Cognitive Decline in Elderly Predicted by Brain Imaging

June 1, 2006

Diagnosing Alzheimer disease at its earliest stage can lead to effective early interventions.

Improved ability to diagnoseAlzheimer disease (AD) at the earliestpossible stage has the potentialto lead to effective early interventions.William Jagust, MD, andcolleagues hypothesized that baselineglucose metabolism and medialtemporal lobe brain volumes wouldpredict cognitive decline in normalolder persons. The results of theirstudy were published in the April2006 issue of Annals of Neurology(Jagust W, et al. Ann Neurol.2006;59:673-681).

The investigators tested 60cognitively normal older adults(mean age 69.5 years) using[18F]fluorodeoxyglucose positronemission tomograpy (PET) andMRI scans. Monitoring the participantsfor an average of 3.8 years,they found an association betweenPET measures of glucose metabolismin the temporal and parietalcortices at the start of the study andthe rate of decline on a test of globalcognitive function. The authors,from the University of Californiaat Berkeley, Lawrence BerkeleyNational Laboratory, and theUniversity of Michigan, concludedthat their findings suggest that PETand MRI have predictive value forcognitive decline but not specificallyfor AD--although the areasof the brain that predicted declinein their study are the same regionsthat have been associated with ADin the past.