AD and Brain Activation

Contributed by: Michael Rafii, M.D., Ph.D - Director of the Memory Disorders Clinic at the University of California, San Diego.
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The brains of people at risk of developing Alzheimer’s disease may go into hyperactive mode in the very early stages of the disease in order to compensate for deterioration, according to a Cleveland Clinic study published in the medical journal Neurology. Researchers at Cleveland Clinic’s Lou Ruvo Center for Brain Health studied a group of 69 cognitively healthy adults. About 2/3 of the participants were at risk to develop Alzheimer’s disease based on family history or genetic markers. Participants were placed in a functional magnetic resonance imaging (fMRI) scanner and then asked if they recognized the names of famous celebrities. Unfamiliar names also were mixed in during the questions.

The brain activity of the participants was measured during the questioning to determine if persons at risk for Alzheimer’s disease would react differently than persons not at risk. On the fMRI scans, there was increased activation of certain parts of the brain in at-risk individuals. This is thought to potentially reflect a compensatory brain response by these participants to the earliest stages of Alzheimer’s disease. In the study, one third of the participants had no family history or genetic markers (ApoE 4 +) to indicate they are at risk of developing Alzheimer’s disease. Another third had a family history of Alzheimer’s disease, but no genetic markers, and the last third had both a family history and genetic markers indicating risk. It was this last group that showed a substantial amount of brain activation with the memory task. Further research will be needed to look at the use of fMRI in Alzheimer's Disease diagnosis.

Semantic memory activation in individuals at risk for developing Alzheimer disease.Seidenberg M, Guidotti L, Nielson KA, Woodard JL, Durgerian S, Antuono P, Zhang Q, Rao SM. Neurology. 2009 Aug 25;73(8):612-20.