascertain."
"We hope to develop new experiments that can be analyzed in real-time while the experiments are underway and which can change depending on an individual's responses. Ideally, they would be shorter and more precise experiments," said Dr. Tatsuoka. "We don't want to under- test someone, and we don't want to over-test someone."
With help from engineers at Philips, he will test statistical models that dynamically detect blood flow changes in research participants. He predicts that real-time analysis of the fMRI data will reduce brain scanning times by up to 50 to 60 percent in healthy participants.
They also are looking for ways of measuring cognitive reserve. Cognitive reserve refers to the brain's neural capacity, its efficiency in activation while conducting tasks, and its ability to compensate for neural damage. It thus relates to the resilience of the brain to the disease. Cognitive reserve can vary greatly among AD patients. "Some patients may have considerable neural damage, yet retain cognitive abilities, and it interesting to see how this arises," said Dr. Tatsuoka.
"This pilot study has the potential to offer a way of quantifying cognitive reserve as well as potentially offering neurologists an additional tool to gauge the stage of cognitive impairment," said Dr. Lerner. "While there is no cure for Alzheimer's, better and earlier diagnosis can help improve a patient's quality of life."
This UH study will include research subjects in early stage of Alzheimer's disease (AD), those with mild cognitive impairment, and healthy patients of the same age. Currently, Drs. Tatsuoka and Lerner and the Philips engineers are running tests on the MRI in preparation for the study.
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