Alzheimer’s disease has traditionally been thought of as a gray matter disease. But emerging evidence has shown that changes in white matter structure, particularly the loss of myelin, a fatty white substance that wraps around neurons and helps brain signals run faster, precede changes in gray matter. With this new knowledge, Dr. Sean Deoni, a professor of Engineering at Brown University, has developed a new MRI technique called mcDESPOT. mcDESPOT is not only clinically realistic and tolerable for the elderly—the procedure only takes 15 minutes—but it also specifically measures myelin changes.
My honors thesis uses this new MRI technique to examine the relationship between myelin loss and functional disability in patients with Alzheimer ’s disease. An understanding of this relationship could be useful in predicting which patients are at greatest risk for functional decline. The results showed that there was a significant association between posterior myelin loss in the brain and functional ability, and even myelin loss and cognitive impairment. Knowing risk levels can help preserve independence, lessen caregiver burden, and ease eventual long-term placement into nursing homes. This new MRI technique measuring myelin could be a new biomarker to help identify patients in the earliest stages of Alzheimer’s disease.